Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The semiempirical quantum chemical method CNDO/2 was used in the calculation of the electronic structure of TT and GG conformers of d,1-2,4-dichloropentane and TG' conformer of meso-2,4-dichloropentane. Relative stability of their model conformations was determined and compared with data of ¹H-NMR spectroscopy. The TT conformer of d,l-2,4-dichloropentane was found to possess the highest stability. The chlorination mechanism of 2,4-dichloropentane was discussed using the knowledge of the total electron densities on atoms, frontier orbital electron densities and interatomic bond indices. The INDO method was employed to calculate the spin densities of stereoisomers of 2,4-dichloropentane. Results thus obtained led to a conclusion that the reactivity of monocarbon groups in the chlorination of 2,4-dichloropentane decreased in the order CH₃-> -CH₂-> -CHCl-.