New monocyclopentadienyl complexes of Group 4 and 5 metals with chelating nitrogen ligands. Crystal and molecular structures of [Zr(η3-C3H5)(η4-Ph2N2C2Me2-2,3)Cp″] and [TaCl2{η4-C6H4(NSiMe3-1,2)2}Cp″] [Cp″ = C5H3(SiMe3)2-1,3]†
Abstract
Reduction of [MCl3Cp″] [M = Zr or Hf; Cp″ = C5H3(SiMe3)2-1,3] with magnesium in the presence of 1,4-diphenyl-2,3-dimethyl-1,4-diazabuta-1,3-diene (DAD) gave the diazadiene complexes [MCl(DAD)Cp″] in high yield. Alkylation with RMgCl affords the alkyls [MR(DAD)Cp″] (R = CH3 or CH2Ph) and the more stable allyl complexes [M(η3-C3H5)(DAD)Cp″] as yellow to light brown solids. The reaction of Li2[C6H4(NSiMe3)2-1,2] with [MCl3Cp″] leads to the bis(amido) complexes [MCl{C6H4(NSiMe3)2-1,2}Cp″], while the analogous reaction with [MCl4Cp″] (M = Nb or Ta) generates the red to red-brown niobium and tantalum half-sandwich compounds [MCl2{C6H4(NSiMe3)2-1,2}Cp″]. The crystal structures of two representative examples, [Zr(η3-C3H5)(DAD)Cp″] and [TaCl2{C6H4(NSiMe3)2-1,2}Cp″], are reported.