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DOI: 10.1039/A805764H (Paper) Reference Section for: J. Chem. Soc., Dalton Trans., 1998, 3489-3494

Halide titanium(IV) Schiff base complexes; fluoride and bromide derivatives and evidence for a new seven-coordinate chloride intermediate

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Simon J. Coles, Michael B. Hursthouse, David G. Kelly, Andrew J. Toner and Neil M. Walker

Abstract

The synthesis of titanium(IV) Schiff base complexes has been investigated using the tetradentate salen ligand and its derivatives [L = salenH2 = N,N[hair space]′-bis(salicylidene)ethylenediamine]. Complexes of the form [TiX2(L)], [(thf[hair space])TiX2(L)] and [TiX4(LH2)] have been observed with the nature of these products being dependent on the salen derivative, halide and reaction condition employed. The reaction of [(thf[hair space])2TiF4] with salenH2 yields the complex [TiF4(salenH2)] 1 which does not eliminate HF to form [TiF2(salen)] 2 even after toluene reflux. Compound 2 can be obtained in 90% yield using the silylated Schiff base salen(TMS)2 (TMS = Me3Si) and [(thf[hair space])2TiF4] in thf. Compound 2 has been characterised by single crystal X-ray diffraction. Refluxing an equimolar ratio of salenH2 and TiCl4 gave the previously prepared [TiCl2(salen)] 3, while stirring the same reactants at room temperature afforded the seven-coordinate solvent adduct [(thf[hair space])TiCl2(salen)] 4 in quantitative yield. TiBr4 reacts similarly with salenH2 or salen(TMS)2 to give [TiBr2(salen)] 5. The bromide analogue of 4 was identified from its characteristic FAB+ mass spectrum. Reaction of TiI4 with salen(TMS)2 or salenH2 in thf or MeCN gave the µ-oxo bridged species [TiI(salen)]2(µ-O) 6 in preference to the iodide analogue of [TiX2(salen)]. Substituted Schiff bases (MeO)2salenH2, salphenH2 and (MeO)2salphenH2 [salphenH2 = N,N[hair space]′-bis(salicylidene)-1,2-phenylenediamine] react with TiCl4 (1∶1) to yield the corresponding dichloride complexes [TiCl2(L)] [L = (MeO)2salen 7, salphen 8, (MeO)2salphen 9] via the elimination of HCl. In contrast, the α-methylated salen derivative dmsalenH2 [N,N[hair space]′-bis(α-methylsalicylidene)ethylenediamine] reacts in an analogous manner to the TiF4–salen system affording [TiCl4(dmsalenH2)] 10.

References

  1. M. Pasquali, F. Marchetti, A. Landi and C. Floriani, J. Chem. Soc., Dalton Trans., 1978, 545 RSC.
  2. M. Mazzanti, J. Rosset, C. Floriani, A. Chiesi-Villa and C. Guastini, J. Chem. Soc., Dalton Trans., 1989, 953 RSC.
  3. F. L. Bowden and D. Ferguson, J. Chem. Soc., Dalton Trans., 1974, 460 RSC.
  4. N. S. Biradar and V. H. Kulkarni, J. Inorg. Nucl. Chem., 1971, 33, 3847 CrossRef CAS.
  5. M. Mazzanti, C. Floriani, A. Chiesi-Villa and C. Guastini, Inorg. Chem., 1986, 25, 4158 CrossRef CAS.
  6. E. B. Tjaden, D. C. Swenson, R. F. Jordan and J. L. Petersen, Organometallics, 1995, 14, 371 CrossRef CAS.
  7. R. D. Archer, R. O. Day and M. L. Illingworth, Inorg. Chem., 1979, 18, 2908 CrossRef CAS.
  8. N. S. Biradar and A. L. Locker, J. Inorg. Nucl. Chem., 1975, 37, 1308 CrossRef CAS.
  9. F. Corazza, E. Solari, C. Floriani, A. Chiesi-Villa and C. Guastini, J. Chem. Soc., Dalton Trans., 1990, 1335 RSC.
  10. T. Repo, M. Klinga, P. Pietikainen, M. Leskela, A. M. Uusitalo, T. Pakkanen, K. Hakala, P. Aaltonen and B. Lofgren, Macromolecules, 1997, 30, 171 CrossRef CAS.
  11. C. Floriani, E. Solari, F. Corazza, A. Chiesi-Villa and C. Guastini, Angew. Chem., Int. Ed. Engl., 1989, 28, 64 CrossRef.
  12. E. Solari, C. Floriani, A. Chiesi-Villa and C. Rizzoli, J. Chem. Soc., Dalton Trans., 1992, 367 RSC.
  13. J.-M. Rosset, C. Floriani, M. Mazzanti, A. Chiesi-Villa and C. Guastini, Inorg. Chem., 1990, 29, 3991 CrossRef CAS.
  14. D. G. Kelly, A. J. Toner, N. M. Walker, S. J. Coles and M. B. Hursthouse, Polyhedron, 1996, 15, 4307 CrossRef CAS.
  15. S. J. Coles, M. B. HursthouseD. G. Kelly, A. J. Toner and N. M. Walker, submitted.
  16. N. S. Biradar and V. H. Kulkarni, Rev. Roum. Chim., 1970, 15, 1993 Search PubMed.
  17. G. Gilli, D. W. J. Cruickshank, R. L. Beddoes and O. S. Mills, Acta Crystallogr., Sect. B, 1972, 28, 1889 CrossRef CAS.
  18. E. Gallo, E. Solari, F. Franceschi, C. Floriani, A. Chiesi-Villa and C. Rizzoli, Inorg. Chem., 1995, 34, 2495 CrossRef CAS.
  19. J. Gindl, F.-Q. Liu, M. Noltemeyer, H.-G. Schmidt and H. W. Roesky, Inorg. Chem., 1995, 34, 5711 CrossRef CAS.
  20. J. A. Darr, S. R. Drake, M. B. Hursthouse and K. M. A. Malik, Inorg. Chem., 1993, 32, 5704 CrossRef CAS.
  21. G. M. Sheldrick, Acta Crystallogr., Sect. A, 1990, 46, 467 CrossRef.
  22. G. M. Sheldrick, SHELX-93. University of Göttingen, 1993.
  23. N. P. C. Walker and D. Stuart, Acta Crystallogr., Sect. A., 1983, 39, 158, adapted for FAST geometry by A. Karaulov, University of Wales, Cardiff, 1991 Search PubMed.
  24. M. Calligaris and L. Randaccio, Comprehensive Co-ordination Chemistry, ed. G. Wilkinson, R. D. Gillard and J. A. McCleverty, Pergamon, Oxford, 1987, vol. 2, ch. 20.1 Search PubMed.
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