One Chiral and Two Achiral 3-D Coordination Polymers Constructed by 2-Phenyl Imidazole Dicarboxylate

Two chiral three-dimensional (3-D) coordination polymers, [Cd4(μ3-HPhIDC)2(μ4-HPhIDC)2(H2O)] (1) and two achiral 3-D coordination polymers, [Mn1.5(μ3-PhIDC)(H2O)3] (2) and [Mn(μ3-HPhIDC)(H2O)]2} (3), have been synthesized by hydro(solvo)thermal reaction, employing 2-phenyl-1H-imidazole-4,5-dicarboxylic acid (H3PhIDC) as organic ligand, and characterized by single-crystal X-ray diffraction, elemental analyses, and IR spectra. Polymer 1 crystallizes in the orthorhombic chiral space group P2(1)2(1)2(1) and exhibits a 3-D framework, in which two-dimensional (2-D) layers are composed of right-handed helices along the b-axis and are further pillared by μ4-HPhIDC2− linkages. Polymer 2 crystallizes in trigonal chiral space group R3̅ and presents a novel 3-D structure, which is generated from 2-D honeycomb-like layers, containing similar right-handed helical chains along the a or b axes, respectively. Polymer 3 also has a 3-D architecture and is composed of novel 2-D stairlike layers in the bc plane. The theoretical prediction of the phenyl substituent effect of the H3PhIDC ligand has first been presented.

本研究以2-苯基-1H-咪唑-4,5-二羧酸（H3PhIDC）为有机配体（organic ligand），通过水（溶剂）热反应（hydro(solvo)thermal reaction）合成了两种手性三维配位聚合物[Cd4(μ3-HPhIDC)2(μ4-HPhIDC)2(H2O)]（1）以及两种非手性三维配位聚合物[Mn1.5(μ3-PhIDC)(H2O)3]（2）和[Mn(μ3-HPhIDC)(H2O)]2（3），并采用单晶X射线衍射（single-crystal X-ray diffraction）、元素分析（elemental analyses）与红外光谱（IR spectra）对上述产物进行了表征。
聚合物1结晶于正交晶系手性空间群P212121，呈现三维骨架结构：其二维层沿b轴方向由右手螺旋链构成，并通过μ4-HPhIDC2-桥联配体进一步柱撑形成整体三维框架。
聚合物2结晶于三方晶系手性空间群R-3，展现出新颖的三维结构：该结构由类蜂窝状二维层构筑而成，层内分别存在沿a轴与b轴延伸的右手螺旋链。
聚合物3同样具有三维骨架结构，其骨架由bc平面内的新颖二维阶梯状层构筑而成。本研究首次提出了H3PhIDC配体苯基取代基效应的理论预测。