Synthesis of bimetallic fulvalene and bis(cyclopentadienyl)methane derivatives of niobium and tantalum tetracarbonyl

Ring coupled bimetallic derivatives (μ-η5:5-C5H4C5H4)[Nb(CO)4]2 and [μ-CH2(η5-C5H4)2][M(CO)4]2, where M = Nb and Ta have been prepared. The molecular structures of the latter two compounds have been determined: View the MathML source[μ-CH2(η5-C5H4)2][Nb(CO)4]2·12C6H6, triclinic, View the MathML sourceP1¯, a = 8.028(2) Å, b = 11.414(1) Å, c = 12.711(2) Å, α = 75.020(8)°, β = 80.34(2)°, γ = 79.46(2)°, V = 1097.3(4) Å3, Z = 2, R (F ) = 2.79%; [μ-CH2(η5-C5H4)2][Ta(CO)4]2, triclinic, View the MathML sourceP1¯, a = 7.815(3) Å, b = 10.275(4) Å, c = 13.135(4) Å, α = 104.25(3)°, β = 100.26(4)°, γ = 96.86(3)°, V = 991.2(6) Å3, Z = 2, R(F) = 3.00%.