dna binding test, x-ray crystal structure, spectral ...1).pdf · tg-dta, and electrochemistry of...

Research ArticleDNA Binding Test X-Ray Crystal Structure Spectral StudiesTG-DTA and Electrochemistry of [CoX2(dmdphphen)](Dmdphphen Is 29-Dimethyl-47-diphenyl-110-phenanthrolineX = Cl and NCS) Complexes

Mousa Al-Noaimi1 Mohammed Suleiman2 Hany W Darwish34 Ahmed H Bakheit3

Muneer Abdoh5 Iyad Saadeddin5 Naveen Shivalingegowda6

Neartur Krishnappagowda Lokanath7 Odey Bsharat2 Assem Barakat89 and Ismail Warad2

1Department of Chemistry Hashemite University Zarqa 13115 Jordan2Department of Chemistry Science College An-Najah National University PO Box 7 Nablus Palestine3Department of Pharmaceutical Chemistry College of Pharmacy King Saud University PO Box 2457 Riyadh 11451 Saudi Arabia4Department of Analytical Chemistry Faculty of Pharmacy Cairo University Kasr El-Aini Street Cairo 11562 Egypt5Department of Physics Science College An-Najah National University PO Box 7 Nablus Palestine6Institution of Excellence Vijnana Bhavan University of Mysore Manasagangotri Mysore 570 006 India7Department of Studies in Physics University of Mysore Manasagangotri Mysore 570 006 India8Department of Chemistry College of Science King Saud University PO Box 2455 Riyadh 11451 Saudi Arabia9Department of Chemistry Faculty of Science Alexandria University PO Box 426 Ibrahimia Alexandria 21321 Egypt

Correspondence should be addressed to Mousa Al-Noaimi manoaimihuedujo and Ismail Warad waradnajahedu

Received 20 October 2014 Revised 2 December 2014 Accepted 3 December 2014 Published 29 December 2014

Academic Editor Claudio Pettinari

Copyright copy 2014 Mousa Al-Noaimi et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Two new neutral mixed-ligand cobalt(II) complexes [CoCl2(dmdphphen)] 1 and [Co(NCS)

2(dmdphphen)] 2 where dmdphphen

is 29-dimethyl-47-diphenyl-110-phenanthroline were synthesized and characterized by an elemental analysis UV-Vis IRTGDTA cyclic voltammetry CV and single X-ray diffraction Complex 2 crystallized as monoclinic with a space group P2

1c

Co(II) ions are located in a distorted tetrahedral environment TGDTA result shows that these complexes are very stable anddecomposed through one-step reaction The two complexes exhibit a quasireversible one-electron response at minus550 and 580mVversus Cp

2FeCp

2Fe+ which has been assigned to Co(I)Co(II) and Co(II)Co(III) couples Absorption spectral studies reveal that

such complexes exhibit hypochromicity during their interaction with CT-DNA

1 Introduction

110-Phenanthroline ligands and their derivatives are veryattractive in metal complexes [1ndash3] In addition their metalcomplexes are frequently used as catalyst for the enantios-elective hydrolysis of 119873-protected amino acid esters allylicsubstitutions reduction of acetophenone [3ndash6] and oxida-tion of olefins [7] Also cobalt(II) complexes with a reversibleCo(II)Co(III) are a good oxygen carrier and can oxidize thedouble bond of the olefins [8ndash10]

The ability of the cobalt phenanthroline complexes tobind and to cleave DNA under physiological conditions isof current interest because of their potential applications innucleic acids chemistry [11] Also these complexes are usefulin footprinting studies [12ndash17] The cleavage of DNA usuallyoccurs through the heterocyclic bases deoxyribose sugarmoiety or phosphodiester linkage [18ndash20] For the mixed-ligand complexes to interact efficiently with DNA the ligandsneed to be flat have large surface area and have a spatialgeometry to interact with the base pairs in DNA [15ndash23]

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2014 Article ID 914241 7 pageshttpdxdoiorg1011552014914241

2 Bioinorganic Chemistry and Applications

By changing the ligands or the metal ions it is possible tomodify the interaction with nucleic acids [23ndash26]

Previously a series of several mixed-ligand mononuclear[27 28] and dinuclear [29 30] metal complexes have ageneral formula MX

2(dmphen) (29-dimethyl-110-phenan-

throline X = Cl NCS) prepared in our lab These complexeswere found to be suitable precursors for spherical shapemetal oxide nanoparticles [31] Herein two new neutralmixed-ligand cobalt(II) complexes [CoCl

2(dmdphphen)]

1 and [Co(NCS)2(dmdphphen)] 2 where dmdphphen is

(29-dimethyl-47-diphenyl-110-phenanthroline) were syn-thesized and characterized by different spectroscopic meth-ods Also the DNA binding and the catalytic oxidation ofstyrene in the presence of H

