SPILL DENSITY IN THE FREE-RADICAL NITPY(C-C-H)

The nitronyl nitroxide compound NitPy(C = C-H) (space group P2(1)/n) c rystallizes in chains with molecules connected via an hydrogen bond. E ach molecule carries a delocalized S = 1/2, unpaired electron. The int rachain magnetic interactions are positive. We have investigated the s pin density distribution of this radical by polarized neutron diffract ion. Both the spin density population on the hydrogen, and the depleti on of spin density on the related oxygen, give evidence that the hydro gen bond is involved in the path of the ferromagnetic interactions.