Syntheses, crystal structures and thermal properties of six coordination polymers based on 2-(p-methylphenyl)-imidazole dicarboxylate

Abstract

Through solvothermal reactions of 2-(p-methylphenyl)-1H-imidazole-4,5-dicarboxylic acid (p-MePhH₃IDC) with transition-metal ions, six coordination polymers [Pb₂(p-MePhHIDC)(p-MePhH₂IDC)₂(phen)₂]_n (phen = 1,10-phenanthroline) (1), [Pb(p-MePhH₂IDC)₂]_n (2), [Cd₃(p-MePhHIDC)₂(p-MePhH₂IDC)₂(H₂O)₂]_n (3), {[Cd(p-MePhHIDC)(H₂O)]₄·H₂O}_n (4), {[Cd₂(p-MePhHIDC)₂(4,4′-bipy)]·4H₂O}_n (4,4′-bipy = 4,4′-bipyridine) (5) and [Mn₃(p-MePhHIDC)₂(p-MePhH₂IDC)₂(4,4′-bipy)]_n (6) have been synthesized successfully. X-ray single-crystal analyses show that polymers 1–6 have rich structural chemistry ranging from one-dimensional (1), two-dimensional (3) to three-dimensional polymers (2, 4, 5 and 6). In these polymers, the p-MePhH₃IDC ligand shows flexible coordination modes tuned by different synthetical conditions, including the addition of coligands, temperature, pH value and so on. Furthermore, the polymers have been investigated by solid-state ultraviolet spectra and thermogravimetric analyses.