Comparison of the J values and NO–NO distances (RNO–NO) of several bis-nitroxides.
| Compound | J/mT (MHz) | R NO–NO a/nm |
|---|---|---|
| 2 | 0–0.04 (0–1)b | 2.04b |
| 3 | 0.77 (21.7)b and ref. 41, 0.43 (12)3 | 2.11b,e, 2.08 (trans), 2.07 (cis)41, c 2.13,c |
| 20 | 40 (≥1121)b | 1.22b,e |
| 21 | 0.7 (19.6)43 | 1.1043,d,f |
| 22 | 0.44 (12.5)41,44 | 2.2341,44,d, 2.3341,44,d |
| 23 | 30 (>850)45 | 0.8845,f |
| 24 | 21 (>600)45 | 0.9245,f |
| 25 | 128 (≥3600)46 | 0.8246,f 0.8546,d |
| 26 | 54 (≥1500)46 | 1.1046,e,f |
a
Refers to the middle of each N–O bond.
b
Presented here.
c
Based on geometrical model.
d
Based on DFT calculation.
e
Based on X-ray structure.
f
Based on simulations of rigid limit CW-EPR spectrum.