flexible dicarboxylate based pillar-layer metal organic frameworks: differences in structure and...
TRANSCRIPT
CrystEngComm
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
PAPER View Article OnlineView Journal | View Issue
CrystEngCommThis journal is © The Royal Society of Chemistry 2014
aDepartment of Chemistry, Jadavpur University, Jadavpur, Kolkata, 700 032, Indiab Physical/Materials Chemistry Division, CSIR–National Chemical Laboratory,
Dr. Homi Bhabha Road, Pune – 411008, India. E-mail: [email protected],
† Electronic supplementary information (ESI) available: Selected bond lengthand bond angle tables, packing diagram for 1, TGA diagrams and PXRDpatterns of all compounds. CCDC 965111–965116. For ESI and crystallographicdata in CIF or other electronic format see DOI: 10.1039/c3ce42028k
Cite this: CrystEngComm, 2014, 16,
2305
Received 7th October 2013,Accepted 9th December 2013
DOI: 10.1039/c3ce42028k
www.rsc.org/crystengcomm
Flexible dicarboxylate based pillar-layer metalorganic frameworks: differences in structure andporosity by tuning the pyridyl based N,N′ linkers†
Rajdip Dey,a Biswajit Bhattacharya,a Pradip Pachfule,b Rahul Banerjee*b
and Debajyoti Ghoshal*a
Dicarboxylate supported metal organic hybrids of Co(II), Zn(II) and Cd(II) have been synthesized using two
different pyridyl based N,N′ linkers having Schiff base functionalized site. The use of flexible dicarboxylate
glutarate in designing such frameworks has created a marked diversity in topology. The different N,N′
donor linkers also played an active part in the channel modification in the synthesized MOFs. The
structural and topological diversity has been analyzed from the single crystal X-ray structure. Five compounds,
{[Co(azpy)(glut)]·(CH3OH)}n (1), {[Co(meazpy)(glut)(H2O)2]·(H2O)3}n (2), {[Zn(azpy)0.5(glut)(H2O)]·(azpy)0.5}n (3),
{[Zn(meazpy)0.5(glut)(H2O)]·(H2O)2}n (4) and {[Cd(azpy)(glut)]·(CH3OH)}n (5), show porous structures with
solvent accessible voids. The nature of the pores as well as the existence of lattice solvent molecules in 1 and
2 are different due to the use of a different pillar ligand in their fabrication. In case of 3 and 4 there are some
nice effects of non-covalent interaction in the construction of their solid state structure, which has also
originated by the change of pillar N,N′ donor linkers. Complex 5 is topologically as well as structurally similar
to 1 forming a 2D-grid like structure. In {[Cd2(meazpy)2(glut)(NO3)]2}n (6) there is a formation of 2D sheets
with the coordinated counter anion. Interestingly, here the sheets are disposed in a perpendicular fashion to
each other and do not contain any solvent accessible void. Upon removal of the solvent molecules, the
frameworks 1–5 show moderate CO2 and H2 uptake at 273 K and 77 K, respectively. The desolvated
frameworks show different quantities of CO2 and H2 uptake which has been corroborated to their structures.
Introduction
Coordination polymer based multifunctional materials,1 builtfrom metal ions and multitopic organic linkers, have beencomprehensively studied in the last two decades for their richstructural diversities, fascinating topology and of course awide range of applications in separation,2 gas storage,3 selectivegas adsorption,4 conductivity,5 drug delivery,6 magnetism,7
heterogeneous catalysis,8 ion exchange9 and sensor devices10
etc. The adsorption properties of MOF appears most interestingamong the above properties as this can be tuned either by themodification of building block linkers11 or by adopting newsynthetic strategies.12 In this context, different polycarboxylicacids have played a marvellous role, as the carboxylic groups
of such acids can partially or completely get deprotonateddepending upon the reaction conditions, resulting differentcoordination modes (monodentate, chelating, and/or bridging).13
As a result when such dicarboxylates are used as buildingblocks, one is able to create an enormous diversity in the struc-ture without a structural modification of the same dicarboxylatebuilding block.14 So far, the majority of the landmark frame-works reported in the literature are prepared using rigid aro-matic dicarboxylates,15 but the role of flexible dicarboxylatesin designing such functional framework has yet to be standard-ized. The diversity in topology becomes more pronounced inthe case of aliphatic dicarboxylates because flexible ligands canadopt different conformations according to the geometricneeds of the different metal ions in comparison to thearomatic dicarboxylates. In order to explore the structuralaspects and porous property of the frameworks containingflexible dicarboxylate building blocks, we have concentratedhere on glutarate due to its moderately long spacer length andflexibility in binding mode.16 In addition to that, the coligandpyridyl based N,N′ donor linkers17 used here for the fabricationof the desired pore wall have a comparable length to that ofglutarate. There is a considerable number of porous coordination
, 2014, 16, 2305–2316 | 2305
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
polymers which have been synthesized using a neutral pyridylN,N′ donor spacer,17 in combination with dicarboxylate usingthe pillar-layer technique.18 The pyridyl based spacer can act asa pillar to link the metal-carboxylate layer to produce higherdimensional crystalline novel topological frameworks containingthe channels or cavities.19 Thus, the effective design on the N,N′donor linker can enable one to decorate the channels20 in MOFsto stabilize the structure and conveniently arrange the surfacefeatures of the compound.
Here we represent the synthesis of six new mixed ligandcoordination polymers of glutarate using three divalent metalions [Co(II), Zn(II), and Cd(II)] and two different N,N′ donorlinkers; N,N′-bis-pyridin-4-ylmethylene-hydrazine (azpy) andN,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine (meazpy). The singlecrystal X-ray structure of all six coordination polymers namely,{[Co(azpy)(glut)]·(CH3OH)}n (1), {[Co(meazpy)(glut)(H2O)2]·(H2O)3}n(2), {[Zn(azpy)0.5(glut)(H2O)]·(azpy)0.5}n (3),{[Zn(meazpy)0.5(glut)(H2O)]·(H2O)2}n (4), {[Cd(azpy)(glut)]·(CH3OH)}n(5), and {[Cd2(meazpy)2(glut)(NO3)]2}n (6) (where, glut = glutarate),indicates their extended structures (Scheme 1) with a distinc-tive topological diversity.
In each case, the metal coordination geometry, flexiblecarboxylate binding mode, conformation of glutarate alongwith the ratio of N,N′ linkers synergistically played an importantrole in forming their solid-state architecture. All the frameworksexcept 6, contain some void space after the removal of latticevolatiles (guest solvent molecules) and the gas adsorptionstudy of the activated frameworks indicates certain selectivegas adsorption property. The desolvated frameworks show aconsiderable uptake of H2 and CO2 depending on their struc-ture although most of them show a negligible uptake towardsN2 adsorption.
2306 | CrystEngComm, 2014, 16, 2305–2316
Scheme 1 Simplified schematic representation of the six newly synthesizthree divalent metal ions [Co(II), Zn(II) and Cd(II)].
Experimental sectionMaterials
N,N′-Bis-pyridin-4-ylmethylene-hydrazine (azpy) and N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine (meazpy) were synthesizedby the procedures reported earlier.21 The starting material forthese syntheses viz. 4-pyridinecarboxaldehyde, 4-acetyl pyridineand hydrazine hydrate were purchased from Aldrich ChemicalCo. Inc. and used as received. High purity cobalt(II) nitratehexahydrate, zinc(II) nitrate hexahydrate and cadmium(II)nitrate tetrahydrate were also purchased from Aldrich ChemicalCo. Inc. and used as received. All other chemicals were of ARgrade and were used as received.
