Novel zwitterionic complexes of Ti(IV) via reaction of Lewis acids M(C₆F₅)₃ (M = B, Al) with a titanium diene complex (η⁵-C₅Me₄SiMe₂N^tBu)Ti(1,3-pentadiene)

Abstract

The reaction of (η⁵-C₅Me₄SiMe₂N^tBu)Ti(1,3-pentadiene) with B(C₆F₅)₃ or Al(C₆F₅)₃ in 1:1 mole ratio in hexane solution at room temperature results in the formation of titanium borate or aluminate zwitterions which both feature stabilisation of the Ti(IV) centre by two agostic Ti⋯H–C interactions.

References

1. (a) B. Temme, G. Erker, J. Karl, H. Luftmann, R. Fröhlich and S. Kotila, Angew. Chem., Int. Ed. Engl., 1995, 34, 1755; (b) B. Temme, J. Karl and G. Erker, Chem. Eur. J., 1996, 2, 919; (c) J. Karl, G. Erker and R. Fröhlich, J. Am. Chem. Soc., 1997, 119, 11 165.
2. For other examples of a zirconium borate zwitterion featuring Zr···F stabilisation, see J. Ruwwe, G. Erker and R. Fröhlich, Angew. Chem., Int. Ed. Engl., 1996, 35, 80; Y. Sun, R. E. v. H. Spence, W. E. Piers, M. Parvez and G. P. A. Yap, J. Am. Chem. Soc., 1997, 119, 5132.
3. D. D. Devore, F. J. Timmers, D. L. Hasha, R. K. Rosen, T. J. Marks, P. A. Deck and C. L. Stern, Organometallics, 1995, 14, 3132.
4. R. G. Kidd, in NMR of Newly Accessible Nuclei, vol. 2, ed. P. Laszlo, Academic Press, New York, 1983.