12 Inter-spin Interactions of Organic Radical Chains in Organic 1D. . .
451
τ R of 0.17 and 0.036 mT and 1.3 × 10 −8 s, respectively. These results show that
the rotational axis is also approximately parallel to the molecular long axis of the
PhIN molecules (i.e., the molecular long axis is parallel to the channel axis of the
TPP nanochannels, if it is assumed that the rotational axis is parallel to the channel
axis). Every ESR spectrum collected over the range from 165 to 239 K was also
reproduced using this same approach. Based on the spectral reproduction process,
it is evident that at least some PhIN radicals are included in the TPP nanochannels,
although other PhIN radicals in 1a/2h/3e may be adsorbed on the surfaces of the
TPP crystals.
PhNN radicals can also be included in TPP nanochannels [44]. However,
as some PhNN is reduced to PhIN during the synthetic process, [(TPP) 2 -
(PhNN) x /(PhIN) y /(N-PhMI) 1.0 ] (x ≈ 5 × 10 −4 and y ≈ 2 × 10 −4 , 1a/2f/2h/3e)
is produced. According to the ESR results, PhNN radicals included in the TPP
nanochannels undergo anisotropic rotational diffusion around a rotational axis tilted
by (θ , φ) = (90 ◦ , 89 ◦ ) relative to the principal axis system of the g tensor above
253 K.
Figure 12.11 summarizes the effect of temperature on τ R for isolated organic radicals in TPP nanochannels, including PhNN (1a/2f/3e), PhIN (1a/2h/3e), TEMPOL
(1a/2c/3a), TEMPONE (1a/2b/3a), TEMPO (1a/2a/3a), and DTBN (1a/2e/3d) [40,
41, 43, 44] The τ R of each radical can be approximately determined from the
rotational Stokes-Einstein relationship, assuming that the material behaves as an
anisotropic liquid (see Sect. 12.2.3.4) [45]. The E a values of several nitroxide
radicals (such as DTBN, TEMPO, and TEMPONE) increase as the substituent
groups become larger (with values 3, 5, and 10 kJ mol −1 ) [40, 41]. In addition,
Fig. 12.11 Temperature
dependence of the rotational
diffusion correlation time τ R ,
for the isolated organic
radicals in the TPP
nanochannels such as DTBN
(1a/2e/3a), TEMPO
(1a/2a/3a), TEMPONE
(1a/2b/3a), TEMPOL
(1a/2c/3a), PhIN (1a/2h/3e),
and PhNN (1a/2f/3e) [40, 41,
43, 44]
451
τ R of 0.17 and 0.036 mT and 1.3 × 10 −8 s, respectively. These results show that
the rotational axis is also approximately parallel to the molecular long axis of the
PhIN molecules (i.e., the molecular long axis is parallel to the channel axis of the
TPP nanochannels, if it is assumed that the rotational axis is parallel to the channel
axis). Every ESR spectrum collected over the range from 165 to 239 K was also
reproduced using this same approach. Based on the spectral reproduction process,
it is evident that at least some PhIN radicals are included in the TPP nanochannels,
although other PhIN radicals in 1a/2h/3e may be adsorbed on the surfaces of the
TPP crystals.
PhNN radicals can also be included in TPP nanochannels [44]. However,
as some PhNN is reduced to PhIN during the synthetic process, [(TPP) 2 -
(PhNN) x /(PhIN) y /(N-PhMI) 1.0 ] (x ≈ 5 × 10 −4 and y ≈ 2 × 10 −4 , 1a/2f/2h/3e)
is produced. According to the ESR results, PhNN radicals included in the TPP
nanochannels undergo anisotropic rotational diffusion around a rotational axis tilted
by (θ , φ) = (90 ◦ , 89 ◦ ) relative to the principal axis system of the g tensor above
253 K.
Figure 12.11 summarizes the effect of temperature on τ R for isolated organic radicals in TPP nanochannels, including PhNN (1a/2f/3e), PhIN (1a/2h/3e), TEMPOL
(1a/2c/3a), TEMPONE (1a/2b/3a), TEMPO (1a/2a/3a), and DTBN (1a/2e/3d) [40,
41, 43, 44] The τ R of each radical can be approximately determined from the
rotational Stokes-Einstein relationship, assuming that the material behaves as an
anisotropic liquid (see Sect. 12.2.3.4) [45]. The E a values of several nitroxide
radicals (such as DTBN, TEMPO, and TEMPONE) increase as the substituent
groups become larger (with values 3, 5, and 10 kJ mol −1 ) [40, 41]. In addition,
Fig. 12.11 Temperature
dependence of the rotational
diffusion correlation time τ R ,
for the isolated organic
radicals in the TPP
nanochannels such as DTBN
(1a/2e/3a), TEMPO
(1a/2a/3a), TEMPONE
(1a/2b/3a), TEMPOL
(1a/2c/3a), PhIN (1a/2h/3e),
and PhNN (1a/2f/3e) [40, 41,
43, 44]