2O2for the complexes were

investigated

2 Experimental Section

21 Materials and Instrumentation 29-Dimethyl-47-diphenyl-110-phenanthroline ligand CoCl

2sdot6H2O and

Co(NCS)2were purchased from Acros Organics Elemental

analyses were carried out on an Elementar vario EL analyzerThe IR spectra for samples were recorded using PerkinElmerSpectrum 1000 FT-IR SpectrometerTheUV-Vis spectra weremeasured by using a TU-1901 double-beam UV-Vis spectro-photometer TGDTA spectra were measured by usinga TGA-7 PerkinElmer thermogravimetric analyzer Thecyclic voltammograms for the complexes were measured inCH3CN and 01M tetrabutylammonium hexafluorophos-

phate (TBAHF) using BAS 100 BW electrochemical work-station (Bioanalytical Systems West Lafayette IN USA) andcontrolled by a standard 80486 personal computer (BAS con-trol program version 20) All electrochemical experimentswere carried out at room temperature under argon with athree-electrode cell Voltalab 80 potentiostat PGZ402 withPt-disk electrode (Metrohm 119860 = 00064 cm2) was usedas working electrode Platinum wire (m 1mm) spiral withdiameter 7mm was used as a counter electrode Haber-Luggin double reference electrode was used as a referenceone All potentials in this paper are reported to an externalCp2Fe0+ standard [32]

22 General Procedure for the Preparation of the Desired Com-plexes A mixture of CoX

2salt (2mmol) in distilled ethanol

(15mL) and free ligand (21mmol) in methanol (10mL) isstirred for around 05 h at room temperature until the pre-cipitation appeared which was filtered washed with ethanoland dried Suitable crystals for X-ray diffraction analysis weregrowing up by slow diffusion of ethanol into a solution of thecomplex in CH

2Cl2after two days (yield 88)

221 Complex 1 Yield 076 g (90) Anal Calc forC26H20Cl2CoN2 C 6369 H 411 N 571 Found C 6343

H 421 N 548 UV-Vis (nm) bands in dichloromethane655 572 360 240 280 and 304 Mp 320∘C Conductivity inCH3CN 1028 (120583Scm)

222 Complex 2 Yield 094 g (88) C28H20CoN4S2 Cal C

6280 H 376 N 1046 S 1197 Found C 6292 H 385N 1033 S 1186 UV-Vis (nm) bands in dichloromethane645 566 358 242 282 and 305 Mp 290∘C Conductivity inCH3CN 952 (120583Scm)

23 Crystallography A suitable single-crystal complex 2withdimensions of 023 times 022 times 021mmwas chosen for an X-raydiffraction measurement X-ray intensity data were collectedat 296K on a Bruker CCD diffractometer equipped withCu K

120572radiation (119897 = 154178 A) Data were collected with

the 120593 and 120596 scan method The final unit cell parameterswere based on all reflections Data reduction of all thecollected reflections and absorption correction were carriedout using the APEX 2 [33] package The structure was solvedby direct methods using SHELXS [34] The structure wasthen refined by a full-matrix least-squares method withanisotropic temperature factors for nonhydrogen atoms usingSHELXL [34] All the nonhydrogen atoms were revealed inthe first Fourier map itself After several cycles of refinementthe final difference Fourier map showed peaks of no chemicalsignificance and the residual saturated to 00671 Detailsof data collection and refinement are given in Table 1 Thegeometrical calculations were carried out using the programPLATON [35] The molecular and packing diagrams weregenerated using the softwareMERCURY [36]

24 DNA Binding and Cleavage Experiments Absorbancemeasurement was performed to clarify the binding affinityof cobalt(II) complexes by emissive titration at room tem-perature The complexes were dissolved in mixed solvent ofTris-HCl buffer (5mMTris-HCl50mMNaCl buffer for pH=72) for all the experiments and stored at 4∘C for furtheruse and used within 2 days Tris-HCl buffer was subtractedthrough baseline correction The absorption experimentswere performed by keeping the concentration of cobalt(II)complexes constant (15 times 10minus4molL) and increasing theconcentration of DNA gradually (10 times 10minus4ndash1times 10minus3molL)

3 Results and Discussion

31 Synthesis of the Desired Complexes The mononuclearCoCl2(dmdphphen) complex 1 and Co(NCS)

2(dmdphphen)

complex 2 were isolated in a good yield without side productas seen in Scheme 1

The structures of the desired complexes were confirmedby using elemental analysis IR UV-Vis TGDTA and X-ray single-crystal measurement for complex 2 The analyt-ical data of the complexes show the formation of [1 1 2][M dmdphphen 2X] ratio in a good agreement with thesuggested formula [CoX

2(dmdphphen)] of the isolated com-

plexes The isolated solid complexes are insoluble in waterethanol 119899-hexane and ethers but soluble in chlorinatedsolvents as CHCl

3and CH

2Cl2The solubility andmolar con-

ductance showed that the two complexes are nonelectrolyticin their nature

Bioinorganic Chemistry and Applications 3

N

N

CH3 CH3

CH3CH3

+ CoX2 Co

N

N

X

X

EtOH

X = Cl (complex 1) or NCS (complex 2)

Scheme 1 Synthesis of the Co(II) complexes 1 and 2

Table 1 Crystal data and structure refinement for ligand andcomplex 2

Complex 2Empirical formula C28H20N4S2CoFormula weight 53555Temperature 293(2) KWavelength 154178 ACrystal system MonoclinicSpace group P2

