STUDY OF EFFECTS ON THE COORDINATION OF THIOETHER LIGANDS .2. STEREOSPECIFIC LIGAND SUBSTITUTIONS IN MANGANESE(I) COMPLEXES

Treatment of fac-[(P(2)SPh-P,P')Mn(CO)(3)Br] and fac-[(PS(2)Ph-P,S)Mn( CO)3Br] [P(2)SPh: Z = PPh(2); PS(2)Ph: Z = SPh in CH3C-(CH(2)PPh(2)) ( CH(2)SPh)(CH(2)Z)] with silver hexafluorophosphate yields the eta(3)-t ripodal manganese complexes [(P(2)SPh-P,P',S)Mn(CO)(3)]PF6 (7) and [(P S(2)Ph-P,S,S')Mn(CO)(3)]PF6 (9), respectively, whereas the reaction of CH3C(CH(2)PPh(2))2(CH2SH) with Mn(CO)(5)Br gives directly [CH3C(Ph(2) -PCH2)(2)(CH2S)-P,P',S]Mn(CO)3 (11). Both ionic complexes 7 and 9 unde rgo stereospecifically ligand substitution upon treatment with Br-, I- , N-3(-) SCN- and CN- to give syn-fac-[(P(2)SPh-P,P')Mn(CO)(3)X] and s yn-fac-[(PS(2)Ph-P,S)Mn(CO)(3)X] (X = Br, I, SCN, N-3, CN) respectivel y, but the neutral complex 11 fails to undergo such a substitution rea ction with these ions. However, reaction of I- with the complex [(PSMe )-P,P',S]Mn(CO)(3)]BF4 (20) {P(2)SMe = CH3C(CH2-PPh(2))(2)(CH2SCH3)}, which is obtained from the S-alkylation of 11 with (CH3)(3)OBF4, affor ds syn-fac-[(P(2)SMe)-P,P']Mn(CO)(3)I (22s) exclusively. The possible reaction mechanism of this ligand substitution is discussed.