兩個含[MS4Cu4]簇核的一維配位聚合物{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo，W；ani=苯胺)的組裝及其晶體結構

劉泉　陳秋芳　虞虹　趙鑫　張文華　郎建平＊,

(1蘇州大學材料與化學化工學部，蘇州215123)

(2南通大學化學化工學院，南通226019)

兩個含[MS4Cu4]簇核的一維配位聚合物
{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo，W；ani=苯胺)的組裝及其晶體結構

劉泉1,2陳秋芳1虞虹1趙鑫1張文華1郎建平＊,1

(1蘇州大學材料與化學化工學部，蘇州215123)

(2南通大學化學化工學院，南通226019)

前驅團簇[Et4N]4[MS4Cu4I6](M=Mo(1a)；W(1b))與雙齒橋連配體1，2-雙(4-吡啶基)乙烷(bpe)在苯胺溶液中反應，生成2個結構相似的一維[MS4Cu4]團簇基配位聚合物{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo(2)，W(3)；ani=苯胺)。通過元素分析、紅外光譜和X-射線單晶衍射對2和3進行了表征。晶體結構分析表明前驅團簇1a和1b中五核馬鞍形[MS4Cu4]簇核分別在2和3中得以保留，2個橋連配體bpe連接相鄰的簇核，在[111]方向延伸形成一維“Z”字形鏈結構。

Mo(W)-Cu-S簇；苯胺；配位聚合物；組裝；晶體結構

0　Introduction

In view of their intriguing bonding,unique physical and chemical characteristics,the assembly of discrete transition metal clusters derived from[MOxS4-x]2-(M= Mo,W;x=0～3)into extended molecular assemblies has been the focus of intense research[1-10].The successful combination of the versatile cluster joints and awide range of bridging ligands have offered a powerful tool for the construction of a new family of materials with aesthetically appealing structures,tailor-made properties and advanced functions.For example,the reactions of[WES3]2-(E=S,O)with CuX(X=NCS,CN, I)in the presence of 1,4-bis(imidazole-1-ylmethyl) benzene under solvothermal conditions gave rise to a family of topologically interesting cluster-supported polymeric assemblies[11].We demonstrated that,by employing the preformed saddle-shaped cluster precursor[Et4N]4[WS4Cu4I6]as a starting material,its reaction with a ditopic ligand 4,4′-bipyridine(4,4′-bipy) in MeCN produced a novel 3D porous framework of{[WS4Cu4(4,4′-bipy)4][WS4Cu4I4(4,4′-bipy)2]}nwhich showed interesting host behaviors towards elemental I2[12].Further attempts using[Et4N]4[WS4Cu4I6]and longer spacers such as 1,2-bis(4-pyridyl)ethane,1,2-bis(4-pyridyl)ethylene and 1,3-bis(4-pyridyl)propane undersimilarconditionsinthepursueofnew structural motifs with enlarged pore sizes remained unsuccessful.This is probably due to the extremely fast reaction rates in MeCN or DMF solutions and low solubility of the resultant precipitates.To tackle this problem,we carried out the reactions of[Et4N]4[MS4Cu4I6](M=Mo(1a);W(1b))with 1,2-bis(4-pyridyl) ethane(bpe)in aniline solution.Aniline has proven a promising solvent due to its high solubility toward a series of discrete cluster precursors as well as some high dimensional arrays such as[{(η5-C5Me5)MoS3Cu3}2(NCS)3(μ-NCS)(bpe)3]n(2Dnetwork),[(η5-C5Me5)MoS3Cu3(NCS)(μ-NCS)(H2tpyp)0.4(Cu-tpyp)0.1]n(2Dnetwork; H2tpyp=5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin)and[(η5-C5Me5)MoS3Cu3(NCS)2(1,4-pyz)]n(3D net; 1,4-pyz=1,4-pyrazine)[13].Reactions of 1a and 1b with bpeinaniline,however,gaverisetotwoone-dimensional [MS4Cu4]-based coordination polymers{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo(2),W(3);ani=aniline).We herein report their syntheses and crystal structures.