1c

Unit cell dimensions

119886 = 148373(12) A120572 = 90∘

119887 = 210942(11) A120573 = 100191(4)∘119888 = 82470(6) A120574 = 90∘

Volume 25404(3) A3

119885 4Density (calculated) 1400Mgm3

Absorption coefficient 7017mmminus1

119865(000) 1100Crystal size 030 times 025 times 015mm3

Theta range for data collection 303∘ to 6394∘

Index ranges minus15 le ℎ le 17 minus21 le 119896 le 24minus9 le 119897 le 6

Reflections collected 8247Independent reflections 3934 [119877(int) = 00671]

Refinement method Full-matrix least-squareson 1198652

Datarestraintsparameters 39340318Goodness-of-fit on 1198652 1047Final 119877 indices [119868 gt 2sigma(119868)]

1198771 = 00671 1199081198772 = 01910119877 indices (all data)

1198771 = 01715 1199081198772 = 02661Largest diff peak and hole 0641 and minus0870 esdotAminus3

32 X-Ray Crystal Structure Crystal structure data andselected bonds length for complex 2 are compiled in Tables 1and 2 respectively ORTEP drawing of the complex is shown

Table 2 Selected bond distances (A) and bond angles (∘) of thecomplex 2

Bond angles (∘) Bond distances (A)N2ndashCo1ndashN13 8211(18) Co1ndashN13 2035(4)N2ndashCo1ndashN30 1087(2) Co1ndashN2 2032(4)N2ndashCo1ndashN33 1223(2) Co1ndashN30 1923(7)N13ndashCo1ndashN30 1093(2) Co1ndashN33 1905(5)N13ndashCo1ndashN33 1228(2) N2ndashC15 1374(6)N30ndashCo1ndashN33 1090(2) N13ndashC14 1360(6)

S34

C34

N33 S32

C31N30

N2

Co1C16

C3

C4

C5

C18C19

C22

C23C20

C21

C6

C7 C8

C9C10

C11

C17

C12

C14C15

C24C29

C27

C28C26

C25

N13

Figure 1 ORTEP of the complex 2 with atom labelling Thermalellipsoids are drawn at the 50 probability level

in Figure 1 The central cobalt metal ion is coordinated to thetwo nitrogen atoms (N2 and N13) of the dmdphphen ligandand to two nitrogen atoms (N30 and N33) of the isothio-cyanate ligand in a tetrahedral symmetryThephenanthrolinering in the dmdphphen moiety is essentially planar with anrms deviation of 00752 A The phenyl rings (C8ndashC13 andC24ndashC29) are twisted out of the plane of the dmdphphen


a

b

c

o

Figure 2 A crystal packing of complex 2 viewed (perspective) along crystallographic 119886 direction

moiety as indicated by the dihedral angle values of 432(4)∘and 472(4)∘ respectively All coordination distances andbond angles are similar to those found in similar compounds[37] No classic hydrogen bonds were observed In the crystalstructure there is a 120587-120587 stacking interaction between adjacentdmdphphen and distances 37109(17) A and 38070(17) Awhich may account for stabilizing the crystal structure(Figure 2) The packing of the molecules when viewed downalong the 119886 axis indicates that the molecules are interlinkedby weak hydrogen bonds to form one dimensional chain

33 IR Spectrum The IR spectrum of complex 1 (Figure 3(b))showed four characteristic absorptions peaks in the range of3060 2950 550 and 350 cmminus1 [7ndash10] which was assignedto HndashPh HndashCH

3 CondashN and CondashCl stretching vibrations

respectively New band at 2150 cmminus1 which was assigned toNCS vibrations was observed in IR spectrum of complex 2(Figure 3(c)) The HndashPh H of CH

3in dmdphphen bands

appeared in their expected areas (Figure 3(a))

34 Electronic Absorption Spectral Study The experimentalabsorption spectra (UV-Vis) of the [CoX

2(dmphen)] com-

plexes 1 2 in dichloromethane solution presented three dom-inant bands in the regions 200ndash800 nm (Figure 4)The bands

in the UV region centered at around 240 280 and 300 nmwere assigned ligand-centered 120587-120587lowast transitions (in bothcomplexes) The bands at 360 572 and 655 nm for complex 1(above) and at 365 560 and 645 nm for complex 1 (down) canbe assigned to the d rarr d transition and MLCT respectively[14ndash20]

35 Thermal Decomposition Analysis of Complexes 1 Thethermal analysis of complex 1 (Figure 5) was investigated inthe range of 0ndash600∘C and heating rate of 10∘Cmin Figure 5shows that there is no uncoordinated or coordinated waterin the range of 0ndash150∘C and 150ndash180∘C respectively Alsoit shows that there are no decomposition intermediate stepsof the coordinated chloride and dmdphphen ligands bothinorganic and organic ligands were destructured away fromthe Co metal with one-step broad decomposition in 200ndash330∘C with weight loss sim81 and an exothermic DTA signalat sim315∘C the final residue was confirmed by IR to be CoO

36 Electrochemistry The electron-transfer behavior of thecomplexes in acetonitrile solution was examined by cyclicvoltammetry As a representative example the cyclic voltam-mogram for complex 2 is shown in Figure 6 Complex 2exhibited two single electron reversible oxidative responses


a

1

2

3200

3100

3000

2900

2800

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (1cm)

