Photoisomerization of azobenzene derivatives is a versatile tool for devising light-responsive materials for a broad range of applications in photonics, robotics, microfabrication, and biomaterials science. Some applications rely on fast isomerization kinetics, while for others, bistable azobenzenes are preferred. However, solid-state materials where the isomerization kinetics depends on the en...

Of the sugars recovered from lignocellulose, D-glucose can be readily converted into ethanol by baker's or brewer's yeast (Saccharomyces cerevisiae). However, xylose that is obtained by the hydrolysis of the hemicellulosic portion is not fermentable by the same species of yeasts. Xylose fermentation by native yeasts can be achieved via isomerization of xylose to its ketose isomer, xylulose. Iso...

The isomerization of 1,3-dihydroxyactone and d-glucose over Sn-Beta zeolite was investigated by in situ 13 C NMR spectroscopy. The conversion rate at room temperature is higher when the zeolite is dehydrated before exposure to the aqueous sugar solution. Mass transfer limitations in the zeolite micropores were excluded by comparing Sn-Beta samples with different crystal sizes. Periodic density ...

A decalin gel consisting of a 3,3'-bis[{(octylamino)carbonyl}propoxy]azobenzene derivative with H-aggregation showed a photon-density dependent E-Z isomerization, indicating the cooperating isomerization of each module.

Light-driven unidirectional molecular rotary motors have the potential to power machines. Consequently, optimizing their speed and efficiency is an important objective. Here, we investigate factors controlling photochemical yield of prototypical motor, a sterically overcrowded alkene, through detailed investigation its excited-state dynamics. An isoviscosity analysis ultrafast fluorescence deca...

Two intramolecularly hydrogen-bonded arylhydrazone (aryl = phenyl or naphthyl) molecular switches have been synthesized, and their full and reversible switching between the E and Z configurations have been demonstrated. These chemically controlled configurational rotary switches exist primarily as the E isomer at equilibrium and can be switched to the protonated Z configuration (Z-H(+)) by the ...

The influence of water-miscible alcohols (methanol, 1-propanol, 2-propanol, and t-butyl alcohol) on the isomerization of glucose to fructose and mannose was investigated under subcritical aqueous conditions (180-200 °C). Primary and secondary alcohols promoted the conversion and isomerization of glucose to afford fructose and mannose with high and low selectivity, respectively. On the other han...

To establish an advantageous method for the production of l-amino acids, microbial isomerization of d- and dl-amino acids to l-amino acids was studied. Screening experiments on a number of microorganisms showed that cell suspensions of Pseudomonas fluorescens and P. miyamizu were capable of isomerizing d- and dl-phenylalanines to l-phenylalanine. Various conditions suitable for isomerization by...

The kinetics of the ruthenium-promoted cis,cis to trans,trans isomerization of 1,1,2,2,5,5,6,6-octamethyl-1,2,5,6-tetrasilacycloocta-3,7-diene were investigated. Incubation of a ruthenium alkylidene complex, (Cy(3)P)RuCl(2)(==CHPh)Ru(p-cymene)Cl(2), in CD(2)Cl(2) for 5 days at 40 degrees C afforded a catalytically active ruthenium species that was shown to be responsible for promoting the isome...

In the framework of quantum-chemical methods (RHF, MP2, and DFT), we study the reaction of photoinduced isomerization of biological molecules—retinal in rhodopsin (Rh) and bacteriorhodopsin (BRh)—the key intermediates in the vision process. The charge redistribution in the retinal chromophore of these biological molecules as the mechanism of the photoinduced isomerization is investigated. The r...