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The synthesis of a series of RuII complexes incorporating thiacrown ligands ([12]ane-S4, [14]ane-S4, [16]ane-S4), as well as 2,2'-bipyridine (bpy) or pyridine, is reported. Structural studies on these complexes have been carried out using a variety of techniques. Detailed 1H NMR spectroscopic studies on the previously reported [Ru([12]ane-S4)(bpy)]2+ (1) reveal that-contrary to earlier reports-the observed fluxional 1H NMR behavior is not due to chemical exchange involving cleavage of the bpy Ru--N bond but is, in fact, due to lone-pair inversion of coordinated macrocyclic sulfur donor atoms. This phenomenon is also observed for the [14]ane-S4 and [16]ane-S4 analogues of 1. For the first time, using a combination of X-ray crystallography, more detailed 1H NMR experiments, and computational methods, an in-depth study on the energetics and dynamics of invertomer formation and conversion for macrocyclic coordination complexes has been carried out. These studies reveal that the steric constraints of assembling each sulfur macrocycle and bpy ligand around the octahedral Ru(II) center lead to close intramolecular contacts. These contacts are largely dependent on the orientation of the electron lone pairs of equatorial sulfur donor atoms and correlate with the comparative stability of the different invertomeric forms. Thus, the conformational preferences of the three macrocyles in [Ru([n]ane-S4)(bpy)]2+ complexes are determined by steric rather than electronic effects.

Research has been conducted on the ligand-bridged bimetallic complexes containing [RuCl-([9]aneS (sub)3)] (super)+ metal centers. The electron transfer and chemical properties of these complexes have been investigated and the results indicate that the complexes display intense bimetallic interactions.