Ionothermal syntheses and characterization of 2-D coordination polymers with 4-(1H-imidazol-1-yl) benzoic acid

Abstract

4-(1H-imidazol-1-yl) benzoic acid and its coordination polymers [M(IBA)Cl] n (M = Zn (1) and Co (2)) have been synthesized. Compounds 1 and 2 were obtained under ionothermal conditions and possess a 2-D laminar [M(IBA)] n layer based on M2(CO2)2 building blocks with coordinated chloride completing tetrahedral coordination of the metal. Compound 1 exhibits two photoluminescence emission peaks at 410 and 510 nm. The low-energy emission can be attributed to ligand-centered transition and the high-energy band can be assigned to ligand-to-metal charge transfer between the aromatic systems of the organic ligands and the 4s orbitals of Zn(II). The role of the ionic liquid in ionothermal synthesis and crystallization of 1 and 2 are briefly discussed.