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 κ2-2-NMe2-3-PiPr2-indene (1b) or κ2-2-NMe2-3-PiPr2-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 °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}2Cl]+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-.