164
4 Toward More Sophisticated Problems
(a)
(c)
(b)
Fig. 4.13 a Generation of ferromagnetic spin correlation of m-phenylene diamine (MPD) dication
radical by two-electron oxidation, b stabilization of a spin in p-phenylenediamine (PPD) cation
radical, and c MO diagram of MPD with the generation of the two parallel spins in two degenerated
NBMO’s
total. In fact, it has been demonstrated that an actually synthesized molecule with
three meta-para motifs shown in Fig. 4.14 has been proved to have quartet-spin
state (2S + 1 = 4) when it is oxidized up to a trication (Ito et al. 2008). Moreover, an
oligoarylamine molecule with more extended meta-para motifs as shown in Fig. 4.15
has been observed to reveal the septet state when it is oxidized up to hexacationic
state (Sakamaki et al. 2009).
Degeneracy of the SOMO levels in the above would cause a super-degenerated
band being half-filled, which works as the spin supplier in the polymer containing
meta-phenylene linkages as illustrated in Fig. 4.16. An extended molecular design
using this linkage toward 2D polymers as shown in Fig. 4.17 have been attempted and
N
N
N
N
N
N
N
N
N
MeO
OMe
OMe
OMe
OMe
MeO
• +
• +
• +
Fig. 4.14 Generation of stable quartet spin radicals in terms of the combination of meta and para
(m, p) PD linkages
4 Toward More Sophisticated Problems
(a)
(c)
(b)
Fig. 4.13 a Generation of ferromagnetic spin correlation of m-phenylene diamine (MPD) dication
radical by two-electron oxidation, b stabilization of a spin in p-phenylenediamine (PPD) cation
radical, and c MO diagram of MPD with the generation of the two parallel spins in two degenerated
NBMO’s
total. In fact, it has been demonstrated that an actually synthesized molecule with
three meta-para motifs shown in Fig. 4.14 has been proved to have quartet-spin
state (2S + 1 = 4) when it is oxidized up to a trication (Ito et al. 2008). Moreover, an
oligoarylamine molecule with more extended meta-para motifs as shown in Fig. 4.15
has been observed to reveal the septet state when it is oxidized up to hexacationic
state (Sakamaki et al. 2009).
Degeneracy of the SOMO levels in the above would cause a super-degenerated
band being half-filled, which works as the spin supplier in the polymer containing
meta-phenylene linkages as illustrated in Fig. 4.16. An extended molecular design
using this linkage toward 2D polymers as shown in Fig. 4.17 have been attempted and
N
N
N
N
N
N
N
N
N
MeO
OMe
OMe
OMe
OMe
MeO
• +
• +
• +
Fig. 4.14 Generation of stable quartet spin radicals in terms of the combination of meta and para
(m, p) PD linkages