Doi: 10.1016/j.theochem.2007.08.026

Computational studies of the structure of aldazines and ketazines: Part 2. Halogen and alpha,beta-unsaturated derivatives

Nine azines bearing F, Cl, Br, CF₃, CF₂CF₃, CH(CF₃)₂, CH─CH═CH₂, CH─CH═CH(CH₃) and CH─CH═CH(C₆H₅) substituents have been theoretically studied at the B3LYP/6-311++G(d,p) level. Concerning the E/Z isomerism, in all cases, the large groups prefer to be “outside” (in general, E), i.e. for conjugated azines the extended conformation (EEEE) is always preferred. In the case of the CH(CF₃)₂ substituent, the imine–enamine tautomerism has been studied, the imine one being clearly more stable. The differences in energy between the different isomers and conformers have been statistically analyzed.