Table of Contents
Metal-Based Drugs
Volume 6, Issue 4-5, Pages 247-253
http://dx.doi.org/10.1155/MBD.1999.247

Reactions of Organic Disulfides and Gold(I) Complexes

Department of Chemistry, University of Maine, Orono 04469-5706, Maine, USA

Received 3 October 1998; Accepted 1 March 1999

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Gold-thiolate/disulfide exchange reactions of (p-SC6H4Cl)2 with Ph3PAu(SC6H4CH3) , dppm(AuSC6H4CH3)2, and dppe(AuSC6H4CH3)2 were investigated. The rate of reactivity of the gold-thiolate complexes with (p-SC6H4Cl)2 is: dppm(AuSC6H4CH3)2>> dppe(AuSC6H4CH3)2>Ph3PAu(SC6H4CH3). This order correlates with conductivity measurements and two ionic mechanisms have been evaluated. H1 NMR experiments demonstrate that in the reaction of dppm(AuSC6H4CH3)2 with (p-SC6H4Cl)2, the mixed disulfide, ClC6H4SSC6H4CH3, forms first, followed by the formation of (p-SC6H4CH3)2. The rate law is first order in (pp-SC6H4Cl)2 and partial order in dppm(AuSC6H4CH3)2. Results from electrochemical and chemical reactivity studies suggest that free thiolate is not involved in the gold-thiolate/disulfide exchange reaction. A more likely source of ions is the dissociation of a proton from the methylene backbone of the dppm ligand which has been shown to exchange with D2O. The implications of this are discussed in terms of a possible mechanism for the gold-thiolate/disulfide exchange reaction.