1　Experimental

1.1General procedure

The two cluster precursors[Et4N]4[MS4Cu4I6](M= Mo(1a)[14]or W(1b)[15])were prepared according to the literature methods.All other chemicals were used as purchased.Aniline was freshly distilled under reduced pressure,while other solvents were pre-dried over activated molecular sieves and refluxed over the appropriate drying agents under nitrogen and collected by distillation.The elemental analyses for C,H and N were performed on a Carlo-Erba CHNO-S microanalyzer.IR spectra were recorded on a Varian 1000 FTIR spectrometer as KBr disks(4 000～400 cm-1).

1.2Preparation of{[MoS4Cu4(bpe)2(ani)2I2]· 3.5ani}n(2)

A dark red solution of 1a(35 mg,0.02 mmol)in aniline(2.0 mL)was placed in a zigzag glass tube(30 cm in length,6 mm in inner diameter)followed by careful addition of 1.5 mL of aniline serving as a buffer band.A solution containing bpe(8 mg,0.04 mmol)in aniline(1.5 mL)was slowly added onto the buffer band.Finally,diethyl ether(3 mL)was carefully layered onto the top solution and then the glass tube was capped with a rubber plug,which was further sealed with parafilm.The glass tube was allowed to stand at room temperature for 10 days, forming black prisms of 2,which were collected by filtration and washed with cold aniline and Et2O(1∶5, V/V)and dried in vacuo.Yield:20.3 mg(63%)based on Mo.Anal.Calcd.for C57H62Cu4I2MoN9.5S4(%):C 42.46,H 3.88,N 8.25;Found(%):C 42.56,H 3.88,N 8.20.IR(KBr disk,cm-1):2 925(w),2 045(w),1 937 (s),1 875(s),1 798(w),1 744(s),1 605(s),1 544 (w),1 497(s),1 428(s),1 382(m),1 281(w),1 219 (w),1 065(w),1 019(w),825(m),756(m),695(m), 648(w),594(w),548(w),509(w),448(m).

1.3Preparation of{[WS4Cu4(bpe)2(ani)2I2]· 3.5ani}n(3)

Compound 3 was prepared in a manner similar to that described for 2,using 1b(37 mg,0.02 mmol)and bpe(8 mg,0.04 mmol)as starting materials.Yield:27 mg(78%)based on Mo.Anal.Calcd.for C57H62Cu4I2N9.5S4W(%):C 40.26,H 3.68,N 7.83;Found(%):C 40.18,H 3.60,N 7.69.IR(KBr disk,cm-1):2 932(w), 1 937(w),1 613(vs),1 540(w),1 497(s),1 428(s), 1 382(m),1 281(w),1 227(w),1 173(w),1 065(w), 1 018(w),880(w),826(m),756(m),695(m),548(w),509(w),440(m).

1.4X-ray crystallography

X-ray quality crystals of 2 and 3 were obtained directly from the above preparations.The measurements of 2 and 3 were made on a Rigaku Mercury CCD X-ray diffractometer by using graphite-monochromated Mo Kα(λ=0.071 073 nm)radiation.Single crystals were mounted with grease at the top of a glass fiber and cooled at 153(2)K in a liquid N2stream.Cell parameterswererefinedbyusingtheprogram CrystalClear(Rigaku and MSC,version 1.3,2001). The collected data were reduced by using the program CrystalStructure(Rigaku and MSC,version 3.60, 2004)while an absorption correction(multi-scan) applied.The reflection data were also corrected for Lorentz and polarization effects.

The structures were solved by direct methods and refined with a full-matrix least-squares technique using the SHELXTL-97 program package[16].For both 2 and 3,all the non-hydrogen atoms were refined anistropically.Since all the nitrogen atoms in aniline molecules were attached to conjugated systems,it was reasonable to assume that each-NH2group was coplanar with the phenyl unit,which enabled the two hydrogen atoms to be placed as an ethylenic hydrogen using a riding model with N-H distances of 0.088 nm and Uiso(H)=1.2Uiso(N).All other hydrogen atoms were placed in their geometrically idealized positions and constrained to ride on their parent atoms,with d(C-H) =0.095 nm for phenyl and d(C-H)=0.099 nm for methylene and with Uiso(H)=1.2Uiso(C)for all H atoms. Crystal data as well as details of data collection and refinements for these complexes are summarized in Table 1.

CCDC:685673,2;685674,3.

