Reactivity of (NBu(4))[Pt(C6F5)(2)(acac)] toward electrophilic metal centers: Metal-metal vs metal-C-gamma(acac) bond formation. Crystal structure of [PtAg(C6F5)(2)(acac)(CH2Cl2)](2), a complex containing a mu(2)-acac-O,O' bridging ligand and a coordinated dichloromethane

The reaction between (NBu(4))[Pt(C6F5)(2)(acac)] and AgClO4 (1:1 molar ratio) in CH2Cl2 at room temperature gives the neutral tetranuclear complex [PtAg(C6F5)(2)(acac)](2) (1) in a good yield. The structure, which has been determined by single-crystal X-ray diffraction methods, shows two anionic fragments [Pt(C6F5)(2)(acac)](-) linked by two Ag+ atoms, each silver center being bonded to a Pt atom of one fragment and to an oxygen atom of the acac ligand of the other fragment. Noteworthy structural features are the O-acac coordination of the silver atom (instead of the more usual C-gamma coordination) and the unexpected presence of a dichloromethane molecule coordinated to the silver center. The reaction of 1 with tht (tht = SC4H8, tetrahydrothiophene) or PPh(3) gives the dinuclear complexes [PtAg(C6F5)(2)(acac)(L)] (L = tht (2), PPh(3) (3)) by cleavage of the O-Ag bond; alternatively, complexes 2 and 3 can be one-pot synthesized by reaction of (NBu(4))[Pt(C6F5)(2)(acac)] and O(3)ClOAgL (L = tht, PPh(3)). Their structural characterization points to the presence of donor-acceptor Pt-->Ag bonds, Different behavior is observed in the reaction of (NBu(4))[Pt(C6F5)(2)(acac)] with O(3)ClOAuPPh(3), giving the dinuclear complex [PtAu(mu-acac)(C6F5)(2)(PPh(3))] (4) in which, as can be seen from its spectroscopic data, the gold atom is bonded to C-gamma of the acac ligand.