june 21 – 26 2015 · frauenchiemsee germany · june 21 – 26 2015 · frauenchiemsee germany ....
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June 21 – 26 2015 · Frauenchiemsee Germany
Supported by:
1
16th European Symposium on Gas Electron Diffraction
Frauenchiemsee, Germany June 21st – 26th 2015
PROGRAMME
Sunday June 21 Until 18:00
Arrival
From 15:00 to 18:00
Registration
18:00 Come together / Buffet
Monday June 22 8:50 Norbert Mitzel Bielefeld, GE Opening Chair: Norbert Mitzel
9:00 Anatoli Ischenko Moscow, RU Electron diffraction: structure and dynamics of free molecules and condensed matter
9:45 Derek Wann York, UK Towards time-resolved electron diffraction at York 10:15 Coffee break
Chair: Heinz Oberhammer
10:45 Yury Vishnevskiy Bielefeld, GE Low-pressure gas electron diffraction
11:15 Nathaniel Gunby Christchurch, NZ UCONGA: A new, general, fast conformer generation
method 11:45 End of session
12:00 Lunch
Chair: Derek Wann
14:00 Nobuhiko Kuze Tokyo, JP GED, MW and quantum chemical studies of the molecules with the large-amplitude motions
14:30 Valery Sliznev Ivanovo, RU Structure of some molybdenum and tungsten halide complexes MX3 and MX4 (X = F, Cl): Jahn-Teller effect and spin-orbit coupling
15:00 Arseniy Otlyotov Ivanovo, RU Molecules with linear chains and bulky substituents: problems of estimation of vibrational parameters and role of dispersion interaction
15:30 Coffee break
Chair: Peter Weber
16:00 Richard Mawhorter Pomona, US Electrons in & near nuclei: 3 tales
16:45 Natalja Vogt and Jürgen Vogt Ulm, DE Award of the International Dr. Barbara Mez-Starck Prize
17:15 End of session
18:00 Dinner
2
Tuesday June 23 Chair: Dines Christen
9:00 Peter Baum Garching, GE Recording atomic and electronic motion in space and time
9:45 Detlef Schooss Karlsruhe, GE The structures of ruthenium clusters 10:15 Coffee break
Chair: Richard Mawhorter
10:45 Davy Geldof Antwerp, BE DFT study of modified TiO2 sufaces using phosphonic acids
11:15 Sergey Shlykov Ivanovo, RU Cyclohexane-based heteroatom and heterocyclic structures 11:45 End of Session
12:00 Lunch
13:30 Poster Presentation
E. Altova, N. Vogt, D. Ksena-fontov, A. Rykov
Moscow, RU
Ulm, GE
Accurate determination of molecular structure of succinic anhydride by gas-phase electron diffraction method and quantum-chemical calculations
J. Cautereels, F. Blockhuys Antwerp, BE A new computational tool for the prediction of the mass spectra of peptides
N. Giricheva, M. Fedorov, G. Girichev
Ivanovo, RU Methylbenzenesulfonates: gas-phase electron diffraction vs. vibrational spectroscopy
N. Giricheva, V. Petrov, G. Girichev, M. Dakkouri, H. Oberhammer, V. Petrova, S. Shlykov, S. Ivanov
Ivanovo, RU Ulm, GE Tübingen, GE
Electron diffraction and quantum chemical study of the α- and β-naphthalenesulfonamides molecular structure
D. Hnyk, J. Macháček, D. Rankin, D. Wann
Husinec-Řež, CZ; Edinburgh, Heslington, U.K.
Molecular structures of neutral boranes and heteroboranes from scattering electrons and computational protocols
I. Marochkin, E. Alvova, N. Vogt, A. Rykov, I. Shishkov Moscow, RU
Ulm, GE
Structure of adrenaline in comparison to noradrenaline by the gas electron diffraction method
N. Müller, S. Trippel, J. Küpper Hamburg, GE Electron diffraction of state-selected and spatially aligned gas-phase molecules
A. Petrova, N. Giricheva, N. Tverdova, G. Girichev
Ivanovo, RU Molecular structure and spin-states of acetylacetonato iron(III) by gas-phase electron diffraction and quantum chemical calculations
O. Pimenov, Y. Zhabanov, A. Pogonin, S. Blomeyer, B. Puchkov
Invanovo, RU Bielefeld, GE
Geometry and electronic structure of metal pivalate chelates M(piv)3 (M = Al, Ga, In, Tl): preliminary DFT calculations
A. Pogonin, N. Tverdova, G. Girichev
Ivanovo, RU The molecular structure of metal etioporphyrins-II: capability of a gas-phase electron diffraction
D. Savelyev, N. Tverdova, G. Girichev
Ivanovo, RU Molecular structure of palladium tetraphenylporphyrin (Pd-TPP) by gas-phase electron diffraction and quantum chemical calculations
J. Schwabedissen, B. Neu-mann, H.-G. Stammler, N. Mitzel
Bielefeld, GE Structural effects in and on the isocyanate group (NCO)
3
D. Sharfi, A. Hof, C. Witte, A. Biekert, R. Mawhorter, Z. Glassman, J.-U. Grabow
Claremont, College Park, USA; Hannover, GE
Electron-nucleus overlap & quadrupole moment ratios in RbF, RbCl, RbBr, and Rbl
S. Shlykov, D. Osadchiy Ivanovo, RU Molecular structure and conformational analysis of 3-methyl-3-silathiane by gas-phase electron diffraction and quantum-chemical calculations
D. Tikhonov, Y. Vishnevskiy Bielefeld, GE Moscow, RU
Corrected calculation of vibrational parameters in gas electron diffraction on the basis of molecular dynamics simulations
N. Vogt Ulm, GE Moscow, RU
Benchmark study of molecular structures by different experimental methods and coupled cluster computations
J. Vogt Ulm, GE Release of the MOGADOC update with an enhanced 3D viewer
Y. Zhabanov, O. Pimenov, S. Blomeyer, G. Girichev
Ivanovo, RU Bielefeld, GE
The geometry and electronic structure of a thallium(I) pivalate determined by gas-phase electron diffraction and DFT calculations
Y. Zhabanov Ivanovo, RU New software for the implementation of curvilinear approach
16:00 Coffee break
Chair: Detlef Schooss
16:30 Sebastian Blomeyer Bielefeld, GE Gas-phase structures of torsionally flexible compounds by QM calculations and GED
17:00 Clemens Schulze-Briese
Baden, CH Hybrid photon counting detectors for gas-phase electron diffraction
17:30 End of session
18:00 Dinner
4
Wednesday June 24 Chair: David Rankin
9:00 Dwayne Miller Toronto, CA Hamburg, GE
Mapping Atomic Motions with ultrabright electrons: The chemists’ Gedanken-Experiment enters the lab frame
9:45 Igor Kochikov Moscow, RU Recent Advances in Treatment of Multiple Large Amplitude Motions in Gas Electron Diffraction Studies Guided by Quantum Chemistry
10:15 Coffee break
Chair: Raphael Berger
10:45 Sarah Masters Christchurch, NZ A potential problem – the curious case of P2(SiMe3)4
11:15 Christian Reuter Bielefeld, GE A brief overview of the Bielefeld gas electron diffractometer 2015
11:45 End of session
12:00 Lunch
13:00 Excursion
19:00 Conference Dinner
23:00
End
5
Thursday June 25 Chair: Dwayne Miller
9:00 Peter Weber Providence, US Ultrafast structural dynamics by X-ray diffraction and spectroscopy
9:45 Yury Tarasov Moscow, RU Equilibrium structure and internal rotation in 3-nitrostyrene and 1-nitopropane by the multiple LAM Model in the combined use of gas electron diffraction and quantum chemistry
10:15 Coffee break
Chair: Sarah Masters
10:45 Nicolas Walker Newcastle, UK Exploring the chemistry in transient plasma by broadband rotational spectroscopy
11:30 End of session
12:00 Lunch
Chair: Yury Tarasov
14:00 Raphael Berger Salzburg, AT On the gas-phase structures of P4 and AsP3
14:30 Natalya Belova Ivanovo, RU Structural non-rigidity in Ln(thd)3: GED and QC 15:00 Coffee break
Chair: Georgiy Girichev
15:30 Inna Kolesnikova Moscow, RU Equilibrium structure of gas-phase benzamide. Electron diffraction study and quantum-chemical calculations of clonidine
16:00 Attila Kovács Karlsruhe, GE Modelling of the noble gas behavior in matrix isolation 16:30 Jürgen Vogt Ulm, DE Release of the MOGADOC update with an enhanced
3D viewer 17:00 End of session
18:00 Dinner Presentation of the next symposium venue Friday June 26 8:00–9:30
Breakfast / Departure
_____________
Ischenko, Anatoly – Monday, 9:00 h
6
Electron Diffraction: structure and dynamics of
free molecules and condensed matter
Anatoly A. Ischenko
Moscow Lomonosov State University of Fine Chemical Technologies, Vernadskogo 86, 119517 Moscow, Russia
The introduction of time sweep into diffraction methods and the development of
principles for studying coherent processes have revealed new paradigm to the diffraction
methods and opens the way of analysis of the wave packet dynamics, the intermediate
products and the transition state of the reaction center in gaseous and condensed media.1
Studies in the coupled 4D spatial and temporal continuum are necessary for under-
standing the dynamic features of molecular systems with a complex profile of the potential
energy surface. The whole set of spectral and diffraction methods based on different
physical principles, which are complementary and make it possible to perform the
photoexcitation of nuclei and electrons and carry out diagnostics of their dynamics at
ultrashort time sequences, reveal new possibilities for studies with the necessary inte-
gration of the “structure–dynamics–function” triad in chemistry, biology, and materials
science. In contrast to the traditional approach of electron diffraction and X-ray structural
analysis of equilibrium systems, the data analysis for pump-probe electron and X-ray
diffraction requires the inclusion of the interaction between the molecular ensemble and
the laser field explicitly. The interference term that arises in the molecular scattering
intensity of electrons upon the coherent excitation of a molecular system under study
makes it fundamentally possible to determine the density matrix and carry out the
tomographic reconstruction of the molecular quantum state of this system.
In the last two decades it has become possible to observe nuclear motion on the
time interval corresponding to the oscillation period of nuclei. The observed coherent
changes in the nuclear subsystem on these intervals determine the fundamental transition
from the standard kinetics to the dynamics of the phase trajectory of a molecule. Results of
several internationally renowned research groups are included and cited.
1 A. A. Ischenko, G. V. Girichev, Yu. I. Tarasov, Electron Diffraction: Structure and Dynamics of
Free Molecules and Condensed Matter, Moscow, Fizmatlit, 2013, 648 p.
Wann, Derek – Monday, 9:45 h
7
Towards time-resolved electron diffraction at York
Derek A. Wann, Paul D. Lane, Matthew S. Robinson, and Joao Pedro F. Nunes
University of York, Heslington, York, UK, YO10 5DD
Since 2013 our group at the University of Edinburgh and now at the University of York
have been building and testing a novel apparatus for performing time-resolved electron
diffraction.
In this talk I will present our most recent results using our apparatus,1 including both
polycrystalline and gas-phase diffraction examples. I will also discuss the simulations that
we are undertaking to inform the further development of this apparatus as well as a
collaborative project to perform MeV diffraction in the UK for the first time.
