Synthesis, Characterizations and Luminescent Properties

13Journal of Inorganic andOrganometallic Polymers and MaterialsISSN 1574-1443Volume 23Number 3J Inorg Organomet Polym (2013)23:771-778DOI 10.1007/s10904-013-9825-xSynthesis, Characterizations and Luminescent Properties of TwoCadmium(II) Coordination Polymers Derived from Bis(Benzimidazole)-Based LigandsShu Lin Xiao, Li Qin, Cui Hong He, Xu Du & Guang Hua CuiYour article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. 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The link must be accompanied by the following text: "The final publication is available at ”.13COMMUNICATIONSynthesis,Characterizations and Luminescent Properties of Two Cadmium(II)Coordination Polymers Derived from Bis(Benzimidazole)-Based LigandsShu Lin Xiao •Li Qin •Cui Hong He •Xu Du •Guang Hua CuiReceived:5September 2012/Accepted:11January 2013/Published online:22January 2013ÓSpringer Science+Business Media New York 2013Abstract Two Cd(II)coordination polymers,namely,{[Cd(L1)(chdc)]Á(CH 3CN)Á(H 2O)2}n (1)and [Cd(L 2)Cl 2]n (2)(L1=1,4-bis(5,6-dimethylbenzimidazole-1-ylmethyl)benzene,L2=1,2-bis(5,6-dimethylbenzimidazole-1-ylme thyl)benzene,H 2chdc =1,4-cyclohexanedicarboxylic acid )have been obtained by hydrothermal methods and char-acterized by IR,TG,elemental analysis,XPRD and single crystal structure analysis.The Cd(II)atom has a distorted octahedral coordination geometry in 1and a roughly square-pyramidal coordination geometry in 2.Polymer 1possesses a two-dimensional (2D)flat (6,3)network con-structed with L1and chdc bridging ligands.Polymer 2displays a one-dimensional (1D)loop-like chain structure bridged by chlorine anions and L2ligand,which is further arranged into a 2D supramolecular layer through face-to-face p –p stacking interactions.The luminescent properties of the polymers 1and 2were investigated in the solid-state.Keywords Bis(benzimidazole)ÁCadmium(II)coordination polymer ÁCrystal structure ÁLuminescent properties 1IntroductionThe last two decades have shown impressive progress in the design and synthesis of a new type of material generallyreferred to as metal-organic frameworks (MOFs)and/or coordination polymers.These materials not only have interesting molecular structures and fascinating variety of topologies,but also have potential applications in gas adsorption and separation,luminescence,non-linear optics,phase transformation,magnetism and heterogeneous catal-ysis [1–5].However,the controllable synthesis of MOFs with desired architectures is still a great challenge because there are many chemical and physical factors that play important roles in the assembly process,such as the molecular structures of the ligands,nature of the metal ions,reaction temperature,pH value,solvent,and supra-molecular interactions such as hydrogen bonding and p –p stacking interactions [6–9].Therefore,a great deal of effort is required to extend our knowledge of structural design and to establish proper synthetic strategies that lead to the desired species with predictable structures and properties.Generally,the selection of a suitable ligand is the key step in engendering MOFs with desirable dimension.So far,a variety of coordination polymers with different bridging ligands have been synthesized.In particular,bi-or multi-dentate flexible bridging ligands containing N-or O-donors