Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (09): 844-850.doi: 10.3866/PKU.WHXB19950917

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Study on the Mechanism of the Solvent Effect of Infrared Spectra(IV)

Li Run-Qing, Zhang Jie, Chen Hui-Ming, Li Yu-He, Xu Xiao-Hua, Xie Qing-Lan   

  1. The Analytical Center of Tianjin University,Tianjin 300072|National Key Laboratory of Elements-Organic Chemistry,Nankai University,Tianjin 300071
  • Received:1994-09-23 Revised:1995-01-04 Published:1995-09-15
  • Contact: Li Run-Qing


In the previous paper(Ⅲ), the following equation of solvent effect in organic chemistry was suggested:
Where Ei is a physical or chemical property of the substrate in the solvent i and E0 is that in n-hexane. Ai and Di are constants of electron acception and donation effect of the solvent i respectively. VAi and VDi are constants of electron acception and donation space effect of the solvent i respectively, a and d are the sensitivities of E of the substrate vs the change of Ai and Di. Va and Vd are the constants of electron acception and donation space effect of the substrate respectively. In IR spectra E could be substituted by the wavenumber(ν). Ai and VAi have been established for 18 organic solvents (n-C6H14, n-C7H16, cyclohexane, CCl4, Ph-Me, ClCH:CCl2, Et2O, CHCl3, C6H6, CH2Cl2, ClCH2CH2Cl, Ph-NO2, THF, 1,4-dioxane, Et-NO2. MeCO2Et, Me-NO2, Me-CN).
In this paper Di and VDi have been established for these solvents. The equation also has been tested by the νC-X(X=Cl, Br) of five alkylhalides (t-BuCl, n-C5H11Cl, t-BuBr, Et-Br, EtC(H)BrMe) and νC=O of three carboxyl compounds (t-BuCOMe, Me2CO, MHB) and seven organotin compounds [(Ph2MeSiCH2)3SnO2C-C6H4-X-p(X=H-, CH3-, CH3O-, NO2-, F-. Cl-, I-)].
The relationship (ν=ρ﹒σ+ν0) between νC=O of organotin compounds and Hammett constants(σ) of the substituted groups in different solvents was studied and a relationship betweenρ and Ai, VAi, Di, VDi of the solvents was found.

Key words: Solvent effect, Ralationship analysis, Infrared spectra, Hammett equation