Synthesis and Molecular Structures of Perfluoro-n-alkyl Complexes of Platinum(II) and Platinum(IV) Containing Tetramethylethylenediamine (TMEDA) or 1,2-Bis(diphenylphosphino)ethane (DPPE) Ligands

Reaction of (TMEDA)Pt(CH3)2 with n-perfluoropropyl iodide in hexanes results in an apparent cis addition of the perfluoroalkyl iodide to give the six-coordinate Pt(IV) complex (TMEDA)Pt(n-C3F7)(CH3)2I (6a). Complex 6a slowly and reversibly reductively eliminates CH3I in solution to afford an equilibrium with the Pt(II) complex (TMEDA)Pt(n-C3F7)(CH3) (9a). Addition of triethylamine drives the equilibrium toward 9a. Identical reactions of perfluoroethyl iodide are observed to afford 6b and 9b. Reaction of 6a with AgBF4 generates the cationic Pt(IV) complex [(TMEDA)Pt(n-C3F7)(CH3)2(OH2)]BF4 (11), which reacts with NaCl to form (TMEDA)Pt(n-C3F7)(CH3)2Cl (12); both reactions retain the cis stereochemistry of the starting material 6a. Reaction of 9a with CF3SO3H in moist solvents generates the cationic Pt(II) complex [(TMEDA)Pt(n-C3F7)(OH2)]O3SCF3 (17), which reacts with iodide to afford the neutral iodide complex (TMEDA)Pt(n-C3F7)I (14). Reaction of complex 9a with I2 in hexanes results in trans addition of I2 to generate (TMEDA)Pt(C3F7)(CH3)I2 (13), which is converted to (TMEDA)Pt(n-C3F7)I (7) by treatment with AgBF4 followed by NaI. Complex 14 reacts with NaBH4 to produce (TMEDA)Pt(n-C3F7)H (18). The TMEDA ligand can be displaced from 9a by DPPE to give (DPPE)Pt(n-C3F7)(CH3) (19), which reacts with CF3SO3H to give the triflate complex (DPPE)Pt(n-C3F7)O3SCF3 (20), in equilibrium with a water complex, [(DPPE)Pt(n-C3F7)(OH2)]O3SCF3 (21). Reaction of 20 with iodide, or 19 with I2, gives (DPPE)Pt(n-C3F7)I (22), which can be converted to the hydrido complex (DPPE)Pt(n-C3F7)H (23) with NaBH4. The X-ray crystal structures of complexes 6a, 9a, 9b, 10, 13, 18, 19, 20, and 23 have been determined, and structural comparisons in terms of ligand cis and trans influences are discussed.