have been comprehensively used to bind metal centers to generate one-,two-and three-dimensional infinite metal–organic frameworks [10–15].Bis(benzimidazole)-containing flexible ligands on para -,meta -and ortho -xylene as a bridging spacer moiety have been well-used in crystal engi-neering and are of particular interest in coordination chem-istry [16–19],since they are effective bridging ligands.The flexible nature of –(Ph-CH 2)–spacers allows the ligand to bend and rotate when it coordinates to metal centers so as to conform to the coordination geometries of metal ions [20–22].In contrast,the most outstanding compound of benzimidazole derivatives are 5,6–dimethylbenzimidazole,which serves as an axial ligand for cobalt in vitamin B 12[23].To the best ofElectronic supplementary material The online version of this article (doi:10.1007/s10904-013-9825-x )contains supplementary material,which is available to authorized users.S.L.Xiao ÁL.Qin ÁC.H.He ÁX.Du ÁG.H.Cui (&)College of Chemical Engineering,Hebei United University,46West Xinhua Road,Tangshan 063009,Hebei,People’s Republic of China e-mail:tscghua@123J Inorg Organomet Polym (2013)23:771–778DOI 10.1007/s10904-013-9825-xour knowledge,coordination polymers based onflexible bis(5,6–dimethylbenzimidazole)ligands have been scarcely studied[24–26].In this paper,we have embarked on the synthesis of twoflexible bis-benzimidazole-based ligands, 1,4-bis(5,6-dimethylbenzimidazole-1-ylmethyl)benzene and 1,2-bis(5,6-dimethylbenzimidazole-1-ylmethyl)benzene.We used these ligands to react with a Cd(II)salt under hydro-thermal conditions;and,a2D[3,6]flat topology, {[Cd(L1)(chdc)]Á(CH3CN)Á(H2O)2}n(1),and a1D loop-like chain structure,[Cd(L2)Cl2]n(2),were obtained and characterized.2Experimental2.1Materials and Physical MeasurementsAll chemicals used were analytical reagents and commer-cially purchased(Sinopharm Chemical Reagent Co,Ltd).The hydrothermal syntheses were performed in Teflon-lined stainless steel autoclaves.Ligands L1and L2were prepared according to the literature[27](Scheme1).IR spectra were obtained with a Bruker Tensor27FT-IR spectrometer using KBr pellets in the4,000–400cm-1range.Elemental analyses for C,H and N were carried out with a Vario EL III elemental analyzer.The TG measurements were carried out with a NETZSCH TG209thermal analyzer from room temperature to800°C in a nitrogen atmosphere with a heating rate of 10°C min-1.X-ray powder diffraction(XRPD)was recor-ded on a Rigaku D/Max-2500diffractometer at40kV, 100mA for a CuK a tube(k=1.54178A˚).The photolumi-nescence spectra for compounds samples were determined with a Cary Eclipsefluorescence spectrophotometer.UV-Vis spectra of1,2and ligands L1and L2were obtained with an Hitachi UV-3010spectrophotometer in DMF solution (2.0910-5mol dm3)at298K.2.2Crystallographic Data Collection and Refinement The single crystal X-ray data of coordination polymers1 and2were collected using MoK a X-ray radiation with a Bruker SMART1000CCD diffractometer at298K.A single crystal suitable for X-ray diffraction was mounted on a glassfiber.The structure was solved by direct methods and refined by full-matrix least-squares based on F2using SHELXS-97and SHELXL-97[28].The non-hydrogen atoms were refined anisotropically and the H-atoms were geometrically included in thefinal refinement.Thefinal cycle of full-matrix least-squares