Synthesis and Characterization of Six-Coordinate Cationic Technetium(V) And Rhenium(V) Complexes with N-(2-Oxidophenyl)Salicylideneiminate and Bidentate Aromatic Nitrogen-Donor Ligands

Abstract

Six-coordinate cationic complexes of rhenium(V) and technetium(V) with the tridentate N-(2-oxidophenyl)-salicylideneiminate (OPhsal^2-) and the bidentate aromatic nitrogen-donor ligands 2,2′-dipyridine, 1,10-phenanthroline, 2,2′-dipyridylamine and bis(2-pyridyl)ketone (NN) have been prepared. Complexes of general formula [MO(OPhsal)(NN)]X (M = Re, Tc; X = Cl, PF₆) were isolated by the reaction of ReOCl(OPhsal)(PPh₃) and TcOCl(O Phsal) with the bidentate nitrogen-donor ligands. The reaction of TcOCl(O Phsal) with bis(2-pyridyl)ketone (dpk) in ethanol produced the complex [TcO(OPhsal)-(dpk.EtOH)]Cl, in which alcoholation of ethanol across the ketone double bond of dpk has occurred. Spectroscopic and analytical results obtained for all the isolated complexes suggest terdentate coordination of OPhsal^2- in the equatorial plane cis to the oxo oxygen, with the bidentate pyridyl nitrogen-donor ligands bridging the fourth equatorial site and the position trans to the oxo group.

Key Words:

• Technetium(V)
• rhenium(V)
• six-coordination
• cationic complexes