Characterisation of agostic interactions by a topological analysis of experimental and theoretical charge densities in [EtTiCl₃(dmpe)] [dmpe = 1,2-bis(dimethylphosphino)ethane]

Abstract

Topological analysis of the experimental and theoretical electron densities in [EtTiCl₃(dmpe)] (dmpe = Me₂PCH₂CH₂PMe₂) suggests the presence of a (3, –1) bond critical point (CP) between titanium and the β-agostic hydrogen atom; the characteristic curvature in the Ti–C_α bond is proposed as a more general criterion for identifying a β-agostic interaction.

References

1. P. L. A. Popelier and G. Logothetis, J. Organomet. Chem., 1998, 555, 101.
2. W. Scherer, T. Priermeier, A. Haaland, H. V. Volden, G. S. McGrady, A. J. Downs, R. Boese and D. Bläser, Organometallics, 1998, 17, 4406 and references quoted therein.
3. See for example: T. Koritsanszky, R. Flaig, D. Zobel, H.-G. Krane, W. Morgenroth and P. Luger, Science, 1998, 279, 356; P. Macchi, D. M. Proserpio and A. Sironi, J. Am. Chem. Soc., 1998, 120, 1447.
4. T. Koritsanszky, S. Howard, P. R. Mallinson, Z. Su, T. Richter and N. K. Hansen, XD—a Computer Program Package for Multipole Refinement and Analysis of Electron Densities from Diffraction Data, Free University of Berlin, 1997.
5. N. K. Hansen and P. Coppens, Acta Crystallogr., Sect. A, 1978, 34, 909.
6. The ED of 1 was discussed on the basis of the B3LYP//BPW91 level of theory.
7. A. J. H. Wachters, J. Chem. Phys., 1970, 52, 1033; A. D. McLean and G. S. Chandler, J. Chem. Phys., 1980, 72, 5639; R. Krishnan, J. S. Binkley, R. Seeger and J. A. Pople, J. Chem. Phys., 1980, 72, 650; A. W. Ehlers, M. Böhme, S. Dapprich, A. Gobbi, A. Höllwarth, V. Jonas, K. F. Köhler, R. Stegmann, A. Veldkamp and G. Frenking, Chem. Phys. Lett., 1993, 208, 111.
8. M. J. Frisch, G. W. Trucks, H. B. Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Cheeseman, T. Keith, G. A. Petersson, J. A. Montgomery, K. Raghavachari, M. A. Al-Laham, V. G. Zakrzewski, J. V. Ortiz, J. B. Foresman, J. Cioslowski, B. B. Stefanov, A. Nanayakkara, M. Challacombe, C. Y. Peng, P. Y. Ayala, W. Chen, M. W. Wong, J. L. Andres, E. S. Replogle, R. Gomperts, R. L. Martin, D. J. Fox, J. S. Binkley, D. J. Defrees, J. Baker, J. P. Stewart, M. Head-Gordon, C. Gonzales and J. A. Pople, Gaussian 94, Revision C.2 and E.2, Gaussian, Inc., Pittsburgh PA, 1995.
9. See, for example: R. F. W. Bader, Atoms in Molecules: A Quantum Theory, Clarendon Press, Oxford, 1990.
10. R. F. W. Bader, Acc. Chem. Res., 1985, 18, 9.
11. J. Cioslowski and S. T. Mixon, Inorg. Chem., 1993, 32, 3209.
12. E. Clementi and C. Roetti, At. Data Nucl. Data Tables, 1974, 14, 177.