Neutral and cationic platinum(II) complexes supported by a P,N-functionalized indene ligand: Structural and reactivity comparisons with a related gold(III) zwitterion

The structural and reactivity properties of new Pt(II) and Au(III) complexes featuring kappa(2)-2-NMe2-3-(PPr2)-Pr-i-indene (1b) or kappa(2)-2-NMe2-3-(PPr2)-Pr-i-indenide (1c) ancillary ligands are examined. Complex [1c]AuMe2 (3), a formally zwitterionic relative of the neutral complex [1b]PtMe2 (2b), was prepared in 41% isolated yield from [1c]Li and 0.5 [Me2AuCl](2). Whereas 2b was observed to react with H2O, Ph3SiH, and PhSiH3 over 48 h at 50 degrees C, complex 3 proved unreactive under these reaction conditions. Similarly, 2b exhibited modest catalytic activity for the addition of triethylsilane to styrene, while no conversion was achieved by use of 3 as a catalyst. Observations made during the course of examining the catalytic abilities of [1b]PtClMe (7) and 7/AgX (X = BF4 or OTf) for this addition reaction prompted the rational preparation of the dinuclear cation [{(1b)PtMe}(2)Cl]+BF4- ([8]+BF4-; 61%) as well as the monomeric cations [(1b)PtMeL]+BF4- (L = SMe2, [9]+BF4-, 77%; L = MeCN, [10]+BF4-, 84%). Single-crystal X-ray diffraction data are provided for 2b, 3, [8]+BF4-, and [9]+BF4-.