Rotational isomerism and barriers to internal rotation in 3-halopropenes byscf-mo methods

Abstract

Electronic structures of 3 halopropenes have been investigated through semiempirical SCF-MO calculations using valence basis sets of atomic orbitals (AO) constructed from Slater type orbitals (sro). The electronic structures of stable conformers have been predicted and the corresponding calculated dipole moments show good agreement with experimental data. The considerable differences between the dipole moments of various conformers confirm the hindrance to internal rotation about the CC bond, i.e. the existence of a definite potential barrier to rotation. The barrier heights hindering the internal rotation in each system are also estimated. Keywords, cnoo/2 and INDO methods; 3-halopropenes; barrier heights; internal rotation; dipole moment.