Ag SO Research Articles

Luminescent 2D macrocyclic networks based on starburst molecules: [[Ag(CF(3)SO(3)](1.5)(tdapb)] and [[Ag(NO(3)](3)(tdapb)

Luminescent 2D macrocyclic networks based on starburst molecules: [[Ag(CF(3)SO(3)](1.5)(tdapb)] and [[Ag(NO(3)](3)(tdapb)

A modular, self-assembled, separated ion pair binding system.

Assembly of a silver(I) complex of a simple pyridyl ligand containing a urea derivative is templated by nitrate; analogous complexes of Ag(2)SO(4) and AgCF(3)SO(3) exhibit radically different geometries.

Levan fructotransferase from Arthrobacter oxydans J17-21 catalyzes the formation of the di-D-fructose dianhydride IV from levan.

A new levan fructotransferase (LFTase) isolated from Arthrobacter oxydans J17-21 was characterized for the production of difructose dianhydride IV (DFA IV). LFTase was purified to apparent homogeneity by Q-Sepharose ion exchange chromatography, Mono-Q HR 5/5 column chromatography, and gel permeation chromatography. The enzyme had an apparent molecular mass of 54000 Da. The optimum pH for the enzyme-catalyzed reaction was pH 6.5, and the optimum temperature was observed at 45 degrees C. The LFTase was activated by the presence of CaCl(2) and EDTA-2Na but inhibited strongly by MnCl(2) and CuSO(4) at 1 mM and completely by FeSO(4) and Ag(2)SO(4) at 1 mM. A bacterial levan from Zymomonas mobilis was incubated with an LFTase; final conversion yield from the levan to DFA IV was 35%. Neither inulin, levanbiose, sucrose, dextran, nor starch was hydrolyzed by LFTase. DFA IV was very stable at acidic pH and high temperature, thus indicating that DFA IV may be suitable for the food industry and related areas.

Surface enhanced Raman scattering and second-harmonic generation from CN - complexes and SO 2-4 on Ag electrodes during oxidation-reduction cycles

Abstract The temporal evolution of the surface enhanced Raman scattering (SERS) from SO 2− 4 and CN − complexes adsorbed on a Ag electrode immersed in 0.1M K 2 SO 4 +0.01M KCN electrolytes during an electrochemical oxidation-reduction cycle (ORC) has been investigated. The appearance and the disappearance of the high frequency stretching modes of SO 2− 4 and CN − complexes, as well as the low frequency stretching and bending modes of AgSO 4 and AgCN are correlated with cyclic voltammograms recorded during an ORC. Similar correlations were made between the cyclic voltammogram and the increase and decrease of the surface enhanced diffused second-harmonic generation (SHG) from the electrochemically roughened Ag surface itself, from the adherent layer of Ag 2 SO 4 and AgCN, and from the CN − complexes adsorbed on the Ag electrode surface. Diffused SHG from Ag electrodes was investigated in the following electrolytes: (1) 0.1M K 2 SO 4 , (2) 0.1M K 2 SO 4 + 0.01M KCN, (3) 0.1M K 2 SO 4 + 0.01M NaOH and (4) 0.1M K 2 SO 4 + 0.01 M NaOH + 0.01 M KCN. The latter two electrolytes were selected to illustrate the importance of Ag 2 O in decreasing the diffused SHG signal when the Ag electrode, immersed in an electrolyte of pH > 7, is cycled through a specific potential region that involves the formation of Ag 2 O. Differences between the potential dependent evolution of the SERS and SHG signals are postulated.

Surface enhanced raman scattering and second-harmonic generation from CN − complexes and SO 2−4 on Ag electrodes during oxidation-reduction cycles

The temporal evolution of the surface enhanced Raman scattering (SERS) from SO 2− 4 and CN − complexes adsorbed on a Ag electrode immersed in 0.1M K 2SO 4 +0.01M KCN electrolytes during an electrochemical oxidation-reduction cycle (ORC) has been investigated. The appearance and the disappearance of the high frequency stretching modes of SO 2− 4 and CN − complexes, as well as the low frequency stretching and bending modes of AgSO 4 and AgCN are correlated with cyclic voltammograms recorded during an ORC. Similar correlations were made between the cyclic voltammogram and the increase and decrease of the surface enhanced diffused second-harmonic generation (SHG) from the electrochemically roughened Ag surface itself, from the adherent layer of Ag 2SO 4 and AgCN, and from the CN − complexes adsorbed on the Ag electrode surface. Diffused SHG from Ag electrodes was investigated in the following electrolytes: (1) 0.1M K 2SO 4, (2) 0.1M K 2SO 4 + 0.01M KCN, (3) 0.1M K 2SO 4 + 0.01M NaOH and (4) 0.1M K 2SO 4 + 0.01 M NaOH + 0.01 M KCN. The latter two electrolytes were selected to illustrate the importance of Ag 2O in decreasing the diffused SHG signal when the Ag electrode, immersed in an electrolyte of pH > 7, is cycled through a specific potential region that involves the formation of Ag 2O. Differences between the potential dependent evolution of the SERS and SHG signals are postulated.