丁 斌 常若男 武向侠 王 丹 马玲玲

(天津市功能分子结构与性能重点实验室，天津师范大学化学学院，天津 300387)

(1，2-(1H-1，2，4-三唑))乙烷的一维双链 Cu（Ⅱ）配合物合成与表征

丁 斌＊常若男 武向侠 王 丹 马玲玲

(天津市功能分子结构与性能重点实验室，天津师范大学化学学院，天津 300387)

利用高度柔性的双三唑配体(1，2-(1H-1，2，4-三唑))乙烷(L)和铜盐反应合成了1个新的具有一维双链结构的铜(Ⅱ)配合物{[Cu(cis-L)2Br]Br·2H2O}n(1)。单晶结构表明：配合物1的晶体属于三斜晶系，P1空间群。在配合物1中双三唑配体采用反式构型，桥联相邻的中心铜离子形成一维双链结构，晶格中游离的Br原子同配位水分子形成了四元环状的Br…O超分子环。测定了配合物1在2～300 K的变温磁化率，结果表明相邻铜离子间存在弱的反铁磁相互作用。

(1，2-(1H-1，2，4-三唑))乙烷；铜配合物；一维双链；反铁磁

During the lasttwo decades metal-organic coordination polymers have aroused great interest for chemists due to their extremely versatile coordination motifs and potential applications in many areas such as light-emitting diodes(LEDs),catalytic,magnetic properties and so on[1-4].Although a variety of metal coordination frameworks with beautiful topologies and interesting electronic,magnetic,optical properties have been synthesized,rational control in the construction of polymeric networks remains a great challenge.Judicious selection of different flexible or rigid ligands can dramatically tune ultimate structural motifs of these coordination frameworks[5].

1,2,4-triazole and,in particular,its derivatives are very interesting ligands for their important properties[6].For example,these triazole ligands strength is just in the region to give spin crossover compounds with iron(Ⅱ)salts.Such systems are applicable for information storage and some other applications[7].Previously we reported a series of 3,5-substituted triazole-cadmium coordination polymers from zero-to three-dimensional tuned via different triazole ligands and anions[8].In this work the flexible 1,2-bis(1,2,4-triazole-1-yl)ethane(L)ligands was employed.L is highly flexible and can adopt variable trans-and cis-conformations.One new 1D{[Cu(cis-L)2Br]Br·2H2O}n(1)compound can be isolated.In 1 two cis-L molecules bridge central copper(Ⅱ) ions forming 1D double-chain structure,fourmember Br…O supra-molecular cycles can also be observed.The varied temperature magnetic property of 1 from 300 to 2 K was also investigated.

1 Experimental

1.1 Materials and general methods

The bis-triazole ligand 1,2-bis(1,2,4-triazole-1-yl)ethane (L)was prepared according to the literature method[9].Other reagents were purchased commercially and used withoutfurtherpurification.Elemental analyses of carbon,hydrogen and nitrogen were carried out with a CE-440 (Leeman-Labs)analyzer.FTIR spectrum (KBr pellets)was taken on an AVATAR-370(Nicolet)spectrometer in the range 4 000～400 cm-1region.Variable-temperature magnetic susceptibilities were measured using a MPMS-7 SQUID magnetometer.Diamagneticcorrectionsweremadewith Pascals constants for all constituent atoms.

1.2 Synthesis of{[Cu(cis-L)2Br]Br·2H2O}n(1)

Complex 1 was prepared by refluxing L ligand(32.8 mg,0.2 mmol)and CuBr2·2H2O (25.9 mg,0.1 mmol)in 15 mL aqueous solution for 1 h.The precipitate was filtrated and blue crystals were isolated from the filtrate within one week.Yield:44%(based on Cu).Anal.Calc.for C12H20Br2CuN12O2(%):C,24.52;H,3.43;N,28.60.Found(%):C,24.12;H,3.63;N,28.80.IR(KBr,cm-1):3 400(br),3 140(w),3 126(m),3 060(w),1555(s),1475(m),1446(s),1390(s),1362(w),1322(s),1189(s),1078(s),985(s),862(s),835(s),774(s),680(m),625(s),407(w).