Table 1Crystallographic data and refinement results for 2 and 3

2　Results and discussion

2.1Synthetic and spectral aspects

Basedonourpreviousobservations,aniline usually serves more as a solvent than a ligand due to its relatively weak coordination ability.And only one example{[(η5-C5Me5)MoS3Cu3(tpt)(aniline)(NCS)2]· 0.75aniline·0.5H2O}n(tpt=2,4,6-tri(4-pyridyl)-1,3,5-triazine)was isolated wherein one aniline molecule coordinated to one Cu(Ⅱ)centers[13].Compounds{[MS4 Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo(2),W(3);ani= aniline)were isolated in relatively high yields by reactions of[Et4N]4[MS4Cu4I6](M=Mo(1a);W(1b)) with 2 equivalents of bpe in aniline solution.Analogous reactions using different cluster-to-ligand ratios always afforded the same product,suggesting that 2 and 3 are the most stable products in aniline.Compounds 2 and 3 were relatively stable in air,and soluble in aniline, but insoluble in other solvents such as DMF,MeCN, DMSO,CH2Cl2and CHCl3.However,their aniline solutions became unstable and decomposed to some uncharacterizable precipitates if exposed to air for a long time.In both examples,aniline showed three interesting functions.One is that aniline worked as a good solvent for the formation of less soluble M/Cu/S coordination polymers.The second one,as discussed later in this article,is that aniline served as a ligand to coordinate at each Cu(I)center,which prohibits the formationofhigherdimensionalcoordination frameworks.The third one is that the lattice aniline molecules stabilized the one-dimensional chains by strong hydrogen bonding interactions.

The elemental analyses of 2 and 3 were consistent with their formulae.In their IR spectra,the bands at 1 605(2)and 1 613(3)cm-1indicated the presence of bpe ligands,bands at 448(2)and 440(3)were assigned as the bridging Mo(W)-S stretching vibrations. The identities of 2 and 3 were finally confirmed by X-ray crystallographic studies.

1.“嗡嗡”的異響在變速器和輪胎軸承位置特別明顯，初步判斷輪胎軸承有磨損產生異響。另外方向盤向右打時，故障明顯減弱，方向回正，異響特別明顯，同時異響在變速器的差速器位置特別明顯，所以也懷疑異響是由變速器的差速器引起的。

2.2Crystal structures of{[MS4Cu4(bpe)2(ani)2I2]· 3.5ani}n(M=Mo(2),W(3))

Because of the similarities of 2 and 3,only the crystalstructureof2isdiscussedindetails. Compound 2 crystallizes in the triclinic space group P1 and the asymmetric unit contains one neutral [MoS4Cu4(bpe)2(ani)2I2]molecule,three and a half aniline solvent molecules.Fig.1 demonstrates the structure of the[MoS4Cu4]cluster core of 2 while Table 2 listed its selected bond lengths and angles.

Fig.1　View of the structure of the repeating unit [MoS4Cu4I2(bpe)4(ani)2]of 2

In this core structure,there are four independent Cu(Ⅱ)centers,all of which adopt a distorted tetrahedral coordination geometry.However,their coordination environments are somewhat different,being coordinated by two μ3-S atoms from the[MoS4]2-moiety and two N atoms from one bridging bpe ligand and one aniline ligand(Cu1 and Cu3)or one N atom from one bpe and one terminal iodine atom(Cu2 and Cu4). The mean Mo…Cu contact of 0.267 2 nm is normal and similar to those observed in the precursor compound 1a(0.266 8 nm)[14],[MoOS3Cu3I(phen)2](0.263 8 nm,phen=1,10-phenanthroline)[17]and[MoOS3Cu3I(2,2′-bipy)2](0.266 4 nm,2,2′-bipy=2,2′-bipyridine)[18].The average Mo-S and Cu-S distances(0.223 5 nm vs 0.228 3 nm)are within normal range and comparable to those found in 1a(0.223 3 nm vs 0.229 3 nm), [PPh4]4[MoOS3(CuCl)3][CuCl2](0.227 2 nm vs 0.224 3 nm)[19]and[MoOS3Cu3(PPh3)3Cl](0.225 9 nm vs 0.229 4 nm)[20].The average Cu-I distance of 0.260 7 nm is slightly shorter than those of 1a(0.261 8 nm),[MoS4Cu6I4(py)4]n(0.267 5 nm,py=pyridine)[21]and[PPh4]4[MoS4Cu6I8](0.261 9 nm)[22].Additionally,the mean Cu-N(aniline)distance(0.214 4 nm)is slightly longerthan that of Cu-N(bpe)distance(0.207 4 nm), implying that each aniline molecule is coordinated at Cu(I)center in this cluster core.Interestingly,the two independent bpe ligands show significantly different flexibilities.The dihedral angle between plane N1-C1-C2-C3-C4-C5 and plane C8-C9-C10-N2-C11-C12 is 6.3(3)°,while that between plane N3-C13-C14-C15-C16-C17andplaneC20-C21-C22-N4-C23-C23is 26.9(7)°.Meanwhile,the torsion angles for C3-C6-C7-C8 and C15-C18-C19-C20 are 177.9(12)°and 175.6(15)°,respectively.

