Synthesis of bis (tert-butyl)cyclopentadienyl derivatives of titanium and zirconium. NMR spectra and dynamic behaviour of the base-free [Zr(1,3-tBu2-η5-C5H3)(CH2Ph)2]+ cation

Abstract

Reaction of Si(1,3-tBu2-CsH3)Me3 with MCI 4 (M = Ti, Zr) in toluene or hexane at room temperature affords the new trichloromonociclopentadienyl-type derivatives [M(1,3-tBu2-'qS-CsH3)CI3] (M = Ti (2), Zr (3)]. Treatment of complexes 2 and 3 with appropriate alkylating reagents in hexane gives the 1,3-di(tert-butyl)cyclopentadienyl trialkyl titanium and zirconium complexes [M(1,3-tBu2-r/5-C5H3)R3] [M = Ti, R = CH 3 (4), CH2Ph (5); M = Zr, R = CH 3 (6), CH2Ph (7), CH2CMe2Ph (8)]. Interestingly, when 2 reacts with 3.1 equivalents of LiCH2CMeePh in hexane at room temperature the ring-tert-butyl-metallated complex [Ti(1-tBu-3-CMe2CH2-r/5-CsH3) (CH2CMe2Ph) 2] (9) was isolated in 90% yield. The cationic mono (1,3-di-(tert-butyl)cyclopentadienyl) dibenzyl zirconium species [Zr(1,3-tBu2-@-CsH3)(CH2Ph)2] +, generated in situ by reaction of the tribenzyl complex 7 with B(C6F5) 3 or [CPh3]+[B(C6Fs)4] -reagents, is reported and their dynamic NMR behaviour in CDzCI 2 solutions at low temperatures is studied.

Synthesis, Structures, and Catalytic Reactions of Ring-Substituted Titanium(IV) Complexes

“…74 Single-crystal [3-CMe 2 Ph-η 5 -C 5 H 3 Me] 2 TiCl 2 (33) suitable for X-ray diffraction was recrystallized from toluene and presented in Figure 7. The molecule is C 2 -symmetric with a tetrahedral geometry around the central titanium atom formed by the centroids of the Cp rings and the two chlorine atoms.…”

“…[31][32][33] Route 2, Scheme 1: Treatment of substituted cyclopentadienes with Ti(NMe 2 ) 4 resulted in the formation of amido complexes, which could be transformed to the corresponding trichloride complexes via reaction with appropriate chlorinating reagents. 34 Route 3, Scheme 1: Half-sandwich titanium derivatives containing the RnCp ligand may also be prepared by treating RnCpLi′ with TiCl 3 ‚3THF in THF followed by oxidation of the intermediate Ti(III) complex with HCl to afford RnCpTiCl 3 , which is isolated as a pure complex in a lower yield.…”

Cyclononatetraenyl‐Indenyl Transformation and a Zirconium(III) Trimer from Bulky Alkylcyclopentadienylzirconium Chlorides

“…The half sandwich complexes trichloro-1,2,4-tri(tert-butyl)cyclopentadienylzirconium (1) [4] and its 1,3-di(tert-butyl)cyclopentadienyl derivative 2 [5] were chosen as starting compounds for an investigation on the feasibility of cyclononatetraenylzirconium sandwich complexes.…”

“…By reduction of the starting compound 1 with potassium a dark red, paramagnetic zirconium(III) complex was obtained and characterized as the cyclic trimer 10 with almost equal Zr···Zr distances of 3.384 Å.such as [CpTi(η 8 -C 8 H 8 )], [1][2][3] zirconium should be able to form cyclononatetraenyl sandwich complexes of the [CpZr(η 9 -C 9 H 9 )] type.The half sandwich complexes trichloro-1,2,4-tri(tert-butyl)cyclopentadienylzirconium (1) [4] and its 1,3-di(tert-butyl)cyclopentadienyl derivative 2 [5] were chosen as starting compounds for an investigation on the feasibility of cyclononatetraenylzirconium sandwich complexes. Unlike the racemic di(tert-butyl)-(trimethylsilyl)cyclopentadienylzirconium trichloride 5, the 2,3-diisopropyl-1,4-dimethylcyclopentadienylzirconium trichloride 7 is not a monomer according to its low volatility and the presence of two similar sets of signals in the NMR…”

Neutral and cationic di(tert-butyl) cyclopentadienyl titanium, zirconium and hafnium complexes dynamic NMR study of the ligand-free cations [M(1,3-tBu2-η5-C5H3)(η5-C5H5)(CH3)]+ (M = Zr, Hf)

“…Reaction of 3 with MC14 in toluene or hexane at room temperature provides a route to the monocyclopentadienyl trichlorometal complexes M(1,3-tBu2 -~/5-C5H3)C13 [M = Ti (4), Zr (5)] [10].…”