基于双齿咪唑席夫碱配体的两个手性自旋转换铁(Ⅱ)配合物  

Two Homochiral Spin-Crossover Iron(Ⅱ) Complexes Based on Bidentate Imidazole Schiff Base Ligands

作　　者：顾玲 任冬红 刘志明 孙晓利 邱丹 顾志国[1,2] 李在均 

机构地区：[1]江南大学化学与材料工程学院,无锡214122 [2]食品胶体与生物技术教育部重点实验室,无锡214122

出　　处：《无机化学学报》2015年第7期1357-1364,共8页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21101078;21276105);新世纪优秀人才计划(No.NCET-11-0657);江苏省双创团队资助项目

摘　　要：以含有苯环和咪唑环的手性双齿席夫碱为配体,合成了2个纯手性单核自旋转换铁(Ⅱ)配合物fac-Δ-[Fe(S-L1)3][Cl O4]2(1),mer-Λ-[Fe(R-L2)3][Cl O4]2·Et2O(2)(L1=1-对氯苯基-N-(1-正丙烯基-1H-咪唑-2-亚甲基)乙胺;L2=1-苯基-N-(1-异丙烯基-1H-咪唑-2-亚甲基)乙胺)。利用X-射线单晶衍射、元素分析(EA)、红外光谱(IR)、核磁共振氢谱(1H NMR)、紫外光谱(UV)、圆二光谱(CD)等手段对配合物结构进行了表征。X-射线单晶衍射表明在配合物1和2中,铁(Ⅱ)金属中心与3个不对称双齿手性席夫碱配体中的6个氮原子配位形成八面体配位环境。配合物1中每个结构基元中包含1个[Fe(Ln)3]2+阳离子和2个高氯酸根阴离子。而配合物2中每个结构基元中包含2个[Fe(Ln)3]2+阳离子、4个高氯酸根阴离子和1个乙醚分子。由于铁(Ⅱ)中心周围手性配体的螺旋协调配位使[Fe(Ln)3]2+形成单一构型。Fe(Ⅱ)-N键长表明配合物1中的铁(Ⅱ)在低自旋状态,而配合物2中的铁(Ⅱ)在高自旋状态。在[Fe(Ln)3]2+中,相邻配体中的苯环和咪唑环形成分子内π-π相互作用。配合物1和2通过分子间C-H…π和C-Cl…π相互作用形成超分子结构。CD光谱证实配合物1和2在溶液中的光学活性。磁性测试表明配合物1和2分别在372 K和146 K发生自旋转换。由于配合物1和2具有不同的堆积方式和分子间相互作用,导致1和2表现出不同的自旋转换温度。Based on the bidentate schiff base ligands involving phenyl and imidazole groups, two homochiral mononuclear spin-crossover iron（n） complexes, fac-△-[Fe（S-L1）3][C104]2 （1）, mer-A-[Fe（R-L2）3][CIO4]2·EhO （2） （Ll= 1-parachlorophenyl-N-（1-n-propylenyl-lH-imidazol-2-ylmethylene）ethanamine; L2= 1-phenyl-N-（1-iso-butenyl- 1H- imidazol-2-ylmethylene）ethanamine） have been synthesized. The two complexes have been determined by single- crystal X-ray diffraction analysis, elemental analysis, IR spectra, 1H NMR spectra, UV spectra and CD spectra. X-ray crystallography revealed that the iron（R） center in 1 and 2 assumed an octahedral coordination environment with 6 N donor atoms from three unsymmetrical bidentate chiral schiff base ligands. Each unit contained one [Fe（Ln）3]2＋ cation and two C104- anions in 1. While 2 contained two [Fe（Ln）3]2＋ cation, four C104- anions and one diethyl ether molecular. [Fe（Ln）3]2＋ components were chiral with single configuration due to the screw coordination arrangement of the chiral ligand around Fe（Ⅱ） centers. The Fe（Ⅱ）-N bond distances indicated that the Fe（Ⅱ） sites of 1 were in low-spin state, while the Fe（Ⅱ） centers of 2 were in high-spin state. As for [Fe（Ln）3]2＋, intramolecular π-π interactions were present between phenyl group and imidazole ring of an adjacent ligand. In 1 and 2, supramolecular architectures were formed through intermolecular C-H……cr and/or C-C1……π interactions. Circular dichromism spectra confirmed the presence of non-racemic chiral metal centers in solution for complexes 1 and 2. Magnetic measurements revealed that 1 and 2 displayed obviously spin-crossover behaviour at 372 K and 146 K, respectively. Complexes 1 and 2 crystallized in different packing modes and intermolecular interactions, therefore their SCO bahaviors were different. CCDC： 1020959, 1; 1020960, 2.

关 键 词：纯手性 自旋转换 铁(Ⅱ)配合物 席夫碱 

分 类 号：O614.811[理学—无机化学]