ABSTRACT
The additivity of conformational energies for chloro-substituted saturated hydrocarbons has been studied using various quantum mechanical methods. The starting point of investigation was the analytically predicted [1] additivity rule stating that the conformational energy of any saturated compound can be represented as a sum of transferable increments corresponding to the energies of separate conformational segments and their sequences. The quantum mechanical methods (HF anf MP2) with various bases sets available have been used for evaluation of additivity increments of conformational energy E G X Y https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429081385/85584ebd-a763-4dac-970a-7c0fd00ce0b6/content/eq1406.tif"/> , E G T X Y https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429081385/85584ebd-a763-4dac-970a-7c0fd00ce0b6/content/eq1407.tif"/> , E G G X Y https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429081385/85584ebd-a763-4dac-970a-7c0fd00ce0b6/content/eq1408.tif"/> , E G G ′ X Y https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429081385/85584ebd-a763-4dac-970a-7c0fd00ce0b6/content/eq1409.tif"/> , (X=Y= CH 3 ; X= CH 3 , Y =Cl and X=Y=Cl). It was shown that the evaluated magnitudes of additive increments do not depend on the size of the molecule, the location of the conformational segment in the molecule and the number of substitutes involved. However they are sensitive to the method and the basis set used. The arrangement of relative conformational energies for various conformers in series of polysubstituted chloroalkanes obtained using the additivity rule coincides both with experimental findings and quantum mechanical calculations.
