Direct evidence of coordination on the endocyclic nitrogen atom in the adducts of 2-aminoazoles and 2-aminoazines with copper(II) acetate

Abstract

The coordinative bond has been shown by X-ray structure analysis to be localized at the endocyclic nitrogen atom of pyridine type in the adducts of copper(II) acetate of the composition [Cu(CH 3COO) 2L] 2 where L = 2-aminopyridine or 2-aminothiazole and Cu(CH 3COO) 2·2L where L = 2-amino-1-methylbenzimidazole or 2-amino-1-heptylbenzimidazole. The lowering of the stretching vibration frequencies of the primary amino group in the IR spectra of complex compounds with Lewis acids used earlier as a test for coordination on the exocyclic nitrogen atom is actually caused by the realization of intra- and intermolecular hydrogen bonds in the compounds studied.