Syntheses and Crystal Structures of Bis[(trimethylsilyl)tetramethylcyclopentadienyl]titanium Dichloride and Monochloride

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Title:Syntheses and Crystal Structures of Bis[(trimethylsilyl)tetramethylcyclopentadienyl]titanium Dichloride and Monochloride
Creators:
Horáček, Michal
Gyepes, Róbert
Císařová, Ivana
Polášek, Miroslav
Varga, Vojtech
Mach, Karel
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 61, 9, pp. 1307-1320
Uncontrolled Keywords:(Trimethylsilyl)tetramethylcyclopentadienyl ligand, Titanium, Crystal structures, Titanocene chlorides, Electronic effects of trimethylsilyl group

Abstract

(Trimethylsilyl)tetramethylcyclopentadiene (Cp'H) was obtained from the lithium salt of tetramethylcyclopentadiene and trimethylsilyl chloride. Bis[(trimethylsilyl)tetramethylcyclopentadienyl]titanium dichloride (<strong>1</strong>) and monochloride (<strong>2</strong>) were prepared by the generally known procedures. The X-ray crystal structures of <strong>1</strong> and <strong>2</strong> showed the placement of the bulky trimethylsilyl groups in side positions on opposite sides of the CE-Ti-CE planes. The steric congestion between the two chlorine atoms and two trimethylsilyl groups in <strong>1</strong> resulted in the nearly eclipsed conformation of the rings. Consequently, the steric hindrance between the methyl groups at the hinge position of the Cp' ligands led to a decrease in the angle between the Cp' ring planes by 4.8°, compared with the value of 44.6° in (C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>TiCl<sub>2</sub>. The titanocene skeleton in <strong>2</strong> is virtually the same as in (C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>TiCl. The electronic effect of the trimethylsilyl group upon various properties of <strong>1</strong> and <strong>2</strong> appeared to be ambiguous. Based on the position of λ<sub>max</sub> of electronic absorption bands of <strong>1</strong> the trimethylsilyl group exerted a stronger electron donation effect than the methyl group, however, the affinity of <strong>2</strong> to 2-methyltetrahydrofuran put the effect of the trimethylsilyl group close to that of hydrogen and the anisotropy of the EPR <i>g</i>-tensor of <strong>2</strong> close to that of the methyl group.

Title:Syntheses and Crystal Structures of Bis[(trimethylsilyl)tetramethylcyclopentadienyl]titanium Dichloride and Monochloride
Creators:
Horáček, Michal
Gyepes, Róbert
Císařová, Ivana
Polášek, Miroslav
Varga, Vojtech
Mach, Karel
Uncontrolled Keywords:(Trimethylsilyl)tetramethylcyclopentadienyl ligand, Titanium, Crystal structures, Titanocene chlorides, Electronic effects of trimethylsilyl group
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:61
Number:9
Page Range:pp. 1307-1320
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19961307UNSPECIFIED
ID Code:1036
Item Type:Article
Deposited On:06 Feb 2009 17:06
Last Modified:06 Feb 2009 16:06

Citation

Horáček, Michal; Gyepes, Róbert; Císařová, Ivana; Polášek, Miroslav; Varga, Vojtech; Mach, Karel (1996) Syntheses and Crystal Structures of Bis[(trimethylsilyl)tetramethylcyclopentadienyl]titanium Dichloride and Monochloride. Collection of Czechoslovak Chemical Communications, 61 (9). pp. 1307-1320. ISSN 0010-0765

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