A Beneficial Kinetic Effect of an η5-C5Me4H Ligand

摘要

C−H activation of benzene at 26 °C by (η5-C₅Me₅)W(NO)(CH₂CMe₃)(η3-CH₂CHCHMe) results after 4 h in the production of five new organometallic complexes, only two of which are isomers of the desired (η5-C₅Me₅)W(NO)(C₆H₅)(η3-CH₂CHCHMe) compound. In contrast, the identical reaction involving the η5-C₅Me₄H analogue affords only the phenyl complexes during the first 24 h, thereby facilitating their isolation in good yields. This striking difference in reactivity can be attributed to the lesser steric demands of the η5-C₅Me₄H ligand that result in its complexes reacting at a significantly slower rate.