J. H. Golden, F. J. DiSalvo, J. M. J. Fréchet, Department of Chemistry, Cornell University, Baker Laboratory, Ithaca, NY 14853, USA.
J. Silcox and M. Thomas, Cornell University Materials Science Center, Clark Hall, Ithaca, NY 14853, USA.
J. Elman, Eastman Kodak Company, Rochester, NY 14650, USA.