STRUCTURES, BONDING, AND ENERGETICS OF N2O2 ISOMERS

The structures and energetics of the N2O2 isomers are predicted at sev eral levels of theory. Both single reference and multireference based correlated methods were used to determine the structures and relative energies. Five high-energy minima were located above 2NO with QCISD(T) /6-311+G(2df)//MP2/6-311 +G(d) (PT2F/6-311+G(2df)//MCSCF/6-31G(d)) rel ative energies of ca. 38 (51), 46 (51), 61 (74), 69 (74), and 68 (80) kcaymol for 1,2-diaza-3,4-dioxacyclobutene (1), bond stretch 1,3-diaza -2,4-dioxa[1.1.0]bicyclobutane (2), a-N2O2 (3), 4, and 1,3-diaza-2,4-d ioxa[1.1.0]bicyclobutane (5), respectively. The effect of basis sets o n structures is small within a given level of theory. The MCSCF struct ures agree reasonably with those of MP2.