1 M. S. Robinson, P. D. Lane, D. A. Wann, Rev. Sci. Instrum. 2015, 86, 013109.
Vishnevskiy, Yury – Monday, 10:45 h
8
Low-pressure gas electron diffraction
Yury V. Vishnevskiy
Universität Bielefeld, 33615 Bielefeld, Universitätsstraße 25, Germany
Traditional experiments in gas electron diffraction require a vapour beam with a pressure
of a few mbar as a suitable target.1 Some time ago an alternative experimental setup has
been suggested2 allowing measurements on low-pressure targets. In our work a similar
ring-type evaporator has been designed and constructed for low-volatile compounds.
Additionally, a mass-spectrometer has been attached to our GED apparatus to control
vapour composition. In first experiments electron diffraction patterns of benzoic acid have
been successfully measured at T = 293 K, Iprim = 11 μA and t = 60 s. At the temperature of
experiment the vapour pressure of benzoic acid was 6×10–4 mbar. For comparison, in a
reported earlier GED investigation3 of benzoic acid a temperature of 405 K has been used,
which corresponds to a pressure of about 17 mbar. Thus the experimental approach
tested in our work opens new possibilities to study compounds of low volatility and limited
stability at elevated temperatures. 1 J. Tremmel, I. Hargittai, Gas Electron Diffraction Experiment, in: Stereochemical Applications of
Gas Phase Electron Diffraction, Part A: The Electron Diffraction Technique, VCH Publishers, Inc.,
New York, 1988. 2 A. Ivanov, Moscow Univ. Chem. Bull. 2011, 66, 18. 3 K. Aarset, E. M. Page, D. A. Rice, J. Phys. Chem. A 2006, 110, 9014.
Gunby, Nathaniel – Monday, 11:15 h
9
UCONGA: A new, general, fast conformer generation method
Nathaniel R. Gunby, Deborah L. Crittenden, and Sarah L. Masters
University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
Computational chemistry often plays a key role in analysing data from GED experiments.1
The first step in a computational chemistry investigation is to locate the relevant
conformers. Potential energy surface scans are the most accurate method of locating
conformers, but are only feasible for molecules with a small number of rotatable bonds.
Several methods to locate conformers of protein ligands for docking simulations have been
designed, but they do not accurately model molecules that are not drug-like. We have
developed a new parameter-free method to find conformers of any large molecule. This
method exploits molecular symmetry, if present, to reduce the number of conformers
generated. It also contains tools to analyse the generated conformers for similarity to one
another.
1 N. W. Mitzel and D. W. H. Rankin, Dalton Trans. 2003, 3650.
Kuze, Nobuhiko – Monday, 14:00 h
10
GED, MW and quantum-chemical studies of
molecules with large-amplitude motions
Nobuhiko Kuze,a Atsushi Ishikawa,aYuuki Tajimia and Hiroshi Takeuchib
aDepartment of Materials and Life Sciences, Faculty of Science and Technology Sophia University,
7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
E-mail: [email protected] bGraduate School of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido
060-0810, Japan
Gas electron diffraction (GED) and the microwave spectroscopy (MW) data are the
powerful method to derive the precise structural parameters of the target molecule in the
gas phase, combined data analysis of GED and MW data refinement procedure was
established for the molecules with the small-amplitude vibrational motion. However, there
is some discrepancy between the experimental rotational constants by MW and the
calculated rotational constants derived by the GED data for the molecules with the large-
amplitude vibrational motions. Therefore, the large-amplitude vibrational analysis is still the
important topic to determine the reasonable molecular structure both the GED and MW. In
this talk, we will present the recent development of the GED data refinement procedure for
the molecules with large-amplitude motions such as methyl trifluoroacetate (CF3COOCH3)
and acetaldehyde oxime (CH3CH=NOH). We look at the vibrational effects on the
rotational constants determined by MW and GED. Also, we will present the developing
MW study on methyl trimethylacetate ((CH3)3CCOOCH3) with the GED and quantum
chemical results.
Sliznev, Valery – Monday, 14:30 h
11
Structure of some molybdenum and tungsten halide complexes MX3
and MX4 (X = F, Cl): Jahn-Teller effect and spin-orbit coupling.
Valery V. Sliznev
Ivanovo State University of Chemistry and Technology
Research Institute for Thermodynamics and Kinetics of Chem. Processes, 153460 Ivanovo, Russia
The ground and low-lying excited electronic states of MoXn and WXn (X = F, Cl; n = 3, 4)
molecules were systematically studied by ab initio method. The calculations were emp-
loyed using all-electron Sapporo-rTZP+D basis sets by the complete active space self-con-
sistent field (CASSCF) and multiconfigurational quasi-degenerate second-order perturba-
tion (MCQDPT2) levels of theory. The one and two-electron spin-independent relativistic
effects were taken into account within the scheme of relativistic elimination of small com-
ponents (RESC) in the four-component Dirac equation. Spin-orbit coupling (SOC) was ta-
ken into account using wave functions from MCQDPT2 calculations (SOC-MCQDPT2).
The SOC contribution to the Hamiltonian was described by the full Breit-Pauli operator.
Molecules MX3 possess two close spatial electronic states: high-spin 4A2' (ground in
MoX3, WCl3) and Jahn-Teller low-spin 2E" (ground in WF3) states. The SOC “quenches”
Jahn-Teller effect and leads to two 2E1/2 and 2E3/2 spin-orbit states split by 656(MoF3), 480
(MoCl3), 1712(WF3) and 1218(WCl3) cm-1. In WF3 and WCl3 complexes the 2E1/2 spin-
orbit state becomes the ground state with the equilibrium structure of C2v symmetry. In
WCl3 case strong mixing of the low-lying spin-orbital quadruplet and doublet states results
in D3h symmetry of the equilibrium configuration in four lowest-lying spin-mixed electronic
states.
In all considered MX4 molecules the ground spatial electronic state of the tetrahedral
configuration is triplet term 3A2. The SOC results in three-fold degenerated Jahn-Teller 3T2
state arisen from the 3A2 spatial term. The first excited state 1E of Td configuration pos-
sesses the strong Jahn-Teller distortion and unusual PES. Due to outsize Jahn-Teller sta-
bilization energy the quasi-planar D2d configuration for WF4 becomes energetically more
preferable. This work was supported by the Ministry of education and science of the Russian Federation (the
project N 4.1385.2014/K “The structure, intramolecular dynamics and thermodynamics of the
lanthanide coordination compounds with inorganic and organic ligands”).
Otlyotov, Arseniy – Monday, 15:00 h
12
The molecular structure of 1,8-bis(phenylethynyl)anthracene
by synchronous gas electron diffraction and mass spectrometry and by quantum-chemical calculations
Jan-Hendrik Lamm,a Jan Horstmann,a Hans-Georg Stammler,a Norbert W. Mitzel,a
Natalya V. Tverdova,b Yuriy A. Zhabanov,b Arseniy A. Otlyotov,b Nina I. Giricheva c and
Georgiy V. Girichev b
a Anorganische Chemie und Strukturchemie, Universität Bielefeld, Universitätsstr. 25, D-33615
Bielefeld, Germany
bIvanovo State University of Chemistry and Technology, Ivanovo 153000, Russia c Ivanovo State University, Ivanovo 153025, Russia
The molecular structure of 1,8-bis(phenylethynyl)anthracene (1,8-BPEA) has been deter-
mined for the first time by gas-phase electron diffraction combined with mass spectrometry
and quantum-chemical calculations using B3LYP, B3LYP-D2,
B3LYP-D3, CAM-B3LYP, LC-BLYP, LC-wPBE and M06
functionals with cc-pVTZ basis set. A novel approach1,2 for
calculating the vibrational amplitudes and corrections was
applied since the traditional method (utilizing the SHRINK
program) led to unreasonably large values. The 1,8-BPEA
molecule was found to possess C2 symmetry with co-directio-
nally rotated phenylethynyl groups (τ(C18C13C12C2) =
24.4(180); Rf = 4.3%). The electronic structure of the molecule
was studied by an NBO-analysis. The reason for a non-planar structure of 1,8-BPEA is a
balance between the extended π-electronic delocalization of the phenylethynyl and anthra-
cene fragments and steric repulsion of the phenyl substituents. Dispersive interactions
between phenyl rings do not substantially influence the structure of the molecule because
the value of dispersion energy is much less than that of π-electronic delocalization.
This work was supported by DFG (MI477/25-1 and MI477/27-1) and RFBR (12-03-91333-NNIO_a) 1 D. A. Wann et al. Organometallics, 2008, 27, 4183. 2 D. A. Wann et al. J. Phys. Chem. A, 2009, 113, 9511.
Mawhorter Richard – Monday, 16:00 h
13
Electrons In & Near Nuclei: 3 Tales
Richard Mawhorter,1 Zachary Glassman,2 Carson Witte,1
Andreas Biekert,1 David Sharfi,1 Alexander Hof,1 and Jens-Uwe Grabow3
1Physics Dept., Pomona College, Claremont, CA 91711 USA 2Physics Dept., University of Maryland, College Park, MD USA
3Institut für Physikalische Chemie, Leibniz-Universität, D-30167 Hannover
The diffraction of a beam of electrons by a
molecule can tell us a great deal about its
structure, and we can probe even more
sensitive effects by measuring both the
magnetic and electric hyperfine spectra
arising from the interactions of atomic
nuclei and the surrounding electrons.
There are 3 even more subtle effects
which can arise from an electron in close
proximity or even inside the nucleus, a
situation which arises when the electron
wave function has a large amount of
s-character, as motivated in the accom-
panying textbook figure. When the
nucleus is heavy enough for relativistic
effects to become important, these
include the spin-dependent nuclear anapole moment and the spin-independent electric
dipole moment of the electron, or eEDM. However, on an even more basic level, the
overlap or penetration of the nucleus by the electron can perturb the measured quadrupole
moment Q of the nucleus, and evidence of this may be observed by combining high
resolution microwave spectroscopy with more direct RF molecular beam experiments. The
resulting eQq ratios of several 85RbX and 87RbX rubidium salts that have been measured
using a supersonic jet Fourier transform microwave spectrometer at the Leibniz Universität
in Hannover will be presented, along with new results for YbF and PbF.
Baum, Peter – Tuesday, 9:00 h
14
Recording atomic and electronic motion in space and time
Peter Baum
Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching, Germany
All processes in materials and devices are basically defined by microscopic atomic and
electronic motion. Especially in condensed matter, structural dynamics is rich and involves
complex reaction paths of atomic and electronic motion. Our approach for a direct, real-
space visualization is pump-probe electron diffraction: Picometer-wavelength single-
electron wave packets, controlled in space and time by optical light fields, deliver sub-
atomic and sub-light-cycle resolutions at the same time (picometers and few-
femtoseconds). Any light-driven atomic and electronic motion is therefore directly resolved
on fundamental length and time scales. Showcase results on a strongly correlated material
(VO2), graphite as single crystal or realistic layer, carbon nanotubes and organic molecular
switches reveal the complex interplay of coherent and incoherent dynamics. We mention
some advanced perspectives and discuss the paradigm shifts eventually offered by a real-
space perspective on light-induced electron dynamics.
