A triangular palladium(II) supramolecular coordination complex based on 1,4-bis(1H-imidazol-1-yl)benzene and (2,2'-bipyridyl)palladium(II) nitrate: synthesis and crystal structure.

The self-assembly of ditopic bis(1H-imidazol-1-yl)benzene ligands (L) and the complex (2,2'-bipyridyl-κN,N')bis(nitrato-κO)palladium(II) affords the supramolecular coordination complex tris[μ-bis(1H-imidazol-1-yl)benzene-κN:N]-triangulo-tris[(2,2'-bipyridyl-κN,N')palladium(II)] hexakis(hexafluoridophosphate) acetonitrile heptasolvate, [Pd(CHN)(CHN)](PF)·7CHCN, 2. The structure of 2 was characterized in acetonitrile-d by H/C NMR spectroscopy and a DOSY experiment. The trimeric nature of supramolecular coordination complex 2 in solution was ascertained by cold spray ionization mass spectrometry (CSI-MS) and confirmed in the solid state by X-ray structure analysis.

On the mechanism of nitrosoarene-alkyne cycloaddition.

The thermal reaction between nitrosoarenes and alkynes produces N-hydroxyindoles as the major products. The mechanism of these novel reactions has been probed using a combination of experimental and computational methods. The reaction of nitrosobenzene (NB) with an excess of phenyl acetylene (PA) is determined to be first order in each reactant in benzene at 75 degrees C.

Chemical mechanism of homoisocitrate dehydrogenase from Saccharomyces cerevisiae.

Homoisocitrate dehydrogenase (HIcDH, 3-carboxy-2-hydroxyadipate dehydrogenase) catalyzes the fourth reaction of the alpha-aminoadipate pathway for lysine biosynthesis, the conversion of homoisocitrate to alpha-ketoadipate using NAD as an oxidizing agent. A chemical mechanism for HIcDH is proposed on the basis of the pH dependence of kinetic parameters, dissociation constants for competitive inhibitors, and isotope effects. According to the pH-rate profiles, two enzyme groups act as acid-base catalysts in the reaction.

Complete kinetic mechanism of homoisocitrate dehydrogenase from Saccharomyces cerevisiae.

The kinetic mechanism of homoisocitrate dehydrogenase from Saccharomyces cerevisiae was determined using initial velocity studies in the absence and presence of product and dead end inhibitors in both reaction directions. Data suggest a steady state random kinetic mechanism. The dissociation constant of the Mg-homoisocitrate complex (MgHIc) was estimated to be 11 +/- 2 mM as measured using Mg2+ as a shift reagent.

Efficient synthesis of tris(4-imidazolyl)methanol derivatives.

Biomimetic tris(4-imidazolyl)carbinol derivatives are prepared from imidazole in a short, high-yielding sequence via sulfonamide 1, which is converted to the 2-silylated carbinol 2 by one-pot, sequential 2-functionalization and then 4(5)-functionalization. Alcohol 2 can be transformed either to the parent carbinol 3 or to a desilylated sulfonamide derivative 4. The tripodal alcohol 3 is a convenient precursor to ethers by solvolysis and to metal complexes, as illustrated by the preparation of a bis-tripod complex with iron(III).