The Synthesis and Structure of the Yellow and Green Forms of [Nb(O)Cl3(PMe3)3] and the Orange and Green Forms of [Nb(S)Cl3(PMe3)3]; Examples of Perfectly Matched Bond‐Stretch Isomers?

Four sevenfold coordinated isostructural and isomorphic NbV complexes were isolated as two pairs of pure bond-stretch isomers (a, long NbE bond; b, short NbE bond). Good characterization by IR spectroscopy and X-ray analysis of this new “material” have added fuel to the heated discussion on bond-stretch isomerism.