Bond-stretch isomerism in strained inorganic molecules and in transition metal complexes: A revival?

摘要

A decade after Parkin's statement that 'there is presently no definitive evidence of bond-stretch isomerism in (transition metal) complexes', bond-stretch isomerism (BSI) is re- visited, with special emphasis on inorganic and organome- tallic chemistry. It appears that the characterization of real bond-stretch isomers, distinct, separable and stable at room temperature, remains a very rare event. In fact, the vast majority of reports point out the case of neighboring species that were characterized with structurally distinct cores or frameworks, depending on the electronic or steric influence of peripheral substitutents.