Physical measurements
Elemental analyses (carbon, hydrogen, and nitrogen) wereperformed using a Heraeus CHNS analyzer. Infrared spectra(4000–400 cm−1) were taken on KBr pellets, using a Perkin-ElmerSpectrum BX-II IR spectrometer. Thermal analysis (TGA) wascarried out on a METTLER TOLEDO TGA 850 thermal analyzerunder nitrogen atmosphere (flow rate: 50 cm3 min−1), at thetemperature range 30–500 °C with a heating rate of 2 °C min−1.X-ray powder diffraction (PXRD) patterns in different states ofthe sample were recorded on a high temperature non-ambientsample holder attachment of a Bruker D8 Discover instrumentusing Cu-Kα radiation.
Crystallographic data collection and refinement
The single crystals of compounds 1–6 were mounted on thetips of glass fibers coated with Fomblin oil. X-ray single crystaldata collection of all six crystals was performed at room
This journal is © The Royal Society of Chemistry 2014
ed metal organic hybrids with two different N,N′ linkers, glutarate and
CrystEngComm Paper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
temperature using a Bruker APEX II diffractometer, equippedwith a normal focus, sealed tube X-ray source with graphitemonochromated Mo-Kα radiation (λ = 0.71073 Å). The datawere integrated using SAINT22 program and the absorptioncorrections were made with SADABS. All the structures weresolved by SHELXS 9723 using Patterson method and followedby successive Fourier and difference Fourier synthesis. Fullmatrix least-squares refinements were performed on F2 usingSHELXL-9724 with anisotropic displacement parameters for allnon-hydrogen atoms. All the hydrogen atoms were fixedgeometrically by HFIX command and placed in ideal positionsin case of all six structures. All calculations were carried outusing SHELXS 97,23 SHELXL 97,24 PLATON v1.15,25 ORTEP-3v2,26
and WinGX system Ver-1.80.27 The coordinates, anisotropicdisplacement parameters, and torsion angles for all sixcompounds are submitted as ESI† in CIF format. Data collectionand structure refinement parameters and crystallographicdata for all compounds are given in Table 1. The selectedbond length and bond angles are given in Tables S1–S8.†
Measurement of gas adsorption
Low pressure volumetric gas adsorption measurementsinvolved in this work were performed at 77 K for N2 and H2,maintained by a liquid nitrogen bath, with pressures rangingfrom 0 to 1 bar on a Quantachrome Quadrasorb automaticvolumetric instrument. CO2 adsorption measurements weredone at 273 K on the same instrument and at same pressurerange. In all the adsorption measurements, the ultra high-pureN2, H2 or CO2 were obtained by passing them through calciumaluminosilicate adsorbents to remove trace amounts of water
This journal is © The Royal Society of Chemistry 2014
Table 1 Crystallographic and structural refinement parameters for comple
1 2 3
Formula C36H40N8O10Co2 C19H30N4O9Co C17H18
F.W 862.62 517.40 423.74Cryst system Triclinic Monoclinic TriclinSpace group P1̄ P21/c P1̄a/Å 9.8733(3) 14.9099(5) 7.9410b/Å 13.7275(5) 21.0323(7) 10.715c/Å 16.1107(5) 8.5659(3) 12.071α/° 102.603(1) 90 93.337β/° 105.275(1) 94.401(2) 93.883γ/° 106.803(2) 90 111.13V/Å3 1911.32(11) 2678.26(16) 952.17Z 2 4 2Dc/g (cm)−3 1.499 1.283 1.478μ/mm−1 0.936 0.690 1.325F(000) 892 1084 436θ range/° 1.4–27.5 1.7–27.5 1.7–27Refl collected 30 571 43 051 15 567Unique refls 8641 6154 4359Rint 0.040 0.098 0.038No. of refls I > 2σ(I) 5575 3901 3394Goodness-of-fit 1.01 1.06 1.04R1
a (I > 2σ(I)) 0.0446 0.0715 0.0490wR2
a (I > 2σ(I)) 0.1049 0.2437 0.1483Δ.ρ max/min/e Å3 −0.39, 0.33 −0.54, 0.94 −0.38,a R1 =
P||Fo| − |Fc||/
P|Fo|, wR2 = [
P(w(Fo
2 − Fc2)2)/
Pw(Fo
2)2]1/2.
and other impurities before introduction into the system. Themicro crystalline powder of each compound 1–5 were soakedin 1 : 1 dry dichloromethane and methanol mixture for 12 h.After that a fresh 1 : 1 dry dichloromethane and methanolmixture was subsequently added and the compounds wereallowed to stay for an additional 48 h to remove free solvates(methanol and H2O) present in the frameworks. Then, thesample was dried under a dynamic vacuum (<10−3 Torr) atroom temperature overnight. The remaining solvent, still presentin the framework was removed by heating subsequently at60 °C for 12 h and 130 °C for 12 h under dynamic vacuum.Upon heating after removal of the solvent molecules, complexes1–5 except 2, retain their same nature and framework architec-ture which is supported by the PXRD measurement of thecompounds in their as synthesized as well as desolvated form(Fig. S2–S6†).
Syntheses
{[Co(azpy)(glut)]·(CH3OH)}n (1). An aqueous solution (4 mL)of disodium glutarate (Na2glut) (1 mmol, 0.162 g) was mixedwith a methanolic solution (4 mL) of N,N′-bis-pyridin-4-ylmethylene-hydrazine (azpy) (1 mmol, 0.210 g) and stirred for15 min to mix it well. Co(NO3)2·6H2O (1 mmol, 0.291 g) wasdissolved in 4 mL water and the solution was slowly layered tothe above mixed ligand solution using 5 mL buffer (1 : 1 ofwater and MeOH). The red block single crystals suitable forX-ray diffraction analysis were obtained at the wall of the tubeafter three weeks. The crystals were separated and washedwith a methanol water (1 : 1) mixture and dried under air.(Yield 76%). Anal. calc. for C36H40N8O10Co2: C, 50.13; H, 4.67;
CrystEngComm, 2014, 16, 2305–2316 | 2307
xes 1–6
4 5 6
N4O5Zn C12H19N2O7Zn C18H20N4O5Cd C33H34N10O10Cd2368.68 484.79 955.52
ic Triclinic Triclinic TetragonalP1̄ P1̄ I4̄
(3) 5.2008(3) 8.6482(2) 15.8904(3)7(4) 9.1754(4) 10.2848(2) 15.8904(3)9(4) 16.7077(8) 12.7911(3) 29.0281(10)(2) 96.307(3) 93.530(1) 90.00(2) 97.880(3) 108.249(1) 90.004(2) 101.052(3) 111.453(1) 90.00(6) 767.47(7) 985.47(4) 7329.7(4)
2 2 81.595 1.634 1.7321.636 1.145 1.231382 488 3824
.6 2.3–27.5 1.7–27.5 1.5–27.611 869 16 352 59 3563437 4511 42250.047 0.028 0.0482601 4048 38740.98 1.05 1.050.0451 0.0292 0.02380.1100 0.0721 0.0531
1.16 −0.52, 0.71 −0.75, 0.75 −0.32, 0.43
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
N, 12.99. Found: C, 50.14; H, 4.42; N, 12.56. IR spectra (in cm−1):ν(CN), 1610; ν(C–O), 1310–1230; ν(CH–Ar), 3100–2900 andν(CC), 1600–1420.