Table 2Selected bond distances(nm)and angles(°)for 2

Each[MoS4Cu4]cluster core is linked to two equivalent clusters through a pair of bpe ligands to give a one-dimensional(1D)[MoS4Cu4]-based zigzag chain extending along the[111]direction(Fig.2).The separation of adjacent chains of ca.1.25 nm is filled with aniline solvents(Fig.3).These 1D chains are interlinked by various types of weak interactions including as π-π,C-H…π,C-H…I,C-H…N,N-H…I interactions among the lattice aniline molecules, the coordinated aniline molecules,bpe and iodine atoms,thereby forming a 2D wave-like network(Fig.3) in the approximately[341]direction.Adjacent layers are separated by aniline solvates through a variety of hydrogen bonding interactions and finally formed a three-dimension structure(Fig.4).

Fig.2　View of a section of the 1D zigzag chain of 2 extending along the[111]direction

Fig.3　View of the 2D wave-like network formed by weak interactions in 2,looking down the a axis

Fig.4　View of the 3D structure formed by hydrogen bonding interactions and other weak interactions in 2,viewed along the a direction

3　Conclusions

In summary,we have synthesized two analogous[MS4Cu4]-supported one-dimensional coordination polymers 2 and 3.The pentanuclear saddle-shaped [MS4Cu4]cores in 2 and 3 are inherited from 1a and 1b,respectively.Pairs of bpe bridges connect adjacent [MS4Cu4]cores and afford a one-dimensional[MS4Cu4]-based zigzag chain.This work also demonstrates that aniline can work as an excellent solvent and ligand in the formation of less soluble M/Cu/S clusters.We are currently exploring other systems using aniline.

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Two One-Dimensional[MS4Cu4]-Supported Coordination Polymers:Assembly and Crystal Structures of{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo,W;ani=aniline)

LIU Quan1,2CHEN Qiu-Fang1YU Hong1ZHAO Xin1ZHANG Wen-Hua1LANG Jian-Ping＊,1
(1College of Chemistry,Chemical Engineering and Materials Science,Soochow University,Suzhou,Jiangsu 215123,China)
(2College of Chemistry and Chemical Engineering,Nantong University,Nantong,Jiangsu 226019,China)

Reactions of the preformed cluster precursors[Et4N]4[MS4Cu4I6](M=Mo(1a);W(1b))with a ditopic bridging ligand 1,2-bis(4-pyridyl)ethane(bpe)in aniline solutions gave rise to two analogous one-dimensional cluster-supported coordination polymers{[MS4Cu4(bpe)2(ani)2I2]·3.5ani}n(M=Mo(2),W(3);ani=aniline).Both 2 and 3 are characterized by elemental analysis,IR spectra,and single crystal X-ray diffraction.X-ray analyses revealed that the pentanuclear saddle-shaped[MS4Cu4]cores in 1a and 1b are retained in 2 and 3.The adjacent [MS4Cu4]cores are interconnected by double bpe bridges to afford one-dimensional zigzag chains extending along the[111]direction.CCDC:685673,2;685674,3.

Mo(W)-Cu-S cluster;aniline;coordination polymer;assembly;crystal structure

O614.61+2；O614.61+3

A

1001-4861(2015)09-1805-06

10.11862/CJIC.2015.237

2015-05-24。收修改稿日期：2015-06-04。

國家自然科學基金(No.21373142，21371126)資助項目。

＊通訊聯系人。E-mail：jplang@suda.edu.cn