Effects of Trifluoromethyl and Alkoxycarbonyl Groups on the Structure and Reactivity of Acrylates

Ab initio calculations with full geometry optimization have been performed for -CF₃-substituted cis- and trans-methyl crotonates, methyl-,-bis(trifluoromethyl) acrylate, and dimethylhexafluoroisopropylidene malonate using the restricted Hartree-Fock (RHF) method (6-31G* basis set). The effects of substituents at the multiple bond on the geometrical and electronic structure, dipole moments, polarizability and first molecular hyperpolarizability tensors, normal vibration frequencies, one-electron levels, electrostatic potentials, and local electron density at the C=C bond have been studied. Two substituents in the acrylic system prevent the conjugation of C=C and C=O bonds. The major effect on the structure and properties of the title compounds is produced by - interactions of the CF₃ group with the multiple bond and by incoherent exchange interactions of substituents at the C=C bond.