Substituted metal carbonyls. Part XVII.1 1 For Part XVI see Ref. 1. Thermal decarbonylation and chelation of M(CO)5(η1-dppf) and Fe(CO)4(η1-dppf) [where M = Cr, Mo, W; dppf = (Ph2PC5H4)2Fe]

Abstract

Thermal decarbonylation of the unidentate complexes M(CO)5(η1-dppf) (M = Cr, Mo, W) and Fe(CO)4(η1-dppf) results in ring closure to form the corresponding chelates. The reactions have been followed by IR and NMR spectroscopy in refluxing acetonitrile, tetrahydrofuran, hexane and heptane solutions and in solid-state by thermogravimetric (TG) and differential scanning calorimetric (DSC) means. The solid-state decompositions have been emulated in Schlenk flasks and the chelates formed have been isolated and analysed. Decarbonylations of the W and Fe complexes are found to be the least facile. A kinetic study by the Flynn and Wall method suggests that only the Fe complex follows a first order dissociative mechanism. © 1991.