Synthesis, structure, and characterization of a bridging ethylidene (perfluoroalkyl)phosphine platinum complex

Thermolysis of (dfepe)Pt(Et)(O2CCF3) (dfepe = (C2F5)(2)PCH2CH2P(C2F5)(2)) in benzene at 80 degreesC results in the formation of (dfepe)Pt(eta (2)-C2H4). However, at 120 degreesC in CF3CO2H a bridging ethylidene platinum dimer, [(dfepe)(2)Pt-2(mu -CHMe)(mu -H)][O2CCF3], is produced instead. Product isolation by precipitation with diethyl: ether afforded the neutral dimer (dfepe)(2)Pt-2(mu -CHMe3). Alternatively, (dfepe)(2)Pt-2(mu -CHMe) may be prepared at 20 degreesC by treatment of [(dfepe)Pt(mu -H)](2)(H)(+) with 1 atm of ethylene. Complete characterization of this species was accomplished by H-1, C-13, and P-31 NMR spectroscopy, as well as X-ray diffraction. Investigations probing the mechanism of formation for this mu -alkylidene product are presented. The synthesis of the benzyl complex (dfepe)Pt(CH2Ph)(O2CCF3) and its reversible rearrangement to the eta (3)-benzyl complex [(dfepe)Pt(eta (3)-CH2Ph)](+) upon labilization of trifluoroacetate anion is also reported.