Structural characterization of octahedral metal complexes of [MX 3(py) 3] type with three pyridines as revealed by 2H NMR spectra

Abstract

Deuterium NMR spectra of a series of mer-[MX 3(py-d 5) 3] type complexes where M=Cr(III), Mo(III) and X=Cl −, Br −, F −, NCS − have been measured to determine the geometrical structure. Most of them provided a decisive criteria for this purpose with only one exception of [CrCl 3(py-d 5) 3] where the 2H NMR and visible absorption spectra behave like the fac isomer. The previous assignments of ‘fac’- and ‘mer’- [Cr(NCS) 3(py) 3] by DasSarma and DasSarma were found to be wrong; correctly mer-[Cr(NCS) 3(py) 3] and (Hpy)- [Cr(NCS) 4(py) 2], respectively.