.mu.-Oxo-bis(oxo) dinuclear complexes of technetium(V) with amine phenol ligands: syntheses, characterization, and x-ray crystal structures

Abstract

Technetium(V) complexes of three amine phenol ligands prepared by reducing Schiff bases derived from salicylaldehyde and 1,3-diaminopropane, 2,2-dimethyl-1,3-diaminopropane, and 1,4-diaminobutane have been synthesized. {sup 1}H and proton-decoupled {sup 13}C nuclear magnetic resonance spectra of the complexes have been recorded and compared with those of the parent ligands. The complexes have been characterized by infrared spectroscopy, visible-UV spectrophotometry, and x-ray crystallography. X-ray crystal structures show all three complexes are dinuclear with a {mu}-oxo-bis(oxo) (O{double bond}Tc-O-Tc{double bond}O) backbone. The distorted octahedral coordination of Tc(V) is completed by a tetradentate diamine diphenolate ligand. Neutrality of the complexes is achieved by deprotonation of the phenols and by terminal and bridging oxo ligands. The technetium complexes have either a true crystallographic center of symmetry or an approximate center at the bridging oxygen. 16 refs., 4 figs., 10 tabs.