title: Sulfur-rich zinc chemistry: new tris(thioimidazolyl)hydroborate ligands and their zinc complex chemistry related to the structure and function of alcohol dehydrogenase.
abstract: The 1-substituted tris(2-thioimidazolyl)hydroborate ligands Tt(R) were prepared as the potassium salts from KBH(4) and the corresponding 1-R-2-thioimidazole for R = t-Bu and C(6)H(4)-p-CH(CH(3))(2) (Cum). Their reactions with zinc salts yielded the tetrahedral complexes Tt(R)Zn-X with X = F, Cl, ONO(2) and (Tt(t)()(-)(Bu))(2)Zn. With zinc perchlorate the labile perchlorate complexes Tt(R)Zn-OClO(3) were obtained. They served as starting materials for the incorporation of substrates which are relevant for the chemistry of horse liver alcohol dehydrogenase: Ethanol led to [Tt(t)()(-Bu)Zn.EtOH] ClO(4).EtOH, p-nitrophenol (NitOH) yielded Tt(Cum)Zn-ONit. Pyridine-2-carbaldehyde and salicylic aldehyde were incorporated as N(pyridine) and O(phenolate) coligands with possible additional O(aldehyde) coordination. Substituted pyridyl methanols (R-PyCH(2)OH) yielded the trinuclear complexes [(Tt(t)()(-Bu))(2)Zn(3)(R-PyCH(2)O)(2)] (ClO(4))(2) with bridging Tt and pyridylmethoxide ligands. Preliminary experiments on the functional modeling of alcohol dehydrogenase have shown that TtZn complexes promote both the dehydrogenation of 2-propanol and the hydrogenation of pentafluorobenzaldehyde.
authors.affiliation: Institut für Anorganische und Analytische Chemie der Universität Freiburg, Albertstr. 21, D-79104 Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Tesmer
authors.forename: M
authors.initials: M
authors.lastname: Shu
authors.forename: H
authors.initials: H
authors.lastname: Vahrenkamp
mesh_terms: D000426:Alcohol Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001671:Biochemistry / Q000379:methods; D001881:Borates / Q000737:chemistry; D006736:Horses; D007093:Imidazoles / Q000737:chemistry*; D008099:Liver / Q000201:enzymology*; D008956:Models, Chemical; D015394:Molecular Structure; D009536:Niacinamide / Q000031:analogs & derivatives / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D011725:Pyridines / Q000737:chemistry; D013329:Structure-Activity Relationship; D013455:Sulfur / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D001881:Borates; D007093:Imidazoles; D009942:Organometallic Compounds; D011725:Pyridines; C432864:pyridine-2-carbaldehyde; D009536:Niacinamide; D013455:Sulfur; D000426:Alcohol Dehydrogenase; D015032:Zinc