Aromatic C–H---S interaction in the arenethiolate complexes of cadmium(II) with S2N2 donor set evidenced from 113Cd NMR spectroscopy

Design, syntheses, and characterization of dioxo-molybdenum(VI) complexes with thiolate ligands: effects of intraligand NH...S hydrogen bonding

Presence of the hydrogen bonding near a metal center can influence the properties of the complex. Here, we describe changes in redox and spectral properties in discrete dioxo-molybdenum centers coordinated by a single thiolato ligand that can support an intra-ligand hydrogen bond. We have utilized thiophenolato ligands that can harbor hydrogen bonding between the thiophenolato sulfur with an amide functionality creating either a five- or a six-membered ring. Methylation of the amide functionality removes the NH...S hydrogen bonding thus providing a basis for understanding the effect of hydrogen bonding. These thiophenolato ligands have been used in synthesizing dioxo-MoVI complexes of type Tp*MoO2(S-o-RC6H4), where R=CONHMe (), CONMe2 (), NHCOMe (), and N(Me)COMe (). The complexes have been characterized by NMR, infrared, and UV-visible spectroscopy. Spectroscopic data clearly indicate the presence of hydrogen bonding in both and , and stronger in , where hydrogen bonding stabilizes a five-membered ring. All complexes exhibit a Mo(VI)/Mo(V) redox couple and redox potentials are modulated by the nature of H-bonding. Compound with the electron-releasing N(Me)COMe group has the highest reduction potential and is more difficult to reduce.

Reaction of bis[bis(tri-tert-butoxysilanethiolato) cadmium(II)] with 3,5-dimethylpyridine - 113Cd NMR solution study

NMR studies on the reaction of bis[bis(tri-tert-butoxysilanethiolato)cadmium(II)] with 3,5-dimethylpyridine in benzene-d(6) and toluene-d(8) solutions provide clear evidence for the equilibrium character of formation of mixed S,N-ligand cadmium complex.