title: NH-S hydrogen bonding in zinc enzyme model complex with S2N2 binding set studied by normal coordinate analysis of vibrational spectra.
abstract: In order to provide theoretical evidence for the existence and effect of NH-S hydrogen bonding in the zinc enzyme model complex [Zn(S-2-C6H4NHCOC6H5)2(1-MeIm)2] (1-MeIm = 1-methylimidazole) in addition to the spectroscopic and crystallographic investigations, normal coordinate analysis (NCA) was carried out using a modified Urey-Bradley force field. The vibrational frequencies of the complex with and without the NH-S hydrogen bonding as well as the corresponding internal coordinates were obtained. The good agreement found between the calculated and observed frequencies in the presence of the NH-S hydrogen bond, supports the reliability of the analysis. The stretching force constant of the NH-S hydrogen bond obtained from the calculation is 0.18 mdyne per A. The calculation shows that the N-H bond is weakened by formation of the NH-S hydrogen bond. The results are indicative of the existence of the NH-S hydrogen bond in the complex.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, Nanjing University, PR China.
authors.forename: X F
authors.initials: XF
authors.lastname: Shi
authors.forename: W Y
authors.initials: WY
authors.lastname: Sun
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: C D
authors.initials: CD
authors.lastname: Li
mesh_terms: D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry; D008968:Molecular Conformation; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods; D013455:Sulfur / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D013455:Sulfur; D015032:Zinc; C018100:1-methylimidazole