含有4_對溴苯基_3_5_二_2_吡啶基__省略_氮唑鈷配合物的合成_晶體結構和

1、收稿日期:2007-12-03。收修改稿日期:2008-03-21。國家自然科學基金資助項目(No.20771059和江蘇省高校自然科學研究計劃資助項目(No.05KJB150045。*通訊聯(lián)系人。E-mail :zhudr 第一作者:齊麗,女,25歲,碩士研究生;研究方向:分子信息材料。含有4-對溴苯基-3,5-二(2-吡啶基-1,2,4-三氮唑鈷配合物的合成,晶體結構和磁性齊麗朱敦如*解大景吳艷飛沈旋(南京工業(yè)大學化學化工學院,材料化學工程國家重點實驗室,南京210009摘要:本文合成了一個二價鈷配合物CoL 52(NCS2,(配體L 5=4-對溴苯基-3,5-二(2-吡啶基-1,2,4-

2、三氮唑。其結構由單晶X 衍射結構分析,紅外和電噴霧離子質譜表征。該配合物晶體屬于三斜晶系,空間群為P1,鈷原子和2個三芳基三氮唑配體的4個氮原子(平面和2個硫氰根的氮原子(軸向配位形成扭曲的八面體構型。磁性測定表明在1.8300K 的溫度范圍內該配合物處于高自旋態(tài)。關鍵詞:鈷配合物;晶體結構;三氮唑;磁性中圖分類號:O614.81+2文獻標識碼:A文章編號:1001-4861(200806-0868-05Synthesis,Crystal Structure and Magnetic Property of a Novel Cobalt !Complex with 4-(p-bromophen

3、yl-3,5-bis(2-pyridyl-1,2,4-triazoleQI Li ZHU Dun-Ru *XIE Da-Jing WU Yan-Fei SHEN Xuan(College of Chemistry and Chemical Engineering,State Key Laboratory of Materials-oriented ChemicalEngineering,Nanjing University of Technology,Nanjing 210009Abstract:A new cobalt !complex,CoL 52(NCS2,L 5=4-(p-bromop

4、henyl-3,5-bis(2-pyridyl-1,2,4-triazole,was synthesized and its structure was determined by single crystal X-ray diffraction,FTIR and ESI-MS spectroscopy.The complex crystallizes in triclinic system with space group P1.The cobalt atom is in a distorted octahedral environment with two bidentate chelat

5、ing L ligands in the equatorial plane and two NCS -ions in the axial positions.Magnetic measurements show that the complex is in a high-spin state in the 1.8300K range.CCDC:668715.Key words:cobalt !complex;crystal structure;triazole;magnetic propertySubstituted 1,2,4-triazole is a very useful ligand

6、 in coordination chemistry 1.This is mainly because of the fact that the 1,2,4-triazole systems can act as bridging ligands between transition metal ions thus promising rich and versatile coordination modes.More interestingly,some iron !complexes with the sub-stituted 1,2,4-triazoles have spin-cross

7、over properties which can be used as molecular electronics 2,memorydevices 3,information storage 4and switching mater-ials 5.However,compared with alkyl-substituted 1,2,4-triazole,complexes containing triaryltriazole ligand have been rarely studied up to now 6.Recently,some new triaryltriazole compo

8、unds 714(Scheme 1and their complexes 1522have been prepared by us and the oth-er workers.However,coordination compounds with 4-(p-bromophenyl-3,5-bis (2-pyridyl-1,2,4-triazole (L 58第24卷第6期2008年6月Vol.24No.6868872無機化學學報CHINESE JOURNAL OF INORGANIC CHEMISTRY第6期齊麗等:含有4-對溴苯基-3,5-二(2-吡啶基-1,2,4-三氮唑鈷配合物的合成,

9、晶體結構和磁性 Empirical formula C 38H 24Br 2CoN 12S 2Z1Formula weight931.56D c /(Mgm -31.65which was synthesized in 1998have not been observed so far.This paper deals with the first complex with the ligand L 5.We report here the synthesis,crystal structure and magnetic property of a new cobalt !complex wi

