Reactions of M(CO)(5)X (M = Mn, Re; X = Cl, Br) with {Ph2PCH2}(3)CCH3 (P-3) and {Ph2P(CH2)(2)}(3)P (P3P '): Synthetic, spectroscopic, electrochemical, and electrospray mass spectrometric studies

The reactions of M(CO)(5)X (M = Mn, Re: X = Cl, Br) with {Ph2PCH2}(3)CCH3 ( P-3) and {Ph2P(CH2)(2)}(3)P (P3P') are investigated, and the products are c haracterized by IR, NMR (P-31 and C-13), and electrospray mass spectrometri c (ESMS) techniques. With P-3, the major products are fac-M(CO)(3)(eta (2)- P-3)X (syn and anti isomers) and ci,fac-M(CO)(2)(eta (3)-P-3)X, and with P3 P', the major product for each metal is cis,mer-M(CO)(2)(eta (3)-P3P')X, bu t cis-[M(CO)(2)(eta (4)-P3P')]X and fac-[Re(CO)(3)(eta (3)-P3P')]X are also characterized. Addition of Mel to those complexes containing pendant phosp hine groups produces the corresponding phosphonium cations without affectin g the remainder of the molecule. On the voltammetric time scale, electroche mical oxidation of cis,fac-Mn(CO)(2)(eta (3)-P-3)X yields the corresponding 17e cation cis,fac-[Mn(CO)(2)(eta (3)-P-3)X](+), but on the longer time sc ale of exhaustive electrolysis or chemical oxidation, the product is fac-[M n(CO)(3)(eta (3)-P-3)](+). In contrast, the rhenium cation; cis;fac-[Re(CO) (2)(eta (3)-P-3)X](+) is stable on the synthetic time scale, but upon oxida tion of cis,fac-Re(CO)(2)(eta (3)-P-3)X With NOBF4, he final product is the 18e [Re(CO)(NO)(eta (3)-P-3)X](+). cis,mer-Mn(CO)(2)(eta (3)-P3P')X is rev ersibly oxidized to cis,mer-[Mn(CO)(2)(eta (3)-P3P')X](+) on the voltammetr ic time scale, but on the longer synthetic time scale, the product isomeriz es to trans-[Mn(CO)(2)(eta (3)-P3P')X](+), which can be reduced to trans-Mn (CO)(2)(eta (3)-P3P')X. Upon voltammetric oxidation, the corresponding rhen ium complexes show an initial irreversible response associated with the pen dant phosphine group prior to the reversible oxidation of the metal on the synthetic time scale; spectroscopic data indicate formation of cis,mer-Re(C O)(2)(eta (3)-P3P'O)X. The complex cis,mer-[Re(CO)(2)(eta (3)-P3P'Me)X](+) shows only the reversible metal oxidation response. ESMS data are obtained directly for the methylated cationic complexes, and neutral complexes are e ither oxidized or adducted with sodium ions to produce cationic species.