Zeolite-supported Molecular Metal Complex Catalysts
Structural non-uniformity and complexity of supported metal catalysts used in industry hamper precise determination of the structure of active sites as well as their structure–performance relationships. When metals are atomically dispersed on a high surface area support, non-uniformity of a support causes non-uniformity of the structure of supported metals, leading to diverse catalytic properties. This chapter describes the synthesis, characterization and catalysis of zeolite-supported molecular metal complex catalysts with a high degree of uniformity. Zeolite-supported molecular metal complex catalysts described here is a sub-class of supported metal catalysts and have mono-nuclear transition metal complexes anchored in zeolites. Because zeolites are crystalline and have nearly uniform anchoring sites for metal complexes, they provide the opportunity to synthesize structurally uniform supported metal species. Proper choices of metal complex precursors, zeolites, and a synthesis method are required to form high uniformity of supported species. Such highly uniform supported metal complexes allow one to conduct exact structural determination by spectroscopic characterization, leading to elucidation of their molecular chemistry at an unprecedented level. Deep understanding of molecular chemistry of zeolite-supported metal complex catalysts will shed significant insights into complex chemistry that takes place on industrial catalysts and lead to synthesis of new selective catalysts.