Structure-reactivity relationship in alkane metathesis using well-defined silica-supported alkene metathesis catalyst precursors

Alkane metathesis can be performed by using well-defined silica-supported alkene metathesis catalyst precursors as long as the coordination sphere of the metal centre contains both alkyl and alkylidene groups, such as in [(≡SiO)Mo(≡NAr)(=CHtBu)-(CH₂tBu)]. This system transforms mainly linear alkanes, from propane to hexane, into their lower and higher homologues. Mechanistic studies clearly show that alkene metathesis is a key step of this reaction and also suggest that this system is a single-site single-component system, namely, alkenes are formed and transformed on one site, which is in contrast to that observed with a mixture of catalysts.