Spin distributions, ring conformations, and spiroconjugation in "phosphaverdazyl" radicals
Artikel i vetenskaplig tidskrift, 2001

Reaction of P-dimethylaminophosphonic acid bis(1-methylhydrazide) (6) with trimethyl orthobenzoate gave 1,2,5,6-tetrahydro- 1,5-dimethyl-6-(N,N-dimethylamino)-6-phenyl 1,2,4,5,6-tetrazaphosphorine-6-oxide (7), which was subsequently oxidized to the corresponding P-diemthylamino-6-phosphaverdazyl (5) as a persistent radical. Analysis of the electron paramagnetic resonance spectrum of 5 revealed significant spin density on the exocyclic nitrogen but very little spin density on the phosphorus, in contrast to the previously reported P-phenyl-6-phosphaverdazyl (4). Density functional theory calculations on simplified models of 4, 5, and related radicals were performed and revealed that spin polarization effects and the nature of the substituents on phosphorus have significant effects on the structures and spin distributions of these radicals. The spin transfer to the dimethylamino group in 5 was revealed to arise from spiroconjugation-type overlap between the nitrogen 2p orbital with the verdazyl radical singly occupied molecular orbital.

ferromagnetic exchange

1

charge-transfer complexes

polymerization

3

hydrogen-bonds

nitronyl-nitroxide

molecular

density distribution

magnetic-properties

nitroxide radicals

5-triphenyl-6-oxoverdazyl

magnets

Författare

R. G. Hicks

Lars Öhrström

Institutionen för oorganisk kemi

G. W. Patenaude

Inorganic Chemistry

Vol. 40 1865-1870

Ämneskategorier

Kemi