Stereochemistry at the Chiral Ruthenium Atom in Half-Sandwich Compounds of the Type [(.eta.6-Ar)Ru(LL*)L']X and [(.eta.6-Ar)Ru(LL*)-Hal]. X-ray Structure Analysis of [(.eta.6-cymene)Ru(LL*)(4-Mepy)]PF6 and Appeal to the Proper Use of Stereochemical Terminology
摘要:
In the series of optically active half-sandwich complexes of the type [(eta(6)-Ar)Ru(LL*)L']X and [(eta(6)-Ar)-Ru(LL*)Hal] configurational assignments on the basis of the CD spectra have been made, which are unwarranted, as shown by the X-ray crystallographic analysis of (+)(D)-(R(Ru),S-C)-[(eta(6)-cymene)Ru(LL*)4-Mepy]PF6, 1. Furthermore, the configurational lability at the Ru atom in solution at room temperature and even below leads to equilibrium with respect to the metal configuration, making previous assignments of retention and inversion stereochemistry in substitution reactions meaningless.