{[Co(meazpy)(glut)(H2O)2]·(H2O)3}n (2). This has beensynthesized using the ame procedure as that of 1 using N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine (meazpy) (1 mmol,0.238 g) instead of azpy. The red block single crystals wereobtained after two weeks. The crystals were separated andwashed with a methanol water (1 : 1) mixture and dried underair. (Yield 67%). Anal. calc for C19H30N4O9Co: C, 44.11; H,5.84; N, 10.83. Found: C, 44.04; H, 5.73; N, 10.69. IR spectra(in cm−1): ν(CN), 1610; ν(C–O), 1310–1200; ν(CH–Ar), 3100–2900and ν(CC), 1590–1420.
{[Zn(azpy)0.5(glut)(H2O)]·(azpy)0.5}n (3). This has beensynthesized using the same procedure as that of 1 usingZn(NO3)2·6H2O (1 mmol, 0.297 g) instead of Co(NO3)2·6H2O.The yellowish block crystals were obtained after three weeks.The crystals were separated and washed with a methanolwater (1 : 1) mixture and dried under air. (Yield 72%). Anal.calc. for C17H18N4O5Zn: C, 48.19; H, 4.28; N, 13.22. Found: C,47.82; H, 4.15; N, 13.03. IR spectra (in cm−1): ν(CN), 1616;ν(C–O), 1310–1240; ν(CH–Ar), 3100–2900 and ν(CC), 1600–1410.
{[Zn(meazpy)0.5(glut)(H2O)]·(H2O)2}n (4). This has beensynthesized using the same procedure as of 3 using meazpy(1 mmol, 0.238 g) instead of azpy. The yellowish blocksingle crystals were obtained after three weeks. The crystalswere separated and washed with a methanol water (1 : 1)mixture and dried under air. (Yield 77%). Anal. calc. forC12H19N2O7Zn: C, 39.09; H, 5.19; N, 7.60. Found: C, 38.74; H,5.12; N, 7.46. IR spectra (in cm−1): ν(CN), 1615; ν(C–O),1300–1220; ν(CH–Ar), 3100–2900 and ν(CC), 1600–1380.
{[Cd(azpy)(glut)]·(CH3OH)}n (5). This has been synthesizedusing the same procedure as that of 1 using Cd(NO3)2·4H2O(1 mmol, 0.308 g) instead of Co(NO3)2·6H2O. The yellowishblock crystals were obtained after two weeks. The crystalswere separated and washed with a methanol water (1 : 1)mixture and dried under air. (Yield 69%). Anal. calc. forC18H20N4O5Cd: C, 44.59; H, 4.16; N, 11.56. Found: C, 44.23;H, 4.07; N, 11.44. IR spectra (in cm−1): ν(CN), 1609; ν(C–O),1320–1210; ν(CH–Ar), 3100–2900 and ν(CC), 1600–1410.
{[Cd2(meazpy)2(glut)(NO3)]2}n (6). This has been synthesizedusing the same procedure as that of 5 using meazpy (1 mmol,0.238 g) instead of azpy. The yellow crystals were obtained afterten days. The crystals were separated and washed with amethanol water (1 : 1) mixture and dried under air. (Yield72%). Anal. calc. for C33H34N10O10Cd2: C, 41.48; H, 3.59; N,14.65. Found: C, 41.26; H, 3.42; N, 14.47. IR spectra (in cm−1):ν(CN), 1615; ν(C–O), 1300–1220; ν(CH–Ar), 3100–2900 andν(CC), 1600–1400.
Results and discussionStructural descriptions of {[Co(azpy)(glut)]·(CH3OH)}n (1) and{[Co(meazpy)(glut)(H2O)2]·(H2O)3}n (2)
Complexes 1 and 2 crystallize in triclinic P1̄ and monoclinicP21/c space group, respectively. In both the cases each
2308 | CrystEngComm, 2014, 16, 2305–2316
hexacoordinated Co(II) center has the same coordinationenvironment of CoN2O4, which shows a distorted octahedralgeometry. In the case of 1, the structure determinationreveals the formation of a 2D sheet with two differenthexacoordinated Co(II) center (Co1 and Co2 respectively),linked with the dicarboxylate (glut) and a linear Schiff baselinker, azpy; while in compound 2, another linear Schiff baseligand meazpy has been used which also constructs the 2Dsheets (Fig. 2).
Atom labeling diagram of 1 (Fig. 1a) indicates that apartfrom two different Co(II), the asymmetric unit comprises oftwo different glutarate, where one has bridged in a chelatingfashion and the other is in a monodentate–bidentate coordi-nation fashion. These two crystallographically independentCo(II) centers are propagated along the b-direction with thebridging glut to form a 1D ladder like structures (Fig. 1b).This 1D ladder is pillared with the azpy ligands perpendicularlyforming a 2D-grid like structure in the crystallographic ab plane(Fig. 1c). The slipped packing diagram for the 2D sheets is alsodepicting the disposition of the sheets (Fig. S1†). These 2Dsheets are arranged in the c direction and further connectedthrough π–π interaction (centroid–centroid distances are in therange of 3.8426–3.8761 Å) forming a supramolecular 3D net-work. There are lattice methanol molecules in between theadjacent sheets which possess H-bonding interaction operatingbetween the alcoholic –OH group and the O atom (O7) of thebridging glut (Table S2†). Upon removal of the lattice solventmolecules, the framework structure shows void ~6.6% to thetotal crystal volume as suggested by the PLATON25 crystallo-graphic software. The glutarate di-anions can be assigned tothree-connected nodes, while Co(II) ions can be considered asfive-connected nodes, and the azpy ligands can be regarded as atwo-connected node. Thus, the structure of 1 can be simplifiedby TOPOS28 software, as a trinodal (2,3,5)-connected topologywith the Schläfli symbol of {42·6·86·12}{42·6}{8} (Fig. 1c).
In 2, in each asymmetric unit, the Co(II) center is linkedby bridging monodentate glutarate, one N,N′ linear Schiffbase ligand meazpy and two coordinated water molecules.The glut and meazpy ligands connect to the Co(II) centersconstructing a (4,4) net in the ac plane (Fig. 2b). When thedisposed 2D sheets are viewed along the c axis, thisuncoordinated carboxylate end of glut and the coordinatedwater molecules are organized in such a fashion, so that theycan form stable H-bonding (Table S2†). This H-bondingresults in the formation of a supramolecular 3D structurewith a pore containing lattice water molecules (Fig. 2c). Thewater molecules present in the lattice are also H-bonded toeach other as well as with the O atom of glut (Table S2†). It isworth to mention that the pores created here are by H-bondinginteraction and this type of pores are generally referred to assupramolecular pores.29 Upon removal of the lattice solventmolecules the framework suggests ~13.9% void space to thetotal crystal volume as suggested by the PLATON25 crystallo-graphic software. Topologically, the Co(II) ions can be definedas 4-connected nodes, glutarate dianions and meazpy ligandsboth can be considered as 2-connected nodes, thus, the
This journal is © The Royal Society of Chemistry 2014
Fig. 1 (a) View of coordination environment of both pentacoordinated and hexacoordinated Co(II) with atom labeling scheme of 1; (b) 1Darrangement in 1 constructed by metal-glutarate moiety (azpy has been omitted for clarity); (c) 2D-grid structure with trinodal (2,3,5)-connectedtopology in 1; (colour code of node: N,N donor ligand: blue, Co(II): green, dicarboxylate: pink) and (d) 2D structure in 1 with MeOH filled channels.
