Metallo-organic compounds containing metal–nitrogen bonds. Part VI. Infrared and nuclear magnetic resonance of dialkylamidoderivatives of titanium, vanadium, zirconium, niobium, hafnium, tantalum, and thorium

I.r. and n.m.r. spectra have been measured on solutions of a number of dialkylamido-compounds M(NR2)x of titanium, vanadium, zirconium, niobium, hafnium, tantalum, and thorium and on the alkylimido-trisdialkylamidotantalums RNTa(NR2)3. Assignments of characteristic bands are made and the metal–nitrogen stretching frequencies are discussed in terms of a significant contribution of nitrogen → metal pπ–dπ bonding. The variable temperature n.m.r. studies on Zr(NMe2)4 confirmed the presence of polymeric species in solution.