Systematic investigation of relationship between strength of NH···S hydrogen bond and reactivity of molybdoenzyme models.

A series of monooxomolybdenum(IV) and dioxomolybdenum(VI) complexes containing two intramolecular NH···S hydrogen bonds were synthesized and characterized by (1)H NMR, UV-visible, IR, and Raman spectroscopies, and electrochemical measurements. Elimination of the steric effects enabled the accurate and quantitative evaluation of NH···S hydrogen bonds. Strong correlations among the strength of the hydrogen bond, the strength of the Mo(VI)═O bond, and the redox potential were clearly shown.