1.3 X-ray crystallography and structural refinement

Structure measurement of 1 was performed on a computer controlled Bruker SMART APEX-ⅡCCD diffractometer equipped with graphite-monochromated Mo Kα radiation with radiation wavelength 0.071 073 nm by using a ω-scan technique.Semi-empirical absorption corrections using SADABS program were applied.The structure was solved by direct methods and refined with the full-matrix least-squares technique usingtheSHELX-97programs[10].Hydrogenbondlengths and bond angles for 1 are listed in Table 3.Anisotropic thermal parameters were assigned to all non-hydrogen atoms.The organic hydrogen atoms were generated geometrically.The crystallographic data and selected bond lengths and angles are listed in Table 1 and Table 2,respectively.

CCDC:753647.

Table 1 Crystallographic data and structure refinement summarya

Table 2 Selected bond distance(nm)and angles(°)

Table 3 Hydrogen bond lengths and bond angles for 1

2 Results and discussion

As is shown in Fig.1,1 is a 1D chain structure bridged by two L molecules.The central copper(Ⅱ) ion is five-coordinated by four nitrogen atoms of four cis-L ligands and one bromide anion.The central copper(Ⅱ)ion also has weak interaction with lattice bromide anion(0.338 6 nm).The Cu(1)-N distances(from 0.200 3(19)to 0.2.0072(17)nm)are comparable with those of other Cu(Ⅱ)-triazole complexes[11].Neighboring copper(Ⅱ) ions are linked by two cis-Lligands to form 1D double-chain structure.The Cu… Cu separation across bridging ligands is 0.8772(3)nm.It is interesting that bromide anions and lattice water molecules O(1)have weak interaction to generate intermolecular hydrogen bonds.Thus four-membered Br2O2cycle clusters constructed via hydrogen bonding can be found in the supramolecular structure (Fig.2).The four-member cycle clusters link two neighboring chains to form ladder structure.Furthermore,the lattice water O(2)also has the hydrogen-bonding interaction with O(1)i,which help to stabilize the supra-molecular structure.

Fig.1 An ORTEP drawing of 1 showing the coordination environment of five-coordinated CuⅡions

Fig.2 Four-membered Br2O2cycles link two neighboring chains to form 1D ladder structures

2.1 Magnetic properties of 1

Fig.3 μeffversus T and 1/χMversus T plot for 1 indicating the existence of weak anti-ferromagnetic interactions

The complex 1 was studied by magnetic susceptibility measurements in the 2～300 K regions.The magnetic behaviour of 1 is shown in the form of a χMT versus T plot(Fig.3).A magnetic moment of 1.87 B.M./Cu2+is observed,a value typical μeffvalue for a Cu(Ⅱ)atom with d9configuration[12].The magnetic behaviour of 1 can be interpreted by the Curie-Weiss law with Curie value and Weiss constant of 0.44(5)cm3·K·mol-1and-5.02(5)K,which also reveal the existence of weak anti-ferromagnetic interaction in 1.The result should be ascribed that the long L ligands can not effectively transmit the magnetic interactions between neighbouring copper(Ⅱ)ions.

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Synthesis and Characterization of One Novel 1D Double-Chain Copper(Ⅱ)Complex with 1,2-Bis(1,2,4-triazole-1-yl)ethane

DING Bin＊CHANG Ruo-Nan WU Xiang-XiaWANG Dan MA Ling-Ling
(Tianjin Key Laboratory of Structure and Performance for Functional Molecule,Tianjin Normal University,Tianjin 300387,China)

Using the highly flexible bis-triazole ligand 1,2-bis(1,2,4-triazole-1-yl)ethane(L),one new complex{[Cu(cis-L)2Br]Br·2H2O}n(1)has been synthesized and characterized by elemental analysis,FTIR and single crystal X-ray diffraction analysis.It belongs to triclinic system with space group P1,a=0.757 0(2)nm,b=0.877 2(3)nm,c=1.6415(5)nm,α=104.187(5)°,β=90.905(5)°,γ=98.589(5)°,V=1.0434(5)nm3,Z=2.In 1 two cis-L molecules bridge central copper(Ⅱ) ions forming 1D double-chain structure,four-member Br…O supra-molecular cycles can also be observed.The varied temperature magnetic property of 1 has been investigated from 300 to 2 K indicating weak antiferromagnetic interactions between neighboring copper(Ⅱ) ions.CCDC:753647.

1,2-bis(1,2,4-triazole-1-yl)ethane;copper complex;one-dimentional double-chain;anti-ferromagnetic

O614.121

A

1001-4861(2011)01-0189-04

2010-06-21。收修改稿日期：2010-08-08。

天津市教委基金(No.20090504)资助项目。

＊通讯联系人。E-mail：qsdingbin@yahoo.com.cn