CrystEngComm Paper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
structure of 2 can be described by TOPOS28 software, as a(2,4)-connected net with the Schläfli symbol {84·122}{8}2 (Fig. 2d).
It is interesting to note that in 2, only one carboxylate endof glut has taken part in bridging here and the other part hasnot. But in the case of 1, two different glutarate are present,where one has bridged in a chelating fashion and the otherin a monodentate–bidentate coordination fashion. It is impor-tant to note that the pore dimension and solvent accessiblevoid is higher in case of 2. But instead of same reaction condi-tion in both the cases, 1 crystallized with bigger methanolmolecules in the pore whereas 2 with smaller water mole-cules. This is probably due to the flexible nature of the porein 2 which has been created by H-bonding.
Structural descriptions of {[Zn(azpy)0.5(glut)(H2O)]·(azpy)0.5}n(3) and {[Zn(meazpy)0.5(glut)(H2O)]·(H2O)2}n (4)
Complexes 3 and 4 crystallize in triclinic P1̄ space group butthe coordination environments are different in each case. Incomplex 3, each hexacoordinated Zn(II) have distorted octahedralgeometry with ZnO5N coordination environment (Fig. 3a); whilein 4, each Zn(II) ion has coordination environment ZnO4N,which shows a distorted trigonal bipyramidal geometry with anAddison parameter (τ) value of 0.3.30
In 3, in each asymmetric unit, the Zn(II) is coordinatedwith two glutarate ligands, one N,N′ linear Schiff base ligand
This journal is © The Royal Society of Chemistry 2014
azpy and one coordinated water molecule. The chelatingbridging glut moiety connects the Zn(II) center to create achain and two such chains are connected by azpy to form the1D ladder structure. There is also a terminal coordinatedwater molecule attached to each Zn(II) center, which directsinwards the ladder and is involved in intramolecular H-bonding(Table S2†). Apart from this water molecule, there is anuncoordinated lattice azpy molecule which is also present inthe crystal structure. In the crystal packing, the lattice azpymolecule fits like a socket between the hole of the 1D ladderand the aromatic rings of the lattice azpy and coordinated azpyare organized face-to-face and stabilized by π–π interactions(Table S5†). This supramolecular force converts the ladderstructure into a ribbon like arrangement, which extended inthe c direction (Fig. 3b).
In 4, in each asymmetric unit the Zn(II) centers arepentacoordinated as in this case the dicarboxylate units areattached in a different fashion i.e. chelating and monodentatebridging mode. The structure contains one coordinated waterand two lattice water molecules. Upon removal of the latticesolvent molecules the structure contains ~16.9% void spacecalculated from PLATON25 crystallographic software. Here theterminal coordinated water molecules are oriented outwardsand connect the 1D ladders by intramolecular H-bonding toproduce a supramolecular 2D structure in the bc plane(Fig. 4b).
CrystEngComm, 2014, 16, 2305–2316 | 2309
Fig. 3 (a) View of the coordination environment of hexacoordinated Zn(II) with atom labeling scheme of 3; (b) 1D arrangement showing theinterlocking by π–π interaction of 3 along the ab plane and (c) (2,3)-connected 1D ladder in structure 3 (colour code of node: N,N donor ligand:blue, Zn(II): green, dicarboxylate: pink).
Fig. 2 (a) View of the coordination environment of hexacoordinated Co(II) with atom labeling scheme of 2; (b) 2D arrangement in 2 constructedby the metal-glutarate moiety with H-bonding (meazpy and non-bonded part of glut have been omitted for clarity); (c) H-bonded 3D structure bythe disposition of 2D sheets in 2 with water filled supramolecular channels and (d) the Co(II) ions can be defined as 4-connected nodes, glutaratedianions and meazpy ligands both can be considered as 2-connected nodes (colour code of node: N,N donor ligand: blue, Co(II): green, dicarboxy-late: pink).
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
As observed in the crystal structure of 3, the chelating-monodentate bridging glut moiety connects the Zn(II) centerto create a chain and two such chains are connected bymeazpy to form the 1D ladder structure (Fig. 4c). There isalso a terminal coordinated water molecule attached toeach Zn(II) center. Unlike 3, in complex 4; two lattice watermolecules are present instead of the aromatic ligand probablydue to the steric factor. The lattice water molecules areattached with H bonding (Table S2†) to the uncoordinated Oatom of the glut moiety (Fig. 4b-inset). This involvement of
2310 | CrystEngComm, 2014, 16, 2305–2316
glut O atom in H-bonding31 is probably responsible forthe formation of the chelated monodentate bridging modeof glut which results in the formation of a coordinatelyunsaturated metal center.32 Topologically, in both complexeseach Zn(II) ion connects two glut and one N,N′ donor linker(azpy for compound 3 and meazpy for compound 4) andis 3-connected. The glut ligand is 2-connected. Each N,N′donor linker (azpy or meazpy) is also 2-connected. TheSchläfli symbol of the (2,3)-connected 1D ladder is {84·12}2{8}3(Fig. 3c and 4d).28
This journal is © The Royal Society of Chemistry 2014
Fig. 4 (a) View of the coordination environment of pentacoordinated Zn(II) with atom labeling scheme of 4; (b) supramolecular 2D sheets in 4constructed by intramolecular H-bonding; (c) 2D arrangement in 4 along the bc plane and the H-bonding with the lattice water molecule and (d)(2,3)-connected 1D ladder in structure 4 (colour code of node: N,N donor ligand: blue, Zn(II): green, dicarboxylate: pink).
CrystEngComm Paper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
Structural descriptions of {[Cd(azpy)(glut)]·(CH3OH)}n (5) and[Cd2(meazpy)2(glut)(NO3)2]n (6)
Complex 5 and 6 crystallize in triclinic P1̄ and tetragonal I4̄2dspace group respectively. In both the cases each heptacoordinatedCd(II) center has the same coordination environment CdN2O5,which shows distorted pentagonal bipyramidal geometry.
For complex 5, in each asymmetric unit, the Cd(II) is coor-dinated with one bridging glutarate ligand, one N,N′ linearSchiff base ligand azpy. One lattice methanol is also presentin the asymmetric unit of 5. These two heptadented Cd(II)centers are propagated along the c-direction with the bridgingglut to form a 1D-ladder like structure (Fig. 5b). This 1Dladder is pillared with the azpy ligands perpendicularlyforming a 2D-grid like structure in the crystallographic abplane (Fig. 5c). There are lattice methanol molecules inbetween the adjacent sheets and these methanol moleculesare stabilized by C–H⋯O interactions operating between thealcoholic oxygen and CH of the azpy linker (Table S2†).
In each asymmetric unit of 6, there are two coordinatelysimilar heptacoordinated Cd(II) along with one bridgingglutarate ligand, two meazpy and two coordinated nitrateanion. In the crystal packing, interestingly sheets are arrangedin the ab plane in an alternate fashion i.e. each sheet isperpendicularly oriented to its adjacent sheet but parallelto its alternate sheet (Fig. 3c). To better simplify thenature of this 2D layer, the topology analysis is provided:the glut dianions and Cd(II) ions both can be regarded
This journal is © The Royal Society of Chemistry 2014
as a 4-connected nodes. And the meazpy ligands act as2-connected nodes. Therefore, the whole structure can thusbe represented as a (2,4)-connected net topology with theSchläfli symbol {4·84·12}2{4
2·84}{8}2 (Fig. 6b).28
Complex 1 and 5 are topologically as well as structurallythe same. Similar to that of 1, even the 1D ladders arepillared with the azpy ligands perpendicularly forming a2D-grid like structure. Unlike 1 and 5, in 6 a 1D chain alongthe c direction has formed instead of the 1D ladder due tothe presence of one glut per pair of Cd(II). Thus the counteranion nitrate enters into the coordination environment andsits in the terminal position neutralizing the charge. Thiscarboxylate linked 1D chains are pillared by meazpy ligand tocreate the 2D sheet along the ac plane.
