Inorganic Chemistry, Vol.48, No.8, 3866-3874, 2009
Multimetallic Arrays: Bi-, Tri-, Tetra-, and Hexametallic Complexes Based on Gold(I) and Gold(III) and the Surface Functionalization of Gold Nanoparticles with Transition Metals
Reaction of [AuCl(PPh3)] with the zwitterion S2CNC4H8NH2 yields [(Ph3P)Au(S2CNC4H8NH2)]BF4. Treatment of this species with NEt3 and CS2 followed by [AuCl(PPh3)] leads to [{(Ph3P)Au}(2)(S2CNC4H8NCS2)], which can also be obtained directly from [AuCl(PPh3)] and KS2CNC4H8NCS2K. A heterobimetallic variant, [(dppm)(2)Ru(S2CNC4H8-NCS2)Au(PPh3)](+), can be prepared by the sequential reaction of [(dppm)(2)Ru(s(2)CNC(4)H(8)NH(2))](2+) with NEt3 and CS2 followed by [AuCl(PPh3)]. Reaction of the same ruthenium precursor with [(dppm)(AuCl)(2)] under similar conditions yields the trimetallic complex [(dppm)(2)Ru(S2CNC4H8NCS2)Au-2(dppm)](2+). Attempts to prepare the compound [(dppm)Au-2(S2CNC4H8NH2)](2+) from [(dppm)(AuCl)(2)] led to isolation of the known complex [{(dppm)-Au-2)(2)(S2CNC4H8NCS2)](2+) via a symmetrization pathway. [{(dppf)Au-2}(2)(S2CNC4H8NCS2)](2+) was successfully prepared from [(dppf)(AuCl)(2)] and crystallographically characterized. In addition, a gold(III) trimetallic compound, [{(dPPm)(2)Ru(S2CNC4H8NCS2)}(2)Au](3+), and a tetrametallic gold(I) species, [{(dPPm)(2)Ru(S2CNC4H8NCS2)Au)(2)](2+), were also synthesized. This methodology was further exploited to attach the zwitterionic (dPPm)(2)Ru(S2CNC4H8NCS2) unit to the surface of gold nanoparticles, which were generated in situ and found to be 3.4 (+/- 0.3) and 14.4 (+/- 2.5) nm in diameter depending on the method employed. Nanoparticles with a mixed surface topography were also explored.