Design and construction of six metal–organic frameworks with 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylate

Abstract

Six novel transition-metal–organic frameworks, [Cu(μ₂-HMOPhIDC)(H₂O)]_n (H₃MOPhIDC = 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylic acid) (1), [Zn(μ₂-HMOPhIDC)(2,2′-bipy)]_n (2,2′-bipy = 2,2′-bipyridine) (2), [Co(μ₂-HMOPhIDC)(2,2′-bipy)]_n (3), [Co(μ₂-HMOPhIDC)(phen)]_n (phen = 1,10-phenanthroline) (4), [Cd_1.5(μ₂-H₂MOPhIDC)(μ₃-HMOPhIDC)(H₂O)]_n (5) and {[Co_1.5(μ₂-H₂MOPhIDC)(μ₃-HMOPhIDC)(py)]·2H₂O}_n (py = pyridine) (6) have been successfully synthesized under hydrothermal conditions, and characterized by means of elemental analyses, IR and single-crystal X-ray diffraction. The organic ligand H₃MOPhIDC can be singly deprotonated or doubly deprotonated, and coordinate to metal ions in various modes. Polymers 1–4 display an infinite polymeric chain structure connected by μ₂-HMOPhIDC²⁻ ligands, but show different crystal packing fashions. Polymers 5 and 6 exhibit two-dimensional sheet structures built from double-stranded chains. The thermal properties of polymers 1–6 and luminescence properties of 2 and 5 have been determined. Also, the magnetic properties of polymers 1, 3, 4 and 6 have been investigated.