Mono- and diphosphine platinum(0) complexes of methylenecyclopropane, bicyclopropylidene, and allylidenecyclopropane

Article abstract of DOI:10.1021/om200630z

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)₃PPh ₂, Cyp₂P(CH₂)₂PCyp₂, ^tBu₂P(CH₂)₂P^tBu ₂, ^tBu₂PCH₂(o-C₆H ₄)CH₂P^tBu₂) 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 = PPh ₃, PCy₃) were synthesized by the addition of the free alkene to bis-ethene precursors.