refinement is based on observed reflections and variable parameters.In the struc-ture of1,the two lattice water and one CH3CN molecules are disordered.Thus,this structure was refined by the SQUEEZE routine of the PLATON program[29].The void solvent accessible volume of1is595.4A˚3and the percent of per unit cell volume is17.4%.Selected crystallographic and experimental details and also interatomic distances are summarized in Tables1and2.2.3Synthesis of{[Cd(L1)(chdc)]Á(CH3CN)Á(H2O)2}n(1)A mixture of Cd(NO3)2.4H2O(23.6mg,0.1mmol),L1(39.5mg,0.1mmol),H2chdc(34.4mg,0.1mmol),CH3 CN(1mL),and H2O(4mL)was sealed in a25mL Teflon-lined stainless vessel and heated to140°C for3-d under autogenous pressure,and then cooled to room tem-perature at a cooling rate of5°C h.The slightly yellow block-shaped crystal of1was obtained byfiltration.1was washed with distilled water and dried in the air;yield, 50.4%[based on Cd(NO3)2.4H2O].Anal.Calc.for C36H43CdN5O6(Mr=755.22)(%):C,57.2;H,5.7;N, 9.3.Found:C,56.9;H,5.6;N,9.1.FT-IR(KBr pellets, cm-1):3,380s,3,130m,2,939m,1,630w,1,539s,1,419s, 1,210m,1,060m,856s,630w,470m.2.4Synthesis of[Cd(L2)Cl2]n(2)By employing the above described procedure with a mixture of CdCl2(18.3mg,0.1mmol),L2(39.5mg,0.1mmol), ethanol(4mL),and H2O(6mL),colorless block-shaped crystals of2were obtained.2wasfiltered,washed with distilled water and dried in the air;yield,72.4%(based on CdCl2).Anal.Calc.for C26H26CdCl2N4(Mr=578.06)(%): C,54.0;H,4.5;N,9.7.Found:C,53.8;H,4.4;N,9.6.FT-IR123(KBr pellets,cm-1):3,088m,2,934m,1,490s,1,218m, 1,059w,863m,762m,622w,615w,432w.3Results and Discussion3.1IR and UV Absorption SpectraIn the FTIR spectra of1and2,the bands at1,539,1,210 and1,060cm-1for1and1,490,1,218,1,059cm-1for2 are assigned to benzimidazolyl ring vibrations.In1,a strong band at3,380cm-1is assigned to m OH stretching vibrations of the lattice water molecules.The broadness of this band suggests the H-bonding.The C=N stretching vibration of the benzimidazolyl group(1,539cm-1)is blue-shifted by48cm-1relative to free the free ligand (1,491cm-1),and is consistent with coordination of L1to Cd(II).Furthermore,the carboxylate group asymmetric and symmetric stretching vibrations are observed at1,720and 1,410cm-1,respectively,for free1,4-cyclohexanecarbox-ylic acid,while in1these bands occur at1,630and 1,419cm-1,respectively.The separation,D m[m as(COO)-m s(COO)],is111cm-1and indicates the presence of che-lating coordination of the carboxylic groups[30].The absorption spectra of the ligands1and2in DMF solution were measured at room temperature(Figure S1–S2,Supporting Information).The strong bands at266,282,291nm (for L1),265,283,291nm(for complex1),282,291nm(for L2),and264,285,291nm(for complex2)are ascribed to the p?p*transition within the benzimidazolyl rings.Table1Crystallographic data and structure refinement parameters for1and2Crystal data12Formula C36H43CdN5O6C26H26CdCl2N4 Formula weight755.22577.81 Crystal system Monoclinic Triclinic Space group C2/m P-1a(A˚)21.074(2)10.8341(15)b(A˚)16.5844(17)10.8631(15)c(A˚)11.4834(12)12.1669(17)a/deg9064.502(2)b/deg127.2760(10)85.092(2)c/deg9071.087(2)V(A˚3)3,430.2(6)1,220.3(3)Z42q calcd(g cm-3) 1.311 1.573l,mm-10.677 1.136F(000)1,392584 Collected reflection15,92610,219 Independent reflection4,0714,806 Goodness-of-fit on F20.9370.874R(int)0.07070.0310R1,wR2(I[2r(I))0.0421,0.08130.0337,0.0722 