Molecular Design Of Environmentally Friendly BDE-138,BDE-183 And BDE-209 Derivatives(Raman Spectral Characteristics/Functional)

Polybrominated diphenyl ethers(PBDEs)are a typical type of brominated flame retardants.Because of their outstanding properties,they can endow polymer materials the characteristics of difficult combustion,easy extinguishment,and prevention of combustion spread.At the same time,the negative environmental impacts of PBDEs(toxicity,bioaccumulation,persistence,long-distance migration)and the harmful effects on human health(carcinogenicity-mutagenicity-teratogenicity,endocrine disruption effects)have became the focus of societyThe traditional detection method of PBDEs has the disadvantages such as long measurement cycle and tedious steps.Simultaneously,PBDEs have many homologues with low content in samples.Therefore,there are certain detection difficulties.In this paper,Raman spectroscopy detection method is introduced to make up for the deficiency of traditional detection methods.At the same time,few researchers have considered the functional characteristics of PBDEs in their environmental harmful behavior control research.In summary,PBDEs were selected as the research target,and PBDEs pollution control schemes have been established from the aspects of spectral enhancement and functional advantages,high efficiency and environmental protection Guidding the design of new PBDEs flame retardants with easy detection,high performance and environmentally friendly,and provide a theoretical basis for pollution control in the application of PBDEs.Based on the Raman spectral data of PBDEs and the values of their functional characteristics,the PBDEs Raman spectral pharmacophore model Hypo 1 and the PBDEs functional characteristics comprehensive activity 3D-QSAR model CoMFA were established.The results show that the pharmacophore model(Hypo 1)has the largest correlation coefficient(R2=0.88)and the lowest root mean square(RMS=0.231).Its total cost(81.488)and configuration value(12.56)both satisfy the model evaluation indicators.CoMFA’s cross-validation coefficient q2 is greater than 0.5(0.571),the non-cross-validation coefficient r2 is greater than 0.6(0.860),the optimal principal component n is 4,and the external prediction set interaction test coefficient r2pred is greater than 0.6(0.793).The above model parameters show that the Hypo 1 and CoMFA models have robustness and good predictability.Taking BDE-138,BDE-183 and BDE-209 as examples,Hypo 1 and CoMFA models were used to enhance the Raman spectral and the comprehensive activity of functional characteristics.25 PBDEs derivatives with significantly enhanced Raman spectral characteristics and functional properties were designed and screened for toxicity,bioconcentration,migration and degradability to confirm that the designed derivatives are environmentally friendly.The 2D-QSAR model and fractional factorial method were used to analyze the relevant mechanisms.It was found that the main reason for the significant enhancement of Raman spectra of PBDEs derivatives was the change in the number of the most positive Milliken charge and the lowest occupied molecular orbital energy of the molecules before and after modification of PBDEs.The reduction effect due to the enhancement of positive correlation substituents and lack of negative correlation substituents is the main factor that influence the functional characteristics comprehensive activity of PBDEs derivatives.The reason for the reinforcement simultaneously of functional characteristics comprehensive activity and insulation as well as flame retardant single activity for PBDEs derivatives is the same molecule substitution position.The positive correlation contribution rate of substituents can characterize the enhancement degree of the functional properties single activity for derivatives.