Investigate and Calculation Electron Transfer Rate Constant in the N749 Sensitized Dye Contact to ZnSe Semiconductor

The dye–semiconductor interface between N749 sensitized and zinc semiconductor (ZnSe) has been investigated and studied according to quantum transition theory with focusing on the electron transfer processes from the N749 sensitized (donor) to the ZnSe semiconductor (acceptor). The electron transfer rate constant and the orientation energy were studied and evaluated depended on the polarity of solvents according to refractive index and dielectric constant coefficient of solvents and ZnSe semiconductor. Attention focusing on the influence of orientation energies on the behavior of electron transfer rate constant. Differentdata of rate constant was discussion with orientation energy and effective driving energy for N749-ZnSe system. Furthermore, the electron transfer rate constant is increased with less orientation energy at less effective driving energy while the electron transfer rate constant increased with large orientation energy with large effective driving energy, as seen as the electron transfer rate reach to 1.3109 × 1011 with less orientation energy has 0.188708eV at effective driving energy E=0.22eV comparing the rate reach to 9.7207× 10−96 with driving energy E=1.89eV and same orientation energy. In general, the electron transfer rate constant increases with increases the coupling coefficient of system, its indicate that alignment of energy levels are very good between N749 sensitized metal and ZnSe semiconductor.

Synthesis of 3,4,5-Trisubstituted Isoxazoles in Water via a [3+2]-Cycloaddition of Nitrile Oxides and 1,3-Diketones, β-Ketoesters, or β-Ketoamides: Base-mediated and Keto-enol-controlled Mechanism

A selective [3+2]-cycloaddition reaction of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides in water without the need of a metal catalyst is described. The selectivity of the reaction can be controlled by the polarity of solvents in the presence of an appropriate base. The optimized reaction condition circumvents other reactions, such as O-imidoylation or hetero [3+2]-cycloaddition. The reaction happens fast in water to provide an environment friendly access to 3,4,5-trisubstituted isoxazoles, specifically acyl-substituted, ester-substituted, or amide-substituted isoxazoles, which are important structures found in numerous bioactive natural products and pharmaceuticals.

Synthesis of 3,4,5-Trisubstituted Isoxazoles in Water via a [3+2]-Cycloaddition of Nitrile Oxides and 1,3-Diketones, β-Ketoesters, or β-Ketoamides: Base-mediated and Keto-enol-controlled Mechanism

A selective [3+2]-cycloaddition reaction of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides in water without the need of a metal catalyst is described. The selectivity of the reaction can be controlled by the polarity of solvents in the presence of an appropriate base. The optimized reaction condition circumvents other reactions, such as O-imidoylation or hetero [3+2]-cycloaddition. The reaction happens fast in water to provide an environment friendly access to 3,4,5-trisubstituted isoxazoles, specifically acyl-substituted, ester-substituted, or amide-substituted isoxazoles, which are important structures found in numerous bioactive natural products and pharmaceuticals.

The Effects of the Solvents on the Macrocyclic Structures: From Rigid Pillararene to Flexible Crown Ether

The differences in the macrocyclic structures lead to different flexibilities, and yet the effect of solvents on the conformations is not clear so far. In this work, the conformations of four representational macrocyclic molecules (pillar[5]arene, p-tert-butyl calix[6]arene, benzylic amide macrocycle and dibenzo-18-crown-6) in three solvents with distinct polarity have been studied by all-atom molecular dynamics simulations. The structural features of the macrocycles in the solvents indicate that the conformations are related to the polarity of the solvents and the formation of hydrogen bonds. For the pillar[5]arene, the benzylic amide macrocycle and the dibenzo-18-crown-6, that cannot form intramolecular hydrogen bonds, the polarity of solvents is the major contributing factor in the conformations. The formation of intramolecular hydrogen bonds, in contrast, determinates the conformations of the calix[6]arene. Furthermore, the slight fluctuations of the structures will result in tremendous change of the intramolecular hydrogen bonds of the macrocycles and the intermolecular hydrogen bonds between the macrocycles and the solvents. The current theoretical studies that serve as a basis for the macrocyclic chemistry are valuable for the efficient structural design of the macrocyclic molecules.

Ground and Excited State Dipole Moment of 2,5-Dihydroxybenzoic Acid from Solvatochromic Shifts

In present work we explore the role of solvents on the 2, 5-dihydroxybenzoic acid by using fluorescence techniques. It was found that DHBA shows spectral behaviour depending on polarity of solvents. DHBA shows generally three components at 405-415nm, 430-450nm, and 450-470nm. The effects of zwitterion as well as the interplay ionic species are involved to explain the observed results

Ground and Excited State Dipole Moment of 2,5-Dihydroxybenzoic Acid from Solvatochromic Shifts

In present work we explore the role of solvents on the 2, 5-dihydroxybenzoic acid by using fluorescence techniques. It was found that DHBA shows spectral behaviour depending on polarity of solvents. DHBA shows generally three components at 405-415nm, 430-450nm, and 450-470nm. The effects of zwitterion as well as the interplay ionic species are involved to explain the observed results.

A monolithic anti-freezing hydro/organo Janus actuator with sensitivity to the polarity of solvents

A monolithic anti-freezing hydro/organo Janus actuator which was synthesized by a one-step interfacial copolymerization shows various deformation patterns with solvent polarity.

Irradiation Effect on Stability of Plasticized Poly(Fluorostyrene) Isomers in Solution

The UV irradiation and blending effects on stability of Poly(Fluorostyrene) isomers in solution were studied at different intervals of irradiation time in presence of air. The increase in irradiation time of these isomers caused an increase in the intensity of the absorption band and an increase in the intensity of the absorption of new broad band at longer wavelength, thus indicating a possibility of photodegradation of polymeric chains. The influence of added dioctyl phthalate and dioctyl terephthalate plasticizers on photooxidative degradation was also investigated and was found to increase the photodegradation processes in polymeric chains. On the other hand, the intensity of excimer and monomer fluorescence bands maxima was also found to decrease with increase in irradiation times. These changes may be attributed to the formation of new photoproducts resulted from the photodegradation of irradiated polymeric chains. The decrease in polarity of used solvents caused a considerable enhancement to the intensity of the polymer fluorescence band and accelerated photodegradation. A proposed mechanism is suggested to account for the effects of added plasticizers, the increase in irradiation time, and polarity of solvents on photodegradation and photooxidation processes in polymeric chains.