Bis(pentamethylcyclopentadienyl) ytterbium: Electron-transfer reactions with organotransition metal complexes

摘要

The divalent lanthanide complex, (Me(sub 5)C(sub 5))(sub 2)Yb, reacts with methylcopper to produce the base-free, ytterbium-methyl complex, (Me(sub 5)C(sub 5))(sub 2)YbMe. This product forms a asymmetric, methyl-bridged dimer in the solid state. The bulky alkyl complex, (Me(sub 5)C(sub 5))(sub 2)YbCH(SiMe(sub 3))(sub 2), displays similar chemistry to (Me(sub 5)C(sub 5))(sub 2)YbMe, but at a reduced reaction rate due to the limited accessibility of the metal in (Me(sub 5)C(sub 5))(sub 2)YbCH(SiMe(sub 3))(sub 2). Copper and silver halide salts react with (Me(sub 5)C(sub 5))(sub 2)V to produce the trivalent halide derivatives, (Me(sub 5)C(sub 5))(sub 2)VX (X + F, Cl, Br, I). The chloride complex, (Me(sub 5)C(sub 5))(sub 2)VCl, reacts with lithium reagents to form the phenyl and borohydride species. Nitrous oxide transfers an oxygen atom to (Me(sub 5)C(sub 5))(sub 2)V producing the vanadium-oxo complex, (Me(sub 5)Ce(sub 5))(sub 2)VO. The trivalent titanium species, (Me(sub 5)C(sub 5))(sub 2)TiX (X = Cl, Br, Me, BH(sub 4)), form bimetallic coordination complexes with (Me(sub 5)C(sub 5))(sub 2)Yb. The magnetic behavior of the products indicates that electron transfer has not occurred. The solid state structures of the chloride and bromide complexes show unusual bend angles for the halide bridges between ytterbium and titanium. A model based on frontier orbital theory has been proposed to account for the bending behavior in these species. The bimetallic methyl complex contains a linear methyl bridge between ytterbium and titanium.