Thermogravimetric analysis and framework stability
Thermogravimetric analyses of the crystalline powder sampleof compounds 1–6 have been performed in the temperaturerange 25–400 °C. From TGA it is revealed that thesecompounds have moderate thermal stability. The TGA ofthese six as-synthesized compounds shows a gradual weightloss step of 7.1% (30–110 °C), 6.7% (20–170 °C), 4.01%(40–140 °C), 14.65% (30–130 °C), 4% (20–115 °C) and 11.55%(25–87 °C) for 1–6 respectively, which corresponds to theremoval of MeOH, and H2O guest and coordinated solventmolecules from the pores. Complex 1 is stable up to ~200 °Calthough two guest methanol molecule completely leave the
CrystEngComm, 2014, 16, 2305–2316 | 2311
Fig. 5 (a) View of the coordination environment of heptacoordinated Cd(II) with atom labeling scheme of 5; (b) 1D chain in 5 along the ab plane,(c) 2D structure in 5 with MeOH filled channel and (d) 2D-grid structure with trinodal (2,3,5)-connected topology in 5 (colour code of node: N,Ndonor ligand: blue, Cd(II): green, dicarboxylate: pink).
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
framework at 110 °C. Similarly 2 is stable up to ~200 °C andafter that it decomposed to an unidentified product. Thedehydrated framework of 3 and 4 are stable up to ~210 °Cand ~250 °C, respectively and then decompose. Complex 5loses one guest methanol molecule at ~130 °C, but it is stableup to 170 °C. Complex 6 is stable up to ~87 °C (Fig. S2–S7†).
In order to confirm the phase purity of the bulk materials,powder X-ray diffraction (PXRD) experiments were carried outfor all MOFs. All major peaks of the experimental powderX-ray patterns (PXRDs) of compounds 1–6, match quite wellwith their simulated PXRDs from their single crystal data,indicating their reasonable crystalline phase purity. PXRDpatterns of the dehydrated frameworks of 1–5 show sharppeaks with almost similar positions except 2 suggestingretention and the stability of the framework structures(Fig. S8–S13†).
Gas adsorption properties
The single crystal X-ray diffraction analysis reveal compounds1–5 with two dimensional architecture with pore sizes compa-rable with kinetic diameters of N2, H2 and CO2; with guestwater or methanol molecules occupying the pores/interlayerspacing. Also, it reveals the presence of open metal sites inone case along with free N atoms from the imine based
2312 | CrystEngComm, 2014, 16, 2305–2316
ligands present inside the pores, which usually shows enhancedphysical interactions with adsorbing gas molecules. Thisinformation prompted us to study the gas uptake propertiesof the compounds (Table 2).
The N2 adsorption isotherms performed on the compoundsshow that 2, 3 and 5 are more or less non-porous towardsnitrogen gas, while compounds 1 and 4 show a moderatenitrogen uptake (Fig. S14†). The calculated BET surface areafrom the N2 adsorption isotherms for 1 and 4 are 35 and58 m2 g−1, respectively (Fig. S14†). The probable reason for thenon-porous behaviour of 3 and 5 with respect to N2 may bedue to their pore sizes being less or comparable to the kineticdiameter of nitrogen (3.65 Å) and in the case of 2 the pore isnot robust at all, although it contains large solvent accessiblevoid. In spite of the non-porous nature of 2, 3 and 5 towardsnitrogen, studies have been made to explore their porositytowards H2 and CO2 adsorption as these molecules have lowerkinetic diameter (H2 = 2.89 Å, CO2 = 3.30 Å) than N2. The H2
adsorption studies performed at 77 K and up to 1 bar pressureindicate different H2 adsorption depending on the porosity ofthe compounds. As shown in Fig. 7, the compounds 1 and 4have the highest porosity with high solvent accessible voids aswell as the largest pores adsorbing 0.58 and 0.71 wt% of H2,respectively. On the other hand, compound 2, 3 and 5 having
This journal is © The Royal Society of Chemistry 2014
Fig. 6 (a) View of the coordination environment of heptacoordinated Cd(II) with atom labeling scheme of 6; (b) 2D arrangement with(2,4)-connected net topology in 6 (colour code of node: N,N donor ligand: blue, Cd(II): green, dicarboxylate: pink); (c) disposition of sheets in 6.
Table 2 Summary of gas adsorption properties of complexes 1–5
Complex BET surface area (m2 g−1) H2 uptake at 77 K (wt%) CO2 uptake at 273 K (mmol g−1)
1 35 0.58 1.582 — 0.23 0.623 — 0.07 0.314 58 0.71 1.875 11 0.32 0.96
CrystEngComm Paper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
lower porosity with less solvent accessible voids adsorb only0.23, 0.07 and 0.32 wt% of H2, respectively as pressureapproaches to 1 atm. The trends observed in the H2 uptakestudies correlate with the free space available (solvent accessiblevoids) and pore sizes of these compounds for the adsorptionof gaseous molecules. The higher H2 uptake observed in thecases of 1 and 4 is well justified as both of these compoundshave high solvent accessible volume (1 = 13.2% and 4 =16.9%) with large pore sizes as shown in Fig. 7a and b. It isevident from the H2 adsorption study that 4 shows a greateruptake in comparison to 1 and the probable reason forthis uptake in 4 may be on account of the pore partitioningfacilitated by the protruding –CH3 groups of N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine (meazpy). This phenome-non is very similar to the high gas uptakes observed incomparatively small pores created due to interpenetration.33
This journal is © The Royal Society of Chemistry 2014
The lower H2 uptake in compounds 2 and 5 is naturally areflection of the very low solvent accessible volume with tinypores. The non-porous behaviour of 3 towards H2 uptake isdue to the blocking of pores by the lattice azpy ligands whichreside inside the pores.
After observing such interesting trends in the H2 adsorp-tion profile, a CO2 adsorption study was also performed forall compounds. As shown in Fig. 7c and d, similar trends tothose observed in the H2 adsorption study were found. TheCO2 uptake was studied at 273 K for compounds 1, 3 and 5and it shows an adsorption of 1.58, 0.31 and 0.96 mmol g−1
respectively as the pressure reaches to 1 bar (Fig. 7c).Similarly, compounds 2 and 4 show a CO2 uptake of 0.62and 1.87 mmol g−1, respectively, at the same pressure of 1bar (Fig. 7d). The higher uptake of CO2 in 1 and 4 is welljustified as per aforementioned reasons. The two-dimensional
CrystEngComm, 2014, 16, 2305–2316 | 2313
Fig. 7 H2 and CO2 adsorption isotherms for compounds 1–5. (a) H2 adsorption isotherms for 1, 3 and 5 collected at 77 K. Cartoon presentationshows the pores available for gas adsorption. (b) H2 adsorption isotherms for 2 and 4 collected at 77 K. Cartoon presentation shows the poresavailable for gas adsorption. (c) CO2 adsorption isotherms for 1, 3 and 5 collected at 273 K. (d) CO2 adsorption isotherms for 2 and 4 collected at273 K (the filled and open symbols in all the figures represent the adsorption and desorption branches, respectively).
