Covalence and spin polarisation in tetraphenylarsonium tetrachloronitridotechnetate(VI) studied by polarised neutron diffraction

(Note: The full text of this document is currently only available in the PDF Version )

Philip A. Reynolds, Brian N. Figgis, J. Bruce Forsyth and Francis Tasset


Abstract

Polarised neutron diffraction from two orientations of tetragonal single crystals of [AsPh4][TcNCl4] at 1.5 K and a magnetic field of 4.6 T gave a combined data set of 116 magnetic structure factors. These were fitted by a 26-parameter model which includes proton nuclear-spin orientation to give a spin-density model for the formally 4d1 [TcNCl4]- ion. This model revealed substantial anistropic π bonding between Tc and Cl resulting in 29(2)% of the spin being delocalised onto the chlorine in-plane 3pπ orbitals, -15(1)% onto the nitrogen as a result of spin-polarising the short Tc–N bond, and substantial spin polarisation on the technetium site of 4d and more diffuse density. Three unconstrained Hartree–Fock and density functional calculations with good basis sets failed to reproduce these observations adequately, but an unconstrained density functional calculation with gradient corrections and a relativistic treatment of the core gave encouraging agreement with experiment.


References

  1. B. N. Figgis, J. B. Forsyth, E. S. Kucharski, P. A. Reynolds and F. Tasset, Proc. R. Soc. London, Ser. A, 1990, 428, 113 CAS; P. J. Brown, B. N. Figgis and P. A. Reynolds, J. Phys. Condens. Matter, 1990, 2, 5309 CrossRef CAS; C. D. Delfs, B. N. Figgis, J. B. Forsyth, E. S. Kucharski, P. A. Reynolds and M. Vrtis, Proc. R. Soc. London, Ser. A, 1992, 436, 417 CAS.
  2. P. A. Reynolds, B. Moubaraki, K. S. Murray, J. W. Cable, L. M. Engelhardt, B. N. Figgis and A. N. Sobolev, unpublished work.
  3. P. A. Reynolds, B. Moubaraki, K. S. Murray, J. W. Cable, L. M. Engelhardt and B. N. Figgis, J. Chem. Soc., Dalton Trans., 1997, 263 RSC.
  4. S. P. Best, B. N. Figgis, J. B. Forsyth, P. A. Reynolds and P. L. W. Tregenna-Piggott, Inorg. Chem., 1995, 34, 4605 CrossRef CAS.
  5. J. Baldas, J. F. Boas, J. Bonnyman and G. A. Williams, J. Chem. Soc., Dalton Trans., 1984, 2395 RSC.
  6. B. N. Figgis, P. A. Reynolds, F. K. Larsen, G. A. Williams and C. D. Delfs, Aust. J. Chem, 1996, 49, 663.
  7. J. B. Raynor, T. J. Kemp and A. M. Thyer, Inorg. Chim. Acta, 1992, 193, 191 CrossRef CAS.
  8. R. Kirmse, K. Kohler, U. Abram, R. Bottcher, L. Golic and E. de Boer, Chem. Phys., 1990, 143, 75 CrossRef CAS.
  9. K. Kohler, R. Kirmse, R. Bottcher, U. Abram, M. C. M. Gribnau, C. P. Keijzers and E. de Boer, Chem. Phys., 1990, 143, 83 CrossRef.
  10. B. N. Figgis, P. A. Reynolds and J. W. Cable, J. Chem. Phys., 1993, 98, 7743 CrossRef CAS.
  11. H. Glättli and M. Goldman, Methods Exp. Phys., 1987, 23C, 241 Search PubMed.
  12. A. Abragam, G. L. Bacchella, C. Long, P. Meriel, J. Peisvaux and M. Pinot, Phys. Rev. Lett., 1972, 28, 805 CrossRef CAS.
  13. M. Leslie, G. T. Jenkin, J. B. Hayter, J. W. White, S. Cox and G. Warner, Philos. Trans. R. Soc. London, Ser. B, 1980, 290, 497 Search PubMed and refs. therein.
  14. A. Zheludev, V. Barone, M. Bonnet, B. Delley, A. Grand, E. Ressouche, P. Rey, R. Subra and J. Schweizer, J. Am. Chem. Soc., 1994, 116, 2019 CrossRef CAS.
  15. B. N. Figgis, P. A. Reynolds and G. A. Williams, J. Chem. Soc., Dalton Trans., 1980, 2339 RSC.
  16. E. Clementi and C. Roetti, At. Data Nucl. Data Tables, 1974, 14, 177 CrossRef CAS.
  17. J. M. Stewart, E. R. Davidson and W. T. Simpson, J. Chem. Phys., 1965, 87, 3175 CrossRef CAS.
  18. A. Neuhaus, A. Veldkamp and G. Frenking, Inorg. Chem., 1994, 33, 5278 CrossRef CAS.
  19. P. J. Hay and W. R. Wadt, J. Chem. Phys., 1985, 82, 299 CrossRef CAS.
  20. V. Jonas, G. Frenking and M. T. Reetz, J. Comput. Chem., 1992, 13, 919 CrossRef CAS.
  21. W. J. Hehre, R. Ditchfield and J. A. Pople, J. Chem. Phys., 1972, 56, 2257 CrossRef CAS.
  22. M. W. Schmidt, K. K. Baldridge, J. A. Boatz, S. T. Elbert, M. S. Gordon, J. H. Jensen, S. Kaseki, N. Matsunaga, K. A. Nguyen, S. J. Su, T. L. Windus, M. Dupuis and J. A. Montgomery, J. Comput. Chem., 1993, 14, 1347 CrossRef CAS.
  23. Gaussian basis sets for molecular calculations, eds. S. Huzinaga, J. Andzelm, M. Klobukowski, E. Radzio-Andzelm, Y. Sakai and H. Tatewaki, Elsevier, Amsterdam, 1984 Search PubMed.
  24. C. Fonseca Guerra, in Methods and Techniques in Computational Chemistry, eds. E. Clementi and G. Corongiu, STEF, Cagliari, 1995 Search PubMed; G. te Velde and E. J. Baerends, J. Comput. Phys., 1992, 99, 84 Search PubMed; E. J. Baerends, D. E. Ellis and P. Ros, Chem. Phys., 1973, 2, 41 CrossRef CAS.
  25. B. N. Figgis, J. B. Forsyth and P. A. Reynolds, Inorg. Chem., 1987, 26, 101 CrossRef CAS.
Click here to see how this site uses Cookies. View our privacy policy here.