(a)

(b)

(c)

Figure 3 IR-KBr disk spectra of free ligand (a) and their desiredcomplexes 1 and 2

at minus550 and 580mV versus Cp2FeCp

2Fe+ which has been

assigned to Co(I)Co(II) and Co(II)Co(III) couples respec-tively The dmdphphen ligand is electroinactive over thestudied range of +15 to minus15 V Both complexes exhibit thesimilar behavior during the cyclic voltammetry experiments

37 DNA-Complex 1 Binding Test The affinity of Co(II) com-plexes for double-stranded CT-DNAwas explored using UV-Vis titrations in deionised water The results of representativetitrations are shown in Figure 7 Complex 1 showed goodDNA binding affinity Complex 1 has three characteristicabsorption peaks at 360 nm 572 nm and 655 nm respec-tively There is a decrease in an intensity for all peaks forcomplex 1 by adding several concentrations of DNA Thissuggests that the cobalt complex might be bind to DNAby an intercalative mode [38] However by comparing thesmall shift for complex 1 with 7 nm red-shift values forOs(phen)

2(dppz)2+ [39] and 9 nm for [Co(phen)

2(pdtp)]3+

[40] this demonstrates that the intercalative strength of suchcomplexes into DNA is not very strong

4 Conclusions

Tetrahedral cobalt(II) complexes [CoCl2(dmdphphen)] 1 and

[Co(NCS)2(dmdphphen)] 2 were made available in good

yield Complex 2 was solved by XRD as monoclinic witha space group P2

1c Co(II) ions are located in a distorted

tetrahedral environment TGDTA result shows that thesecomplexes are very stable and decomposed through one-step

12

10

08

06

04

02

00

120582 = 572nm

120582 = 360nm

120582 = 655nm

1

Abs

Wavelength (nm)400 500 600 700 800

(a)

20

15

10

05

00

120582 = 365nm

120582 = 645nm2Ab

s

Wavelength (nm)400 500 600 700 800

(b)

Figure 4 UV-Vis spectrum of the desired complexes (1 and 2) indichloromethane at RT

(Wt

)

100

80

60

40

20

0

0 100 200 300 400 500 600

Temperature (∘C)

TGDTA = 315

DTA

Figure 5 TGDTA thermal curves of the desired complex 1

6 Bioinorganic Chemistry and ApplicationsI(120583

A)

200

100

0

minus100

minus200

minus15 minus10 minus05 00 05 10 15

E (V)

Figure 6 Voltammogram diagram of complex 2 (119888 = 1times 10minus3M inacetonitrile solution 01M TBAHF scan rate 100mVs at RT)

020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)

Figure 7 Visible spectra of 15 times 10minus4molL of complex 1 interactingwith (a)mdash0 (b)mdash10 times 10minus4 (c)mdash5 times 10minus4 and (d)mdash1 times 10minus3molLCT-DNA at RT

reaction the complexes exhibit a quasireversible one-electronresponse atsimminus550mVassigned toCo(I)Co(II) andsim580mVassigned to Co(II)Co(III) versus Cp

2FeCp

2Fe+ Absorption

spectral studies reveal that such complexes exhibit goodDNAbinding

Additional Material

Crystallographic data for complex 1 has been deposited withthe Cambridge Crystallographic Data Centre as supple-mentary publication number CCDC 1014019 Copies of thisinformation may be obtained free of charge via httpswwwccdccamacukcontsretrievinghtml (or from the CCDC12 Union Road Cambridge CB2 1EZ UK fax +44-1223-336033 e-mail depositccdccamacuk)

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to extend their sincere appreciation tothe Deanship of Scientific Research at King Saud Universityfor its funding of this research through the Research GroupProject no RGP-VPP-322 The authors are thankful to theIOE Vijnana Bhavan University of Mysore Mysore forproviding the single-crystal X-ray diffractometer facilityIsmail Warad and Mousa Al-Noaimi would like to thankAn-NajahNationalUniversity andTheHashemiteUniversityJordan for their research support

References

[1] C Allen Chemistry of Heterocyclic Compounds Six MemberedHeterocyclic Nitrogen Compounds with Three Condensed Ringsvol 12 Interscience New York NY USA 1958

[2] A Bencini and V Lippolis ldquo110-Phenanthroline a versatilebuilding block for the construction of ligands for various pur-posesrdquo Coordination Chemistry Reviews vol 254 no 17-18 pp2096ndash2180 2010

[3] F Barigelletti B Ventura J-P Collin R Kayhanian P Gavinaand J-P Sauvage ldquoElectrochemical and spectroscopic proper-ties of cyclometallated and non-cyclometallated ruthenium(II)complexes containing sterically hindering ligands of the phe-nanthroline and terpyridine familiesrdquo European Journal of Inor-ganic Chemistry vol 2000 no 1 pp 113ndash119 2000

[4] J G J Weijnen A Koudijs and J F J Engbersen ldquoSynthesisof chiral 110-phenanthroline ligands and the activity of metal-ion complexes in the enantioselective hydrolysis of N-protectedamino acid estersrdquoThe Journal of Organic Chemistry vol 57 no26 pp 7258ndash7265 1992

