Preferred molecular conformations of the hindered α-diazo ketones CH2ClCOCHN2 and CH3COCCH3N2 by semiempirical molecular orbital calculations

Abstract

Semiempirical CNDO/2 calculations have been applied to the rotational isomerism of the hindered α-diazo ketones CH₂ClCOCHN₂ and CH₃COCCH₃N₂. It is concluded that the cis form is the more energetically stable for the chloroderivative, whilst both cis and trans forms are present in the other compound. These results are in agreement with spectroscopic measurements and experimental electric dipole moments.