183486-28-4Relevant academic research and scientific papers
Zirconium complexes of a cyclopentadienylamido ligand with a pendant amine donor via amine and alkane elimination
Mu, Ying,Piers, Warren E.,MacQuarrie, Donald C.,Zaworotko, Michael J.
, p. 1696 - 1703 (1996)
Zirconium complexes of the multidentate ligand CpHNMeSiN(H)R (SiNR = -SiMe2N-t-butyl; NMe = -CH2CH2NMe2, 1) were prepared and characterized via amine and alkane elimination procedures. Reaction of 1 with Zr(NMe2)4 gave a mixture of bis-amido complexes 2 in which the ligand was 1,2 and 1,3 substituted. This mixture was converted to the analogous dichlorides 3 using Me2NH·HCl and 1,3-3 was purified at this stage; alternatively, 1,3-3 was obtained in one pot from 1 and Zr(NMe2)4 in ≈70% yield. Conversion of 1,3-3 to dimethyl compound (CpNMeSiNR)Zr(CH3)2, 1,3-4, was accomplished via reaction of the dichloride with methyllithium; methide abstraction with the Lewis acids B(C6F5)3 and [Ph3C]+[B(C6F5)4] generated the cationic alkyls [(CpNMeSiNR)Zr(CH3)]+[R′B(C 6F5)3]- (R′ = CH3, 6a; C6F5, 6b), which were characterized by NMR spectroscopy. Zirconium complexes containing 1 ligated as its 1,2 isomer were obtained from alkane elimination reactions between 1 and in situ prepared RnZrCl4-n (R = CH3, n = 3; R = CH2SiMe3, n = 2). 1,2-3 and the methyl chloride complex 1,2-(CpNMeSiNR)Zr(CH3)Cl, 5, were obtained in 18 and 30% yield, respectively. Complex 5 was characterized by X-ray crystallography (monoclinic, space group P 21/a, a = 9.6951(10) A, b = 14.3794(16) A, c = 14.364(3) A, V = 1990.3(5) A3, Z = 4, R = 0.046, Rw = 0.041.).
