Unpredicted concurrency between P,P-chelate and P,P-bridge coordination modes of 1,5-diR-3,7-di(pyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane ligands in copper(I) complexes

Abstract

Several new mono- and binuclear copper(I) complexes of pyridyl containing 1,5-diaza-3,7-diphosphacylcooctanes with bis-P,P-chelate and unusual P,P-bridged coordination modes of heterocyclic ligands were obtained and characterized. The 1,5-diaza-3,7-diphosphacyclooctane, containing p-tolyl substituents at nitrogen atoms forms bis-P,P-chelate mononuclear as well as metalacyclic binuclear complexes with P,P-bridged coordination mode of a ligand, whereas the N-1-phenylbezyl substituted ligand gives the expected P,P-chelate complexes only. Reasons for the differences in coordination modes have been found in the ligands geometry, where configuration of nitrogen atoms plays an important role.