Preparation, Crystal Structure, and Properties of Five Metal‐Organic Complexes Based on a Triangular Nonplanar Carboxylate Ligand

Abstract

AbstractA nonplanar triangular carboxylate ligand has been synthesized and applied to assemble metal‐organic frameworksunder hydro‐ or solvothermal conditions. Five new metal‐organic complexes, [H2N(CH3)2]2[Cd(HTMBTC)2]·2H2O·dmf (1), [Cu3(TMBTC)2(2,2′‐bpy)2]·H2O (2), [Zn3(TMBTC)2(H2O)2]·H2O (3), [Cd3(TMBTC)2(H2O)4]·4H2O (4), and [Cu3(TMBTC)2](5), (dmf = dimethylformamide; TMBTC = 2,4,6‐trimethylbenzene‐1,3,5‐tricarboxylic acid; bpy = bipyridine) were crystallized; they possess four different structural types. In 1, the nonplanar carboxylate ligand connects the cadmium ion to give rise to a 2D (4,4) topological layer that contains two vertical left‐ and right‐handed helical chains. In 2, the carboxylate ligands first link the copper ions to generate a 1D tubular unit, which can be considered the basic building block. The 1D tubular units are further connected by the ligand to form a 2D layer structure. Complexes 3 and 4 have similar structural types. The zinc and cadmium ions are connected by the ligand to form a bilayer framework that contains double (6,3) topological nets. Different from complexes 1–4, complex 5 has a 3D framework. The copper ions are first connected by the ligand to generate a bilayer structure that contains double (6,3) nets, which are further connected by sharing the copper ion to form the final 3D framework. Photoluminescence measurements of 1, 3, and 4 in the solid state at room temperature show that all three coordination networks exhibit similar, strong luminescence, which can be assigned to an intraligand π → π* transition.