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A novel method for investigating changes in fluxional Re(V)=O complexes of the analogous meso N2S2 ligands using nuclear magnetic resonance spectroscopy was developed. The new strategy used ligands with selected stereochemical features such as meso isomers of EC-type ligands. It was found that ReO has predominant from between pH 6 and 10 with the usual N2S2 basal donors. This form contains unusual determinant of chirality.

Exchange-NOE nuclear magnetic resonance spectroscopy data is shown to be an efficient method for determining the extent of planar N-donor heterocyclic coordinated ligands (L's) rotation about the metal-N bond, the direction of L rotation and even the halves of C2-symmetrical L's that interchange during dynamic processes. It marks the first time that preferred pathways of rotation were demonstrated.

The Co-C-N three-membered ring in organocobalt complexes related to B12 is formed when an equatorial nitrogen donor is added to a ligated axial carbon through a facile interligand nucleophilic addition. The Co-C-N ring angle is 43.7 degrees with Co-N and Co-C ring linkages having the greatest distortion of the coordination sphere. Phi-bending is a significant factor in the weakening of the Co-C bond, and causes Co-C bond cleavage along with theta-bending. Hypotheses regarding Co-C bond activation in B12 chemistry and calculations of the activation can be assessed using evidence from the highly distorted structure of the resulting complex.

The crystalline-octahedral Re2O3Cl4(Me3Bzm)4 (1) and cis,cis, cis-RuCl2(Me2SO)2(Me3-Bzm)2 (2) synthesized from ReOCl3(Me2S)(OPPh3) and cis-RuCl2(Me2SO)4 exhibit a rare head-to-head conformation of untethered lopsided ligands. Properties typical of extremely fluxional species are evident in the H NMR spectra of 1 and 2 in CDCl3.