Insertion of carbon dioxide, of Co2-like molecules, and of other unsaturated compounds into the platinum–nitrogen bond of [Pt(PPh3)2(PhNO)]

Abstract

The compound [Pt(PPh₃)₂(PhNO)](1) reacts reversibly with carbon dioxide to give [[graphic omitted]}(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 [[graphic omitted]}(PPh₃)₂](3), [[graphic omitted]}(PPh₃)₂](4), and [[graphic omitted]}(PPh₃)₂](5), respectively have been obtained. Compound (2) is an isomer of the insertion product (6), [[graphic omitted]}(PPh₃)₂], obtained from the reaction of [Pt(PPh₃)₂(O₂)] with PhNCO. A labile insertion product, [[graphic omitted]}(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–NN–CO₂Et to give the substitution product (8), [[graphic omitted]}(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.