Quantum Chemical Studies of Structural Parameters and Molecular Properties of Pigment 2-[(2-methoxy-4-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-butanamide

Pigments play an important role in the paint industry. The structural parameters and molecular properties of 2-[(2-methoxy-4-nitrophenyl)azo]-N-(2-methoxyphenyl)-3-oxo-Butanamide (pigment P.Y.74) has been determined by quantum calculation at the B3LYP/6-31+G(d) level of theory. Our results show that the trans – trans structure of pigment P.Y.74 is the most stable. The 46th orbital is the HOMO orbital when the 47th orbital is the LUMO orbital and the HOMO-LUMO energy gap of the title molecule is found to be 0.067815 a.u. Besides, the potential energy surface for its decomposition has been investigated at the same level of theory. The results may be helpful for experimental studies in the future.

Synthesis and Characterization of 4,4′-Dibromoazobenzene

Azobenzene molecules show excellent application potential in many fields due to their photoisomerization properties. Azobenzene molecules will gradually change from trans-structure to cis-structure under the irradiation of UV. In this paper, we have synthesized 4,4'-dibromoazobenzene molecules and characterized their photoisomerization properties. We found that with the extension of UV time, the trans absorption peak at 343 nm decreased significantly, while the cis absorption peak at 435 nm showed an upward trend. Furthermore, photoisomerization of azobenzene is not a first-order reaction.

First-Principles Study of the Reaction between Fluorinated Graphene and Ethylenediamine

The reaction process between gauche- and trans-structure ethylenediamine (EDA) and fluorinated graphene (CF) was studied based on density functional theory (DFT). Firstly, the reaction between the most stable gauche-structure EDA and CF was discussed. Some of the reaction results were verified in experiment, but the overall reaction energy barrier was higher. Then, the reaction between the trans-structured EDA and CF was simulated, which concluded that CF is reduced in the main reaction channel and HF is generated at the same time. In this reaction process, the reaction energy barrier is as low as 0.81 eV, which indicates that the reaction may occur spontaneously under natural conditions The Mulliken charge population analysis and the calculation of bond energy prove that the NH bond is more stable than CH and that the H atoms in the CH2 of trans-structure EDA more easily react with CF.

Conserved residues that modulate protein trans-splicing of Npu DnaE split intein

The first crystal trans-structure of Npu DnaE intein identified the role of two conserved residues NArg50 and CSer35 in asparagine cyclization. In vitro splicing assays prove that these two residues synergistically enhance the protein trans-splicing efficiency.

Synthesis in water-free DMF, characterization, electrical, and gas sensing properties of bis[2-(2-aminoethylamino)ethanol]copper(II) dibromide

Abstract2-(2-Aminoethylamino)ethanol (L) reacts with cupric bromide in dimethylformamide to give a mononuclear complex of Cu(II) [L2Cu]Br2, with six-coordinate distorted octahedral geometry, in which two molecules of tridentate (N,N,O) ligand are involved. The structure was confirmed by spectroscopic methods, elemental and thermogravimetric analyses, and magnetic measurements. Optimization of possible configurations indicated the formation of the trans structure of the complex. Experimental results indicate that the investigated complex, bis[2-(2-aminoethylamino)ethanol] copper(II) bromide, behaves as a semiconductor in the studied temperature range of 298–388 K. Gas sensing properties of the film for the volatile organic compounds (VOCs): acetone, tetra-chloromethane, chloroform, ethanol, and methanol, were also investigated as a function of vapor concentration and temperature in dark. The film showed maximum sensitivity to tetrachloromethane and ethanol vapors at room temperature. Responses of the film to the tested gases are reversible.