High- and low-valency organometallic compounds of technetium and rhenium

Abstract

Organometallic technetium chemistry is a relatively poorly developed field, although the location of this element in the periodic table implies the possession of a very diverse chemistry. This article aims to review critically the progress that has been made in this field during the past five to ten years. In particular, the focus is put on synthetic strategies that start from a few important synthons. To evaluate the usefulness and potential of these starting materials, subsequent reactions, that have been published will be discussed in detail, particularly in relation to the prospects for further development. For this reason, this article is not divided into sections defined by oxidation state or type of ligand, but by the relevant synthon. Thus, similar compounds may appear in different sections of the article, whereas differing types of compound may be discussed in the same section, because of their common starting material. Where necessary, the chemistry of technetium will be compared with that of its homologs, especially in the case of any observed catalytic activity or other practical applications. Furthermore, structural characterization or another physical measurement, such as i.r. spectroscopy, often affords an insight into the electronic properties of a compound and consequently allows predictions about chemical properties. For most of the compounds discussed, X-ray structure analysis and i.r. spectroscopy has been performed; thus emphasis will be put on these physical measurements.