The first acidity scale to be established in a pure solvent other than water was the result of the pioneering work of Conant, Wheland, and McEwen in ether or ben~ene .~ During the past 20 years an ion-pair acidity scale covering an "effective pKa rangefrom about 15 to 40 has been developed in cyclohexylamine (CHA),6 and similar studies in other low-dielectric-constant solvents including 1,2-dim...

the study aimed to investigate the adsorption mechanism of di-n-butyl phthalate (dbp) onbrown soil and red soil in shenyang and hunan province, respectively, china. adsorption kinetics andisotherms experiments were conducted at 288, 298 and 308 k, respectively. results of kinetics showed thatadsorption of dbp exhibited a two-step process in both brown and red soil. different models were used to...

Escherichia coli class I ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to deoxynucleotides and is composed of two subunits: α2 and β2. β2 contains a stable di-iron tyrosyl radical (Y122 •) cofactor required to generate a thiyl radical (C439 •) in α2 over a distance of 35 Å, which in turn initiates the chemistry of the reduction process. The radical transfer process is p...

The decarboxylative Mannich reaction (DMR) of b-ketoacids with imines has emerged as a very important tool for the synthesis of natural products and biologically active compounds. The elegant work of Robinson on the total synthesis of ( )-tropinone represents the first practical example of utilizing the DMR as a key step in organic synthesis. Herbert and co-workers and Mangla and Bhakuni then d...

1 This thesis describes applications in co-crystal reactivity, structure determination, and mechanochemical preparation. We also investigate the solution-phase reactivities of products derived from a template-directed synthesis. Specifically, we described the acid treatment of an achiral molecular ladder of C2h symmetry composed of five edge-sharing cyclobutane rings, or a [5]-ladderane, that r...

There are now several crystal structures of antibody Fab fragments complexed to their protein antigens. These include Fab complexes with lysozyme, two Fab complexes with influenza virus neuraminidase, and three Fab complexes with their anti-idiotype Fabs. The pattern of binding that emerges is similar to that found with other proteinprotein interactions, with good shape complementarity between ...

The hydrogen bond (HB) is one of the fundamental noncovalent interactions between a drug molecule and its local environment. For drug molecules, this local environment may be a biological target, a biological off-target, aqueous solution, a lipid membrane, or even a crystalline solid. Consequently, hydrogen bonding impacts a wide range of molecular properties critical to drug design including p...

Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Its long-term modulating affect on synaptic transmission is mediated by the metabotropic glutamate receptors (mGluR), a family of class III G protein-coupled receptor (GPCR) proteins. This class of GPCRs is characterized by the typical seven transmembrane domain and an additional large extracellular liga...

Dynamic mechanical measurements were used to investigate the effect of small molecule additives on the order-todisorder transitions (ODTs) of Pluronic, poly(ethylene oxide) (PEO)−poly(propylene oxide) (PPO)−PEO triblock copolymer surfactant melts. The small molecule additives contain multiple functional groups (carboxyl or hydroxyl), which selectively interact with the PEO component of Pluronic...

Hydrogen bonds play critical roles in protein structure, stability, and function. Most hydrogen bonds in proteins are derived from their crystal structures and the use of standard covalent geometry information, because the positions of hydrogen atoms are defined only in a limited number of ultrahigh-resolution crystal structures. On the other hand, NMR structure calculations rely mostly on the ...