1 S. Lahme, C. Kealhofer, F. Krausz, P. Baum, Femtosecond single-electron diffraction, Structural
Dynamics 2014, 1, 034303. 2 F. O. Kirchner, A. Gliserin, F. Krausz, P. Baum, Laser streaking of free electrons at 25 keV,
Nature Photonics 2014, 8, 52–57. 3 F. O. Kirchner, S. Lahme, F. Krausz, P. Baum, Coherence of femtosecond single electrons
exceeds biomolecular dimensions, New J. Phys. 2013, 15, 063021. 4 A. Gliserin, A. Apolonski, F. Krausz, P. Baum, Compression of single-electron pulses with a
microwave cavity, New J. Phys. 2012, 14, 073055. 5 P. Baum, A. H. Zewail, Attosecond Electron Pulses for 4D Diffraction and Microscopy, PNAS
2007, 104, 18409. 6 P. Baum, D.-S. Yang, A. H. Zewail, 4D Visualization of Transitional Structures in Phase
Transformations by Electron Diffraction, Science 2007, 318, 788. 7 P. Baum and A. H. Zewail, Breaking Resolution Limits in Ultrafast Electron Diffraction and
Microscopy, PNAS 2006, 134, 16105.
Schooss, Detlef – Tuesday, 9:45 h
15
The Structures of Ruthenium Clusters
Eugen Waldt,1 Reinhart Ahlrichs,2 Manfred M. Kappes1,2 and Detlef Schooss1,2
1 Institut für Nanotechnologie, Karlsruher Institut für Technologie (KIT), Postfach 3640, 76021
Karlsruhe, Germany 2 Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Kaiserstraße 12,
76128 Karlsruhe, Germany
Small ruthenium particles are well known for their important role in catalysis. The study of
ruthenium cluster in gas phase potentially offers a route to model such catalytic systems
and can contribute towards clarifying the mechanisms involved. However, an important
prerequisite for such studies is knowledge of the cluster structure. Very recently we have
shown, that Ru55– forms a close packed structure.1 Here we extended the size regime to
smaller nuclearities and present the structures of small and medium sized ruthenium
clusters anions (Ru9– – Ru44
–). We use combination of trapped ion electron diffraction2 and
density function theory (DFT) which has been extensively used by us and others for
structure determination of clusters ions.
Three different structural motifs were found in the size range studied. The smallest clusters
are based on simple cubic structures. From Ru13– on double layered hexagonal structures
are dominant. Finally, for cluster sizes larger than 17, close packed structures based on
the ν2- and ν3-octahedra Ru19– and Ru44
–, respectively, were found.
Figure 1: Octahedral Ruthenium clusters Ru19
–, Ru28– and Ru44
– 1 T. Rapps, R. Ahlrichs, E. Waldt, M. M. Kappes, D. Schooss, Angew. Chem. Int. Ed. 2013, 52,
6102–6105. 2 D. Schooss, M. N. Blom, J. H. Parks, B. von Issendorff, H. Haberland, M. M. Kappes, Nano Lett.
2005, 5, 1972-1977; M. Maier-Borst, D. B. Cameron, M. Rokni, J. H. Parks, Phys. Rev. A 1999, 59,
R3162–R3165.
Geldof, Davy – Tuesday, 10:45 h
16
DFT study of modified TiO2 surfaces using phosphonic acids
Davy Geldof and Frank Blockhuys
University of Antwerp, Department of Chemistry,
Groenenborgerlaan 171, B-2020 Antwerp, Belgium
Chemical modification of metal oxide surfaces is of general interest in a wide range of
applications such as organic electronics, medical implants, solar cells etc. The possible
functional groups which are available to covalently attach organic monolayers onto the
surface were recently discussed.1 We will focus on the modification of the TiO2 surface
using phosphonic acids (PAs) due to the formation of strong P–O–Ti bonds. Several
experimental studies were performed to characterize the modified surface, but the binding
state of the PAs on the surface and consequently the precise assignment of both NMR
and IR spectra remains unclear.2,3
A DFT study of the different adsorption modes of butyl- and phenylphosphonic acid on the
(101) and (001) surfaces of anatase TiO2 was performed using the Quantum Espresso
(QE)4 software package. The surface is described as a semi-infinite periodic system using
periodic boundary conditions (PBC). Vibrational frequencies of the isolated molecules and
adsorption complexes were calculated and compared with available IR spectra. NMR
chemical shifts were calculated using the GIPAW method5 as implemented in the QE
software package. In order to analyse the possible bonding modes of the adsorption
complexes, experimental 17O and 31P NMR spectra were compared with the calculated
chemical shifts.
1 S. P. Pujari, L. Scheres, A. T. M. Marcelis, H. Zuilhof, Angew. Chem. Int. Ed. 2014, 53, 6322. 2 G. Guerrero, P. H. Mutin, A. Vioux, Angew. Chem. Mater. 2001, 13, 4367. 3 F. Brodard-Severac, G. Guerrero, J. Maquet, P. Florian, C. Gervais, P. H. Mutin, Chem. Mater.
2008, 20, 5191. 4 P. Giannozzi et al., J. Phys.: Condens. Matter 2009, 21, 395502. 5 C. J. Pickard, F. Mauri, Phys. Rev. B 2001, 63, 245101.
Shlykov, Sergey – Tuesday, 11:15 h
17
Molecular structure and conformational properties of
N-cyclohexylpiperidine as studied by gas-phase electron diffraction, IR spectroscopy and quantum chemical calculations
Sergey A. Shlykov,# Tran Dinh Phien,# Yan Gao$ and Peter M. Weber$
# Department of Physical Chemistry, Ivanovo State University of Chemistry and Technology,
Research Institute for Thermodynamics and Kinetics of Chemical Processes, Sheremetev ave, 7,
153000, Ivanovo, Russian Federation. E-mail: [email protected]. $ Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
E-mail: [email protected].
N-Cyclohexylpiperidine (NCHP) is one of a series of N-alkylpiperidines studies that we started
recently. In this work the conformational properties and molecular structure of NCHP were studied
by quantum chemical (QC) calculations (DFT/B3LYP and MP2 with 6-311G** and cc-pVTZ basis
sets), combined gas-phase electron diffraction/mass spectrometry (GED/MS) and IR-spectroscopy.
According to the QC calculations, NCHP may exist as eight conformers. The three most favorable
structures, all with equatorial position of the cyclohexane ring relative to the piperidine ring, are
shown in Fig.1.
I (EqC–EqN–orthogonal) II (EqC–EqN–twist) III (AxC–EqN)
Fig. 1. Structures of the most stable conformers of NCHP
In the gas phase at 298 K, the conformers should be present in ratios of I:II:III as 85:13:2
(DFT/B3LYP) and 45:7:48 (MP2). Refinement of the GED intensities resulted in 74(13):21(13):5(5)
at 303 K, which is in excellent agreement with the DFT method predictions. Experimental IR
spectra in liquid and gas phases at room temperature are similar to the calculated one for the
dominating conformer, I. Structural parameters for the stable conformers, calculated by B3LYP/6-
311G**, are in good agreement with the results, obtained by GED. QC results for some other
substituents attached to piperidine – methyl, ethyl and isopropyl – also predict noticeable
predominance of equatorial conformers.
The financial support of this work by the Ministry of Education and Science of the Russian
Federation (Base Part, Project No. 1800), DTRA, grant number HDTRA1-14-1-0008 and the
National Science Foundation, grant number CBET-1336105 is greatly acknowledged.
Blomeyer, Sebastian – Tuesday, 16:30 h
18
Gas-phase structures of torsionally flexible compounds by
quantum-chemical calculations and GED experiments
Sebastian Blomeyer, Christian G. Reuter, Yury V. Vishnevskiy, Norbert W. Mitzel
Faculty of Chemistry and Centre for Molecular Materials CM2, Bielefeld University, 33615
Bielefeld, Universitätsstraße 25, Germany
Treatment of large amplitude torsional motions is one of the most challenging tasks in the
analysis of gas-phase electron diffraction data. Employing relative abundancies of pseudo-
conformers based on high-quality quantum-chemical calculations allowed us to determine
the gas-phase structures of different ethyl(thio)esters (1–3) as well as 1,2,3,4,5-penta-
fluoroferrocene1 (4) (see Fig.). For compounds 1–3 quantum chemical calculations (1:
MP2/cc-pVTZ, 2, 3: MP2/6-311G(d,p)) yielded two stable conformers,
namely syn-anti (Φ(C–O/S–C–C) = 180°, Cs symmetry) and syn-gau-
che (Φ = 81° (1), 82° (2) and 111° (3)) separated by low rotational
barriers of 5.0 kJ mol−1 (1), 4.2 kJ mol−1 (2) and 2.0 kJ mol−1 (3),
respectively. R-factors of subsequent GED data analyses could be
improved by up to 3 % using Boltzmann weighted pseudoconformers
instead of single- or two-conformer models. According to a DFT study
(PBE0/cc-pVTZ) 4 exhibits an eclipsed (C5v symmetry) minimum
conformer with a barrier of the rotation of the Cp rings against each
other of 2.2 kJ mol−1. GED data refinement accounting for the
eclipsed conformer only yielded an R-factor of 5.8 %, which decrea-
sed to 4.4 % by explicit modelling of the potential energy distribution
by means of the above-mentioned method. Furthermore the barrier
itself could be determined from the GED experiment as
2.4(3) kJ mol−1.
We thank Dr. Aida Ben Altabef and her group for supplying us with the (thio)esters.
1 K. Sünkel, S. Weigand, A. Hoffmann, S. Blomeyer, C. G. Reuter, Yu. V. Vishnevskiy, N. W.
Mitzel, J. Am. Chem. Soc. 2015, 137(1), 126–129.
Schulze-Briese, Clemens – Tuesday, 17:00 h
19
Hybrid photon counting pixel detectors for gas-phase electron diffraction
Clemens Schulze-Briese,1 Helder Marchetto,2 Gemma Tinti3 and Bernd Schmitt3
1DECTRIS Ltd., Neuenhoferstrasse 107, 5400 Baden, Switzerland 2ELMITEC Elektronenmikroskopie GmbH, 38678 Clausthal-Zellerfeld, Germany
3 Paul Scherrer Institute, 5232 Villigen, Switzerland
Hybrid photon counting (HPC) pixel detectors have the potential to transform the detection of electrons in a similar manner as they have transformed synchrotron research by enabling new data acquisition modes and even novel experiments. During the last years prototype experiments have been carried out to demonstrate their potential in electron microscopy,1 electron diffraction2 as well as low energy electron detection.3 PILATUS HPC detectors, first introduced in 2007,4 have completely changed the way X-rays are detected. Data quality has improved due to the noise-free operation and the direct conversion of X-rays, while millisecond readout time and high-frame rates allow for hitherto unknown data acquisition speed and efficiency. With a pixel size of 75 µm and continuous frame read-out, the recently introduced EIGER5 opens new horizons in high-resolution imaging and time-resolved experiments. The modular architecture and the vacuum-compatibility of the detector modules are ideal prerequisites to design specific detector solutions with properties well beyond those of the standard models. In-vacuum operation is ideally suited to eliminate all background arising from windows and air, resulting in optimal signal-to-noise ratio. Furthermore, the lowest experimental energy is no longer limited by windows and air absorption but rather by the beamline spectrum and the detector. The minimal X-ray energy compatible with noise-free counting of the PILATUS is 1.8 keV. Here we present the prospects EIGER detectors in gas phase electron diffraction experiments as well as results from recent Photo Electron Emission Microscopy (PEEM) experiments as proof of principle. A single-chip EIGER setup, with 256 x 256 pixels and a pixel size of 75 microns corresponding to an active area of 19.2 mm x 19.2 mm was used. The single chip is mounted on a PCB, which also acts as a vacuum interface. With this simple setup a pressure of 5·10-9 mbar was reached quickly. The non-active layers of the sensor reduce the electron energy by at least 3 keV and limit the minimal detectable energy to approximately 15 keV. Results of characterisation measurements as well as microscopy images demonstrating the improved resolution will be presented. 1 G. McMullan et al., Ultramicroscopy 2009, 109, 1126. 2 D. Georgieva et al., JINST 2011, 6, C01033. 3 R. van Gastel et al., Ultramicroscopy 2009, 109, 111 4 P. Kraft et al., J. Synchrotron Rad. 2009, 16, 368. 5 R. Dinapoli et al., NIM A. 2011, 650(1), 79.
