NA-23 MAS-NMR AND FT-MID-FAR-IR CATION PROTON PROBES OF THE PHOTOTOPOTACTIC OXIDATION OF INTRAZEOLITE HEXACARBONYLTUNGSTEN(0) TO TUNGSTEN(VI) OXIDE QUANTUM DOTS AND SUPRALATTICES - EXPLORING ANCHORING SITES AND AGGREGATION PROCESSES

Adsorption-induced 23Na MAS-NMR chemical shifts and far-IR Na+ translatory mode frequency shifts provide direct and complementary evidence for the anchoring of W(CO)6 and WO3 moieties to α-cage Na+ cations in the precursor n{W-(CO)6}-Na56Y, as well as in the intrazeolite phototopotactic oxidation product n(WO3)-Na56Y. Similar experiments, in conjunction with mid-IR spectroscopy conducted in HmNa56-mY (where m = 8, 16), allow one to clarify W(CO)6 and WO3 homogeneity questions, as well as to map details of W(CO)6 precursor loading effects on the intrazeolite aggregation processes of the WO3 photooxidation product. In this way one is able to monitor the birth and population growth of (WO3)2 dimers, which at half-loading (n = 16) constitutes an intrazeolite (WO3)2 quantum supralattice and at full-loading (n = 32) creates an intrazeolite (WO3)4 quantum supralattice. © 1990 American Chemical Society.