10、th the ligand L 5:CoL 52(NCS2.1Experimental1.1Materials and measurementsAll chemicals used were of analytical grade.Solvents were purified by conventional methods.The ligand (L 5was prepared as reported earlier 8.Elemental analyses were performed with a Perkin-Elmer 240instrument.FTIR spectrum was r

11、ecorded on a Vector 22Br üker spectrometer with KBr pellets in the 4000400cm -1region.Electrospray ionization mass spectrum (ESI-MSwas recorded with an Agilent 1100LC/MSD SL spectrometer,with MeOH on the mobile phase;theflow rate of the mobile phase was 0.2cm 3min -1.The capillary voltage and t

12、emperature was 2500V and 325,respectively.The flow of nebulizer gas and dry gasis 12and 8cm 3min -1,respectively.Variable temperat-ure magnetic susceptibilities of crystalline of the complex were measured on a Quantum Design MPMS SQUID-XL7magnetometer in the temperature range of 1.8300K.Diamagnetic

13、corrections were made with Pascal s constants for all the constituent atoms.1.2Synthesis of CoL 52(NCS2To a solution of KSCN (0.4mmolin anhydrousMeOH (3mLwas added a solution of CoCl 26H 2O (0.2mmolin MeOH (2mL.The mixture was stirred for 15min and filtered.The KCl precipitate was washed with 2mL of

14、 anhydrous MeOH.The methanolic fractions containing Co(SCN2were collected,and then was added dropwise to a solution of the L 5(0.4mmolin MeOH (5mL.A light-yellow microcrystalline product,which formed immediately,was filtered and washed with H 2O,and dried under vacuum to give 0.132g (71%of the compl

15、ex.The light-yellow single crystals suitable for X-ray diffraction were obtained by evaporation from an acetonitrile solution.Elemental analyses Found(%:C 49.12,H 2.82,N 18.31.C 38H 24Br 2CoN 12S 2calcd.(%:C48.99,H 2.60,N 18.05.IR (cm -1:(CN2071.8vs;(py ring1601s,1585m,1571w;(ph ring832.1m,794.2s;(A

16、r-Br1068m.ESI-MS:m/z 873.1,597.1,514.0,407.6,380.2.1.3Crystal structure determinationA light-yellow plate crystal of the complex was selected for lattice parameter determination and collection of intensity data at 293K on a FR590CAD4four-circle diffractometer with monochromatized Mo K radiation (=0.

17、071073nmusing a 2scan mode.The data was corrected for Lorenz and polarization effects after data reduction.An empirical absorption correction based on scans was applied.The structure was solved by the direct methods and refined on F 2by full-matrix least-squares methods using SHELXTL version 6.1023.

18、All non-hydrogen atoms were refined anisotropically.Hydrogen atoms for C-H were placed in calculated positions (C-H,0.096nmand assigned fixed isotropic thermal parameters at 1.2times of the equivalent isotropic U of the C atoms to which they are attached.The contribution of these hydrogen atoms was

19、included in the structure factor calculations.All computations were carried out usingthe SHELXTL program package.Analytical anomalous dispersion corrections were incorporated.Crystallographic data for the complex are summarized in Table 1.CCDC:668715.Scheme 1Table 1Crystallographic data for the comp

20、lex869第24卷無機化學學報Temperature /K 293(2F(000465Crystal size /mm 0.20×0.15×0.10Absorption coefficient /mm -12.747Crystal color,shape Light-yellow,plate range /(°1.5425.00Crystal system Triclinic Index range (h,k,l(-9/9,-10/10,0/15Space group P1Reflections collected 3175a /nm 0.82165(8Inde

21、pendent reflections 3175b /nm 0.86737(10Data /restraints /parameters 3175/139/214c /nm 1.33235(15Goodness-of-fit on F 20.943/(°95.20(3Final R,wR indices I>2(I0.0774,0.1498/(°92.23(3R,wR indices (all data0.1775,0.1897/(°96.80(3Largest diff,peak and hole /(e nm -3532and -631V /nm 30.

