1. Conseil National de Recherches Canada, Institut de Genie des Materiaux, 75 Boul. de Mortagne, Boucherville, Quebec, Canada, J4B 6Y4 (R.M.P., J.L., J.-J. H., K.C.C.); and Department of Chemistry, McGill University, 801 Sherbrooke St. W, Montreal, Quebec H3A 2K6, Canada (I.S.B.)