A theoretical study of substituted dioxiranes: Difluorodioxirane, fluorofluoroxydioxirane, (fluoroimino)dioxirane, and hydrazodioxirane

Equilibrium geometries and harmonic vibrational frequencies of three substi tuted dioxiranes, CO2FOF, CO2NF, End CO2(NH)(2), which have not been previo usly investigated, are reported. Results are based on second-order Moller-P lesset (MP2) and quadratic configuration interaction through single and dou ble excitation (QCISD) calculations using 6-31G(d) and 6-311G(d,p) basis se ts. Molecular geometric characteristics, vibrational frequencies, dipole mo ments, as well as local atomic charges, are compared with those of known di oxiranes (CO2H2, CO2F2, CO2N2, CO4). It is found that bond lengths and angl es of the dioxirane ring are sensitive to the electropositivity of the cent ral carbon. Hydrazodioxirane, CO2(NH)(2), is found to be a high-energy dens ity molecule; whereas fluorofluoroxydioxirane (CO2FOF) may be of further in terest as a powerful oxidizer. Equilibrium geometries and vibrational frequ encies of the previously uncharacterized energetically low-lying 1(3)B(1) a nd 1(3)B(2) triplet states of CO2F2 and the ground state of its cation, CO2 F2+(1(2)A(2)), are predicted and analyzed.