Heteroatom-incorporated Trimethylenemethane: Synthesis and Properties of Triphenylphenylnitroxide-(Nitronyl Nitroxide) Dyad

We designed and synthesized a triphenylphenylnitroxide-(nitronyl nitroxide) dyad with a structure isoelectronic with trimethylenemethane. Crystal structure analysis demonstrated that the dihedral angle between the nitroxide and nitronyl nitroxide moieties was excessively small due to the steric effects of the triphenylphenyl moiety. The coplanarity of the two radical systems induced an excessively strong ferromagnetic intramolecular interaction (2J/k(B) >= +2000K; H = -2JS(1/2)center dot S-1/2).

Automated summary

We have designed and synthesized a new compound with a similar electronic structure to trimethylenemethane. Crystal structure analysis reveals that the dihedral angle between the two radical moieties is very small due to steric effects. The coplanarity of the radicals leads to a strong ferromagnetic interaction.