Theoretical Studies on Structures, Properties and Dominant Debromination Pathways for Selected Polybrominated Diphenyl Ethers

Abstract

The B3LYP/6-311+G(d)-SDD method, which considers the relativistic effect of bromine, was adopted for the calculations of the selected polybrominated diphenyl ethers (PBDEs) in the present study, in which the B3LYP/6-311+G(d) method was also applied. The calculated values and experimental data for structural parameters of the selected PBDEs were compared to find the suitable theoretical methods for their structural optimization. The results show that the B3LYP/6-311+G(d) method can give the better results (with the root mean square errors (RMSEs) of 0.0268 for the C–Br bond and 0.0161 for the C–O bond) than the B3LYP/6-311+G(d)-SDD method. Then, the B3LYP/6-311+G(d) method was applied to predict the structures for the other selected PBDEs (both neutral and anionic species). The lowest unoccupied molecular orbital (LUMO) and the electron affinity are of a close relationship. The electron affinities (vertical electron affinity and adiabatic electron affinity) were discussed to study their electron capture abilities. To better estimate the conversion of configuration for PBDEs, the configuration transition states for BDE-5, BDE-22 and BDE-47 were calculated at the B3LYP/ 6-311+G(d) level in both gas phase and solution. The possible debromination pathway for BDE-22 were also studied, which have bromine substituents on two phenyl rings and the bromine on meta-position prefers to depart from the phenyl ring. The reaction profile of the electron-induced reductive debromination for BDE-22 were also shown in order to study its degradation mechanism.

Tetracycline Encapsulated in Au Nanoparticle-Decorated ZnO Nanohybrids for Enhanced Antibacterial Activity

“…The geometries of Zn 12 O 12 were optimized at the level of DFT using the B3LYP , exchange–correlation functional and 6-311++G­(d,p) basis set . To prepare Au nanoparticle-decorated ZnO nanoparticles, different doping configurations were prepared and optimized with the B3LYP/6-311++G­(d,p)-SDD basis sets . Further calculations were performed with the most favorable structure of Au-doped ZnO nanoparticles.…”

Dual Sensitization via Electron and Energy Harvesting in a Nanohybrid for Improvement of Therapeutic Efficacy

“…Geometric optimization of the pristine Zn 12 O 12 nanocage was performed at the level of DFT using the B3LYP − exchange correlation functional and the 6-311++g­(d,p) basis set. It is composed of eight (ZnO) 3 and six (ZnO) 2 rings forming a cluster. , To prepare the Au-doped Zn 12 O 12 structure of NPs, several doping configurations were optimized with the B3LYP/6-311++G­(d,p)-SDD-based method, and further calculations were carried out with the most favorable structure. The band-gap energies ( E g ) were calculated from the energy of the lowest unoccupied molecular orbital ( E LUMO ) and the energy of the highest occupied molecular orbital ( E HOMO ) in the following form …”

Solvatochromism and Theoretical Studies of Dicyanobis(phenylpyridine)iridium(III) Complex Using Density Functional Theory

“…More precisely, Becke's three-parameter functional and the Lee-Yang-Parr functional (B3LYP) have been used throughout. In all calculations, an extensive basis set was used, consisting of 6-311G** [11][12][13][14] on all atoms (C, H, N, O) apart from iridium, which was described using a Stuttgart-Dresden pseudo-potential [15][16][17][18]. Besides, bulk solvent effects were treated via the polarizable continuum model (PCM) [19][20][21][22].…”