Synthesis of three-co-ordinate mono-, bis-, and tris-olefin complexes of platinum with dimethyl or diethyl fumarate, dimethyl maleate, or maleic anhydride ligands

Abstract

Bis(cyclo-octa-1,5-diene)platinum, [Pt(cod)2], reacts with dimethyl or diethyl fumarate (dmf or def) or maleic anhydride (ma) to give the complexes [Pt(cod)(olefin)](olefin = dmf, def, or ma). Dimethyl or diethyl maleate (dmm or dem) yield the fumarate complexes [Pt(cod)(olefin)](dmf or def). In the presence of 1 mol equivalent of ButNC or PPh3, complexes of the type [PtL(olefin)2](L = CNBut or PPh3; olefin = dmf, def, dmm, or ma) are produced. With an excess of ButNC the complexes [Pt(CNBut)2(olefin)] are formed. The latter species can also be obtained from the triplatinum complex [Pt3(CNBut)6] and the respective olefin. Addition of tricyclohexylphosphine to [Pt(CNBut)(dmf)2] gives [Pt(CNBut)(dmf){P(C6H11)3}]. The tris(olefin) complexes [Pt(C2H4)(olefin)2](olefin = dmf or dmm) and [Pt(olefin)3](olefin = dmf or def) are formed by treating [Pt(C2H4)3] with the respective olefin. Tetra-alkylammonium halides react with a mixture of [Pt(cod)(dmf)] and dmf to give ionic complexes [NR4][PtX(dmf)2](X = Cl, Br, or I). Protonation of [Pt(cod)(dmf)] with trifluoroacetic acid gives selectively the platinum(II)σ-bonded complex [Pt{CH(CO2Me)CH2(CO2Me)}(O2CCF3)(cod)].