Dialkyl- and diaryl-platinum(II) complexes with secondary phosphines: Preparation, structure and thermal reaction giving the metallopolymer

Alkyl and arylplatinum complexes with 1,5-cyclooctadiene ligand, [PtR2(cod)] (R = Me, Ph, C6H4-p-CF3, C6F5), react with secondary phosphines, PHR'(2) (R' = i-Bu, t-Bu, Ph), to afford the mononuclear platinum complexes, cis-[PtR2(PHR'(2))(2)] (1a: R = Me, R' = i-Bu; 1b: R = Me, R' = t-Bu; 1c: R = Me, R' = Ph; 2a: R = Ph, R' = i-Bu; 2b: R = Ph, R' = t-Bu; 2c: R = R' = Ph; 3a: R= C6H4-p-CF3, R' = i-Bu; 3b: R= C6H4-p-CF3, R' = t-Bu; 3c: R = C6H4-p-CF3, R' = Ph; 4a: R = C6F5, R' = i-Bu; 4c: R = C6F5, R' = Ph) in 81-98% yields. Molecular structures of the complexes except for 1a, 1c and 2a were determined by X-ray crystallography. Complex 1b has a square-planar structure with Pt-C(methyl) bonds of 2.083(8) and 2.109(8) angstrom, while the Pt-C(aryl) bonds of 2b-c, 3a-c, 4a and 4c (2.055(1)-2.073(8) angstrom) are shorter than them. Thermal decomposition of 1b, 2a-c, and 3a-c releases methane, biphenyl or 4,4'-bis(trifluoromethyl)biphenyl as the organic products, which are characterized by NMR spectroscopy. The solid product of the thermal reactions of 2b and 2c were characterized as the metallopolymers formulated as [Pt(PR'(2))(2)](n) (5b: R' = Bu-t; 5c: R' = Ph), based on the solid-state NMR and elemental analyses. (C) 2009 Elsevier B. V. All rights reserved.