Stepwise construction of polynuclear complexes of rhodium and iridium assisted by benzimidazole-2-thiol. NMR and X-ray diffraction studies

The mononuclear complex (MCl(H2Bzimt)(cod)), where M = Rh, Ir, cod = 1,5 cyclooctadiene, and Bzimt = benzimidazole-2-thiol, is a precursor for synthesizing homo- and hetero-tetranuclear complexes such as (MM'(mu-Bzimt)(cod)2)2, which have S-coordinated ligands. The dinuclear and trinuclear complexes appear as intermediates during the process. The impact of steric and anisotropic effects is reflected in the chemical shift values of olefinic protons. The 1H-NMR spectra is carried out by selective decoupling, NOE, and H,H-COSY experiments.