22、93779(182Results and discussion2.1SynthesisThe triaryltriazole ligand L 5reacts with CoCl 26H 2O and KSCN in molar ratio 212to form a neutral mononuclear hexacoordinate complex of formula CoL 52(NCS2,which is stable in air.Yield for the com-plex is 71%.The elemental analysis was satisfactory and ind

23、icates that the complex contains one cobalt atom,two L 5ligands,two thiocyanate groups.2.2Crystal structureFig.1presents an OPTEP 24plot of the complex with its atom numbering scheme.The complex crystallizes in the triclinic space group P1and there is an inversion center at the cobalt !atom.The crys

24、tal structure consists of CoL 52(NCS2,which is consistent with the elemental analysis result.Relevant interatomic distances and angles are given in Table 2.The cobalt atom is surrounded by four nitrogen atom from two L 5ligands in the equatorial plane and two nitrogen atoms from two NCS -ions in the

25、 axial positionsto form a distorted octahedral geometry.The NCS -group is almost linear N(6-C(19-S 178.0(11°,and the Co-N-C(Slinkage is bent Co-N(6-C(19158.7(9°,the angle is larger than those found in some analogous trans-NCS -metal !complexes,for example,148.3(3°for FeL 22(NCS25,147.

26、8(3°for MnL 22(NCS215,but smaller than that 172.4(4°observed in a trans-CoL 22(NCS22CH 2Cl 2complex 16,L 2=4-(p-methylphenyl-3,5-bis(2-pyridyl-1,2,4-triazole.It is worthwhile to note that Co-N(CSbond length 0.2101(9nmis equal to Co-N(trzdistance 0.2101(8nm.This result is differentContinued

27、 Table 1Symmetry codes:A:-x,2-y,-z.Table 2Selected bond distances (nmand angles (°for complexCo(1-N(60.2101(9N(3-C(70.1309(10N(6-C(190.1185(12Co(1-N(30.2101(8N(5-C(140.1375(11C(19-S0.1567(13Co(1-N(50.2158(7N(5-C(180.1322(12N(3-N(20.1370(10N(4-C(80.1438(10Co(1-N(6-C(19158.7(9N(5-Co(1-N(376.6(3N(

28、3-Co(1-N(3A180.000(1N(6-Co(1-N(6A180.0(4N(5-Co(1-N(5A180.000(1N(6-C(19-S178.0(11N(6-Co(1-N(587.8(3N(6-Co(1-N(390.0(3Symmetry code:A:-x,2-y,-zFig.1Structure of CoL 52(NCS2,H atoms are omitted for clarity870第6期齊麗等:含有4-對溴苯基-3,5-二(2-吡啶基-1,2,4-三氮唑鈷配合物的合成,晶體結構和磁性2.4Magnetic propertyThe temperature depende

29、nce of the molar magnetic susceptibility of CoL 52(NCS2is depicted inFig.3in the form of m and m -1vs T.The result reveals that the complex is paramagnetic at 1.8300K range,which indicates that the cubic crystal-field splitting (=10Dqis lower than the electron pairing energy (P.For the high-spin com

30、plex a magnetic moment of 4.96B.M./Co 2+is observed,as expected for an ion with 4T 1ground term.The eff value is in the normalfrom those found in two homologous cobalt !comp-lexes,trans-CoL 12(NCS221L 1=4-(p-methoxyphenyl-3,5-bis(2-pyridyl-1,2,4-triazoleand trans-CoL 22(NCS2,where the Co-N(CSbond di

31、stance is shorter than the Co-N(trzone.In addition,the Co-N(CSbond distance is also shorter than Co-N(pyone,which is similar to the features in complexes CoL 12(NCS2and CoL 22(NCS2.The coordination mode of the ligand (L 5is the same as those of the triaryltriazoles found in complexes CoL 12(NCS2and

