title: Rhenium and technetium complexes with tridentate N-[(N'',N''-dialkylamino)(thiocarbonyl)]-N'-substituted benzamidine ligands.
abstract: N-[(Dialkylamino)(thiocarbonyl)]benzimidoyl chlorides react with functionalized amines such as 2-aminophenol, 2-methylaminopyridine, and 2-aminobenzoic acid in clean and high-yield procedures with the formation of the novel tridentate N-[(N'', N''-dialkylamino)(thiocarbonyl)]- N'-substituted benzamidine ligands H2L1, HL2, and H2L3. By starting from (NBu4)[MOCl4] (M = Re, Tc) or [ReOCl3(PPh3)2] and H2L1, a series of oxorhenium(V) and oxotechnetium(V) complexes of the composition [MOCl(L1)] were synthesized and characterized by spectroscopic methods and X-ray crystallography. The monomeric, five-coordinate compounds are air-stable and bind (L1)(2-) tridentate in the equatorial coordination sphere. Dimeric products of the compositions [(ReOCl(L2))2O] and [ReOCl(L3)]2 were isolated during reactions with HL2 and H2L3. While dimerization in [(ReOCl(L2))2O] is established via an oxo bridge, the metal atoms in [ReOCl(L3)]2 are connected by the carboxylic group of the ligand, and the product represents the first example of a high-oxidation state rhenium complex displaying such a bonding feature.
authors.affiliation: Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.
authors.forename: Nguyen
authors.initials: N
authors.lastname: Hung Huy
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Grewe
authors.forename: Jennifer
authors.initials: J
authors.lastname: Schroer
authors.forename: Bernd
authors.initials: B
authors.lastname: Kuhn
authors.forename: Ulrich
authors.initials: U
authors.lastname: Abram