Largest residuals,e A˚-30.421/-0.5280.423/-0.393Table2Selected bond lengths(A˚)and angles(°)for1and2 Complex1Bond lengths(A˚)Cd1–N1B 2.278(2) Cd1–O3A 2.238(4) Cd1–N1 2.278(2) Cd1–O1 2.429(2) Cd1–O1B 2.429(2) Cd1–O2A 2.455(4) Bond angles(°)O3A–Cd1–N1132.81(16) O3A–Cd1–N1B110.39(17) N1–Cd1–N1B104.12(13) O3A–Cd1–O186.83(14) N1–Cd1–O1128.05(8)N1B–Cd1–O184.97(8)O3A–Cd1-O1B97.60(14) N1–Cd1–O1B84.97(8)N1B–Cd1–O1B128.05(8)O1–Cd1–O1B53.03(11) O3A–Cd1–O2A51.73(15) N1–Cd1–O2A94.95(8)N1B–Cd1–O2A94.95(8)O1–Cd1–O2A135.78(10) O1B–Cd1–O2A135.78(10) Complex2Bond lengths(A˚)Cd1–N3 2.261(3) Cd1–N1 2.357(3) Cd1–Cl2 2.4432(10) Cd1–Cl1 2.4769(9) Cd1–Cl1A 2.8101(9) Bond angles(°)N3–Cd1–N198.53(10) N3–Cd1–Cl2109.29(8)N1–Cd1–Cl295.94(7)N3–Cd1–Cl1111.10(7)N1–Cd1–Cl188.67(7)Cl2–Cd1–Cl1138.13(4)N3–Cd1–Cl1A91.62(7)N1–Cd1–Cl1A167.18(7)Cl2–Cd1–Cl1A87.99(3)Cl1–Cd1–Cl1A80.34(3) Symmetry codes1,A:-x?1,y,-z?1,B:x,-y?1,z;2,A: -x?1,-y?1,-z?21233.2Crystal Structure of 1and 2The structure of polymer 1was determined by single X-ray crystal diffraction.The ORTEP diagram of the coordination environment of Cd(II)atom is depicted in Fig.1a.The structural motif of 1consists of one 6-coordinated Cd(II)ion that located in the mirror plane of the C2/m space group,one-half a L1ligand,and one-half a chdc diatomic anion possessing chelating bis-bidentate carboxylate groups.The crystallographically independent Cd(II)center lies in a dis-torted octahedral coordination environment and is completed by two N-donors (N1and N1B)of two L1ligands and four O-donors (O1,O1B,O2A,and O3A,symmetry codes:A =-x ?1,y,-z ?1,B =x,-y ?1,z )from two chelating carboxylate groups of distinct chdc ligands.The atoms O1,O3A,O2A,N1compose the equatorial positions and N1B,O1B hold the axial positions.The Cd–O bondlengths range from 2.238(4)to 2.455(4)A˚,while the Cd–N1and Cd–N1B bond lengths are both 2.278(2)A˚,all lying within the reasonable bonding range as estimated from crystallographic determination (Table 2).The O–Cd–O or O–Cd–N or N–Cd–N bond angles are far from the typical octahedral 90°or 180°;they range from 51.73°to 135.78°for O–Cd–O,84.97°to 132.81°for O–Cd–N and 104.12°forFig.1a ORTEP drawing of 1with thermal ellipsoids drawn at 30%probability and the coordination environment of Cd(II)atom.The hydrogen atoms are omitted for clarity (Symmetry codes:A =-x ?1,y,-z ?1,B =x,-y ?1,z).b 2D flat structure of 1.c 2D (6,3)flat network of 1.d 2D supramolecular network of 1stabilized by p …p stacking interactions123N–Cd–N angles.Thus,as a node,the adjacent Cd(II)-atoms are infinitely linked by L1ligands to generate a zigzag chainwith shorter separations of Cd •••Cd being 14.8789(13)A˚and the angle of Cd–Cd–Cd being 67.74°.The zigzag chains are further bridged by chdc ligands,which adopt a bis-bidentate l 2-g 4bridging mode to connect two Cd(II)-atoms to form an 18-membered ring with the nearest Cd •••Cddistance between the zigzag chains of 7.8343(8)A˚(Fig.1b).The L1ligands exhibit a trans form with two coplanar benzimidazole rings from same L1ligand;the chdc ligands possess a cis form and the two hexamethylene rings from two chdc diatomic anions within one 18-membered annulus are parallel.Therefore,each 6-coordinated Cd(II)center is connected by two L1and two chdc ligands to form a 2D flat topography with honeycomb like 63topology (Fig.1c).In addition,the strong p –p stacking interactions