Synthesis and properties of η 5-C 5R 5Fe(CO) 2(CH 2) 3Si(OCH 3) 3 (R = H or Me). An example of electrooxidative-induced carbonyl insertion

Abstract

Propyltrimethoxysilane compounds of the type η 5-C 5R 5Fe(CO) 2(CH 2) 3Si (OCH 3) 3 (R = H ( 3); R = Me ( 4)), can be conveniently prepared by reaction between the anionic complexes M +[η 5-C 5R 5Fe(CO) 2] − (M + = K + or Na +, R = H ( 1); M + = Na +; R = Me ( 2)) and Cl(CH) 2) 3Si(OCH 3) 3 in THF. Triphenylphosphine reacts with complex 3 in refluxing acetonitrile, to give the carbonyl insertion product η 5-C 5H 5(CO)(PPh 3)FeC(O)(CH 2) 3Si(OCH 3) 3 ( 5). Complex 4 behaves in a very different way in carbon monoxide insertion induced by triphenylphosphine. The oxidation of complexes 3 and 4 in acetonitrile have been studied by a combination of electrochemical and spectroscopic techniques. The results indicate migratory insertion oxidation of complexes 3 and 4, which is very rapid at room temperature and seems to be accompanied by nucleophilic attack by the solvent. If the reactions are carried out in the presence of triphenylphosphine, the carbon monoxide-insertion reaction is induced by this phosphorus ligand only in the case of complex 3.