Catalytic Reactions Carried Out with Metals Derived from Clusters

Synthesis and Characterization of Tetrahedral Ru3O Clusters with Intrinsic Framework Chirality: A Chiral Probe of the Intact Cluster Catalysis Concept

“…The motivation for this work was to demonstrate the implication of intact metal clusters in catalytic reactions, since intrinsically chiral metal clusters used as catalysts for the conversion of prochiral substrates may give rise to an enantiomeric excess of the chiral products, subject to the condition that the metal cluster stays intact throughout the catalytic process. So far, this demonstration still remains to be done, because only very few intrinsically chiral metal clusters have been separated into their enantiomers, 13a, and in these cases the clusters either showed no catalytic activity or became active only under UV irradiation, which caused racemization of the cluster framework 15a. Whereas the intrinsically chiral metal clusters known so far, based on a tetrahedral framework with four different vertices, contain a M 3 S, ,, a M 3 (CR), 13a,b or a M 4 framework with different metal atoms, we report here homometallic trinuclear clusters containing a chiral Ru 3 O skeleton capped by a μ 3 -oxo ligand, the three ruthenium atoms being coordinated to three different arene ligands.…”

Synthesis of Optically Active Tetrahedral Clusters through Ester Exchange Catalyzed by Lipase

“…The metal exchange procedure, which Richter and Vahrenkamp pioneered, was considered to be the most efficient and versatile way to prepare tetrahedral mixed-metal clusters. The unambiguous evidence that the chiral metal cluster frameworks serve as the catalysts is obtaining the chiral products when they have been involved in an asymmetric reaction …”

“…However, the enantiomeric resolution of the tetrahedral clusters remains a major problem 3b. A single pure enantiomer could be obtained by introducing an optically active phosphine into a chiral cluster .…”