[5] E Pena-Cabrera P-O Norrby M Sjogren et al ldquoMolecularmechanics predictions and experimental testing of asymmet-ric palladium-catalyzed allylation reactions using new chiralphenanthroline ligandsrdquo Journal of the American ChemicalSociety vol 118 no 18 pp 4299ndash4313 1996

[6] S Gladiali G Chelucci F Soccolini G Delogu and G ChessaldquoOptically active phenanthrolines in asymmetric catalysis IIEnantioselective transfer hydrogenation of acetophenone byrhodiumalkyl phenanthroline catalystsrdquo Journal of Organo-metallic Chemistry vol 370 no 1ndash3 pp 285ndash294 1989

[7] R A Sheldon ldquoChapter 11mdashalkanesrdquo in Metal-Catalyzed Oxi-dations of Organic Compounds pp 340ndash349 Academic Press1981

[8] Y Zhang Z Li W Sun and C Xia ldquoA magnetically recy-clable heterogeneous catalyst cobalt nano-oxide supportedon hydroxyapatite-encapsulated 120574-Fe

2O3nanocrystallites for

highly efficient olefin oxidation with H2O2rdquo Catalysis Commu-

nications vol 10 no 2 pp 237ndash242 2008[9] Y He and C Cai ldquoPolymer-supported macrocyclic Schiff base

palladium complex an efficient and reusable catalyst for Suzukicross-coupling reaction under ambient conditionrdquo CatalysisCommunications vol 12 no 7 pp 678ndash683 2011

[10] M Ma Q Zhang D Yin J Dou H Zhang and H Xu ldquoPrep-aration of high-magnetization Fe

3O4-NH2-Pd (0) catalyst for


heck reactionrdquo Catalysis Communications vol 17 pp 168ndash1722012

[11] G Pratviel J Bernadou and B Meunier ldquoDNA and RNAcleavage by metal complexesrdquo Advances in Inorganic Chemistryvol 45 pp 251ndash312 1998

[12] R M Burger ldquoCleavage of nucleic acids by bleomycinrdquo Chemi-cal Reviews vol 98 no 3 pp 1153ndash1169 1998

[13] K E Erkkila D T Odom and J K Barton ldquoRecognition andreaction of metallointercalators with DNArdquo Chemical Reviewsvol 99 no 9 pp 2777ndash2796 1999

[14] H T Chifotides and K R Dunbar ldquoInteractions of metalmdashmetal-bonded antitumor active complexes with DNA frag-ments and DNArdquo Accounts of Chemical Research vol 38 no2 pp 146ndash156 2005

[15] C J Burrows and J G Muller ldquoOxidative nucleobase modifica-tions leading to strand scissionrdquo Chemical Reviews vol 98 no3 pp 1109ndash1151 1998

[16] C Metcalfe and J A Thomas ldquoKinetically inert transitionmetal complexes that reversibly bind to DNArdquoChemical SocietyReviews vol 32 no 4 pp 215ndash224 2003

[17] K Szaciłowski W Macyk A Drzewiecka-Matuszek M Brin-dell and G Stochel ldquoBioinorganic photochemistry frontiersand mechanismsrdquo Chemical Reviews vol 105 no 6 pp 2647ndash2694 2005

[18] S E Wolkenberg and D L Boger ldquoMechanisms of in situ acti-vation for DNA-targeting antitumor agentsrdquo Chemical Reviewsvol 102 no 7 pp 2477ndash2496 2002

[19] A Sreedhara and J A Cowan ldquoCatalytic hydrolysis of DNAby metal ions and complexesrdquo Journal of Biological InorganicChemistry vol 6 no 4 pp 337ndash347 2001

[20] B Macıas M V Villa F Sanz J Borras M Gonzalez-Alvarezand G Alzuet ldquoCu(II) complexes with a sulfonamide derivedfrom benzoguanamine Oxidative cleavage of DNA in the pres-ence of H

2O2and ascorbaterdquo Journal of Inorganic Biochemistry

vol 99 no 7 pp 1441ndash1448 2005[21] Y Li Y Wu J Zhao and P Yang ldquoDNA-binding and cleavage

studies of novel binuclear copper(II) complex with 111015840-dim-ethyl-221015840-biimidazole ligandrdquo Journal of Inorganic Biochem-istry vol 101 no 2 pp 283ndash290 2007

[22] S Dhar D Senapati P K Das P Chattopadhyay M Nethajiand A R Chakravarty ldquoTernary copper complexes for pho-tocleavage of DNA by red light direct evidence for sulfur-to-copper charge transfer and d-d band involvementrdquo Journal ofthe American Chemical Society vol 125 no 40 pp 12118ndash121242003

[23] A E Friedman J C Chambron J P Sauvage N J Turroand J K Barton ldquoMolecular ldquolight switchrdquo for DNA Ru(bpy)2(dppz)2+rdquo Journal of the American Chemical Society vol112 no 12 pp 4960ndash4962 1990

[24] T Shields and J Barton ldquoSequence-selective DNA recognitionand photocleavage a comparison of enantiomers of Rh(en)

