Three new metal–organic frameworks based on 2-propyl-1H-imidazole-4,5-dicarboxylate: Synthesis, crystal structure and luminescent properties

Abstract: Three new complexes [Cd(H2pimda)2(H2O)2]·4H2O (1), [Zn(H2pimda)2(H2O)2]·3.5H2O (2) and [Cd2(Hpimda)2(DMF)2] n (3) (H3pimda=2-propyl-1H-imidazole-4,5-dicarboxy acid, DMF= N,N′-dimethylformamide) have been synthesized under hydrothermal or solvothermal conditions, respectively. Crystal structures of complexes 1–3 were determined by single crystal X-ray diffraction. Crystallographic studies on 1 and 2 reveal that both complexes are six-coordinated, whose geometries can be best described as distorted octahedron. Complex 3 was synthesized based on that of complexes 1 and 2. We change the coordination environment of H3pimda during the synthesis process of complex 3 using organic acid and organic solvent, accordingly, result in different structures ranging from 0D molecule (for 1 and 2) to infinite 2D network (for 3). Complexes 1–3 have blue fluorescent emissions at room temperature in the dimethylsulfoxide (DMSO) solution, which indicate they are potential blue luminescence materials. The blue fluorescent emissions of complexes 1–3 are due to the π∗ →π transitions of intra-ligand. [Copyright &y& Elsevier]