Miller, Dwayne – Wednesday, 9:00 h
20
Mapping Atomic Motions with Ultrabright Electrons: The Chemists’ Gedanken Experiment Enters the Lab Frame
R. J. Dwayne Miller
Max Planck Institute for the Structure and Dynamics of Matter/Hamburg
The Hamburg Centre for Ultrafast Imaging and
Departments of Chemistry and Physics, University of Toronto
Electron sources have achieved sufficient brightness to literally light up atomic motions during transition state processes to directly view the unifying conceptual basis of chemistry. Two new electron gun concepts have emerged from detailed calculations of the propagation dynamics of nonrelativistic electron pulses with sufficient number density for single shot structure determination (Siwick et al. JAP 2002). The atomic perspective, that these sources have opened up, has given a direct observation of the far from equilibrium motions that lead to structural transitions (Siwick et al. Science 2003). Recent studies of formally a photoinduced charge transfer process in charge ordered organic systems has directly observed the most strongly coupled modes that stabilize the charge separated state (Gao et al Nature 2013). It was discovered that this nominally 280 dimensional problem distilled down to projections along a few principle reaction coordinates. Similar reduction in dimensionality has also been observed for ring closing reactions in organic systems (Jean-Ruel et al. JPC B 2013). ). Even more dramatic reduction in complexity has been observed for the material, Me4P[Pt(dmit)2]2, which exhibits a photo-induced metal to metal centre charge transfer process for unit cells on par with proteins. This study represents the first all atom resolved structural dynamics with sub-Å and 100 fs timescale resolution. We are tuned to see correlations. At this resolution, without any detailed analysis, the large-amplitude modes can be identified by eye from the molecular movie. The structural transition clearly involves a dimer expansion and a librational mode that stabilizes the charge transfer. This phenomenon appears to be general and arises from the very strong anharmonicity of the many body potential in the barrier crossing region. The far from equilibrium motions that sample the barrier crossing region are strongly coupled, which in turn leads to more localized motions. In this respect, one of the marvels of chemistry, and biology by extension, is that despite the enormous number of possible nuclear configurations for any given construct, chemical processes reduce to a relatively small number of reaction mechanisms. We now are beginning to see the underlying physics for these generalized reaction mechanisms. The “magic of chemistry” is this enormous reduction in dimensionality in the barrier crossing region that ultimately makes chemical concepts transferrable. With the new ability to see the far from equilibrium nuclear motions driving chemistry, it will ultimately be possible to characterize reaction mechanisms in terms of reaction modes, or reaction power spectra, to give a dynamical structure basis for understanding chemistry. In keeping with this meeting, the natural extension of this work to gas phase will be discussed in the context of solving open issues of signal to noise problems unique to the gas phase. This effort in combination with recent advances in nanofluidics holds great promise in determining the role of solvent in directing the chemistry in solution phase where most chemistry occurs.
Kochikov, Igor – Wednesday, 9:45 h
21
Recent Advances in Treatment of Multiple Large Amplitude Motions in Gas Electron Diffraction Studies Guided by Quantum Chemistry
Igor V. Kochikov,a Dmitry M. Kovtun,a,b Yury I. Tarasovb,c
a Lomonosov Moscow State University, Leninskie gory, 119991 Moscow, Russia; b Joint Institute for High Temperatures of the Russian Academy of Sciences,
Izhorskaya st. 13, Bd.2, 125412 Moscow, Russia; c Lomonosov Moscow State University of Fine Chemical Technologies,
Vernadskogo prosp. 86, 119571 Moscow, Russia
The use of dynamic molecular model based on the concept of pseudo-conformers has
been successfully applied to GED investigations for many years. However, until recently
most research done in this area was limited to the molecules possessing only one large-
amplitude degree of freedom (usually internal rotation). In the last two years, the method
was applied to the molecules with
multiple internal rotors.
Theoretical treatment of the large
amplitude motion based on the
adiabatic separation of LAM coor-
dinates in a molecular Hamiltonian
remains essentially the same in
the case of multiple floppy mot-
ions1, and the main limiting factor is technical complexity of such analysis. Recent
progress in computing facilities has made it possible to apply accurate dynamic molecular
models to the complex molecules. This application, however, is far from being trivial. We
discuss relevant problems arising in quantum chemical calculations, solution of multi-
dimensional Schrödinger’s equation, procedures of averaging and interpolation that
present serious challenges due to the greatly increased number of the pseudo-conformers.
The results of processing several medium-sized molecules show that commonly available
computing facilities allow treatment of up to several hundred pseudo-conformers that
proves sufficient for the molecules possessing up to three large-amplitude degrees of
freedom. This work is supported by the Russian Scientific Foundation, grant No. 14-50-00124 1 I. V. Kochikov, Y. I. Tarasov, N. Vogt, V.P. Spiridonov, J. Mol. Struct. 2002, 607, 163−174.
Masters, Sarah – Wednesday, 10:45 h
22
A potential problem – the curious case of P2(SiMe3)4
Heather L. Humphrey-Taylor and Sarah L. Masters
University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
More often than not, the molecular structure determined by gas electron diffraction (GED)
is reasonably well-predicted by quantum chemical methods. However, there are well-
documented examples where molecular structures change dramatically between the solid
and gaseous phases.1,2 We use computational methods to screen for minima on the
potential energy surface of the molecule to enable us to predict what conformers may be
present in the vapour at the temperature of the experiment. This is an incredibly useful tool
to deconvolute what would otherwise be insolvable experimental data.
The structure of tetrakis(trimethylsilyl)diphosphine, P2(SiMe3)4, had been the subject of
several previous investigations using computational methods.3,4 In both studies only one
conformer on the potential energy surface was reported and discussed. In this work we
have used computational methods to reinvestigate the potential energy surface of
P2(SiMe3)4 and discovered that, not only is there more than one conformer, the previously
reported conformer was not the global minimum. GED studies have also been undertaken,
guided by the results of the potential energy surface scan, and the outcomes are
presented here.
1 S. L. Hinchley, H. E. Robertson, L. J. McLachlan, C. A. Morrison, D. W. H. Rankin, S. J. Simpson,
E. W. Thomas, J. Phys. Chem. A 2004, 108, 185. 2 S. L. Hinchley, C. A. Morrison, D. W. H. Rankin, C. L. B. Macdonald, R. J. Wiacek, A. Voigt, A. H.
Cowley, M. F. Lappert, G. Gundersen, J. A. C. Clyburne, P. P. Power, J. Am. Chem. Soc. 2001,
123, 9045. 3 G. Tekautz, K. Hassler, In Organosilicon Chemistry VI: From Molecules to Materials [European
Silicon Days], 2nd, Munich Germany, Sept. 11–12, 2003; 2005, 1, 368. 4 K. B. Borisenko, D. W. H. Rankin, Inorg. Chem. 2003, 42, 7129.
Reuter, Christian – Wednesday, 11:15 h
23
A brief overview of the Bielefeld gas electron diffractometer 2015
Christian G. Reuter, Yury V. Vishnevskiy, Norbert W. Mitzel
Bielefeld University, D-33615 Bielefeld, Germany
A rotating sector is known to be a vital part in GED measurements, as hardly any struc-
tures have been successfully recorded and
refined without.1 The diffractometer at Biele-
feld University2 has been refitted to enable
sectorless recordings which we have
realized for CCl4, CHCl3, C6H6, CS2 and
CO2. These substances are well
investigated and widely used as standards.
Therefore they are well suited as a base
reference for our experiments.
Different beam-stop variants were tested at
different primary beam currents during the
refitting process.
PC-aided monitoring of an experiment has
obvious advances. Gathering more experimental parameters during apparatus changes for
one, but also for statistical reasons. Due to shortened experiment times of down to three
seconds, digital recording gets almost necessary.
Accordingly a PC control panel was introduced centralizing the recording of parameters.3
1 I. Hargittai, Stereochemical applications of gas phase electron diffraction, VCH, Weinheim, 1988. 2 R. J. F. Berger, Z. Naturforsch., 2009, 64B, 1259. 3 C. Elliott, V. Vijayakumar, W. Zink, R. Hansen, J. Lab. Automatisation 2007, 12(1), 17–24.
Weber, Peter – Thursday, 9:00 h
24
Ultrafast Structural Dynamics by X-Ray Diffraction and Spectroscopy
Peter M. Weber
Brown University, Department of Chemistry, Providence, RI 02912 USA
The structural observation of molecules, in real time just as they undergo a chemical
reaction, is expected to aid the exploration of new reaction mechanisms, the development
of catalysts, the understanding of biomolecular processes and the control of chemical
reactions and material properties on a molecular level. As a step toward this goal, we have
developed a gas-phase x-ray diffraction experiment that uses the ultrashort x-ray pulses
from the Linac Coherent Light Source (LCLS) to capture atomic motions within molecules
in a dilute gas (<5 Torr). The time evolving X-ray diffraction pattern of 1,3-cyclohexadiene
is measured in a pump-probe scheme with 267 nm excitation laser and 8.3 keV X-ray
probe pulses. Upon optical excitation the molecule accelerates past a conical intersection
down the 2A potential energy surface before opening the ring on a 140 fs time scale. The
wavelength of the X-rays allows only for a limited range of scattering vectors. To assemble
a “molecular movie” of the dynamics we therefore compare the experimental diffraction
signal to ab initio quantum molecular dynamics simulations. This allows us to determine
weighted trajectories that provide a representation of the structural dynamics, with the
weighted ensemble of trajectories corresponding to the nuclear flux during the chemical
reaction. The X-ray structural data thus provide reaction pathways for which ionization
energies can be calculated at each step. To test these results, we use ultrafast time-
resolved multiphoton - ionization photoelectron spectroscopy to measure the travel time
required for the molecule to reach the calculated resonance windows to Rydberg states.
By so combining the results from the ultrafast X-ray diffraction with observations from
ultrafast spectroscopy, it appears that we can make significant progress towards the
ultimate goal: a comprehensive understanding of the spatially resolved photochemical
reaction dynamics.
