Subvalent germanium and tin complexes supported by a dianionic calixarene ligand: structural characterization of exo and endo isomers of [Bu^tcalix^(TMS)2]Ge

Abstract

The 1,3-bis(trimethylsilyl) ether of p-tert-butylcalix[4]arene, [Bu^tcalix^(TMS)2]H₂, has been synthesized and used as a dianionic ligand for Ge and Sn; notably, the Ge complex [Bu^tcalix^(TMS)2]Ge exhibits exo/endo isomerism, and provides the first calixarene system for which both isomers have been structurally characterized.

References

1. (a) G. D. Gutsche, Calixarenes, Royal Society of Chemistry, Cambridge, 1989; (b) Calixarenes: A Versatile Class of Macrocyclic Compounds, ed. J. Vincens and V. Böhmer, Kluwer, Dordrecht, 1991; (c) V. Böhmer, Angew. Chem., Int. Ed. Engl., 1995, 34, 713.
2. D. M. Roundhill, Prog. Inorg. Chem., 1995, 43, 533.
3. For recent examples of the use of calix[n]arenes as ligands in main group metal chemistry, see: (a) M. G. Gardiner, S. M. Lawrence, C. L. Raston, B. W. Skelton and A. H. White, Chem. Commun., 1996, 2491; (b) M. G. Gardiner, G. A. Koutsantonis, S. M. Lawrence, P. J. Nichols and C. L. Raston, Chem. Commun., 1996, 2035; (c) J. L. Atwood, M. G. Gardiner, C. Jones, C. L. Raston, B. W. Skelton and A. H. White, Chem. Commun., 1996, 2487; (d) J. L. Atwood, P. C. Junk, S. M. Lawrence and C. L. Raston, Supramol. Chem., 1996, 7, 15; (e) J. M. Smith and S. G. Bott, Chem. Commun., 1996, 377; (f) S. G. Bott, A. W. Coleman and J. L. Atwood, J. Incl. Phenom., 1987, 5, 747.
4. M. C. Kuchta and G. Parkin, J. Chem. Soc., Chem. Commun., 1994, 1351.
5. M. C. Kuchta and G. Parkin, J. Am. Chem. Soc., 1994, 116, 8372.
6. M. C. Kuchta and G. Parkin, Chem. Commun., 1996, 1669.
7. (a) C. D. Gutsche, B. Dhawan, K. H. No and R. Muthukrishnan, J. Am. Chem. Soc., 1981, 103, 3782; (b) C. D. Gutsche, B. Dhawan, J. A. Levine, K. H. No and L. J. Bauer, Tetrahedron, 1983, 39, 409.
8. For some other examples of O-silylated calixarenes see: (a) M. M. Olmstead, G. Sigel, H. Hope, X. Xu and P. P. Power, J. Am. Chem. Soc., 1985, 107, 8087; (b) X. Delaigue, M. W. Hosseini, A. De Cian, J. Fischer, E. Leize, S. Kieffer and A. Van Dorsselaer, Tetrahedron Lett., 1993, 34, 3285; (c) S. Shang, D. V. Khasnis, J. M. Burton, C. J. Santini, M. Fan, A. C. Small and M. Lattman, Organometallics, 1994, 13, 5157; (d) M. Fan, H. Zhang and M. Lattman, Organometallics, 1996, 15, 5216.
9. (a) B. Cetinkaya, I. Gümrükcü, M. F. Lappert, J. L. Atwood, R. D. Rogers and M. J. Zaworotko, J. Am. Chem. Soc., 1980, 102, 2088; (b) T. Fjeldberg, P. B. Hitchcock, M. F. Lappert, S. J. Smith and A. J. Thorne, J. Chem. Soc., Chem. Commun., 1985, 939.