1. For example, see the following and references cited therein: (a) Y. Xie, R.S. Grev, J. Gu, H.F. Schaefer III, P.v.R. Schleyer, J. Su, X.-W. Li, G.H. Robinson, J. Am. Chem. Soc. 120 (1998) 3773. (b) F.A. Cotton, A.H. Cowley, X. Feng, J. Am. Chem. Soc. 120 (1998) 1795. (c) J. Müller, J. Am. Chem. Soc. 118 (1996) 6370. (d) W.H. Fink, P.P. Power, T.L. Allen, Inorg. Chem. 36 (1997) 1431. (e) T.L. Allen, A.C. Schreiner, H.F. Schaefer III, Inorg. Chem. 29 (1990) 1930.
2. (a) Boron and Nitrogen. Gmelin Handbook of Inorganic and Organometallic Chemistry, 4th Supplement, Springer, Berlin, 1991 (Vol. 3a) and 1992 (Vol. 3b).
3. (b) R.T. Paine, H. Nöth, Chem. Rev. 95 (1995) 343.
4. (c) M.A. Petrie, M.M. Olmstead, H. Hope, R.A. Bartlett, P.P. Power, J. Am. Chem. Soc. 115 (1993) 3221.
5. (d) M.A. Mardones, A.H. Cowley, L. Contreras, R.A. Jones, C.J. Carrano, J. Organomet. Chem. 455 (1993) C1.