32、CoL 22(NCS2.The pyridyl ring where nitrogen atom is involved in coordination makes an angle of 9.4(8°with respect to the triazole ring,whereas the non-coordinating pyridyl ring makes an angle of 13.5(8°with respect to the triazole ring.The similar features are 14.6(4°,45.0(4°and

33、11.7(2°,40.7(1°found in the complexes CoL 12(NCS2and CoL 22(NCS2,respectively.2.3Spectral characterization2.3.1FTIR spectraThe IR spectrum of CoL 52(NCS2is similar tothose observed for the related complexes CoL 22(NCS22CH 2Cl 216and MnL 22(NCS215.A very strong band at 2071.8cm -1is assigne

34、d to C N stretching vibrationsof two trans-oriented thiocyanate groups.A band at 1601cm -1(sand two bands at 1585(mand 1571cm -1(wcan be assigned to one coordinated and one uncoor-dinated pyridine ring,respectively.This means that in this complex,the ligand L 5use one pyridine nitrogen and one triaz

35、ole nitrogen for chelate binding.In addition,the diagnostic symmetrical stretching frequen-cy of Ar-Br is at 1068cm -1(m.The C-H out of plane absorption of the para-substituted phenyl is located around 832.1(mand 794.2cm -1(s.The triazole out-of-plane ring absorption is observed at 637.3cm -1(m.2.3.

36、2ESI-MS spectrumThe structure of CoL 52(NCS2in solution was also studied by electrospray ionization mass spectrometry (ESI-MS2527.Fig.2displays a positive ion ESI mass spectrum of the complex in the methanol solution.The base peak at m/z 873.1is CoL 52(NCS+ion and the peak at m/z 597.1is CoL 53+.The

37、 peak at m/z 514.0is assi-gned to CoL 5(NCS(H 2O+,which indicates that CoL 5(NCS+structure unit combine with a H 2O molecule.The peaks at m/z 407.6and 380.2are CoL 52+and (L 5+2+,respectively.Fig.2Positive ion ESI mass spectrum of the complex in methanol solutionFig.3m (and m -1(vs T plot for CoL 52

38、(NCS2871第24卷無機化學學報range observed for a high-spin cobalt!complex(eff= 4.35.2B.M.of O h symmetry.According to the Curie-Weiss law,m=C/(T-,the data are in a good linear relationship betweenm-1vs T.The complex is antiferromagnetic with C=3.07(2and=-8.7(9K. Current works seeks to investigate further the

39、coordination of the ligand L5to other transition metal ions,especially to iron!ion,in order to find new spin-crossover complexes.3ConclusionsIn this paper a new cobalt!complex with triarylt-riazole ligand has been synthesized and characterized by elemental analyses,IR,ESI-MS spectra and X-ray diffra

40、ction crystal structure analysis.The cobalt atom is in a distorted octahedral environ-ment and is coordin-ated by two trans-oriented thiocy-anate anions.Each triaryltriazole entity coordinates via one triazole nitrogen atom and one pyridine nitrogen atom.Magnetic measurements show that the complex i

41、s high-spin species in the1.8300K range.References:1Haasnoot J G.Coord.Chem.Rev.,2000,200202:1311852Kr"ber J,Codjovi E,Kahn O,et al.J.Am.Chem.Soc.,1993,115:981098113Kahn O.Chem.Britain,1999,35:24274Kahn O,Martinez C J.Science,1998,279:44485Zhu D R,Xu Y,Yu Z,et al.Chem.Mater.,2002,14:8388436Klingele M H,Brooker S.Coord.Chem.Rev.,2003,24:1191327Wang Z X,Bai Z P,Yang J X,et al.Acta Crystallogr.,1998,C54:4384398Chen W,Wang Z X,Jian F F,et al.Acta Crystallogr.,1998,C54:8518529Fun H K,C