Tarasov, Yury – Thursday, 9:45 h
25
Equilibrium Structure and Internal Rotation in 3-Nitrostyrene and
1-Nitropropane by the Multiple LAM Model in the Combined Use of Gas Electron Diffraction and Quantum Chemistry
Dmitry M. Kovtun,a,b Igor V. Kochikov,b Yury I. Tarasova,c
a Joint Institute for High Temperatures of the Russian Academy of Sciences, Izhorskaya st. 13,
Bd.2, 125412 Moscow, Russia; b Lomonosov Moscow State University, Leninskie gory, 119991 Moscow, Russia;
c Lomonosov Moscow State University of Fine Chemical Technologies, Vernadskogo prosp. 86,
119571 Moscow, Russia
The procedure of the combined treatment of QC results and GED data based on the
adiabatic separation of LAMs developed earlier1 is applied to the molecules with two
internal rotors slightly (3-nitrostyrene)2 or more strongly (1-nitropropane) interacting. Two
stable conformers are present in both molecules. In 3-nitrostyrene stable syn- and anti-
conformations are almost equally populated. In 1-nitropropane gauche-conformations
dominate. The presence of up to 10 percent of anti-conformation is not excluded.
Equilibrium structural parameters are determined for both molecules.
Figure 1. Probability density of the 3-nitrostyrene conformations
Figure 2. Probability density of the 1-nitropropane conformations
This work is supported by the Russian Scientific Foundation, grant No. 14-50-00124 1 I. V. Kochikov, Y. I. Tarasov, N. Vogt, V. P. Spiridonov. J. Mol. Struct. 2002, 607, 163−174. 2 D. M. Kovtun, I. V. Kochikov, Y. I. Tarasov. J. Phys. Chem. A, 2015, 119, 1657−1665.
Walker, Nicholas – Thursday, 10:45 h
26
Exploring the Chemistry in Transient Plasma by
Broadband Rotational Spectroscopy
Nicholas R. Walker
School of Chemistry, Bedson Building, Newcastle University,
Newcastle upon Tyne, Tyne and Wear, NE1 7RU, United Kingdom.
Electronics capable of digitising waveforms at gigahertz frequencies now allow rotational
spectroscopy to be performed at high resolution, high bandwidth and with minimal or no
cost to sensitivity. The technique provides outstanding precision in molecular structure
determination of isolated, gas phase species and a new method by which plasma
chemistry can be explored. Molecules and complexes form when precursors within an
expanding gas sample are allowed to interact with plasma generated by an electrical
discharge or laser vaporisation of a solid. This presentation will describe recent experi-
ments1,2 that have applied broadband rotational spectroscopy to study molecules and
complexes generated (in whole or in part) through chemistry occurring within transient
plasma.
1 D. P. Zaleski, S. L. Stephens and N. R. Walker, Phys. Chem. Chem. Phys. 2014, 16, 25221. 2 D. P. Zaleski, D. P. Tew, N. R. Walker and A. C. Legon, J. Phys. Chem. A, 2015, 119, 2919.
Berger, Raphael – Thursday, 14:00 h
27
On the Gas-Phase Structures of P4 and AsP3
Raphael J. F. Berger
Chemistry of Materials, Hellbrunnerstr. 34, Paris-Lodron University
Salzburg, A-5020 Salzburg, Austria
Experimental and theoretical studies on the molecular structure of gaseous white
phosphorous (P4) and its heavier congener AsP3 are critically reviewed. P4 appears as a
perfect acid-test for the capabilities of gas electron diffraction (GED). Due to its high
symmetry, it contains only one interatomic distance parameter and one vibrational
parameter, practically allowing for a constraint-free and purely experimental determination
of these values. The first GED study of P4 has been undertaken in 19351 using very
rudimentary methods of data acquisition and analysis, still there was a close to perfect
agreement between predictions, based on the Pauling bond radii (2.20 Å),2 and the
experimental value (2.21 Å). Today the technical capabilities in both theory and experi-
ment appear to be much more potent and sophisticated than when the first GED study of
P4 has been undertaken. In the light of the new possibilities it turns out that we have to go
beyond the simplistic models of molecular structure as well as it appears to be necessary
to improve on the common two-center approximations of the electron scattering process.
As the most recent GED study of P4 from 2010 shows,3 these improvements are
necessary if we want to get a closer agreement between experiment and theory than 80
years ago. 1 L. R. Maxwell, S. B. Hendricks, V. M. Mosley J. Chem. Phys. 1935, 3, 699. 2 L. Pauling Proc. Nat. Acad. Sci. 1932, 18, 293. 3 B. M. Cossairt, C. C. Cummins, A. R. Head, D. L. Lichtenberger, R. J. F. Berger, S. A. Hayes, N.
W. Mitzel, G. Wu, J. Am. Chem. Soc. 2010, 132, 8459.
Belova, Natalya – Thursday, 14:30 h
28
Structural non-rigidity in Ln(thd)3: GED and QC
Natalya V. Belova, Valery V. Sliznev, and Georgiy V.Girichev
Ivanovo State University of Chemistry and Technology,
Research Institute for Thermodynamics and Kinetics of Chemical Processes, 153460 Ivanovo,
Russia
The DFT(PBE0/RECP(Ln)/cc-pVTZ) calculations for tris-2,2,6,6-tetramethyl-heptane-3,5-
dionato of lanthanides, Ln(thd)3, show that the structure of D3 symmetry corresponds to
the minimum of the potential energy hypersurface for all complexes studied. The distortion
of the coordination polyhedron from a near prismatic to antiprismatic structure increases
systematically in the series from La(thd)3 to Lu(thd)3.
Two types of non-rigid intramolecular rearrangement have been predicted in Ln(thd)3. The
first one concerns the ligand rotation. These intramolecular rearrangements could pass
through C2v or D3h structures, which correspond to the first-order saddle points on the
PES. The second type of rearrangement is connected with the internal rotations of tert-
butyl groups.
All rearrangements mentioned above possess rather low potential barriers. This
circumstance is the evidence of high flexibility of LnO6 coordination polyhedron and
slightly hindered rotation of tert-butyl groups. Calculated thermal average values of the
torsional angles γ (for internal rotation of C(CH3)3) and ϕ (pitch angle characterizing the
ligand movement) are closer to the experimental parameters than to the equilibrium ones.
Furthermore, despite quite different values of the intramolecular rearrangement barriers
the average values of the pitch angles, ϕav, seem to be close for all Ln(thd)3 complexes.
This work was supported by the Ministry of Education and Science of the Russian Federation (the
project N 4.1385.2014/K “The structure, intramolecular dynamics and thermodynamics of the
lanthanide coordination compounds with inorganic and organic ligands”).
Kolesnikova, Inna – Thursday, 15:30 h
29
Equilibrium structure of gas-phase benzamide. Electron diffraction
study and quantum-chemical calculations of clonidine
Inna N. Kolesnikova,a Anatolii N Rykov,a Igor F. Shishkov,a István Hargittaib
a Department of Chemistry, M.V. Lomonosov Moscow State University, 11999, Moscow,
Russia b Department of Inorganic and Analytical Chemistry, Budapest University of Technology
and Economics, PO Box 91, H-1521, Hungary
Benzamide and its derivatives possess potential antitumor activity.1 The molecular
structure of benzamide was investigated by gas-phase electron diffraction (GED)
and high-level ab initio calculations. To take into account vibrational effects, the
corrections to the experimental bond lengths (ra) were calculated using quadratic
and cubic force constants at the MP2/cc-pVTZ level of theory. The amide group
twist relative to the benzene ring is 19°.
Molecular geometry and tautomeric equilibria of clonidine are of particular interest
due its pharmacological activity.2 We considered two sets of tautomeric structures:
imino and amino. The imino form was more stable, by about 25-30 kcal mol-1, than
the amino. The geometry of the imino tautomer was completely optimized at the
B3LYP/6-31G(d,p) and MP2/cc-pVTZ levels of theory. According to computations,
the six-membered ring of clonidine is planar and the imidazoline ring is slightly
puckered with an angle of 73.5° between the ring planes. The structural analysis of
the experiment data is in progress.
Benzamide ↑ Clonidine → Clonidine
1 P. J. Wang, H. R. Guo, The Journal of Headache and Pain 2004, 5, 30. 2 M. J. Neil, Current Clinical Pharmacology 2011, 6(4), 280–7.
H(23)
H(16)
H(21)
N(1)
N(6)
H(19)
H(18)
H(20)
C(4)
Cl(17)
N(3) H(22)
C(2) C(5)
Cl(13)
C(10)
H(15)
C(9) H(14)
C(11)
C(7)
C(12)
C(8)
H(10)
H(13)
N(9)
C(1)
O(8) H(14)
H(16)
H(15) C(4) C(7)
C(3)
H(11) C(6)
C(2)
C(5)
H(12)
Kovács, Attila – Thursday, 16:00 h
30
Modelling of the noble gas behaviour in matrix isolation
Attila Kovács,a Jan Cz. Dobrowolski,b Joanna Rodeb and Sławomir Ostrowskib
aEuropean Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box
2340, 76125 Karlsruhe, Germany bInstitute of Nuclear Chemistry and Technology, 16 Dorodna-Street, 03-195 Warsaw, Poland
Matrix isolation is a powerful tool for trapping gas-phase species in frozen rare gases in
order to study their molecular properties. The technique can be combined with various
spectroscopic methods like UV-VIS, FT-IR, Raman spectroscopy. The study of inorganic
compounds requiring high evaporation temperatures can, however, be accompanied by
some difficulties: Reactions in the high-temperature vapour, weak interactions with the
matrix can result in complex experimental spectra. Thus, for the interpretation of the
spectra additional information is welcome, e.g. from quantum chemical calculations.
In the present study we used DFT calculations to assess these effects of rare gas (Rg =
Ne, Ar, Kr) matrices on the spectroscopic properties of ThO. We performed a comparative
analysis of several theoretical levels including a few basis sets and exchange-correlation
functionals, for the latter applying the new dispersion corrections of Grimme et al.1 on Rg2
dimers. The interaction with ThO was probed on the ThO⋅⋅⋅Rg model structure. The main
results include the determination of the first and second Rg solvation shells as well as their
effect on the geometry and vibrational frequencies of ThO. The computed matrix-shifts are
compared with experimental results.
1 S. Grimme, J. Antony, S. Ehrlich, H. Krieg, J. Chem. Phys. 2010, 132, 154104.
Vogt, Jürgen – Thursday, 16:30 h
31
Release of the MOGADOC Update with an Enhanced 3D-Viewer
Jürgen Vogt, Evgeny Popov, Rainer Rudert, and Natalja Vogt
Chemical Information Systems, University of Ulm, 89069 Ulm, Germany
On previous workshops of this conference series several improvements of the MOGADOC
database (Molecular Gas-Phase Documentation) were already reported. In the meantime the
database has grown up to 11,500 inorganic, organic, and organometallic compounds, which
were studied in the gas-phase mainly by electron diffraction, microwave spectroscopy and
radio astronomy. For 9,200 compounds the structural parameters such as internuclear
distances, bond and dihedral angles are given numerically, which have been excerpted from
the literature and critically evaluated, whereas spectroscopic parameters and electric,
magnetic and dynamic properties can only be retrieved by keyword search terms. The retrieval
features of the HTML-based database have been described elsewhere.1,2 The molecular
structures can be visualized in three dimensions by a specially developed Java-applet.3
The project has been supported by the Dr. Barbara Mez-Starck Foundation.
