Supramolecular Cluster Catalysis: A Case Study of Benzene Hydrogenation

The hydrogenation of benzene to give cyclohexane, catalysed under biphasic conditions by the water-soluble trinuclear arene ruthenium cluster cations [H3Ru3(C6H6)(C6Me6)2(O)]+ (1), [H3Ru3(C6H5Me)(C6Me6)2(O)]+ (2), [H3Ru3(1,4-MeC6H4Pri)(C6Me6)2(O)]+ (3), [H3Ru3(1,2,4,5-C6H2Me4)3(O)]+ (4), [H3Ru3{C6H5(CH2)2OH}(C6Me6)2(O)]+ (5), and [H3Ru3{C6H5(CH2)3OH}(C6Me6)2(O)]+ (6), is believed to occur within the hydrophobic pocket spanned by the three arene ligands of the trinuclear cluster, thus forming a supramolecular catalyst–substrate host–guest complex. This paper is a short overview of our research efforts directed to a new catalytic concept for which we coined the term 'supramolecular cluster catalysis'