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
architecture of 1 and 4 with considerable pore sizes on bothcompounds (pore size of 4 being larger) favours the CO2
uptake compared to the other compounds. Although, N2 andCO2 have the same kinetic diameter, the preferential uptakeof CO2 (273 K) over N2 (77 K) observed in all the compoundsmay be due to the higher quadrupole interactions of CO2 thanthe thermal energy in the case of CO2 adsorption at 273 K,which does not block the windows of the pore openings.29,34
While, in case of N2 due to the absence of quadrupolemoment; it probably blocks the pore openings due to its lowerthermal energy at very low temperature (273 K). Although,the uptake of H2 and CO2 shown by the aforementionedcompounds is moderate, the trends in these uptakes observedare interesting, which are mostly dependant on the pore size,pore environment and space available for the adsorption ofthese gases.
Conclusions
The results demonstrated that an aliphatic dicarboxylate(glut) along with two different pyridyl based N,N′ linkers cancreate a diversity of coordination frameworks, where the porewalls are decorated with –CHN– or –CMeN– Schiff basenitrogen site. The use of the glutarate has become the vitalfactor as it has longer spacer length and flexibility of bindingmode. To fabricate these six solid state structures, metal
2314 | CrystEngComm, 2014, 16, 2305–2316
coordination geometry of three different transition metalsand structurally different linear Schiff bases played an interactiverole. After removal of the solvent molecules the frameworkshow different quantities of CO2 and H2 uptake depending onthe structural variations. In the case of 1 and 4, having higherporosity with high solvent accessible voids, those complexesadsorb H2 moderately, while 3, due to the presence of the azpyligand inside the pore, behaves as non-porous for H2 uptake.For the same reason, the CO2 uptake studies also show thesame trends.
Acknowledgements
Authors acknowledge UGC, Govt. of India for the financialassistance. RD acknowledges CSIR for the senior researchfellowship. The X-ray diffractometer facility under the DST-FISTprogram is also gratefully acknowledged.
References
1 (a) H. Deng, S. Grunder, K. E. Cordova, C. Valente,
H. Furukawa, M. Hmadeh, F. Gándara, A. C. Whalley, Z. Liu,S. Asahina, H. Kazumori, M. O'Keeffe, O. Terasaki,J. F. Stoddart and O. M. Yaghi, Science, 2012, 336, 1018; (b)B. Zheng, J. Bai, J. Duan, L. Wojtas and M. J. Zaworotko,J. Am. Chem. Soc., 2011, 133, 748; (c) K. Otsubo, T. Haraguchi,This journal is © The Royal Society of Chemistry 2014
CrystEngComm Paper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
O. Sakata, A. Fujiwara and H. Kitagawa, J. Am. Chem. Soc.,2012, 134, 9605; (d) N. C. Jeong, B. Samanta, C. Y. Lee,O. K. Farha and J. T. Hupp, J. Am. Chem. Soc., 2012, 134, 51;(e) M. L. Foo, S. Horike, Y. Inubushi and S. Kitagawa, Angew.Chem., Int. Ed., 2012, 51, 6107.
2 (a) S.-C. Xiang, Z. Zhang, C.-G. Zhao, K. Hong, X. Zhao,
D.-R. Ding, M.-H. Xie, C.-D. Wu, M. C. Das, R. Gill,K. M. Thomas and B. Chen, Nat. Commun., 2011, 2, 204; (b)D. Britt, H. Furukawa, B. Wang, T. G. Glover andO. M. Yaghi, Proc. Natl. Acad. Sci. U. S. A., 2009, 106, 20637;(c) Y. Liu, W. Xuan and Y. Cui, Adv. Mater., 2010, 22, 4112;(d) J.-R. Li, J. Sculley and H.-C. Zhou, Chem. Rev., 2012, 112,869; (e) B. Chen, C. Liang, J. Yang, D. S. Contreras,Y. L. Clancy, E. B. Lobkovsky, O. M. Yaghi and S. Dai, Angew.Chem., Int. Ed., 2006, 45, 1390; ( f ) J. A. Bohrman andM. A. Carreon, Chem. Commun., 2012, 48, 5130.3 (a) S. S. Kaye, A. Dailly, O. M. Yaghi and J. R. Long, J. Am.
Chem. Soc., 2006, 128, 14176; (b) R. Banerjee, A. Phan,B. Wang, C. Knobler, H. Furukawa, M. O'Keeffe andO. M. Yaghi, Science, 2008, 319, 939; (c) Q. R. Fang, D. Q. Yuan,J. Sculley, W. G. Lu and H. C. Zhou, Chem. Commun., 2012, 48,254; (d) T. Fukushima, S. Horike, Y. Inubushi, K. Nakagawa,Y. Kubota, M. Takata and S. Kitagawa, Angew. Chem., Int. Ed.,2010, 49, 4820; (e) A. Hazra, P. Kanoo and T. K. Maji, Chem.Commun., 2011, 47, 538.4 (a) J.-R. Li, R. J. Kuppler and H.-C. Zhou, Chem. Soc. Rev.,
2009, 38, 1477; (b) P. Kanoo, K. L. Gurunatha and T. K. Maji,J. Mater. Chem., 2010, 20, 1322; (c) R. Vaidhyanathan,S. S. Iremonger, K. W. Dawson and G. K. H. Shimizu, Chem.Commun., 2009, 5230; (d) Z. R. Herm, J. A. Swisher, B. Smit,R. Krishna and J. R. Long, J. Am. Chem. Soc., 2011,133, 5664; (e) T. Panda, P. Pachfule, Y. Chen, J. Jiangand R. Banerjee, Chem. Commun., 2011, 47, 2011; ( f )S. S. Nagarkar, R. Das, P. Poddar and S. K. Ghosh, Inorg.Chem., 2012, 51, 8317.5 (a) J. A. Hurd, R. Vaidhyanathan, V. Thangadurai,
C. I. Ratcliffe, I. M. Moudra-kovski and G. K. H. Shimizu,Nat. Chem., 2009, 1, 705; (b) F. Gándara, F. J. Uribe-Romo,D. K. Britt, H. Furukawa, L. Lei, R. Cheng, X. Duan,M. O'Keeffe and O. M. Yaghi, Chem.–Eur. J., 2012, 18, 10595;(c) T. Kundu, S. C. Sahoo and R. Banerjee, Chem. Commun.,2012, 48, 4998; (d) N. C. Jeong, B. Samanta, C. Y. Lee,O. K. Farha and J. T. Hupp, J. Am. Chem. Soc., 2012, 134, 51;(e) S. Sen, N. N. Nair, T. Yamada, H. Kitagawa andP. K. Bharadwaj, J. Am. Chem. Soc., 2012, 134, 19432; ( f )M.-H. Zeng, Q.-X. Wang, Y.-X. Tan, S. Hu, H.-X. Zhao,L.-S. Long and M. Kurmoo, J. Am. Chem. Soc., 2010,132, 2561.6 (a) M. D. Rowe, D. H. Thamm, S. L. Kraft and S. G. Boyes,
Biomacromolecules, 2009, 10, 983; (b) J. Rocca, D. Liu andW. Lin, Acc. Chem. Res., 2011, 44, 957; (c) P. Horcajada,R. Gref, T. Baati, P. K. Allan, G. Maurin, P. Couvreur,G. Féerey, R. E. Morris and C. Serre, Chem. Rev., 2012, 112,1232; (d) P. Horcajada, T. Chalati, C. Serre, B. Gillet,C. Sebrie, T. Baati, J. F. Eubank, D. Heurtaux, P. Clayette,C. Kreuz, J. S. Chang, Y. K. Hwang, V. Marsaud, P. N. Bories,This journal is © The Royal Society of Chemistry 2014
L. Cynober, S. Gil, G. Ferey, P. Couvreur and R. Gref, Nat.Mater., 2009, 9, 172; (e) A. Dupuis, N. Guo, Y. Gao,N. Godbout, S. Lacroix, C. Dubois and M. Skorobogatiy, Opt.Lett., 2007, 32, 109; ( f ) K. E. deKafft, Z. G. Xie, G. H. Cao,S. Tran, L. Q. Ma, O. Z. Zhou and W. Lin, Angew. Chem., Int.Ed., 2009, 48, 9901.
