Substitution and cyclometallation reactions on Pt(II) phosphite complexes

• Synthesis of platinum(II) complexes.
• Positioning of phosphine and phosphite ligands on a metal center.
• The role of actor and spectator ligands in conducting orthometallation reactions.

This paper describes the formation of newseries of platinum(II) complexes with phosphite and phosphine ligands. Treatment of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 2 equimolar of L, L = P(OiPr)3orP(OPh)3, then adding 2 equimolar of L′, L′ = PPh3 or 4-MePy, gavecis-[Me2PtLL′] complexes,1a–4a, with some side products. Otherwise, reaction of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 4 equimolar of Me2SO, then adding 2 equimolar of PPh3, gavecis-[Me2Pt(Me2SO−κS)(PPh3)]. Addition of 1 equimolar of L, L = P(OPh)3 andP(OiPr)3 and substitution of Me2SO occurred to givecis-[Me2PtLL′]complexes, 2a and 4a with more selectivity. In order tocontrol steric and electronic effects of the ligands, 2 and 4 equimolar of P(OPh)3 were added to cis,cis-[Me2Pt(μ-SMe2)2PtMe2] during refluxing and complexes 1b, [MePt(CˆP))SMe2)] and 2b, [MePt(CˆP){P(OPh)3}],(CˆP = {(κ2-C,P)P(OPh)2(OC6H4)})were formed respectively. With adding 1 equimolar of L, L = PPh3, 4-MePy to complex 1b, the products of substitution reactions were [MePt(CˆP)L], 3b and4b.

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