2

phi3+rdquo Biochemistry vol 34 no 46 pp 15037ndash15048 1995[25] A Sitlani E C Long A M Pyle and J K Barton ldquoDNA pho-

tocleavage by phenanthrenequinone diimine complexes ofrhodium(III) shape-selective recognition and reactionrdquo Jour-nal of the American Chemical Society vol 114 no 7 pp 2303ndash2312 1992

[26] S Ramakrishnan and M Palaniandavar ldquoMixed-ligand cop-per(II) complexes of dipicolylamine and 110-phenanthrolinesthe role of diimines in the interaction of the complexes withDNArdquo Journal of Chemical Sciences vol 117 no 2 pp 179ndash1862005

[27] I Warad A Boshaala S I Al-Resayes S S Al-Deyab and MRzaigui ldquo(29-Dimethyl-110-phenanthroline-1205812 NN1015840)diiod-idocadmiumrdquo Acta Crystallographica Section E StructureReports Online vol 67 no 12 article m1650 2011

[28] IWaradMAl-Noaimi S F Haddad and ROthman ldquoDichlo-rido(29-dimethyl-110-phenanthroline-1205812 NN1015840)mercury(II)rdquoActa Crystallographica Section E Structure Reports Online vol69 no 2 p m109 2013

[29] I Warad B Hammouti T B Hadda A Boshaala and S FHaddad ldquoX-ray single-crystal structure of a novel di-120583-chloro-bis[chloro(29- dimethyl-110-phenanthroline)nickel(II)] com-plex synthesis and spectral and thermal studiesrdquo Research onChemical Intermediates vol 39 no 9 pp 4011ndash4020 2013

[30] I Warad M Al-Ali B Hammouti T B Hadda R Shareiahand M Rzaigui ldquoNovel di-120583-chloro-bis[chloro(47-dimethyl-110-phenanthroline) cadmium(II)] dimer complex synthesisspectral thermal and crystal structure studiesrdquo Research onChemical Intermediates vol 39 no 6 pp 2451ndash2461 2013

[31] A Barakat M Al-Noaimi M Suleiman et al ldquoOne stepsynthesis of NiO nanoparticles via solid-state thermal decom-position at low-temperature of novel aqua(29-dimethyl-110-phenanthroline)NiCl

2complexrdquo International Journal ofMolec-

ular Sciences vol 14 no 12 pp 23941ndash23954 2013[32] G Gritzner and J Kuta ldquoRecommendations on reporting elec-

trode potentials in nonaqueous solventsrdquo Electrochimica Actavol 29 no 6 pp 869ndash873 1984

[33] BrukerAPEX2 SADABS SAINT-Plus and XPREP Bruker AXSInc Madison Wis USA 2009

[34] G M Sheldrick ldquoA short history of SHELXrdquo Acta Crystallo-graphica Section A Foundations of Crystallography vol 64 no1 pp 112ndash122 2007

[35] A L Spek ldquoPLATON an integrated tool for the analysis ofthe results of a single crystal structure determinationrdquo ActaCrystallographica vol A46 supplement p C34 1990

[36] C F Macrae I J Bruno J A Chisholm et al ldquoMercury CSD20mdashnew features for the visualization and investigation ofcrystal structuresrdquo Journal of Applied Crystallography vol 41no 2 pp 466ndash470 2008

[37] M Lalia-Kantouri C D Papadopoulos A G HatzidimitriouM P Sigalas M Quiros and S Skoulika ldquoDifferent geometriesof novel cobalt(II) compounds with 2-hydroxy-benzophenonesand neocuproine crystal and molecular structures of [Co(2-hydroxy-benzophenone)2(neoc)] [Co(2-hydroxy-4-methoxy-benzophenone)(neoc)Br] and [Co(neoc)Br

2]sdotCH3OHsdotH

2Ordquo

Polyhedron vol 52 pp 1306ndash1316 2013[38] A M Pyle J P Rehmann R Meshoyrer C V Kumar N J

Turro and J K Barton ldquoMixed-ligand complexes of ruthe-nium(II) factors governing binding to DNArdquo Journal of theAmerican Chemical Society vol 111 no 8 pp 3051ndash3058 1989

[39] R E Holmlin and J K Barton ldquoOs(phen)2(dppz)2+ a red-emit-

ting DNA proberdquo Inorganic Chemistry vol 34 no 1 pp 7ndash81995

[40] X-L Wang H Chao H Li et al ldquoDNA interactions ofcobalt(III) mixed-polypyridyl complexes containing asymmet-ric ligandsrdquo Journal of Inorganic Biochemistry vol 98 no 6 pp1143ndash1150 2004

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


By changing the ligands or the metal ions it is possible tomodify the interaction with nucleic acids [23ndash26]

Previously a series of several mixed-ligand mononuclear[27 28] and dinuclear [29 30] metal complexes have ageneral formula MX

2(dmphen) (29-dimethyl-110-phenan-

throline X = Cl NCS) prepared in our lab These complexeswere found to be suitable precursors for spherical shapemetal oxide nanoparticles [31] Herein two new neutralmixed-ligand cobalt(II) complexes [CoCl

2(dmdphphen)]

