Raman Spectroscopic Study On Halogen Anions And Hydrogen Bonded Organic Solvents

Weak intermolecular interactions are widespread in supramolecular chemical and biological processes.Hydrogen and halogen bonds are two important molecular interactions.Hydrogen bonds（HB）exist in water and biomolecules,and hydrogen bonds play an important role in various life processes.Hydrogen bonding（HB）plays an important role in various life processes.The study of intermolecular hydrogen bonding in materials science and life science has attracted much attention.Halogen bonds（XB）are ubiquitous in biological systems,and halogen bonds have great potential in the development of new pharmaceutical compounds and materials.As most of the life processes of biomolecules occur in a solution environment,it is also important to understand the effects of solvents on interactions.Therefore,studying the intermolecular interaction of halogen-containing and hydrogen-bonding solutions is one of the current hotspots.This thesis mainly uses a variety of steady-state spectroscopic methods to perform spectral measurements on binary systems of halogenated hydrocarbons（dichloromethane CH₂Cl₂,dibromomethane CH₂Br₂,iodomethane CH₃I） with ethanol,and ternary systems of aqueous brine solutions（potassium chloride KCl,potassium bromide KBr,potassium iodide KI）with ethanol.Combined with high-level non-harmonic correction of quantum chemical calculations,we found evidence of different intermolecular interactions in halogenated hydrocarbons and halogen anion solutions,and explained the rules of intermolecular interactions in solutions.Specifically divided into the following three parts:1、The binary solutions of dichloromethane,dibromomethane,and iodomethane mixed with ethanol were measured by Raman spectroscopy,and the results of spectral tests were discussed in combination with molecular calculations.The intermolecular interactions exhibited by the three systems show a law of iodine（I）> bromine（Br）> chlorine（Cl）.2、Due to the anisotropy of the electron density around the halogen,σ-holes are formed,and the strength of the interaction is related to the magnitude of the σ-hole electrostatic potential.However,the largest σ-hole exists in methyl iodide.The binary system of iodomethane and ethanol has been studied in-depth,and it is found that the accumulation of dimerization is the main intermolecular interaction at low ethanol concentration.When the concentration of iodomethane is low,the molecules of iodomethane are affected by the synergy of hydrogen bonds,halogen bonds and solvents.3 、 By measuring Raman spectra of potassium chloride,potassium bromide,and potassium iodide solutions at different concentrations,combined with theoretical calculations and simulations,it was found that as the sequence of Cl^-<Br^-<I^- changes,the intermolecular interactions increase.This thesis not only studies the spectral results of halogenated hydrocarbons and halogen ion solutions,but also uses the combination of theory and experiment to obtain evidence of molecular interactions in mixed solutions.Provide spectral evidence and theoretical calculation methods to supplement scientific data for establishing a more perfect law of molecular interactions.For practical applications,such as molecular recognition,drug interaction and other directions,it provides a means of spectroscopic characterization,which is more convenient for obtaining information on the interaction between molecules.On this basis,it is possible to achieve more fine-grained regulation of the structure of water,DNA and proteins in the future,which will have a positive impact on drug production and treatment of human diseases.