Gem‐diol Generation in Copper and Zinc N‐methyl‐2‐imidazolecarboxaldehyde Complexes: Solid‐state NMR, EPR and Single‐Crystal X‐ray Studies

Abstract

AbstractNovel coordination compounds, mono‐ (1) and binuclear copper complexes (2) and a zinc complex (3) were synthesized and studied through single‐crystal X‐ray crystallography, solid‐state NMR and EPR techniques to determine the chemical functionalization of the carbonyl group in N‐methyl‐2‐imidazolecarboxaldehyde ligand. Particularly, molecules containing carbonyl groups are versatile ligands that give rise to a wide range of new materials due to the high reactivity of the carbonyl group. However, the chemical identification of the functional group present in these coordination compounds is a challenge because the copper ion affects the NMR signals. In this sense, X‐ray crystallography becomes an indispensable tool for the analysis. The imidazole ligands in copper complexes 1 and 2 were found to be the aldehyde and the gem‐diol forms, respectively. Furthermore, the gem‐diol and carboxylate moieties were detected in the crystal lattice for the zinc complex 3 and studied by solution‐ and solid‐state NMR.