between the benzene and imidazole rings from different L1ligands make the flat topologies more stable and result in self-assembly to a supramolecular structure with a centroid-to-centroid dis-tance of 3.65(7)A˚,slipping angles b or c of 16.12o or 16.62o ,and an average d p –p distance of 3.5034(12)A˚(Fig.1d).The X-ray diffraction study of 2reveals an asymmetric unit consisting of one Cd(II)center,one L2ligand,one terminal chlorine anion and two l 2bridging chlorine anions,which sit on inversion centers in triclinic P -1.Cd1is located in the center of a roughly square-pyramidal geometry (s factor,0.48[31]),which is formed by three Cl-atoms and two N-atoms from two bridging L2ligands (Fig.2a).The four atoms,Cl1,Cl2,Cl1A and N1,form a tapered bottom and the N-atom (N3)is located in the conic node.The distance from the conic node to the taperedbottom is 2.257A˚.The Cd–Cl bond lengths vary from 2.4432(10)to 2.8101(9)A˚,the Cd–N bond lengths vary from 2.261(3)to 2.357(3)A˚and the coordination bond angles range from 80.34(3)°to 167.18(7)°(Table 2).Complex 2displays an interesting infinite 1D loop-like chain structure composed of two kinds of rings;i.e.,a smaller 4-membered ring and the larger 24-membered ring (Fig.2b).The smaller ring is formed by twochlorineFig.2a ORTEP drawing of 2with thermal ellipsoids drawn at 30%probability and the coordination environment of Cd(II)atom.The hydrogen atoms are omitted for clarity.(Symmetry codes:A =-x ?1,-y ?1,-z ?2).b 1D infinite looped-like structure of 2.c 2D supramolecular structure of 2formed by p …p stacking interactions123anions bridging two Cd(II)ions with a CdÁÁÁCd distance is 4.0455(7)A˚;the larger ring is made up of two L2mole-cules bridging two Cd(II)ions with a CdÁÁÁCd distance is 15.834(2)A˚.Each L2exhibits a trans conformation with the dihedral angle between the two benzimidazole planes of81.259°.The above two kinds of rings are connected alternately via Cd(II)ions to form an infinite1D chain.Moreover,the adjacent looped chains are nearly parallel with a dihedral angle of1.267(4)°,which results in for-mation of strong p–p stacking interactions between benz-imidazole rings of distinct L2ligands.Thus,the looped chains are expanded to a2D supramolecular network by p–p stacking interactions(Fig.2c),with a center-to-center distance of3.541(2)A˚,an inter-planar angle a of1.27(2)°, slipping angles b or c of14.67o or13.92°and an average d p–p distance of3.431(4)A˚.In addition,there appears to be C–HÁÁÁCl hydrogen bonding interactions between benzyl C-atoms and Cl-atoms,which stabilize the2D supramo-lecular structure.The distance of H20AÁÁÁCl2is2.60(4)A˚and the bond angel for C20–H20AÁÁÁCl2is167°.Cd(II)coordination polymers based on the L1,L2or similar bis(benzimidazole)derivatives and polycarboxylates have been scarcely reported.Hou and co workers[32]prepared four Cd(II)-ferrocenesuccinate(FcCOC2H4COO)coordination compounds with the formulas[Cd(g2-FcCOC2H4COO)2 (pbbbm)]2,[Cd(g2-FcCOC2H4COO)(pbbbm)Cl]2,[Cd(g2-FcCOC2H4COO)-(pbbbm)I]2and{[Cd(g2-FcCOC2-H4 COO)(mbbbm)Cl].(H2O)2.75}n[pbbbm=1,4-bis(benzimid-azole-1-ylmethyl)benzene),mbbbm=1,3-bis(benzimidazole -1-ylmethyl)benzene)].The former three complexes are dimers and bridged by pbbbm and the last complex has chain-like structure bridged by chlorine anions and adjacent mbbbm ligand.Furthermore,Wang et al.reported two3D Cd(II) coordination polymers:[Cd3(bbbm)3(SIP)2(H2O)4].2H2O and [Cd(bbbm)(NIP)](bbbm=1,1-(1,4-butanediyl)bis-1H-benz-imidazole,H3SIP=5-sulfoisophthalic acid and H2NIP=5-nitroisophthalic acid)[33].In the[Cd3(bbbm)3(SIP)2(H2O)4]. 