Combined QSAR/QSPR,Molecular Docking,and Molecular Dynamics Study Of Environmentally Friendly PBDEs With Improved Insulating Properties

Polybrominated diphenyl ethers(PBDEs)is a class of brominated flame retardants with 209 homologues and has been widely used in electronic building materials and textiles since the 1970 s.With the continuous detection of PBDEs in the environment,a series of environmental problems caused by this have been widely concerned.As a global organic pollutant,PBDEs have become the main research focus in environmental sustainability,longdistance transport,bioaccumulation and toxicity.At present,the research on the functionality of PBDEs is mainly focused on the flame retardancy,but there is still a certain gap in the research on its insulation.Therefore,in order to improve the insulation of PBDEs,this paper uses three-dimensional quantitative structure-activity relationship model(3D-QSAR)and other methods to carry out theoretical research on its insulation.To improve the insulating properties of polybrominated diphenyl ethers(PBDEs),we studied the molecular structures and energy gap(E.G.)values of 209 PBDEs using a threedimensional quantitative structure-activity relationship(3D-QSAR)model,molecular docking,and molecular dynamics.We also analyzed the interaction mechanisms of PBDEs using a 2DQSAR model,molecular substitution characteristics,and molecular docking.The 3D-QSAR model showed that the 2-,4-,5-,and 6-positions significantly influenced the PBDE insulating properties.Using BDE-34 as a template molecule,36 kinds of PBDE derivatives with improved insulation were designed by introducing large volume or positive electric groups.After screening their POPs and functional characteristics,6 derivatives were retained(with insulation enhancement up to 28.44%).Compared with BDE-34,the stability and flame retardancy of the above six derivatives were not adversely affected.These derivatives,except for 2,6-cyanomethyl-BDE,2-cyanomethyl-BDE,and 2-aminomethyl-BDE,were more toxic and biodegradable than BDE-34,but showed weaker bioaccumulation and migration abilities than BDE-34.Mechanism analysis showed that the highest occupied orbital energy,the most negative charge,and the dipole moment were the main quantitative parameters that affected the PBDE insulating properties.PBDE insulation gradually decreased as the number of Br atoms increased.The level of similarity between the substitution patterns on the two benzene rings was significantly correlated with PBDE insulation,with hydrophobic groups having a more significant effect on PBDE insulation.In the paper,a 3D-QSAR model was established to design PBDEs derivatives with high biodegradability,low toxicity bioenrichment and mobility with improved insulation and basically unchanged flame retardancy,providing a theoretical basis for the insulation research of PBDEs.