Organometallics in confined geometries. Ferrocene in zeolite Y

Abstract

Zeolites are crystalline aluminosilicates with a three-dimensional open framework structure of channels and cavities of molecular dimensions. Zeolites can thus act as molecular sieves, making catalytic centres in the interior of the zeolite only accessible to molecules of the correct size. Such catalytic centres, especially clusters of transition metals, can be incorporated in zeolites by vapour phase insertion of volatile compounds, such as organometallics. An often used zeolite is zeolite Y, which contains especially large cavities, called supercages. We study the inclusion of the organometallic ferrocene, Fe(C5H5)2, molecules in the supercages of Y-type zeolites. Ferrocene consists of an iron atom "sandwiched" by two identical parallel cyclopentadienyl, C5H5, rings. The scope of this thesis is to determine the structure and dynamics of ferrocene in zeolite Y, and to illuminate the interaction between the ferrocene molecules and the zeolite supercages. We look into differences between a single ferrocene molecule, solid (crystalline) ferrocene and ferrocene in a zeolite supercage, thus illustrating the influence of a surrounding geometry on an encaged molecule. We focus on two types of zeolites, Na55Y and K55Y.