Essays über Metallorganische Chemie V. Stand und Aussichten der Rhenium-Chemie in der Katalyse

The most recent review article on catalytic epoxidation reactions gives a rather discouraging statement of the heavier group VII transition metal compounds as oxidation catalysts [2]: "The catalytic activity of technetium seems to be comparable to that of rhenium ..., and both seem to be low." The present account briefly describes the status of rhenium chemistry in catalysis, showing that there are many more perspectives than were first believed. It is shown that high-valent organorhenium oxides function as very effective catalysts in both olefin metathesis (heterogeneous catalysis) and in olefin oxidation (homogeneous catalysis). In this content it becomes evident that rhenium chemistry in general has been much less investigated and understood than that of the neighbouring elements tungsten and osmium. Furthermore, work concerning technetium compounds is necessary in order to gain better insight in catalytic and other properties of the corresponding rhenium compounds. Beyond the known, relationship between technetium and rhenium with regard to their inorganic and coordination compounds, the first similarities in the chemistry of their organic compounds are being uncovered, at the same time marked differences cannot be neglected.