1 and [Co(NCS)2(dmdphphen)] 2 where dmdphphen is

(29-dimethyl-47-diphenyl-110-phenanthroline) were syn-thesized and characterized by different spectroscopic meth-ods Also the DNA binding and the catalytic oxidation ofstyrene in the presence of H

2O2for the complexes were

investigated

2 Experimental Section

21 Materials and Instrumentation 29-Dimethyl-47-diphenyl-110-phenanthroline ligand CoCl

2sdot6H2O and

Co(NCS)2were purchased from Acros Organics Elemental

analyses were carried out on an Elementar vario EL analyzerThe IR spectra for samples were recorded using PerkinElmerSpectrum 1000 FT-IR SpectrometerTheUV-Vis spectra weremeasured by using a TU-1901 double-beam UV-Vis spectro-photometer TGDTA spectra were measured by usinga TGA-7 PerkinElmer thermogravimetric analyzer Thecyclic voltammograms for the complexes were measured inCH3CN and 01M tetrabutylammonium hexafluorophos-

phate (TBAHF) using BAS 100 BW electrochemical work-station (Bioanalytical Systems West Lafayette IN USA) andcontrolled by a standard 80486 personal computer (BAS con-trol program version 20) All electrochemical experimentswere carried out at room temperature under argon with athree-electrode cell Voltalab 80 potentiostat PGZ402 withPt-disk electrode (Metrohm 119860 = 00064 cm2) was usedas working electrode Platinum wire (m 1mm) spiral withdiameter 7mm was used as a counter electrode Haber-Luggin double reference electrode was used as a referenceone All potentials in this paper are reported to an externalCp2Fe0+ standard [32]

22 General Procedure for the Preparation of the Desired Com-plexes A mixture of CoX

2salt (2mmol) in distilled ethanol

(15mL) and free ligand (21mmol) in methanol (10mL) isstirred for around 05 h at room temperature until the pre-cipitation appeared which was filtered washed with ethanoland dried Suitable crystals for X-ray diffraction analysis weregrowing up by slow diffusion of ethanol into a solution of thecomplex in CH

2Cl2after two days (yield 88)

221 Complex 1 Yield 076 g (90) Anal Calc forC26H20Cl2CoN2 C 6369 H 411 N 571 Found C 6343

H 421 N 548 UV-Vis (nm) bands in dichloromethane655 572 360 240 280 and 304 Mp 320∘C Conductivity inCH3CN 1028 (120583Scm)

222 Complex 2 Yield 094 g (88) C28H20CoN4S2 Cal C

6280 H 376 N 1046 S 1197 Found C 6292 H 385N 1033 S 1186 UV-Vis (nm) bands in dichloromethane645 566 358 242 282 and 305 Mp 290∘C Conductivity inCH3CN 952 (120583Scm)

23 Crystallography A suitable single-crystal complex 2withdimensions of 023 times 022 times 021mmwas chosen for an X-raydiffraction measurement X-ray intensity data were collectedat 296K on a Bruker CCD diffractometer equipped withCu K

120572radiation (119897 = 154178 A) Data were collected with

the 120593 and 120596 scan method The final unit cell parameterswere based on all reflections Data reduction of all thecollected reflections and absorption correction were carriedout using the APEX 2 [33] package The structure was solvedby direct methods using SHELXS [34] The structure wasthen refined by a full-matrix least-squares method withanisotropic temperature factors for nonhydrogen atoms usingSHELXL [34] All the nonhydrogen atoms were revealed inthe first Fourier map itself After several cycles of refinementthe final difference Fourier map showed peaks of no chemicalsignificance and the residual saturated to 00671 Detailsof data collection and refinement are given in Table 1 Thegeometrical calculations were carried out using the programPLATON [35] The molecular and packing diagrams weregenerated using the softwareMERCURY [36]

24 DNA Binding and Cleavage Experiments Absorbancemeasurement was performed to clarify the binding affinityof cobalt(II) complexes by emissive titration at room tem-perature The complexes were dissolved in mixed solvent ofTris-HCl buffer (5mMTris-HCl50mMNaCl buffer for pH=72) for all the experiments and stored at 4∘C for furtheruse and used within 2 days Tris-HCl buffer was subtractedthrough baseline correction The absorption experimentswere performed by keeping the concentration of cobalt(II)complexes constant (15 times 10minus4molL) and increasing theconcentration of DNA gradually (10 times 10minus4ndash1times 10minus3molL)

3 Results and Discussion

31 Synthesis of the Desired Complexes The mononuclearCoCl2(dmdphphen) complex 1 and Co(NCS)

2(dmdphphen)

complex 2 were isolated in a good yield without side productas seen in Scheme 1

The structures of the desired complexes were confirmedby using elemental analysis IR UV-Vis TGDTA and X-ray single-crystal measurement for complex 2 The analyt-ical data of the complexes show the formation of [1 1 2][M dmdphphen 2X] ratio in a good agreement with thesuggested formula [CoX

2(dmdphphen)] of the isolated com-

plexes The isolated solid complexes are insoluble in waterethanol 119899-hexane and ethers but soluble in chlorinatedsolvents as CHCl