1 J. Vogt, N. Vogt, R. Kramer, J. Chem. Inf. Comput. Sci. 2003, 43, 357. 2 J. Vogt, N. Vogt, J. Mol. Struct. 2004, 695, 237. 3 N. Vogt, E. Popov, R. Rudert, R. Kramer, J. Vogt, J. Mol. Struct. 2010, 978, 201.
Poster session
32
Accurate determination of molecular structure of succinic anhydride by gas-phase electron diffraction method and quantum-chemical
calculations
Ekaterina P. Altova, a,b Natalja Vogt, a,b Denis N. Ksenafontov, a and Anatolii N. Rykov a
a Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia b Chemieinformationssysteme, University of Ulm, 89069 Ulm, Germany
For the first time, the equilibrium structure of succinic anhydride (dihydro-2,5-furandione)
was determined from the gas-phase electron diffraction (GED) data. According to
predictions by B3LYP/cc-pVTZ calculations, the molecule has a planar skeleton (C2v total
symmetry), whereas the MP2/cc-pVTZ optimized structure has a non-planar ring with the
torsional angle φ(C−C−C−C) of 11° (C2 symmetry), and finally, the molecular skeleton is
planar in the best estimated ab initio (CCSD(T)-based) structure. In the GED analysis, the
large-amplitude ring-twisting motion was described by a dynamic model with the
distribution of the pseudo-conformers according to the B3LYP/cc-pVTZ potential energy
function. The relaxation effects as well as harmonic and anharmonic vibrational corrections
to the internuclear distances were also calculated at the DFT level.
The determined structural parameters are the following: re(=C−C) = 1.514(1) Å, re(C−C) =
1.524(1) Å, re(C=O) = 1.188(1) Å, re(C−O) = 1.383(3) Å, ∠e(=C−C−C) = 104.4(1)°,
∠e(O=C−O) = 121.5(2)°.
This work was supported by the Dr. B. Mez-Starck Foundation (Germany).
Poster session
33
A new computational tool for the prediction of the mass spectra of peptides
Julie Cautereels and Frank Blockhuys
University of Antwerp, Department of Chemistry
Groenenborgerlaan 171, B-2020 Antwerp, Belgium
A new computational tool for the prediction of mass spectra based on quantum chemical
calculations called Quantum Chemical Mass Spectrometry for Materials Science (QCMS2)
was developed. The protocol was tested for the prediction of the electron ionisation (EI)
mass spectrum of 2-butoxyethanol and correctly predicted the main peaks in the mass
spectrum. Furthermore, new fragmentation routes and mechanisms were observed and
confirmed by MS/MS experiments.1
Because this method provides detailed insight into the fragmentation behaviour of organic
compounds, it can also be used for the prediction of the mass spectra of biomolecules
such as peptides, thereby offering a solution for the deficiencies of the existing methods
for the prediction of these spectra: they are, for the most part, based on empirical rules
and can, therefore, only provide a partial prediction of the mass spectra.
In this work we focus on the fragmentation pathways of tripeptides and the influence of the
side chains and the possibility of inter-side-chain hydrogen bonding on the fragmentation.
To do this the fragmentation of 132 non-cyclic tripeptides, consisting of His or Trp as the
central amino acid and Arg, Asn, Asp, Gln, Glu, His, Lys, Pro, Ser, Trp and/or Tyr as the
peripheral amino acids, will be studied. Each tripeptide passes through a five-step process
of conformational analysis, ionization, conformational analysis of the protonated tripeptide,
study of the fragmentation routes, and calculation of the peak intensities. The
fragmentation of the 11 non-cyclic Ser-His-X tripeptides (X is one of the peripheral amino
acids) will be presented in detail.
1 J. Cautereels, M. Claeys-Maenhaut, D. Geldof, F. Blockhuys, manuscript in preparation.
Poster session
34
Methylbenzenesulfonates: gas-phase electron diffraction vs. vibrational spectroscopy
Nina I. Girichevaa, Mikhail S. Fedorova and Georgiy V. Girichevb
aIvanovo State University, bIvanovo State University of Chemistry and Technology,
153000 Ivanovo
According to combined gas-phase electron diffraction and mass spectrometry (GED/MS)
complemented by quantum-chemical calculations (DFT/B3LYP/cc-pVTZ and MP2/cc-
pVTZ), two conformers of p-NO2-С6H4SO2OCH3 differing in the mutual position of C–S
and O–C bonds – (I) synclinal (sc, С1 symmetry) or (II) antiperiplanar (ap, Сs symmetry) –
exist in the vapor at Т = 376(5) К, mole fraction ratio I/II = 0.52/0.48. Selected structural
parameters of conformers (I/II) were obtained from experiment: rh1(C–H) =
1.062(6)/1.062(6), rh1(C–C)ср = 1.395(4)/1.395(4), rh1(C–S) =1.786(5)/1.779(5), rh1(S–O)ср
=1.435(3)/1.439(3), rh1(O–C) = 1.445(6)/1.450(6) Å, ∠C–CS–C = 121.8(6)/122.1(6)°, ∠S–
O–C = 119.2(21)/116.4(21)°, C–O–S–CS=74(8)/180°, O–S–CS–C=73(12)/90°. Calculated
barriers to the internal rotation of the SO2ОСН3, ОСН3, СН3 and NO2 groups exceed the
thermal energy value corresponding to the temperature of the GED experiment. It is noted
that the molecular
model with copla-
nar position of S–
O(CH3) bond relati-
ve to the benzene
ring, which was
used in [1] for interpretation of the IR and Raman
spectra is a saddle point (TS) on the potential energy
surface.
This work was supported by Ministry of Education and Science of Russian Federation (Project N
3474). 1 P. D. Suresh Babu, S. Periandy, S. Mohan, S. Ramalingam, B. G. Jayaprakash, Spectrochim.
Acta, Part A, 2011, 78, 168–178.
IR, Raman,
Cs
C1
Cs
GED/MS
Poster session
35
Electron diffraction and quantum chemical study of the α- and β-
naphthalenesulfonamides molecular structure
Nina I. Giricheva,# Vjacheslav M. Petrov,# Georgiy V. Girichev§*, Marvan Dakkouri$*,
Heinz Oberhammer,&* Valentina N. Petrova,§ Sergey A. Shlykov§, Sergey N. Ivanov#
#Ivanovo State University, Ivanovo 153025, Russia §Ivanovo State University of Chemistry and Technology, Ivanovo 153000, Russia
$Department of Electrochemistry, University of Ulm, Germany &Institut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076 Tübingen,
Germany
The saturated vapors of 1- and 2-naphthalene sulfonyl amides (1-NaphSA and 2-NaphSA)
were studied by gas-phase electron diffraction/mass-spectrometric method at 413(5) K
and 431(5) K. On the base of the experimental data, it was found that the gas-phases over
1-NaphSA and 2-NaphSA are represented by molecular species. According quantum
chemical calculations (DFT/B3LYP and MP2 with cc-pVDZ, aug-cc-pVDZ, cc-pVTZ basis
set) 1-NaphSA molecule has four conformers with different orientation of SO2NH2
fragment relative to the naphthalene frame and eclipsed or staggered orientation of the N–
H and S=O bonds; at the same time 2-NaphSA molecule has only two conformers. It was
experimentally established that vapors over 1-NaphSA and 2-NaphSA are, predominantly
(up to 70 mol.%), represented by a low-energy conformers of C1 symmetry in which the C-
S-N planes deviate from perpendicular orientation relative to the naphthalene skeleton
plane with near eclipsed orientation of the N–H and S=O bonds of SO2NH2 fragment. The
following geometrical parameters (Å and degrees) of dominant conformer were derived:
rh1(C–H) = 1.089(4), rh1(C–C)aver. = 1.411(3), rh1(C–S) = 1.761(10), rh1(S–O)aver. =
1.425(3), rh1(S–N) = 1.666(10), ∠C–CS–C = 119.8(2), ∠CS–S–N = 104.5(22); C9–C1–S–N
= 69.5(30) for 1-NaphSA, and rh1(C–H) = 1.083(5), rh1(C–C)aver. = 1.411(3), rh1(C–S) =
1.780(7), rh1(S–O)aver.= 1.427(4), rh1(S–N) = 1.668(6), ∠C–CS–C = 123.0(3), ∠CS–S–N =
103.6(19), C1–C2–S–N = 110(10) for 2-NaphSA. Interrelation between nonequivalence of the C–C bonds in the naphthalene frame and
spatial orientation of the substituents SO2NH2 is discussed. Transition states between
conformers and enantiomers were determined. Manifestation of conformational properties
of 1-NaphSA in crystal structures is considered.
Poster session
36
Molecular structures of neutral boranes and heteroboranes from scattering electrons and computational protocols
Drahomír Hnyk,a Jan Macháček,a David W.H. Rankin,b and Derek A. Wannc
aInstitute of Inorganic Chemistry of the ASCR, v.v.i., No. 1001, CZ-250 68 Husinec-Řež, Czech
Republic, bSchool of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, U.K., EH9
3JJ, cDepartment of Chemistry, University of York, Heslington, York, U.K. YO10 5DD.
The development of modern computational methods, linked to improved methods for
analysis of experimental gas-phase structural data, has allowed the stereochemistry of
many boranes and heteroboranes to be determined with great accuracy over the past two
decades. Many of these compounds have been prepared in the Institute of Inorganic
Chemistry of the Academy of Sciences of the Czech Republic, v.v.i. and gas-phase
electron diffraction (GED) data have been obtained mainly at the University of Edinburgh
and also at the University of Oslo. Structural tools based on the concerted use of GED
(using Edinburgh-based and Oslo based refinement programs) and computations of the
geometries and 11B chemical shifts (MOCED, SARACEN) have been employed.1 (11B
chemical shifts are often employed as an additional refinement condition.) Different closo-,
nido-, arachno-geometrical shapes, as well as those that do not obey Wade’s rules, are
reported. Computed molecular geometry of one example of the so-called macropolyhedral
clusters is shown.
1D. Hnyk, D. W. H. Rankin, Dalton Trans. 2009, 585.
Poster session
37
Structure of adrenaline in comparison to noradrenaline by the gas electron diffraction method
Ilya I. Marochkin,a Ekaterina P. Altova,a Natalja Vogt, a,b Anatolii N. Rykov, a
and Igor F. Shishkov a
a Chemistry Department, Moscow State University, 119991 Moscow, Russia b Chemical Information Systems, University of Ulm, 89069 Ulm, Germany
Among biogenic amines, we decided to focus on the group of catecholamines represented
by adrenaline and noradrenaline. Both compounds belong to the most important
neurotransmitters, and hormones. Their direct acting on α- and β-adrenergic receptors is
overlapping. The rh1-structures of two most favourable conformers of adrenaline and
noradrenaline, AG1a and GG1a, were determined by gas electron diffraction method
augmented by quantum chemical calculations at the B3LYP, MP2 and CCSD (for
noradrenaline) levels of theory. As expected, due to the similarity of these molecules most
of the structural parameters of adrenaline are close to those of noradrenaline. For both
molecules the hydrogen bond N···HO located in the ethanolamine fragment (OCCN) leads
to a significant constriction of the side chain and stabilizing the most abundant conformers.
