Collect. Czech. Chem. Commun. 1997, 62, 1446-1456

Crystal Structures of Titanium(III) Bis(acetylide) Tweezer Complexes with Alkali Metal Cations

Jörg Hillera, Vojtech Vargab, Ulf Thewalta and Karel Machb

a Sektion für Röntgen- und Elektronenbeugung, Universität Ulm, 89069 Ulm, Germany
b J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic,182 23 Prague 8, Czech Republic


Crystal structures of the Ti(III) tweezer complexes [(C5HMe4)2Ti(σ-C≡CSiMe3)2]-[Li(THF)2]+ (2a), [(C5HMe4)2Ti(σ-C≡CSiMe3)2]-Na+ (3) and [(C5HMe4)2Ti(σ-C≡CSiMe3)2]-Cs+ (5) have been determined. In all of them the alkali metal cation is placed away from the Ti-Cα1-Cα2 plane at the distance: Li+ 0.511 Å, Na+ 1.023 Å and Cs+ 0.521 Å. The reason for the deviation of Li+ in 2a is the asymmetrical orientation of the THF ligands in the [Li(THF)2]+ cation with respect to the Ti-Cα1-Cα2 plane, which seems to release the steric congestion between the THF ligands and the trimethylsilyl groups. In 3 and 5, the molecules form polymer chains with a weak intermolecular bonding interaction between the cations and one of the C5HMe4 ligands of the neighbouring molecule in a sandwich manner.

Keywords: Titanium(III) complexes; Octamethyltitanocene; Bis(acetylides); Tweezer complexes.