Reactivity of (NBu4)[Pt(C6F5)2(acac)] toward Electrophilic Metal Centers: Metal−Metal vs Metal−Cγ(acac) Bond Formation. Crystal Structure of [PtAg(C6F5)2(acac)(CH2Cl2)]2, a Complex Containing a μ2-acac-O,O‘ Bridging Ligand and a Coordinated Dichloromethane

The reaction between (NBu 4 )[Pt(C 6 F 5 ) 2 (acac)] and AgClO 4 (1:1 molar ratio) in CH 2 Cl 2 at room temperature gives the neutral tetranuclear complex [PtAg(C 6 F 5 ) 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(C 6 F 5 ) 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 γ coordination) and the unexpected presence of a dichloromethane molecule coordinated to the silver center. The reaction of 1 with tht (tht = SC 4 H 8, tetrahydrothiophene) or PPh 3 gives the dinuclear complexes [PtAg(C 6 F 5 ) 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(C 6 F 5 ) 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(C 6 F 5 ) 2 (acac)] with O 3 ClOAuPPh 3, giving the dinuclear complex [PtAu(μ-acac)(C 6 F 5 ) 2 (PPh 3 )] ( 4 ) in which, as can be seen from its spectroscopic data, the gold atom is bonded to C γ of the acac ligand.