878384-44-2Relevant academic research and scientific papers
Synthesis and structure of gold(III) complexes of asymmetric dithiolene ligands
Tunney, Josephine M.,Blake, Alexander J.,Davies, E. Stephen,McMaster, Jonathan,Wilson, Claire,Garner, C. David
, p. 591 - 598 (2006)
Four new [Au(dithiolene)2]- complexes, each involving two asymmetrically substituted dithiolene ligands (SC(H)C(R)S; R = phenyl, pyridin-2-yl, pyridin-3-yl, or pyridin-4-yl), have been synthesized by reacting K[AuCl4] with the corresponding dithiolene, generated by base hydrolysis of the thione-protected 1,3-dithiolate. Each complex has been isolated as its [PPh4]+ salt and the structures of these [PPh4][Au(dithiolene)2] compounds have been determined by X-ray crystallography; each anion possesses a square planar {AuS4} core with a cis-arrangement of the R groups for R = phenyl and pyridin-2-yl complexes, but a trans-arrangement for R = pyridin-3-yl and pyridin-4-yl. In each compound, the lengths of the C-C (1.34 ± 0.01 A?) and C-S (1.75 0.03 A?) bonds of the metallocycle are consistent with the ene-1,2-dithiolate form of the dithiolene, i.e., these are [Au(III)bis(ene-1,2- dithiolate)]- complexes. Each compound is diamagnetic and 1H NMR studies indicate that, in solution in d6-acetone, both the cis and trans isomers of the [Au(SC(H)C(R)S)2]- anion are present and do not interconvert at room temperature. Each [Au(dithiolene)2]- complex undergoes an oxidation (80a reduction (-1880+/[Fc]); the particular potentials observed correlate with the electron withdrawing ability of the dithiolene substituent (R), as expressed by the Hammett σp-parameter. Comparison of the information obtained in these studies with that determined for related systems leads to the conclusion that the oxidation is a ligand-based process and that reduction involves addition of an electron to an orbital that possesses both metal and ligand character.
