Toluene was allowed to react with methanol in the presence of (H3O)(2)[(W6CLS)Cl-6]-6H(2)O supported on silica gel. When the temperature was raised above 300 degreesC the catalytic activity of the cluster appeared. Toluene alkylation proceeded selectively yielding xylenes with a small amount of trimethylbenzenes. Similarly, the corresponding clusters of Nb, Mo, and Ta catalyzed the reaction. Methylation of xylenes, trimethylbenzenes, and tetramethylbenzenes also proceeded; however. the main reaction of trimethyl- and tetramethylbenzenes was isomerization, Methylation of pentamethylbenzene hardly occurred, but demethylation of pentamethyl-and hexamethylbenzene proceeded. Thus, the clusters catalyzed methylation, demethylation, and isomerization of the methylbenzenes in the presence of methanol. Hydrogen gas accelerated the reactions. IR analyses of adsorbed pyridine on the catalyst showed the presence of a Bronsted acid site; however, a Lewis acid site was not observed. A hydroxo ligand that formed on the cluster complex would be the active site of the catalyst. (C) 2004 Elsevier B.V. All rights reserved.