The molecular structures of the AG1a conformers of adrenaline (left) and noradrenaline
(right) with presented hydrogen bonds and their lengths (in Å).
Poster session
38
Electron diffraction off state-selected and spatially aligned
gas-phase molecules
Nele L. M. Müller,1 Sebastian Trippel,1 and Jochen Küpper1,2,3
1 Center for Free-Electron Laser Science, DESY, Hamburg, Germany 2 The Hamburg Center for Ultrafast Imaging, Hamburg, Germany
3 Department of Physics, University of Hamburg, Germany
The aim of this work is to investigate the structure and intrinsic dynamics of molecules in
the gas-phase by electron diffraction. The contribution presents our newly set up electron
gun that is combined with an existing controlled-molecules apparatus.1 The gas-phase
molecules are prepared in cold, supersonic beams and can be size, isomer, and quantum
state selected by means of electric deflection.2 These samples are strongly aligned by
intense picosecond laser pulses.1 Controlling the molecules' state, structure and spatial
orientation increases the amount of information that can be gained from electron diffraction
patterns.2,3
The developed DC electron gun can produce millions of electrons per pulse and uses an
electro-static lens for focusing to ~100 μm (rms). Pulse durations are tens of picoseconds.
The focusing electrodes are arranged in a configuration similar to a velocity-map-imaging
spectrometer. Besides focusing, this can be used to measure the spatial and momentum
distribution of the electron pulse emitted from the cathode. Benchmark electron diffraction
data from solid-state and gaseous samples as well as electron trajectory simulations allow
for further characterization of the electron beam, for example, the determination of pulse
duration and transverse coherence length.
Here, we present the setup combining the electron gun and the controlled-molecules
apparatus. It allows for laser and electron interaction with the controlled molecules and the
generated ions as well as the scattered electrons can be imaged. Exploiting the controlled
molecules, the recorded data will be available directly in the molecular frame.
1 Trippel, Mullins, Müller, Kienitz, Długołȩcki, Küpper, Mol. Phys. 2013, 111, 1738.
2 Filsinger, Meijer, Stapelfeldt, Chapman, Küpper, PCCP 2011, 13, 2076.
3 Hensley, Yang, Centurion, PRL 2012, 109, 133202.
Poster session
39
Molecular structure and spin-states of acetylacetonato iron(III) by gas-phase electron diffraction and quantum chemical calculations
A.A. Petrova1, Nina I. Giricheva2, Natalya V. Tverdova1, Georgiy V. Girichev1
1Ivanovo State University of Chemistry and Technology, 2Ivanovo State University, 153000 Ivanovo
The molecular structure of tris-acetylaceto-
nato iron, Fe(O2C5H7)3 (Fig.), has been
studied by a synchronous gas-phase electron
diffraction (GED) and mass spectrometric
(MS) experiment and by calculations at the
theory level DFT/UB3LYP/cc-pVTZ. The
mass spectrum recorded at 116(10)°C simul-
taneously with diffraction patterns testifies to
that all ions originate exclusively from the
molecular species Fe(O2C5H7)3. Three elec-
tronic states differing by total
spin 5/2, 3/2 and 1/2 were
examined carrying out GED
structural analysis. It was found,
the electronic state with S = 5/2
corresponds to experimental
data, and the molecular struc-
ture belongs to the symmetry
type D3 (Fig.). Table shows the
selected structural parameters.
The study was supported by Ministry of Education and Science of Russia (Project
N4.1385.2014K).
Structural parameters (Å, °)
Calc., re Exp., rh1 S=5/2 S=3/2 S=1/2
D3 С2 С2 D3 r(Fe–O6) 2.022 1.932 1.928 2.017(4) r(Fe–O20) 2.082 1.914 r(O6–C8) 1.269 1.275 1.264 1.269(3) r(O20–C22) 1.260 1.273 r(C8–C10) 1.400 1.394 1.403 1.402(3) r(C22–C24) 1.408 1.394 r(C9–C16) 1.508 1.510 1.507 1.509(3)
∠(O6–Fe–O7) 85.8 88.3 92.9 88.4(3) ∠(O34–Fe–O35) 92.4 95.0
∠(Fe–O6–C8) 130.5 128.8 125.6 128.1(5) ∠(Fe–O34–C36) 126.5 124.6 ∠(O6–C8–C10) 124.7 125.9 125.2 126.0(4)
∠(O34–C36–38) 123.7 125.5 125.7 123.5(4) Rf, % - - - 5.45 E, kcal/mol 0 13.9 8.8 -
Poster session
40
Geometry and electronic structure of metal pivalate chelates M(piv)3 (M = Al, Ga, In, Tl): preliminary DFT calculations
Oleg A. Pimenova, Yuriy A. Zhabanova, Alexandr E. Pogonina, Sebastian Blomeyerb and
Boris V. Puchkova
aIvanovo State University of Chemistry and Technology, Ivanovo 153000, Russia bBielefeld University, Universitätsstraße 25, Bielefeld, Germany
The metal pivalate chelates (M(piv)3) are salts of pivalic acid (CH3)3CCOOH. The M(piv)3
possesses attractive properties for industrial application in the capacity of precursors to
oxide films preparation. Their thermal stability and high volatility is very proper for chemical
vapor deposition (CVD) technology. The first step of our work is a theoretical study of the
geometry and IR-spectra of M(piv)3 (M = Al, Ga, In, Tl) chelates by density functional
theory (DFT/B3LYP).
The equilibrium structures (Fig.) of M(piv)3
exhibits C3 symmetry with planar chelate rings
around metal atom. The coordination polyhedron
MO6 is close to a trigonal prism. The structural
flexibility within the coordination polyhedron MO6
was found to increase in the series
Al→Ga→In→Tl. NBO and QTAIM analyses point
to a predominantly ionic chemical bonding. The
correlations the ionic radii r(M3+) vs. equilibrium
M–O bond length additionally proves this ionicity. The nature of the central metal atom has
a weak influence on the geometry of the tert-butyl groups of pivalate ligands. It should be
noted that the same trend is observed for the M(thd)3 complexes. The assignments of
calculated band intensities in the IR spectra of M(piv)3 (M = Al, Ga, In, Tl) were also
carried out.
The authors thank the Russian Foundation for Basic Research, RFBR (Grant 14-03-31784 mol_a)
for financial support.
Poster session
41
The molecular structure of metal etioporphyrins-II: capability of a gas-phase electron diffraction
Alexander Pogonin, Natalya Tverdova and Georgiy Girichev
Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry of
Macroheterocyclic Compounds, Sheremetev av. 7, Ivanovo, 153000, Russian Federation
Gas-phase molecular structure of cobalt(II), nickel(II), copper(II), zinc(II) etioporphyrins-
II (MEP-II, M = Co, Ni, Cu, Zn) has been studied by a synchronous gas-phase electron
diffraction (GED) and mass spectrometry experiment and DFT calculations (B3LYP,
PBE). Quasiplanar MEP-II has 6 conformers (I-VI) and conformation (VII) differing in
orientation ethyl groups with respect with macroheterocycle.
- Methyl (-CH3) - Ethyl (-C2H5)
Conf. I Conf. II Conf. III Conf. IV Conf. V Conf. VI Conf. VII
Energetic differences of conformers I-V are less than 0.3 kJ/mol. Conformers VI and con-
formation VII have relatively high energies. All bonded internuclear distances in MEP-II
conformers I–V and other isomers MN4C32H36 (MEP-I, MEP-III, MEP-IV) are practically
the same. Comparison of the theoretical radial distribution function f(r) for MEP isomers
and MEP-II conformers was carried out for evaluation the ability of the GED method to
study large molecules. Structural analysis indicated that the GED method is robust for
determination of the macroheterocyclic fragment, but is not enough sensitive to
isomerism and conformational composition of MEP-II. Using spacing Δs ≤ 0.15 Å-1 of
complete scattering intensity curves is necessary for the investigation of large
molecules with internuclear distances r ≥ 12 Å.
Structural parameters of the MEP-II molecules yielded by the GED are generally in good
agreement with DFT calculations and X-ray data on crystalline related compounds.
The authors thank the Russian Foundation for Basic Research, RFBR (Grant 13-03-00975a) for financial
support.
Poster session
42
Molecular structure of palladium tetraphenylporphyrin (Pd-TPP) by gas-phase electron diffraction and quantum chemical calculations
Denis S. Savelyev, Natalya V. Tverdova, Georgiy V. Girichev
Ivanovo State University of Chemistry and Technology, 153000 Ivanovo
The molecular structure of palladium tetraphenylporphyrin, C44H28N4Pd (Fig.), has
been studied by a synchronous gas-phase electron diffraction (GED) and mass
spectrometric (MS) experiments and by calculations at different theory levels (DFT/B3LYP,
B97D with SDD, 6-31G*, cc-pVTZ, aug-cc-pVTZ-PP basis sets). A mass spectrum
recorded at 350(10)°C simultaneously with diffraction patterns testifies to that all ions
originate exclusively from the molecular species C44H28N4Pd.
Possible conformations with different
positions of phenyl rings relative to the
macrocycle were examined, and only three
conformers have been found to be stable
One of them possesses the symmetry D4,
two others – C2. Dihedral angle “phenyl -
macrocycle” lays in the diapason 60 – 83°,
and bond length Pd–N equals 2.030 –
2.045 Ǻ depending on theory method.
According to GED, D4 and one of C2
structures correspond to equal Rf = 4.85%,
r(Pd-N) = 2.040(5) Å, angle “phenyl - macrocycle” equals 83(7)°. It should be noted that
the perpendicular arrangement of the rings is energetically unfavorable for a molecule, and
it is associated with the destroying of conjugation of π-systems of the ligands and the
macrocycle. Planar position of phenyl fragments corresponds to the maximal value of the
relative energy (by about 200 kcal/mol).
The study was supported by Russian Foundation for Basic Research: grant 13-03-00975a.
Poster session
43
Structural Effects in and on the Isocyanate group (NCO)
Jan Schwabedissen, Beate Neumann, Hans-Georg Stammler und Norbert W. Mitzel
Universität Bielefeld, Fakultät für Chemie, Lehrstuhl für Anorganische Chemie und Strukturchemie,
Universitätsstraße 25, 33615 Bielefeld; [email protected]
In the past years the structures of many carbonyl as well as phosphorus bound
isocyanates (NCO) were investigated by experimental methods in the solid state by X-ray
diffraction.1 In the gas-phase both, microwave spectroscopy2 and gas-phase electron
diffraction,3 were applied to determine the structure. Furthermore, theoretical investigations
at the Hartree-Fock level on isocyanates revealed their limits in determining the lowest
energy conformer due to the correlation of electrons that occur in these systems.4
In this presentation, the structures in the gasphase along with the solid-state structures of
three molecules containing the isocyanate group, namely dichlorophosphorylisocyanate
(1), dichlorophosphanylisocyanate (2) and carbonyldiisocyanate (3), are discussed. The
conformational properties of all three molecules in the gas-phase were examined by
means of quantum chemical calculations.
