Thin Mo(CO)6–Y-zeolite layers: preparation and in situ transmission FTIR spectroscopy

Abstract

Dehydration of zeolite M⁺–Y (M⁺= Li⁺, Na⁺, K⁺) thin layers at room temperature under dynamic high vacuum and their subsequent loading with gaseous Mo(CO)₆ under static vacuum are reported. The technique described allows loading of zeolite Y with the metal carbonyl in approximately one hour under mild reaction conditions. It leads to a homogeneous distribution of the molecules in the zeolite Y supercages. In situ transmission FTIR spectroscopy was applied to follow the progress of the reaction and to characterize the samples. The maximum loading was found to depend on the extraframework cations of the zeolite and to decrease with increasing radius of the cations. This, and the experimentally observed changes of the ν(CO) bands, are discussed with special emphasis on the weak bands at 2122 and 2116 cm^–1.