title: Synthesis and characterization of a redox-active bis(thiophenolato)amide ligand, [SNS]3-, and the homoleptic tungsten complexes, W[SNS]2 and W[ONO]2.
abstract: A new tridentate redox-active ligand platform, derived from bis(2-mercapto-p-tolyl)amine, [SNS(cat)]H(3), has been prepared in high yields by a four-step procedure starting from commericially available bis(p-tolyl)amine. The redox-active pincer-type ligand has been coordinated to tungsten to afford the six-coordinate, homoleptic complex W[SNS](2). To benchmark the redox behavior of the [SNS] ligand, the analogous tungsten complex of the well-known redox-active bis(3,5-di-tert-butylphenolato)amide ligand, W[ONO](2), also has been prepared. Both complexes show two reversible reductions and two partially reversible oxidations. Structural, spectroscopic, and electrochemical data all indicate that W[ONO](2) is best described as a tungsten(VI) metal center coordinated to two [ONO(cat)](3-) ligands. In contrast, experimental data suggests a higher degree of S→W π donation, giving the W[SNS](2) complex non-innocent electronic character that can be described as a tungsten(IV) metal center coordinated to two [SNS(sq)](2-) ligands.
authors: Department of Chemistry, University of California, Irvine, California 92697, United States.
authors: David W
authors: DW
authors: Shaffer
authors: Géza
authors: G
authors: Szigethy
authors: Joseph W
authors: JW
authors: Ziller
authors: Alan F
authors: AF
authors: Heyduk