1. Contribution from the Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n, Ciudad Universitaria, Apdo. Postal 70-360, Coyoacán CP 04510, México, D.F., Mexico, Department of Chemistry, M. V. Lomonosov Moscow State University, 119899 Moscow, Russia, and D. I. Mendeleev Moscow University of Chemical Technology, Miusskaya sq. 9, 125820 Moscow, Russia