263572-34-5Relevant academic research and scientific papers
Niobium- And tantalum-benzamidinato complexes with trimethylphosphine, imido, or η-cyclopentadienyl derivatives
Chen, Chi-Tien,Doerrer, Linda H.,Cliff Williams,Green, Malcolm L. H.
, p. 967 - 974 (2007/10/03)
The mononuclear benzamidinato compounds, [M{(2,4,6-tri-iPr)C6H2C(NSiMe3)2}Cl4] (M = Nb (1) or Ta (2)), [Nb{(2)4,6-tn-iPr)C6H2C(NSiMe3)2}Ci4(PMe3)](4), [M{(2,4,6-tri-iPr)C6H2C(NSiMe3)2}(N'Bu)(H2N'Bu)Cl2] (M = Nb (5), M = Ta (6)), [Nb{(2,4,6-tri-iPr)C6H2C(NSiMe3)2}(N'Bu)(L)Cl2] (L = THF (7), L = pyridine (8)), and [M{(2,4,6-tri-iPr)C6H2C(NSiMe3)2}(n-C5H5)Cl3] (M = Nb (9), M = Ta (10), and a nitrile tantalum complex, [Ta{(2,4,6-tri-'Pr)C6H2CN}Cl5] (3), obtained in a side-reaction have been prepared:indicates the crystal structures have been determined. Variable temperature NMR studies show there is hindered rotation of the aryl group around Cipso-C bonds for compounds 5 and 6; ΔC = 55.2 kJ mol'1 at 268 K for 5. Hindered rotation about the N-Si bonds for compounds 9 and 10 occurs with the ΔG= 51.0 kJ mol~' at 273 K and 40.6 kJ mol"' at 213 K for 10. The compounds 1,5 and 9 are very poor pre-catalysts for ethene polymerisation. The Royal Society of Chemistry 2000.