ClP
O
ClN
CO
ClP
ClN
CO O
CN N
CO
CO
1 2 3
1 X. Zeng, M. Gerken, H. Beckers, H. Willner, Inorg. Chem. 2010, 49, 3002–3010. 2 R. J. Mahon et al., J. Mol. Struct. 2014, 295, 15–20. 3 D. W. H. Rankin, S. J. Cyvin, J. Chem. Soc., Dalton Trans. 1972, 1277.
4 H. Oberhammer, H.-G. Mack, J. Mol. Struct. (Theochem) 1989, 200, 277.
Poster session
44
Electron-Nucleus Overlap & Quadrupole Moment Ratios in RbF, RbCl, RbBr, and RbI
David Sharfi,1 Alexander Hof,1 Carson Witte,1 Andreas Biekert,1 Richard Mawhorter,1
Zachary Glassman,2 and Jens-Uwe Grabow3
1 Physics Dept., Pomona College, Claremont, CA 91711 USA 2 Physics Dept., University of Maryland, College Park, MD USA
3 Institut für Physikalische Chemie, Leibniz-Universität, D 30167 Hannover
Electron penetration into the nucleus is a
phenomenon rich with applications in molecular
physics. Even without considering the effects of
parity non-conservation, the overlap of s and p½
electrons with the positive charge distribution of
non-spherical nuclei leads to observable shifts in
the energy levels determined by the eQq nuclear
electric hyperfine interaction of the quadrupole
moment of the nucleus and the gradient of the
molecular electric field at the nucleus. These shifts
can be precisely measured using FTMW
spectroscopy in combination with RF molecular
beam studies and other methods.
Given the relatively large abundance of both stable
Rb isotopes and the varying electric field gradients
afforded by using different halogens, diatomic molecules such as RbF, RbCl, RbBr, and
RbI offer ideal environments in which to study these effects. Our work seeks to
characterize the hyperfine structure of these molecules in order to more accurately
determine the ratios of their nuclear quadrupole moments, as well as gain insight into the
more exotic effects arising from the phenomenon of electron penetration. The figure shows
some toy models developed by Rose & Cottenier (Phys. Chem. Chem. Phys. 2012, 14) to
provide physical intuition into related multipole shift phenomena.
Poster session
45
Molecular Structure and Conformational Analysis of 3-Methyl-3-Silathiane
by Gas Electron Diffraction and Quantum Chemical Calculations
Sergey A. Shlykov, Dmitriy Yu. Osadchiy
Ivanovo State University of Chemistry and Technology, Dep. of Physical Chemistry, Research
Institute for Thermodynamics and Kinetics of Chemical Processes, Sheremetev ave., 7, 153000,
Ivanovo, Russian Federation
Molecular structure and conformational behavior of 3-methyl-3-silathiane, 1, was
studied by gas-phase electron diffraction and theoretical calculations (DFT, MP2). Two
conformers, 1-ax and 1-eq, were considered.
S SiS
Si
Me
MeH
H1-ax 1-eq
Relative energies and Gibbs free energies of 1 from quantum chemical calculations,
as well as theoretical and experimental conformer ratios are given in the Table. The
calculations predict the prevalence of the conformers which is noticeably dependent on the
method/basis set combination applied (see Table). From the GED measurements, the
axial conformer is slightly more favorable in gas phase at 270 K, 1-eq:1-ax = 41(9):59(9).
Method/Basis set Calculations GED
∆E ∆G°(298) x1-eq : x1-ax
∆G°(270) 1-eq 1-ax 1-eq 1-ax 1-eq 1-ax
B3LYP/cc-pVTZ 0 0.05 0 0.17 57:43
41(9): 59(9)
0.17 (17)
MP2/6-311G** 0.16 0 0.11 0 44:56 MP4/6-311G**//MP2/6-311G** 0 0.23 – – –
0
MP2/cc-pVTZ 0.38 0 0.31 0 38:62 MP4/cc-pVTZ//MP2/cc-pVTZ 0 0.13 – – – CCSD(T)/6-311G**//MP2/6-311G** 0 0.13 – – –
Financial support by the Russian Foundation for Basic Research (RFBR, grant №14-03-00923- a)
is greatly acknowledged.
Poster session
46
Corrected calculation of vibrational parameters in gas electron diffraction on the basis of molecular dynamics simulations
Denis Tikhonova,b and Yury V. Vishnevskiya
a Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
b M.V. Lomonosov Moscow State University, Department of Physical Chemistry, GSP-1, 1-
3 Leninskiye Gory, 119991 Moscow, Russian Federation
In gas electron diffraction interatomic vibrational amplitudes and corrections are usually
calculated from quantum-chemical force fields. To obtain a semi-experimental equilibrium
molecular structure on this basis a cubic force field is required.1,2 However, calculations of
cubic force fields for large molecular systems are computationally very expensive and can
be too long. Another way for computation of required in GED parameters from molecular
dynamics (MD) trajectories has been previously proposed.3,4 Unfortunately, classical MD
simulations lack for quantum effects3,4 and can be affected by the “flying ice cube effect”.5
We have developed a computationally effective model for approximation of these effects
and correction of parameters obtained from MD simulations. A new program Qassandra
has been written to implement a corresponding computational procedure. A series of
calculations have been carried out to show the applicability of our model on test objects of
different sizes. Results have been compared with those obtained by the conventional
methods.1,2
1 V. Sipachev, Struct. Chem. 2000, 11, 167. 2 I. Kochikov, Yu. Tarasov, G. Kuramshina, V. Spiridonov, A. Yagola, T. Strand, J. Mol. Struct.
1998, 445, 243. 3 D. Wann, R. Less, F. Rataboul, Ph. McCaffrey, A. Reilly, H. Robertson, P. Lickiss, D. W. H.
Rankin, Organometallics 2008, 27, 4183. 4 D. Wann, A. Zakharov, A. Reilly, P. McCaffrey, D. W. H. Rankin, J. Phys. Chem. A 2009, 113,
9511. 5 S. Harvey, R. Tan, Th. Cheatham III, J. Comput. Chem. 1998, 19, 726.
Poster session
47
Benchmark study of molecular structures by different experimental methods and coupled cluster computations
Natalja Vogt a,b
a Chemical Information Systems, University of Ulm, 89069 Ulm, Germany
b Chemistry Department, Lomonosov Moscow State University, 119992 Moscow, Russia
Semi-experimental equilibrium structures (r see ) of thymine (5-methyluracil)1 and some other
derivatives of uracil2,3 have been determined from the microwave (MW) rotational
constants or electron diffraction (ED) data taken into account rovibrational corrections
calculated from ab initio anharmonic force constants. The best estimated ab initio
structures of these molecules have been derived from the results of the CCSD(T)/cc-
pwCVTZ(ae) optimizations with extrapolation to the higher (quadruple-ζ) basis set at the
MP2 level. A remarkable agreement between the computed and semi-experimental
equilibrium structures points to a high accuracy of both experiment and applied theory.
Fig. 1. The bond length deviations relative to the r see (MW) values (in Å).
This work has been supported by the Dr. B. Mez-Starck Foundation.
1 N. Vogt, J. Demaison, D. N. Ksenafontov, H. D. Rudolph, J. Mol. Struct., 2014, 1076, 483. 2 N. Vogt, D. N. Ksenafontov, R. Rudert, A. N. Rykov, et al., manuscript in preparation. 3 N. Vogt, I. I. Marochkin, A. N. Rykov, J. Phys. Chem. A, 2015, 119, 152.
Poster session
48
The geometry and electronic structure of a thallium(I) pivalate determined by gas-phase electron diffraction and DFT calculations
Yuriy A. Zhabanova, Oleg A. Pimenova, Sebastian Blomeyerb and Georgiy V. Giricheva
aIvanovo State University of Chemistry and Technology, Ivanovo 153000, Russia bBielefeld University, Universitätsstraße 25, Bielefeld, Germany
In this study we have investigated the structure of thallium(I) pivalate (Tl(piv)) by a
synchronous gas electron diffraction and mass spectrometric experiment (GED/MS) and
DFT calculations using the B3LYP hybrid functional. All-electron cc-pVTZ basis sets were
applied for atoms C, O, H; the core electron shells of atom Tl were described by the
relativistic effective core potential in combination with aug-cc-pVTZ basis set.
The GED/MS experiments were carried
out on the modified EMR-100 apparatus
combined with the monopole mass
spectrometric unit APDM-1. This allows
real-time monitoring of the vapor
composition by recording the mass spectra simultaneously with recording the diffraction
patterns. The synthesis of thallium(I) pivalate was carried out in situ using the method
developed by authors in work1. This procedure based on heterogeneous reaction of silver
pivalate Ag(piv) and metal Tl. According to calculations the equilibrium structure (Fig.) of
Tl(piv) exhibits Cs symmetry. The theoretical barrier of internal rotation for tert-butyl group
is 0.08 kcal/mol. The thermal energy for the temperature of mass-spectrometric
experiment1 (T = 380 K) RT = 0.76 kcal/mol, and tert-butyl group rotation is practically free
at this conditions. NBO and QTAIM analyses point to a predominantly ionic chemical Tl–O
bonding.
The authors thank the Russian Foundation for Basic Research, RFBR (Grant 14-03-31784 mol_a),
for financial support.
1 N. N. Kamkin, L. G. Kuz’mina, D. B. Kayumova, N. G. Yaryshev, I. A. Dementiev, A. S.
Alikhanyan, Zh. Phys. Meth. Investig. 2012, 57, 1267.
Poster session
49
New software for the implementation of the curvilinear approach
Yuriy A. Zhabanov
Ivanovo State University of Chemistry and Technology, Research Institute of Chemistry of
Macroheterocyclic Compounds, Sheremetev av. 7, Ivanovo 153000, Russia
The values of vibration amplitudes of atom pairs and vibration corrections are needed to
obtain the molecular structures from the results of gas electron diffraction experiments.
The algorithm called “curvilinear approach” was realized by Sipachev in the SHRINK
program.1,2,3 Due to the implementation in Fortran language the program SHRINK has
limitations in the number of internal coordinates, the number of calculated vibrational
amplitude and shrinkage corrections for atom pairs and number of atoms.
We realized the new program using the same algorithm as realized in the SHRINK program.
The new program VIBMODULE was implemented in C language using the UML library of the
UNEX2 project4. The VIBMODULE program has a number of advantages, such as the
unlimited number of atoms in the molecules under study, the versions for different
operating systems and higher speed. The VIBMODULE program features generating internal
coordinates allows using the output files of quantum-chemical packages, such as
Gaussian and Firefly, as input files. The VIBMODULE program can use the Shrink input
files. The VIBMODULE program has the ability to print the results in a UNEX and KCED
formats.
Dr. Yu. A. Zhabanov thanks The Ministry of Education and Science of The Russian Federation
(Project 11.9166.2014) and German academic exchange service DAAD-Germany (Project
A/13/75239) for financial support.
V. A. Sipachev, J. Mol. Struct. THEOCHEM. 1985, 121, 143
V. A. Sipachev, Struct. Chem. 2000, 11, 167.
V. A. Sipachev, J. Mol. Struct. 2001, 567–568, 67.
Yu. V. Vishnevskiy, UNEX version 2, 2015 www http://unexprog.org/