PLATINUM ETA-2-DISILENE COMPLEXES - SYNTHESES, REACTIVITY, AND STRUCTURES

Stable bis (phosphine) platinum η2-disilene complexes analogous to olefin π-complexes have been prepared by various methods. Tetramesityldisilene reacts with bis(tertiary phosphine)platinum oxalates under UV irradiation and with bis(triphenylphosphine)platinum(0) ethylene thermally to produce η2-complexes 2a,b. The reaction of tetrasubstituted 1,2-dihydridodisilanes (R2SiH)2 with bis(phosphine)platinum equivalents, e.g., (diphos)PtCl2/Li or (diphos)Pt(CH2═CH2) also yielded platinum η2-disilene complexes 6a (R = i-Pr), 6b (R = Me), and 6c (R = Ph). Reaction of 6a (R = i-Pr) with H2 yielded a bis(R2SiH) platinum complex 8, which was characterized by X-ray crystallography: monoclinic, P21/n, a = 10.679 (1) Å, b = 16.564 (4) Å, c = 21.854 (3) Å, β = 97.91 (1)°. Reactions of 6a,b with O2 and NH3 afforded new four-membered heterocycles arising from addition across the Si‒Si bond. The crystal structure of the oxygen adduct 9b is triclinic, P1, a = 9.727 (1) Å,b = 11.834 (2) Å, c = 14.867 (2) Å, α = 88.89 (1)°, β = 83.19 (1)°, γ = 66.62 (1)°. This compound exhibits a short Si‒Si distance (2.549 Å), reflecting possible cross-ring bonding between silicon atoms. © 1990, American Chemical Society. All rights reserved.