Convenient preparation of (η-alkadiene)dichloroplatinum(II) complexes from [PtCl6] anions and their reduction to platinum(0) alkene complexes under phase-transfer catalysis conditions

Convenient one-pot reduction-complexation reactions of hexachloroplatinato(IV) anions to (η⁴-alkadiene)dichloroplatinum(II) complexes (η⁴-alkadiene = COD, DAE, DCPD, NBD) under suitable phase-transfer catalysis conditions are reported. Reduction to zerovalent platinum alkene complexes has been obtained in the presence of an excess of alkene, potassium formate and 18-crown-6 as phase-transfer catalyst (alkene = COD, NB, dba). The crystal and molecular structure of Pt_1.03(dba)₃]·CH₂Cl₂ has been studied by X-ray diffraction methods: it can be described as a solid solution of Pt(dba)₃ and Pt₂(dba)₃, the mononuclear complex being largely prevailing.