Semiempirical investigation of stilbene-linked diradicals and magnetic study of their bis(N-tert-butylnitroxide) variants

Semiempirical MO-CI methods enable qualitative determination of ground state spin multiplicities of various stilbenoid diradicals. Substitution of methylene radical sites with heteroatom spin-bearing sites has no influence on ground state multiplicities while nitroxide substitution reduces magnetic interactions. Analysis of the magnetic properties of stilbenebis(N-tert-butyl nitroxide) reveals the higher stabilities of the m,m'- and m,p'-isomers compares to that of the o,m'-isomer.