Gold(I) eta2-arene complexes

The reaction of 9-{[N-n-propyl-N-(diphenylphosphino)amino]methyl}anthracene (1) with Au(SMe2)Cl yields complex 2 with an arm-opening configuration. The latter is treated with AgClO4 to form complex 4 and then respectively reacted with acetonitrile, pyridine, and triphenylphosphine sulfide to afford novel gold(I) eta2-arene complexes 3a-c, which have arm-closing configurations and feeble or weak fluorescence emissions. The observation can be attributed to charge transfer from the anthracene unit to the Au+ ion. When the solution of 3a or 4 in CH2Cl2 was added with 1 equiv of Ph3P, complex 5 with the arm-opening configuration was formed and strong emission was restored.     

Comprehensive theoretical studies on the low-lying electronic states of NiF, NiCl, NiBr, and NiI

The low-lying electronic states of the nickel monohalides, i.e., NiF, NiCl, NiBr, and NiI, are investigated by using multireference second-order perturbation theory with relativistic effects taken into account. For the energetically lowest 11 lambda-S states and 26 omega states there into, the potential energy curves and corresponding spectroscopic constants (vertical and adiabatic excitation energies, equilibrium bond lengths, vibrational frequencies, and rotational constants) are reported. The calculated results are grossly in very good agreement with those solid experimental data. In particular, the ground state of NiI is shown to be different from those of NiF, NiCl, and NiBr, being in line with the recent experimental observation. Detailed analyses are provided on those states that either have not been assigned or have been incorrectly assigned by previous experiments.     

Surface characterization of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl-polyhedral oligomeric silsesquioxane) by inverse gas chromatography

The surface properties of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl polyhedral oligomeric silsesquioxane) (poly(MMA-co-BA-co-styryl-POSS)) were studied by means of inverse gas chromatography (IGC) using 10 non-polar and polar solvents as the probes. Thermodynamic parameters of adsorption, e.g., specific retention volume, the dispersive component of the surface free energy, the specific interaction contribution to the free energy of adsorption and the acid/base constants were obtained to investigate the interactions between the surfaces of the copolymers and different solvents. It was found that incorporation of styryl-POSS into polymer resulted in increasing interactions between polymers and solvents, dispersive component of surface free energy of polymer and acidity of the surfaces of the polymers. The more the styryl-POSS were embedded, the stronger the interaction between the polymer surface and solvent, the dispersive component of the surface free energy and the acidity of the polymer surface were.     

Biological fingerprinting analysis of the interactome of a kinase inhibitor in human plasma by a chemiproteomic approach

In this study, a gel free chemiproteomic method based on chromatography was developed and applied for the biological fingerprinting analysis of complex biological system. p-Aminobenzamidine (ABA), an inhibitor of trypsin-like serine proteases, was immobilized for characterizing their interacting proteins in human plasma. By the proteomic analysis method, 214 proteins were identified with obvious affinity to the immobilized ABA. By searching the sequences of above proteins with consensus patterns of the two active sites, seven proteins belong to trypsin-like serine protease group were found. Based on the Gene Ontology annotation, the identified trypsin-like serine proteases have the function of catalytic activity and calcium ion binding, and are mainly involved in the biological process of blood coagulation. Eight more other proteins related to calcium ion binding and blood coagulation were found. Nearly all of these proteins cannot be identified by directly analyzing the plasma sample demonstrating the chemiproteomics a useful approach to characterize interacting proteins in the low abundance range.     

Supra-assembly of siliceous vesicles

We report a new approach to produce macroporous ( approximately 110 nm in diameter) ordered siliceous foams (MOSF) by using block copolymers as templates in the absence of any organic cosolvent. The fine three-dimensional honeycomb structure of MOSF was determined by electron tomography. A formation mechanism of MOSF that spans from the atomic to macroscopic scale is proposed, which involves the cooperative self-assembly of unilamellar vesicles followed by the supra-assembly of vesicles. The fusion of soft vesicles finally leads to MOSF with well-ordered and defined honeycomb structures.     

NMR observations of 13C-enriched coenzyme B12 bound to the ribonucleotide reductase from Lactobacillus leichmannii

The 13C NMR resonance and one-bond 1H-13C coupling constants of coenzyme B12 enriched in 13C in the cobalt-bound carbon have been observed in the complex of the coenzyme with the B12-dependent ribonucleotide reductase from Lactobacillus leichmannii. Neither the 13C NMR chemical shift nor the 1H-13C coupling constants are significantly altered by binding of the coenzyme to the enzyme. The results suggest that ground-state Co-C bond distortion is not utilized by this enzyme to activate coenzyme B12 for C-Co bond homolysis.     

Monolithic silica capillary column with coated cellulose tris(3,5-dimethylphenylcarbamate) for capillary electrochromatographic separation of enantiomers

Monolithic silica capillary columns were prepared by a sol-gel process in fused-silica capillaries with an inner diameter of 50 microm and were modified by coating of cellulose tris(3,5-dimethylphenylcarbamate). Influences of the factors in the modification process on enantiomer separations were investigated. The prepared columns were used to perform enantiomer separations by CEC. Fifteen and two pairs of enantiomers were separated under aqueous and nonaqueous mobile phases, respectively, and most of them were baseline-separated with very high column efficiencies. The Van Deemter curve was found flat under high linear velocity of the mobile phase, which indicated favorable kinetic properties of the prepared columns. Baseline separation of a pair of enantiomers was achieved in 90 s with high-column efficiency by short-end separation under high voltage.     

Capillary electrochromatography with zwitterionic stationary phase on the lysine-bonded poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolithic capillary column

A polymer-based neutral monolithic capillary column was prepared by radical polymerization of glycidyl methacrylate and ethylene dimethacrylate in a 100 mum id fused-silica capillary, and the prepared monolithic column was subsequently modified based on a ring opening reaction of epoxide groups with 1 M lysine in solution (pH 8.0) at 75 degrees C for 10 h to produce a lysine chemically bonded stationary phases in capillary column. The ring opening reaction conditions were optimized so that the column could generate substantial EOF. Due to the zwitterionic functional groups of the lysine covalently bonded on the polymer monolithic rod, the prepared column can generate cathodic and anodic EOF by varying the pH values of running buffer during CEC separation. EOF reached the maximum of -2.0 x 10(-8) m2v(-1)s(-1) and 2.6 x 10(-8) m2v(-1)s(-1) with pH of the running buffer of 2.25 and 10, respectively. As a consequence, neutral compounds, ionic solutes such as phenols, aromatic acids, anilines, and basic pharmaceuticals were all successfully separated on the column by CEC. Hydrophobic interaction is responsible for separation of neutral analytes. In addition, the electrostatic and hydrophobic interaction and the electrophoretic migration play a significant role in separation of the ionic or ionizable analytes.     

On Dirichlet Problem for a Class of Delayed Reaction–Diffusion Equations with Spatial Non-locality

We consider a very general class of delayed reaction–diffusion equations in which the reaction term can be non-monotone as well as spatially non-local. By employing comparison technique and a dynamical system approach, we study the global asymptotic behavior of solutions to the equation subject to the homogeneous Dirichlet condition. Established are threshold results and global attractiveness of the trivial steady state, as well as the existence, uniqueness and global attractiveness of a positive steady state solution to the problem. As illustrations, we apply our main results to the local delayed diffusive Mackey–Glass equation and the nonlocal delayed diffusive Nicholson blowfly equation, leading to some very sharp results for these two particular models.