Synthesis, Structure, and Characterization of a Bridging Ethylidene (Perfluoroalkyl)phosphine Platinum Complex

Thermolysis of (dfepe)Pt(Et)(O 2 CCF 3 ) (dfepe = (C 2 F 5 ) 2 PCH 2 CH 2 P(C 2 F 5 ) 2 ) in benzene at 80 °C results in the formation of (dfepe)Pt(η 2 -C 2 H 4 ). However, at 120 °C in CF 3 CO 2 H a bridging ethylidene platinum dimer, [(dfepe) 2 Pt 2 (μ-CHMe)(μ-H)][O 2 CCF 3 ], is produced instead. Product isolation by precipitation with diethyl ether afforded the neutral dimer (dfepe) 2 Pt 2 (μ-CHMe 3 ). Alternatively, (dfepe) 2 Pt 2 (μ-CHMe) may be prepared at 20 °C by treatment of [(dfepe)Pt(μ-H)] 2 (H) + with 1 atm of ethylene. Complete characterization of this species was accomplished by 1 H, 13 C, and 31 P NMR spectroscopy, as well as X-ray diffraction. Investigations probing the mechanism of formation for this μ-alkylidene product are presented. The synthesis of the benzyl complex (dfepe)Pt(CH 2 Ph)(O 2 CCF 3 ) and its reversible rearrangement to the η 3 -benzyl complex [(dfepe)Pt(η 3 -CH 2 Ph)] + upon labilization of trifluoroacetate anion is also reported.