2H2O polymer,Cd(II)ions are connected by SIP anions to form 2D layers containing a12-membered macrocycle,which is further connected by the bbbm linkers to form a3D(3,3,4,4,4)-connected framework with a(3.6.73.8)(3.6.7)(3.62.73)(6.72) (6.74.10)topology.The complex,[Cd(bbbm)(NIP)],displays a 3D8-connected framework with a(424.64)topology connected by bbbm ligands and NIP anions.The complexes reported here have diverse structures:1displays a2D(6,3)flat network and2 exhibits a1D loop-like chain.This implies that different car-boxylates and anions play an important role in the assembly and structure of the title complexes.3.3Thermal PropertiesTo investigate the thermal stability of1and2,TGA were performed(Figure S3and Figure S4,Supporting Information).The decomposition of1occurs in two dis-tinct stages.Thefirst weight loss of7.9%from82.2to 202°C corresponds to the removal of water and acetoni-trile which are included in the crystal lattice(calcd.7.81%).The second mass loss occurs from237to502°C was75.6%and is assigned to the decomposition of the organic ligands,L1and chdc(calcd.75.7%).A residue of 16.4%(calcd.16.5%)suggests CdO asfinal decomposi-tion plex2is thermally stable to404°C. Then2rapidly loses weight from405to577°C,which corresponds to the decomposition of L2(observed67.9%, calcd.68.3%).The remaining mass(32.1%)is consistent with a CdCl2residue(calcd.31.7%).3.4XRPD ResultsThe powder XRPD pattern and simulated pattern of1and2 are depicted in Fig.3a–b.The measured and simulated powder patterns are in good agreement with the X-ray single crystal data,indicating phase purities of the samples. The difference in reflection intensities between the exper-imental and simulated patterns is due to the different ori-entation of the crystals in the powdered samples.1233.5Photoluminescence PropertiesCompounds of d 10metals exhibit some interesting photolu-minescent properties [34].The solid-state luminescence spectra of complexes 1and 2(Fig.4a,b)together with corresponding free ligands were investigated at room tem-perature under the same conditions.The free ligands exhibit strong fluorescence at k max =316nm (L1),346nm (L2)upon excitation at 298nm.The emission bands of the ligands are assigned to p ?p *transition [24–26].The emission spectra of the title complexes display photoluminescence with emission maxima at 402nm for 1,and 347nm for 2on excitation at pared to the emission of corre-sponding ligands,a red shift of 86nm for 1and 1nm for 2are observed.This suggests that the photoluminescence of the complexes originates mainly from the free ligands and are assigned to the p ?p *transition of the coordinated ligands since the Cd 2?ion is difficult to oxidize or reduce due to its d 10configuration [35–37].4ConclusionIn summary,two new Cd(II)coordination polymers based on flexible bis(5,6-dimethylbenzi-midazol)benzene,{[Cd(L1)(chdc)]Á(CH 3CN)Á(H 2O)2}n (1)and [Cd(L2)Cl 2]n (2),have been obtained and characterized.Structural analysis showed that 1displays a 2D (6,3)flat network linked by L1and chdc ligands,whereas 2has an infinite loop-like chain connected by L2ligands and chlorine atoms,then extended