Solvent effect on characteristic vibration of IR spectrum of 4,4′-dibromodiphenyl ether

A novel pharmacophore model on PAEs' estrogen and thyroid hormone activities using the TOPSIS and its application in molecule modification

In the proposed model, the estrogen activity values and thyroid hormone activity values of PAEs molecules were normalized using the TOPSIS method by eliminating the dimension coefficients, and the comprehensive activity values of estrogen and thyroid hormone were obtained by analyzing the activity of each hormone and assigning the corresponding weight. The five pharmacophore models of hormone combined activity were constructed using the comprehensive activity values. Hypol 1 was the optimal pharmacophore model, showing good predictive power and significance. Then, the DBP, DNOP, and DMP molecules in environmental priority control pollutants were selected as the target molecules to perform common substitution reactions of hydrogen bond donor. Eleven PAEs derivative molecules with significantly reduced combined activity and single activity were screened. In analysis of the differences before and after modification of the docking parameters and amino acid residues before and after modification of PAEs and their derivatives, the reduced closeness between ligand and receptor leads to the decrease of thyroid hormones and estrogen activities. Moreover, the establishment of the models, not only shows that the PAEs hormone activity has certain linear relationships with the physical parameters of molecules but also shows that thyroid hormone activity and estrogen activity of PAEs is consistent with the hormone combined activity. The results confirmed the feasibility of the modified PAEs modification scheme with reduced combined activities of hormones, providing an important theoretical method for the construction of the pharmacophore model of combined activities of hormones and the study of PAEs derivative molecules.

Molecular structure and vibrational spectra of 2,2',4,4',6-pentabromodiphenyl ether (BDE 100)

In this work, FT-IR ATR and Raman (laser line 532nm) spectra of 2,2',4,4',6-pentabromodiphenyl ether (BDE 100) have been recorded in the range of 4000-650 and 4000-100cm^-1, respectively. A combined experimental and theoretical approach (DFT/B3LYP/6-311++g** and aug-cc-pVDZ) was used to study molecular structure of BDE 100. Optimization of geometry in the gas phase at these levels of theory indicated that the BDE 100 has skew conformation. The detailed assignment of IR and Raman bands of BDE 100 was done on the basis of calculated results for the most stable conformer. The scaled theoretical frequencies are in good agreement with the experimental ones. Both experimental and theoretical IR and Raman spectra of BDE 100, one of the members of the family of flame retardants, are presented here for the first time.