3and CH

2Cl2The solubility andmolar con-

ductance showed that the two complexes are nonelectrolyticin their nature


N

N

CH3 CH3

CH3CH3

+ CoX2 Co

N

N

X

X

EtOH





1c


119886 = 148373(12) A120572 = 90∘

119887 = 210942(11) A120573 = 100191(4)∘119888 = 82470(6) A120574 = 90∘

Volume 25404(3) A3









1198771 = 00671 1199081198772 = 01910119877 indices (all data)





S34

C34

N33 S32

C31N30

N2

Co1C16

C3

C4

C5

C18C19

C22

C23C20

C21

C6

C7 C8

C9C10

C11

C17

C12

C14C15

C24C29

C27

C28C26

C25

N13




a

b

c

o






3in dmdphphen bands



2(dmphen)] com-






a

1

2

3200

3100

3000

2900

2800

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (1cm)

(a)

(b)

(c)



2Fe+ which has been




2(pdtp)]3+


4 Conclusions






12

10

08

06

04

02

00

120582 = 572nm

120582 = 360nm

120582 = 655nm

1

Abs

Wavelength (nm)400 500 600 700 800

(a)

20

15

10

05

00

120582 = 365nm

120582 = 645nm2Ab

s

Wavelength (nm)400 500 600 700 800

(b)


(Wt

)

100

80

60

40

20

0

0 100 200 300 400 500 600

Temperature (∘C)

TGDTA = 315

DTA



A)

200

100

0

minus100

minus200


E (V)


020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)



2FeCp

2Fe+ Absorption


Additional Material




Acknowledgments


References

































2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


N

N

CH3 CH3

CH3CH3

+ CoX2 Co

N

N

X

X

EtOH





1c


119886 = 148373(12) A120572 = 90∘

119887 = 210942(11) A120573 = 100191(4)∘119888 = 82470(6) A120574 = 90∘

Volume 25404(3) A3









1198771 = 00671 1199081198772 = 01910119877 indices (all data)





S34

C34

N33 S32

C31N30

N2

Co1C16

C3

C4

C5

C18C19

C22

C23C20

C21

C6

C7 C8

C9C10

C11

C17

C12

C14C15

C24C29

C27

C28C26

C25

N13




a

b

c

o






3in dmdphphen bands



2(dmphen)] com-






a

1

2

3200

3100

3000

2900

2800

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (1cm)

(a)

(b)

(c)



2Fe+ which has been




2(pdtp)]3+


4 Conclusions






12

10

08

06

04

02

00

120582 = 572nm

120582 = 360nm

120582 = 655nm

1

Abs

Wavelength (nm)400 500 600 700 800

(a)

20

15

10

05

00

120582 = 365nm

120582 = 645nm2Ab

s

Wavelength (nm)400 500 600 700 800

(b)


(Wt

)

100

80

60

40

20

0

0 100 200 300 400 500 600

Temperature (∘C)

TGDTA = 315

DTA



A)

200

100

0

minus100

minus200


E (V)


020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)



2FeCp

2Fe+ Absorption


Additional Material




Acknowledgments


References

































2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


a

b

c

o






3in dmdphphen bands



2(dmphen)] com-






a

1

2

3200

3100

3000

2900

2800

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (1cm)

(a)

(b)

(c)



2Fe+ which has been




2(pdtp)]3+


4 Conclusions






12

10

08

06

04

02

00

120582 = 572nm

120582 = 360nm

120582 = 655nm

1

Abs

Wavelength (nm)400 500 600 700 800

(a)

20

15

10

05

00

120582 = 365nm

120582 = 645nm2Ab

s

Wavelength (nm)400 500 600 700 800

(b)


(Wt

)

100

80

60

40

20

0

0 100 200 300 400 500 600

Temperature (∘C)

TGDTA = 315

DTA



A)

200

100

0

minus100

minus200


E (V)


020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)



2FeCp

2Fe+ Absorption


Additional Material




Acknowledgments


References

































2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


a

1

2

3200

3100

3000

2900

2800

4000 3500 3000 2500 2000 1500 1000 500

Wavenumber (1cm)

(a)

(b)

(c)



2Fe+ which has been




2(pdtp)]3+


4 Conclusions






12

10

08

06

04

02

00

120582 = 572nm

120582 = 360nm

120582 = 655nm

1

Abs

Wavelength (nm)400 500 600 700 800

(a)

20

15

10

05

00

120582 = 365nm

120582 = 645nm2Ab

s

Wavelength (nm)400 500 600 700 800

(b)


(Wt

)

100

80

60

40

20

0

0 100 200 300 400 500 600

Temperature (∘C)

TGDTA = 315

DTA



A)

200

100

0

minus100

minus200


E (V)


020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)



2FeCp

2Fe+ Absorption


Additional Material




Acknowledgments


References

































2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


A)

200

100

0

minus100

minus200


E (V)


020

015

010

005

000

500 600 700 800

Wavelength (nm)

Abs

(a)

(b)

(c)

(d)



2FeCp

2Fe+ Absorption


Additional Material




Acknowledgments


References

































2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



















2

















2]sdotCH3OHsdotH

2Ordquo















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

dna binding test, x-ray crystal structure, spectral ...1).pdf · tg-dta, and electrochemistry of...

Documents