Insertion of carbon dioxide, of CO2-like molecules and of other unsaturated compounds into the platinum-nitrogen bond of Pt(PPh3)2 (PhNO)

The compound [Pt(PPh3)2(PhNO)] (1) reacts reversibly with carbon dioxide to give [Pt{ON(Ph)C(O)O}(PPh3)2] (2). Other CO2-like molecules readily and irreversibly insert into the platinum-nitrogen bond of (1); with CS2, PhNCO, and PhNCS the corresponding 1:1 adducts [Pt{ON(Ph)C(S)S}(PPh3)2] (3), [Pt{ON(Ph)C(NPh)O}(PPh3)2] (4), and [Pt{ON(Ph)C(NPh)O}(PPh3)2] (5), respectively have been obtained. Compound (2) is an isomer of the insertion product (6), [Pt{O2C(CPh)O}(PPh3)2], obtained from the reaction of [Pt(PPh3)2(O2)] with PhNCO. A labile insertion product, [Pt{ON(Ph)CH(Ph)O}(PPh3)2], (7), was obtained by reaction of (1) with PhCHO, while no reaction was observed between (1) and acetone or diethyl carbonate. However, compound (1) reacts with EtO2C-N=N-CO2Et to give the substitution product (8), [Pt{N(CO2Et)N=C(OEt)O}(PPh3)2]. The reactions of compound (2) towards mineral acids, organic acids, benzoyl chloride, and sulphonyl chlorides have been studied. The products are identical to those obtained from the corresponding reactions of (1). l.r., 1H, 31P, and 195Pt n.m.r. spectra of the new compounds are reported and discussed.