Profound insights into the catalytic mechanism of galactose oxidase (GO) are offered by new models of the active form of the metalloenzyme. The important role of the CuII center in the oxidation of benzyl alcohol to benzaldehyde by the CuII–phenoxyl radical complex of ligand 1 has been revealed by comparison with the reactivity of the corresponding ZnII–phenoxyl radical complex; py=2-pyridyl. 相似文献
Nickel oxide and chromium-doped nickel oxide (Ni0.95Cr0.03O1−δ) were prepared by thermal decomposition of nitrates. The obtained NiO and Ni0.95Cr0.03O1−δ samples were utilized as sensing electrodes (SEs) in yttria-stabilized zirconia (YSZ)-based sensors for detection of NO2 at 800 °C under wet condition (5 vol.% H2O). While the mixed-potential-type planar sensor attached with NiO-SE gave rather large NO2 sensitivity, the sensor attached with Ni0.95Cr0.03O1−δ-SE exhibited fast recovery rate with an acceptable sensitivity. The Δemf (electromotive force) of the sensors varied linearly
with NO2 concentration in the examined range of 50–400 ppm on a logarithmic scale. Based on the results of measurements for polarization,
complex impedance and gas phase catalysis, the fast recovery was attributable to the high rate for the anodic reaction of
O2 at the Ni0.95Cr0.03O1−δ/YSZ interface, and the lower NO2 sensitivity was caused by both the high rate for the anodic reaction of O2 and the high degree for the gas phase conversion of NO2 to NO. 相似文献
An 8-endo selective Friedel-Crafts cyclization of vinyloxirane 8 with Co2(CO)6-complexed benzeneacetylene was found to give poly-functional eight-membered cyclic compound 9 in high yields. 相似文献
High performance of Me-BIPAM for enantioselective hydrogenation of α-dehydroamino esters, enamides, and dimethyl itaconate was demonstrated. [Rh(Me-BIPAM)(diene)]X (diene = cod, nbd; X = BF4, PF6, SbF6) gave optically active β-aryl α-amino esters up to 99% ee, 1-arylethylamines up to 97% ee, methyl 2-acetylaminobutanoate with 90% ee, and dimethyl 2-methylsuccinate with 97% ee under 0.3−0.8 MPa dihydrogen with 0.1−1 mol % catalyst loading. 相似文献
The adsorption behavior of lysine on montmorillonite in aqueous solution was investigated by in situ attenuated total reflectance infrared (ATR-IR) spectroscopy. To distinguish the protonation states of α-amino group, side-chain amino group and carboxyl group in lysine structure using ATR-IR spectra (i.e., NH2 versus and COO− versus COOH), pH-induced spectral changes of dissolved lysine were firstly measured and correlated with the thermodynamically calculated dissociation states of lysine (di-cationic, cationic, zwitterionic and anionic states). The obtained result was applied to interpret the ATR-IR spectra of lysine adsorbed on montmorillonite. We found that the adsorbed lysine was dominantly present as cationic state over the whole range of tested pH (pH = 4.9–9.7). This indicates that the adsorption is mainly driven by electrostatic interaction between the negatively charged montmorillonite surface and positively charged cationic lysine. We also found that lysine interacts with montmorillonite surface through the protonated side-chain amino group. This result suggests that lysine has a preferred vertical orientation, with the side-chain amino group pointing toward the surface. 相似文献
Synthesis of 1,3-butadiyne-bridged perfluoroisopropyl binuclear phthalocyanine 2 has been successfully achieved from unsymmetrical A3B-type iodo-perfluoroisopropyl phthalocyanine by palladium-catalyzed cross-coupling with trimethylsilylacetylene and copper-catalyzed Glaser homo-coupling as key reactions. The dyad 2 essentially remains non-aggregated irrespective of solvent and concentration. Electrochemical analysis suggests oxidation is not possible whereas the molecule is more easily reduced. All the results are advantages for photodynamic therapy (PDT). 相似文献
A surface plasmon resonance (SPR) immunosensor for detection of 2,4-dinitrotoluene (2,4-DNT), which is a signature compound of 2,4,6-trinitrotoluene-related explosives, was developed by using a novel oligo (ethylene glycol) (OEG)-based sensor surface. A rabbit polyclonal antibody against 2,4-DNT (anti-DNPh-KLH-400 antibody) was prepared, and the avidity for 2,4-DNT and recognition capability were investigated by indirect competitive ELISA. The sensor surface was fabricated by immobilizing a 2,4-DNT analog onto an OEG-based self-assembled monolayer formed on a gold surface via an OEG linker. The fabricated surface was characterized by Fourier-transform infrared-refractive absorption spectrometry (FTIR-RAS). The immunosensing of 2,4-DNT is based on the indirect competitive principle, in which the immunoreaction between the anti-DNPh-KLH-400 antibody and 2,4-DNT on the sensor surface was inhibited in the presence of free 2,4-DNT in solution. The limit of detection for the immunosensor, calculated as three times the standard deviation of a blank value, was 20 pg mL−1, and the linear dynamic range was found to be between 1 and 100 ng mL−1. Additionally, the fabricated OEG-based surface effectively prevented non-specific adsorption of proteins, and the specific response to anti-DNPh-KLH-400 antibody was maintained for more than 30 measurement cycles. 相似文献
Ligand design by‐pam : A ruthenium‐catalyzed asymmetric arylation of aldehydes with arylboronic acids has been developed, giving chiral diarylmethanols in good yields. The use of a chiral bidentate phosphoramidite ligand ((R,R)‐Me‐bipam) led to excellent enantioselectivities.