7 (a) P. Mahata, S. Natarajan, P. Panissod and M. Drillon,
J. Am. Chem. Soc., 2009, 131, 10140; (b) W. Ouellette,A. V. Prosvirin, K. Whitenack, K. R. Dunbar and J. Zubieta,Angew. Chem., Int. Ed., 2009, 48, 2140; (c) S. R. Batten andK. S. Murray, Coord. Chem. Rev., 2003, 246, 103; (d)P. Kanoo, C. Madhu, G. Mostafa, T. K. Maji, A. Sundaresan,S. K. Pati and C. N. R. Rao, Dalton Trans., 2009, 5062; (e)C. Dey, R. Das, B. K. Saha, P. Poddar and R. Banerjee, Chem.Commun., 2011, 47, 11008.8 (a) J. S. Seo, D. Whang, H. Lee, S. I. Jun, J. Oh, Y. J. Jeon and
K. Kim, Nature, 2000, 404, 982; (b) C.-D. Wu and W. Lin,Angew. Chem., 2007, 119, 1093; (c) L. Ma, C. Abney andW. Lin, Chem. Soc. Rev., 2009, 38, 1248; (d) J. M. Roberts,B. M. Fini, A. A. Sarjeant, O. K. Farha, J. T. Hupp andK. A. Scheidt, J. Am. Chem. Soc., 2012, 134, 3334; (e)T. Uemura, R. Kitaura, Y. Ohta, M. Nagaoka and S. Kitagawa,Angew. Chem., Int. Ed., 2006, 45, 4112; ( f ) S. Horike,M. Dincă, K. Tamaki and J. R. Long, J. Am. Chem. Soc., 2008,130, 5854; (g) D. Saha, R. Sen, T. Maity and S. Koner, DaltonTrans., 2012, 41, 7399; (h) D. Dang, P. Wu, C. He, Z. Xie andC. Duan, J. Am. Chem. Soc., 2010, 132, 14321.9 (a) T. K. Maji, R. Matsuda and S. Kitagawa, Nat. Mater.,
2007, 6, 142; (b) O. M. Yaghi and H. Li, J. Am. Chem. Soc.,1996, 118, 295; (c) J. Fan, W. Y. Sun, T.-A. Okamura,J. Xie, W.-X. Tang and N. Okamura, New J. Chem., 2002,26, 199; (d) F. Nouar, J. Eckert, J. F. Eubank, P. Forsterand M. Eddaoudi, J. Am. Chem. Soc., 2009, 131, 2864; (e)T. K. Prasad, D. H. Hong and M. P. Suh, Chem.–Eur. J.,2010, 16, 14043; ( f ) Z.-J. Zhang, W. Shi, Z. Niu, H.-H. Li,B. Zhao, P. Cheng, D.-Z. Liao and S.-P. Yan, Chem.Commun., 2011, 47, 6425; (g) B. Manna, A. K. Chaudhari,B. Joarder, A. Karmakar and S. K. Ghosh, Angew. Chem.,Int. Ed., 2013, 52, 998.10 (a) G. J. Halder, C. J. Kepert, B. Moubaraki, K. S. Murray and
J. D. Cashion, Science, 2002, 298, 1762; (b) Y. P. Cai,X. X. Zhou, Z. Y. Zhou, S. Z. Zhu, P. K. Thallapally and J. Liu,Inorg. Chem., 2009, 48, 6341; (c) B. Gole, A. K. Bar andP. S. Mukherjee, Chem. Commun., 2011, 47, 12137; (d)S. S. Nagarkar, B. Joarder, A. K. Chaudhari, S. Mukherjeeand S. K. Ghosh, Angew. Chem., Int. Ed., 2013, 52, 2881; (e)B. L. Chen, L. B. Wang, F. Zapata, G. D. Qian andE. B. Lobkovsky, J. Am. Chem. Soc., 2008, 130, 6718; ( f )M. D. Allendorf, C. A. Bauer, R. K. Bhakta and R. J. T. Houk,Chem. Soc. Rev., 2009, 38, 1330.11 (a) B. Moulton and M. J. Zaworotko, Chem. Rev., 2001, 101,
1629; (b) C. Janiak, Dalton Trans., 2003, 2781; (c)K. Jayaramulu, P. Kanoo, S. J. George and T. K. Maji, Chem.Commun., 2010, 46, 7906.12 (a) O. M. Yaghi, M. O'Keeffe, N. W. Ockwig, H. K. Chae,
M. Eddaoudi and J. Kim, Nature, 2003, 423, 705; (b)CrystEngComm, 2014, 16, 2305–2316 | 2315
CrystEngCommPaper
Publ
ishe
d on
10
Dec
embe
r 20
13. D
ownl
oade
d by
Hei
nric
h H
eine
Uni
vers
ity o
f D
uess
eldo
rf o
n 14
/03/
2014
22:
31:2
6.
View Article Online
A. P. Côté, H. M. El-Kaderi, H. Furukawa, J. R. Hunt andO. M. Yaghi, J. Am. Chem. Soc., 2007, 129, 12914; (c)J. R. Hunt, C. J. Doonan, J. D. LeVangie, A. P. Côté andO. M. Yaghi, J. Am. Chem. Soc., 2008, 130, 11872; (d) J. He,Y.-G. Yin, T. Wu, D. Li and X.-C. Huang, Chem. Commun.,2006, 2845; (e) H. Bux, F. Liang, Y. Li, J. Cravillon,M. Wiebcke and J. Caro, J. Am. Chem. Soc., 2009, 131, 16000.