to 2D supramolecular structure by strong intermolecular p –p stacking interactions.This work presents that the different anions (or carboxylate anion)and the flexibility of ligands may exert a crucial influence on the formation of resulting diverse structures and supramolecular architectures.5Supplementary MaterialCrystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre with CCDC No:897111and 897112contain the supple-mentary crystallographic data for 1and 2,respectively.Copies of this information may be obtained free of charge on application to CCDC,12Union Road,Cambridge CB21EZ,UK (Fax:?44-1223-336033;E-mail:deposit@ or on the web ).The absorp-tion spectra of the ligands and complexes and the TG curves of 1and 2(Fig.S1–S4)are available from the corresponding author at tscghua@References1.R.Custelcean,Chem.Soc.Rev.39,3675(2010)2.B.Moulton,M.J.Zaworotko,Chem.Rev.101,1629(2001)3.K.K.Tanabe,S.M.Cohen,Chem.Soc.Rev.40,498(2011)4.M.Pan,X.M.Lin,G.B.Li,C.Y.Su,Coord.Chem.Rev.255,1921(2011)5.F.A.A.Paz,J.Klinowski,S.M.F.Vilela,J.P.C.Tome´,J.A.S.Cavaleiro,J.Rocha,Chem.Soc.Rev.41,1088(2012)6.D.S.Chowdhuri,M.Bera,A.Rana,D.Hazari,S.K.Jana,E.Zangrando,S.Dalai,anomet.Polym.Mater.22,963(2012)7.M.S.Y.Parast,A.Morsali,anomet.Polym.Mater 22,998(2012)8.L.Yan,C.B.Li,D.S.Zhu,L.Xu,anomet.Polym Mater.22,235(2012)9.Y.Ding,Z.B.Fu,X.L.Hu,C.F.Xia,anomet.Polym.Mater.20,642(2010)10.J.C.Geng,G.H.Cui,C.H.Jiao,T.F.Liu,C.H.He,J.Chin.Chem.Soc.59,704(2012)11.X.L.Wang,Y.F.Bi,H.Y.Lin,G.C.Liu,Cryst.Growth Des.7,1086(2007)12.X.L.Wang,H.Y.Lin,G.C.Liu,B.K.Chen,Y.F.Bi,Chem.Res.Chin.Univ.24,129(2008)13.X.L.Wang,J.X.Zhang,G.C.Liu,H.Y.Lin,Y.Q.Chen,Z.H.Kang,Inorg.Chim.Acta 368,207(2011)14.X.L.Wang,S.Yang,G.C.Liu,J.X.Zhang,H.Y.Lin,A.X.Tian,Inorg.Chim.Acta 375,70(2011)15.G.H.Cui,C.H.He,C.H.Jiao,J.C.Geng,V.A.Blatovb,mun.14,4210(2012)16.C.H Jiao,J.C.Geng,C.H.He,G.H.Cui,J.Mol.Struct.1020,134(2012)Fig.4Fluorescence emission spectra of a ligand L1and complex 1.b Ligand L2and complex12317.C.H.Jiao,C.H.He,J.C.Geng,G.H.Cui,J.Coord.Chem.65,2852(2012)18.J.C.Geng,C.H.Jiao,J.M.Hao,G.H.Cui,Z.Naturforsch.67b,791(2012)19.Z.Zhang,M.Pi,T.Wang,C.M.Jin,J.Mol.Struct.992,111(2011)20.J.Yao,Z.D.Lu,Y.Z.Li,J.G.Lin,X.Y.Duan,S.Gao,Q.J.Meng,C.S.Lu,mun.10,1379(2008)21.S.R.Zhu,H.Zhang,Y.M.Zhao,M.Shao,Z.X.Wang,M.X.Li,J.Mol.Struct.892,420(2008)n,S.L.Li,J.S.Qin,D.Y.Du,X.L.Wang,Z.M.Su,Q.Fu,Inorg.Chem.47,10600(2008)23.S.S.Marwaha,R.P.Sethi,J.F.Kennedy,Enzyme Microb.Technol.5,361(1983)24.C.H.He,C.H.Jiao,J.C.Geng,G.H.Cui,J.Coord.Chem.65,2294(2012)25.J.C.Geng,L.Qin,C.H.He,G.H.Cui,Transition Met.Chem.37,579(2012)26.S.L.Xiao,X.Du,L.Qin,C.H.He,G.H.Cui,ano-met.Polym.Mater.22,1384(2012)27.C.B.Aakeroy,J.Desper,E.Elisabeth,B.A.Helfrich,B.Levin,J.F.Urbina,Z.Kristallogr.220,325(2005)28.G.M.Sheldrick,Acta Crystallogr.A64,112(2008)29.A.L.Spek,A.Platon,Multipurpose Crystallographic Tool(Utr-echt University,Utrecht,2000)30.G.B.Deacon,R.J.Phillips,Coord.Chem.Rev.33,227(1980)31.A.W.Addison,T.N.Rao,J.Chem.Soc.,Dalton Trans.1349(1984)32.J.P.Li,L.K.Li,H.W.Hou,Y.T.Fan,anomet.Chem.694,1359(2009)33.X.L.Wang,L.L.Hou,J.W.Zhang,J.X.Zhang,G.C.Liu,S.Yang,mun.14,3936(2012)34.Q.Y.Liu,Y.L.Wang,L.Xu,Eur.J.Inorg.Chem.23,4843(2006)35.Y.B.Dong,H.Y.Wang,J.P.Ma,D.Z.Shen,R.Q.Huang,Inorg.Chem.44,4679(2005)36.J.L.Yin,Y.L.Feng,n,Inorg.Chim.Acta362,3769(2009)37.S.Geranmayeh,A.Abbasi,M.Y.Skripkin,A.Badiei,Polyhedron45,204(2012)123。