First example of mixed azoheterocycles: structural studies of metallo-macrocycle Ag(I) versus tetrahedral Cd(II) complexes of pyridyl-azo-imidazole

Abstract

Imidazolyl and 3 ′-pyridyl are linked by azo bond (–NN–) to synthesize hitherto unknown mixed heterocyclic azo molecules, 2-[(3 ′-pyridyl)azo]imidazole (3 ′-PyaiH). Alkylation in presence of NaH has synthesized 1-alkyl-2-[(3 ′-pyridyl)azo]imidazole (3 ′-PyaiR ′). 3 ′-PyaiR ′ include three types of N-donor centers: N(imidazole), N(azo) and a peripheral N(pyridine). They bind to Ag + to form 2:2 metallo-macrocycle, [Ag(3 ′-PyaiR ′)] 2 2+, while the reaction with Cd 2+ forms Cd(3 ′-PyaiR ′) 4 2+. The complexes are structurally characterized by X-ray diffraction studies.