摘要：

M(CO)6 (M= Mo, W) and (CH3)2M (M = Zn, Cd) have been used as precursors in the synthesis of intrazeolite semiconductor clusters of metal oxides and metal chalcogenides, respectively. These nanoclusters show optical and electronic properties different from the parent bulk semiconductors (quantum size effects). In the synthesis of these novel materials, metal carbonyls and organometallics are sublimed from the vapor phase into supercages of zeolite Y where they are anchored to either framework oxygen or extraframework cation sites. The photooxidation of α-cage encapsulated M(CO)6 provides a mild, clean and quantitative synthetic pathway to molecular dimension monomeric molybdenum(VI) oxide and dimeric tungsten(VI) oxide moieties encapsulated within the void structure of zeolite Y. Thermal vacuum treatment of these materials results in a clean reductive elimination of O2 in two distinct steps around 300 and 400°C for W2O6 and one distinct step around 300°C for MoO3 leaving dimeric W2O5 intermediate phase, monomeric WO2 and MoO2 final phase products, which can be reversibly oxidized in O2 at 300°C back to starting metal(VI) oxides. Dimethylmetal precursors are anchored to the Brnsted acid sites in the α-cages of zeolite Y by releasing methane. Exposure of (CH3M)48Na8Y to H2X (X = S, Se) induces a transformation of the MOCVD type precursors into supralattices ofsemiconductor charge balancing [M6X4]4+ nanoclusters housed within the diamond network of supercages in the zeolite Y host.

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