Eugene Y Chia - Gold(I) Complexes Bearing Mixed-Donor Ligands Derived from N-Heterocyclic Carbenes

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      Publication Details (including relevant citation   information): Eugene Y. Chia, Saira Naeem, Lionel   Delaude, Andrew J. P. White and James D. E. T. Wilton-Ely, Dalton   Trans., 2011, 40, 6645-6658. DOI: 10.1039/C0DT01613F


      The new 2-phenylthiocarbamoyl-1,3-dimesitylimidazolium inner salt   (IMes·CSNPh) reacts with [AuCl(L)] in the presence of   NH4PF6 to   yield [(L)Au(SCNPh·IMes)]+ (L =   PMe3, PPh3,   PCy3, CNBut).   The carbene-containing precursor [(IDip)AuCl] reacts with   IMes·CSNPh under the same conditions to afford the complex   [(IDip)Au(SCNPh·IMes)]+ (IDip =   1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Treatment of   the diphosphine complex [(dppm)(AuCl)2]   with one equivalent of IMes·CSNPh yields the digold metallacycle,   [(dppm)Au2(SCNPh·IMes)]2+,   while reaction of   [L2(AuCl)2]   with two equivalents of IMes·CSNPh results in   [(L2){Au(SCNPh·IMes)}2]2+  (L2 = dppb, dppf, or dppa; dppb =   1,4-bis(diphenylphosphino)butane, dppf =   1,1′-bis(diphenylphosphino)ferrocene, dppa =   1,4-bis(diphenylphosphino)acetylene). The homoleptic complex   [Au(SCNPh·IMes)2]+  is formed on reaction of [AuCl(tht)] (tht = tetrahydrothiophene)   with two equivalents of the imidazolium-2-phenylthiocarbamoyl   ligand. This product reacts with AgOTf to yield the mixed metal   compound   [AuAg(SCNPh·IMes)2]2+.   Over time, the unusual trimetallic complex   [Au(AgOTf)2(SCNPh·IMes)2]+  is formed. The sulfur-oxygen mixed-donor ligands IMes·COS and   SIMes·COS (SIMes =   1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) were used to   prepare [(L)Au(SOC·IMes)]+ and   [(L)Au(SOC·SIMes)]+ from [(L)AuCl] (L =   PPh3, CNtBu).   The bimetallic examples   [(dppf){Au(SOC·IMes)}2]2+  and   [(dppf){Au(SOC·SIMes)}2]2+  were synthesized from the reaction of   [(dppf)(AuCl)2] with the appropriate   ligand. Reaction of [(tht)AuCl] with one equivalent of IMes·COS   or SIMes·COS yields   [Au(SOC·IMes)2]+  and   [Au(SOC·SIMes)2]+,   respectively. The compounds   [(Ph3P)Au(SCNPh·IMes)]PF6,   [(Cy3P)Au(SCNPh·IMes)]PF6  and   [Au(AgOTf)2(SCNPh·IMes)2]OTf   were characterized crystallographically.

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