EFFECT OF AN ADDING RADICALS ELECTRONEGATIVITY ON THE GEOMETRIES AND FORMATION ENERGIES OF NITROSO SPIN ADDUCTS

Ab initio calculations on the nonplanarity of adducts with spin traps H-N=0, CH3-N=0, and CH3-CH2-N=0 indicate that the degree of nonplanari ty at the N correlates weakly with the electronegativity of the adding radical. The degree of nonplanarity depends on the level of theory us ed: extending the basis set beyond the 6-31G(d) level within the Hartr ee-Fock framework reduces the nonplanarity slightly, and including the effects of electron correlation at the MP2/6-31G(d,p) level reduces i t considerably more. However, the trends within a given theory level a nd basis set are essentially the same. Formation energies indicate tha t in general the adducts are strongly favored over the free radical an d the spin trap.