Olefin Isomerization Catalysis by Heterobimetallic Hydrides, HFeM(CO)8L(1-) (M = Cr, Mo, W; L = CO, PR3)

Article abstract of DOI:10.1021/ja00294a037

The bis(triphenylphosphine)iminium (PPN(1+)) salts of HFeM(CO)9(1-) (M = Cr, Mo, W) were shown to be olefin isomerization catalysts under mild conditions (25 degC, fluorescent lighting) toward the conversion of allylbenzene to cis- and trans-propenylbenzenes and 1-hexene to internal olefins.When DFeM(CO)9(1-) was used as catalyst, deuterium label was incorporated into the isomerized products.The olefin isomerization capability of HFe(CO)4(1-) was reviewed.The HFe(CO)4(1-) anion is inactive in THF solution with PPN(1+) as counterion, but activity may be generated in the presence of cocatalysts such as BF3 and Ph3C(1+) (via a 1,3-shift mechanism) or alkali cations, Na(1+) and Li(1+) (via reversible Fe-H addition mechanism).Evidence is presented which supports the action of the group 6 metal carbonyl fragment, M(CO)5(0), to be similar to that of the alkali cations in promoting catalysis on the Fe-H(1-) center.