Heterometallic Molybdenum/p-element compounds: Complexes with novel bonding situations, models for surface species and single-source precursors for functional materials

Acrolein is used in industry on large scales, and to obtain it selectively from O2 and propene bismuth molybdates are employed as catalysts in the SOHIO process. However, neither the exact functioning of these oxide mixture, nor the reason for its uniqueness are clear today, even though commercial interest has driven a good deal of fundamental investigations into the oxidation mechanism. The hey-day of experimentation on the heterogeneous system as applied lasted into the late 1980s, when obviously a limit to the information that can be obtained was nearly reached. After that period the frequency of publications decreased, while homogeneous model systems, synthesised to clarify basic questions, began to appear in the literature. Molybdenum-containing model systems predominated for the remainder of the decade and only in recent years have bismuth-containing model systems been reported. This project deals with compounds containing both molybdenum and bismuth at the same time.
In a previous funding period for the first time molecular compounds containing Mo-O-Bi moieties have been made accessible. On this basis the studies are currently extended, in particular with respect to the functionality of such potential models, in order to obtain a solid basis for mechanistic proposals concerning the proceedings during the SOHIO process.
Independently of this topic the previous funding period has led to the successful isolation of Mo/Bi complexes featuring novel bonding situations, and which thus were of fundamental interest. Now, reactivity studies and directed modifications are carried out to reach a more comprehensive understanding, which will be utilized to transfer this reaction type also onto other p-block element compounds. The bimetallic complexes thus obtained can be tested as single-source precursors for the synthesis of oxidic materials with new nano-scaled morphologies and properties in catalysis or sensing applications.