Mono- and Diphosphine Platinum(0) Complexes of Methylenecyclopropane, Bicyclopropylidene, and Allylidenecyclopropane

The syntheses of the first platinum complexes with η2-bicyclopropylidene ligands are reported herein. Complexes of the formula [Pt(L)(P–P)] (L = η2-bicyclopropylidene, η2-methylenecyclopropane, P–P = Ph2P(CH2)3PPh2, Cyp2P(CH2)2PCyp2, t Bu2P(CH2)2P t Bu2, t Bu2PCH2(o-C6H4)CH2P t Bu2) were synthesized by addition of the free alkene to ethene precursor complexes. Bicyclopropylidene underwent a ring-opening reaction with both Pt(0) and Pt(II) complexes to form allylidenecyclopropane, and the first allylidenecyclopropane complexes were synthesized, some of which underwent a rearrangement to form η2:σ2-metallacyclo-3-pentene complexes. Mixed alkene complexes [Pt(C2H4)(L)(PR3)] (L = η2-bicyclopropylidene, η2-methylenecyclopropane, PR3 = PPh3, PCy3) and bis-methylenecyclopropane complexes [Pt(MCP)2(PR3)] (PR3 = PPh3, PCy3) were synthesized by the addition of the free alkene to bis-ethene precursors.