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 resu lts in an apparent cis addition of the perfluoroalkyl iodide to give the si x-coordinate Pt(IV) complex (TMEDA)Pt(n-C3F7)(CH3)(2)I (6a). Complex 6a slo wly and reversibly reductively eliminates CH3I in solution to afford an equ ilibrium with the Pt(II) complex (TMEDA)Pt(n-C3F7)(CH3) (9a). Addition of t riethylamine drives the equilibrium toward 9a. Identical reactions of perfl uoroethyl iodide are observed to afford 6b and 9b. Reaction of 6a with AgBF 4 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)(2)Cl (12); bot h reactions retain the cis stereochemistry of the starting material 6a. Rea ction of 9a with CF3SO3H in moist solvents generates the cationic Pt(II) co mplex [(TMEDA)Pt(n-C3F7)(OH2)]O3SCF3 (17), which reacts with iodide to affo rd the neutral iodide complex (TMEDA)Pt(n-C3F7)I (14). Reaction of complex 9a with 12 in hexanes results in trans addition of 12 to generate (TMEDA)Pt (C3F7)(CH3)I-2 (13), which is converted to (TMEDA)Pt(n-C3F7)I (7) by treatm ent with AgBF4 followed by NaI. Complex 14 reacts with NaBH4 to produce (TM EDA)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 trif late complex (DPPE)Pt(n-C3F7)O3SCF3 (20), in equilibrium with a water compl ex, [(DPPE)Pt(n-C3F7)(OH2)]O3SCF3 (21). Reaction of 20 with iodide, or 19 w ith 12, gives (DPPE)Pt(n-C3F7)I (22), which can be converted to the hydrido complex (DPPE)Pt(nC(3)F(7))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.