SPECTROSCOPIC STUDY OF THE INTERACTION OF TRICYCLOPENTADIENIDES OF LANTHANOID ELEMENTS WITH METAL-CARBONYL DERIVATIVES .1.

The interaction of samarium tricyclopentadienide, Cp3Sm, with a diverse series of metal carbonyl derivatives has been investigated by IR and 1H NMR spectroscopy, and the variability of Lewis base sites in manganese carbonyl derivatives has been studied in terms of the charge on the manganese atom and the π-accepting ability of the ligands in these derivatives. In the series BrMn(CO)5-xLx, the oxygen atom functioned as the Lewis base site, while the manganese atom was the site of the Lewis basicity in anions of the type [Mn(CO)5-xLx]- (x = 0, 1, 2; L = P(OPh)3). The reactivity of the carbonyl oxygen atom in the series Me4-ySn[Mn(CO)5]y (y = 1, 2, 3) was in the order: MeSn[Mn(CO)5]3 > Me2Sn[Mn(CO)5]2 > Me3SnMn(CO)5; Cp3Sm induced an upfield shift of the methyl proton NMR signal in these SnMn compounds on adduct formation. Attempts to induce shifts of the terminal carbonyls to bridging positions in Mn2(CO)10 [Mn(CO)4P(OPh)3]2, and H3Mn3(CO)12 led instead to complexation at terminal carbonyl ligands. © 1979.