13 (a) R. Kitaura, F. Iwahori, R. Matsuda, S. Kitagawa,
Y. Kubota, M. Takata and T. C. Kobayashi, Inorg. Chem.,2004, 43, 6522; (b) M. O. Awaleh, A. Badia and F. Brisse,Cryst. Growth Des., 2005, 5, 1897; (c) A. Monge, N. Snejko,E. Gutiérrez-Puebla, M. Medina, C. Cascales, C. Ruiz-Valero,M. Iglesias and B. Gómez-Lor, Chem. Commun., 2005, 1291;(d) L. Pan, M. B. Sander, X. Huang, J. Li, M. Smith,E. Bittner, B. Bockrath and J. K. Johnson, J. Am. Chem.Soc., 2004, 126, 1308; (e) P. Pachfule, C. Dey, T. Pandaand R. Banerjee, CrystEngComm, 2010, 12, 2381; ( f )B. V. Harbuzaru, A. Corma, F. Rey, P. Atienzar, J. L. Jordá,H. García, D. Ananias, L. D. Carlos and J. Rocha, Angew.Chem., Int. Ed., 2008, 47, 1080; (g) R.-Q. Zhong, R.-Q. Zou,M. Du, T. Yamada, G. Maruta, S. Takeda and Q. Xu, DaltonTrans., 2008, 2346.14 (a) M.-L. Zhang, D.-S. Li, J.-J Wang, F. Fu, M. Du, K. Zou and
X.-M. Gao, Dalton Trans., 2009, 5355; (b) W.-G. Lu, L. Jiang,X.-L. Feng and T.-B. Lu, Cryst. Growth Des., 2006, 6, 564; (c)K.-B. Shiu and H.-C. Lee, Organometallics, 2002, 21, 4013; (d)G.-P. Yang, L. Hou, Y.-Y. Wang, Y.-N. Zhang, Q.-Z. Shi andS. R. Batten, Cryst. Growth Des., 2011, 11, 936.15 (a) H. Qu, L. Qiu, X.-K. Leng, M.-M. Wang, S. M. Lan,
L.-L. Wen and D.-F. Li, Inorg. Chem. Commun., 2011, 14,1347; (b) A. K. Cheetham, C. N. R. Rao and R. K. Feller,Chem. Commun., 2006, 4780; (c) Y. Qi, Y.-X. Che andJ.-M. Zheng, Cryst. Growth Des., 2008, 8, 3602.16 (a) R. Vaidhyanathan, S. Natarajan and C. N. R. Rao, Dalton
Trans., 2003, 1459; (b) Y.-Y. Lin, Y.-B. Zhang, J.-P. Zhang andX.-M. Chen, Cryst. Growth Des., 2008, 8, 3673; (c) D.-X. Hu,F. Luo, Y.-X. Che and J.-M. Zheng, Cryst. Growth Des., 2007,7, 1733.17 (a) K. Biradha and M. Fujita, Chem. Commun., 2001, 15; (b)
R. Dey, R. Haldar, T. K. Maji and D. Ghoshal, Cryst. GrowthDes., 2011, 11, 3905; (c) C. M. Nagaraja, R. Haldar, T. K. Majiand C. N. R. Rao, Cryst. Growth Des., 2012, 12, 975; (d)B. Chen, S. Xiang and G. Qian, Acc. Chem. Res., 2010, 43,1115; (e) K. Biradha and M. Fujita, J. Chem. Soc., DaltonTrans., 2000, 3805; ( f ) B. Chen, S. Ma, E. J. Hurtado,E. B. Lobkovsky and H.-C. Zhou, Inorg. Chem., 2007,46, 8490.18 (a) P. J. Hagrman, D. Hagrman and J. Zubieta, Angew. Chem.,
Int. Ed., 1999, 38, 2638; (b) S. Kitagawa, R. Kitaura andS. Noro, Angew. Chem., Int. Ed., 2004, 43, 2334; (c)K. Uemura, S. Kitagawa, M. Kondo, K. Fukui, R. Kitaura,H.-C. Chang and T. Mizutani, Chem.–Eur. J., 2002, 8, 3586;2316 | CrystEngComm, 2014, 16, 2305–2316
(d) T. K. Maji, D. Ghoshal, E. Zangrando, J. Ribas and N. RayChaudhuri, CrystEngComm, 2004, 6, 623; (e) K. Biradha,M. Sarkar and L. Rajput, Chem. Commun., 2006, 4169; ( f )D. Ghoshal, G. Mostafa, T. K. Maji, E. Zangrando, T. H. Lu,J. Ribas and N. Ray Chaudhuri, New J. Chem., 2004, 28, 1204.
19 H.-L. Jiang, T. A. Makal and H.-C. Zhou, Coord. Chem. Rev.,
2013, 257, 2232.20 B. Bhattacharya, R. Dey, P. Pachfule, R. Banerjee and
D. Ghoshal, Cryst. Growth Des., 2013, 13, 731.21 A. R. Kennedy, K. G. Brown, D. Graham, J. B. Kirkhouse,
M. Kittner, C. Major, C. J. McHugh, P. Murdoch andW. E. Smith, New J. Chem., 2005, 29, 826.22 SMART (V 5.628), SAINT (V 6.45a), XPREP, SHELXTL, Bruker
AXS Inc., Madison, WI, 2004.23 G. M. Sheldrick, SHELXS-97, Program for the solution of
crystal structures, University of Gottingen, Germany, ActaCrystallogr., Sect. A: Found. Crystallogr., 2008, 64, 112.24 G. M. Sheldrick, SHELXL-97, Program for the refinement of
crystal structures, University of Gottingen, Germany, ActaCrystallogr., Sect. A: Found. Crystallogr., 2008, 64, 112.25 A. L. Spek, Acta Crystallogr., Sect. D: Biol. Crystallogr., 2009,
65, 148.26 L. J. Farrugia, J. Appl. Crystallogr., 1997, 30, 565.
27 L. J. Farrugia, WinGX-A windows program for crystalstructures Analysis, J. Appl. Crystallogr., 1999, 32, 837.28 (a) V. A. Blatov, A. P. Shevchenko and V. N. J. Serezhkin,
J. Appl. Crystallogr., 2000, 33, 1193; (b) V. A. Blatov,L. Carlucci, G. Ciani and D. M. Proserpio, CrystEngComm,2004, 6, 378; (c) A. V. Blatov and D. M. Proserpio, ActaCrystallogr., Sect. A: Found. Crystallogr., 2009, 65, 202.
29 S. Kitagawa and K. Uemura, Chem. Soc. Rev., 2005, 34, 109.
30 A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn andG. C. Verschoor, J. Chem. Soc., Dalton Trans., 1984, 1349.31 D. Ghoshal, A. K. Ghosh, J. Ribas, E. Zangrando, G. Mostafa,
T. K. Maji and N. Ray Chaudhuri, Cryst. Growth Des., 2005,5, 941.
32 (a) P. D. C. Dietzel, V. Besikiotis and R. Blom, J. Mater.
Chem., 2009, 19, 7362; (b) K. M. Thomas, Dalton Trans.,2009, 1487; (c) P. D. C. Dietzel, R. E. Johnsen, R. Blom andH. Fjellvåg, Chem.–Eur. J., 2008, 14, 2389; (d) P. D. C. Dietzel,B. Panella, M. Hirscher, R. Bloma and H. Fjellvåg, Chem.Commun., 2006, 959; (e) A. Mallick, S. Saha, P. Pachfule,S. Roy and R. Banerjee, J. Mater. Chem., 2010, 20, 9073.33 (a) P. Nugent, Y. Belmabkhout, S. D. Burd, A. J. Cairns,
R. Luebke, K. Forrest, T. Pham, S. Ma, B. Space, L. Wojtas,M. Eddaoudi and M. J. Zaworotko, Nature, 2013, 495, 80; (b)S. Yang, X. Lin, W. Lewis, M. Suyetin, E. Bichoutskaia,J. E. Parker, C. C. Tang, D. R. Allan, P. J. Rizkallah,P. Hubberstey, N. R. Champness, K. M. Thomas, A. J. Blakeand M. Schröder, Nat. Mater., 2012, 11, 710.34 S. J. Gregg and K. S. W. Sing, Adsorption, Surface Area and
Porosity, Academic Press, New York, 1982.This journal is © The Royal Society of Chemistry 2014