Ligands that enforce unnatural stereospinomers

摘要

Computational evidence is provided for the existence of combinations of a stereoisomer and a spin state not previously observed in d~4 and d~8 complexes, achieved by means of encapsulating ligands that enforce a tetrahedral coordination. A four-coordinated transition metal may exhibit energy minima of different stereochemistry depending on its different spin states. Each combination of spin state and stereochemistry constitutes a stereo-spin isomer, termed in short stereospinomer. In the case of d~4 ions, for instance, the high spin configuration (S = 2) coexists with a nearly square planar coordination sphere, whereas the low spin configuration (S = 0) prefers a tetrahedral geometry.