217496-64-5Relevant academic research and scientific papers
New ansa-niobocene complexes. X-ray crystal structure of [Me2Si(η5-C5H4) 2]Nb(=NtBu)Cl. Stereoselective synthesis of meso-[Me2Si(η5-C5H3SiMe 3)2]Nb(=NtBu)Cl
Antinolo, Antonio,Otero, Antonio,Prashar, Sanjiv,Rodriguez, Ana M.
, p. 5454 - 5459 (1998)
The ansa-niobocene complex [Me2Si(η5-C5-H4) 2]Nb(=NtBu)Cl (1) has been prepared and its structure determined by single-crystal X-ray diffraction. The alkyl complexes [Me2Si(η5-C5-H4) 2]Nb(=NtBu)(R) (R = Me (2), Et (3), CH2Ph (4), CH2CH=CH2 (5)) were prepared by the reaction of 1 and the corresponding Grignard reagent. Using the trimethylsilyl-substituted ansa ligand Me2Si(C5H3SiMe3)2, [Me2Si(η5-C5-H4) 2]Nb(=NtBu)Cl (6) was prepared and isolated uniquely as the meso-isomer. Nevertheless the synthesis of Me2Si(η5-C5H3SiMe 3)2]NbCl2 (7) yielded a mixture of meso- and rac-isomers. Reduction of 7 in the presence of ligand (RC=CR) (R = Me, Ph) gave [Me2Si(η5-C5H3SiMe 3)2]NbCl(RC=CR) (R = Me (8), Ph (9)). Both complexes were initially isolated as mixtures of meso- and racisomers and in the case of 9 could be separated due to their differing solubilities in hexane.
