ISSN:
0009-2940
Keywords:
1,2,4-Tri-tert-butylcyclopentadienyl complexes
;
Group IV metallocene derivatives
;
Titanocene dichloride, alkylated
;
Zirconocene dichloride, alkylated
;
(Cyclopentadienyl)hafnium trichloride
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Titanium-, Zirconium- and Hafnium Complexes with 1,2,4-Tri-tert-butylcyclopentadienyl LigandsLithium salts of easily available 1,3,5-tri-tert-butylcyclopentadiene and 1,2,3,4,5-pentaethylcyclopentadiene are used to synthesize the trichlorides [Cp‴MCl3] [Cp‴ = C5H2tBu3-1,2,4; M = Zr (1), Hf (2), Ti (3)] and [(Et5C5)ZrCl3] (4). Complex 1 is converted into the mixed zirconocene dichlorides [Cp‴CpZrCl2] (5), [Cp‴Cp-ZrCl2] (6), [Cp‴Cp″ZrCl2] (7), [Cp‴Cp4ZrCl2] (9) (Cp = C5H5, Cp* = C5Me5, Cp″ = C5H3tBu2-1,3, Cp4 = C5iPr4H) and into the benzyl complexes [Cp‴Zr(PhCH2)2Cl] (10) and [Cp‴Zr(PhCH2)3] (11). Variable-temperature 1H-NMR spectra of 6-9 (8 is the Ti analogue of 7) indicated hindered oscillation of the Cp‴ ligand with ΔG≠ values between ≤8 kcal/mol (7, 9) and 13.2 kcal/mol (6). X-ray structural analyses of complexes 7 and 9 reveal strong distortions owing to extreme steric congestion.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270102
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