Chemistry Reference
In-Depth Information
(H
3
C)
2
N
N(CH
3
)
2
S
+
HO
O
S
S
1. P
2
S
5
2. HCl
S
S
(H
3
C)
2
N
N(CH
3
)
2
S
S
H
3
CO
OCH
3
S
S
S
3. AgSbF
6
S
S
SbF
6
-
(TTPLY)
2
Scheme 3.4
Synthetic method for the
TTPLY
cation and a closed shell dimer (
TTPLY
)
2
microcrystalline solid which survives in air for up to 24 hours. In contrast, in solution the radical readily
decomposes, even in the absence of oxygen.
The SbF
6
salt of the
TTPLY
cation is prepared by the reaction of 4,9-dimethoxy-3-
hydroxyphenalenone
18a
with phosphorus pentasulfide followed by the treatment with hydrogen chloride
and metathesis with AgSbF
6
(Scheme 3.4). The reduction with tetrakis(dimethylamino)ethylene gives a
closed shell dimer of
TTPLY
,
(
TTPLY
)
2
, as black needle crystals. X-ray crystal structure analysis reveals
an existence of a S-S
bond formed by the reaction between two
TTPLY
(Figure 3.13). While the solid
sample is silent in an EPR measurement, a weak EPR signal due to
TTPLY
is observed after dissolution
in toluene. The resulting neutral radical shows a high stability in an oxygen-free solvent condition.
The spin density distributions of
DTPLY, TTPLY
,and
HTPLY
obtained by quantum chemical cal-
culations are illustrated in Figure 3.14. The unpaired electron of each derivative delocalizes not only on
the phenalenyl skeleton but also on the sulfur atoms. The calculation also shows that most of the spin
on the phenalenyl skeleton is found on the
σ
α
positions, similar to that found in pristine
PLY
. The redox
Figure3.13
Crystal structure of the closed shell dimer of
TTPLY
,(
TTPLY
)
2
, with S-S
σ
bond. (Reprinted with
permissionfrom[24].Copyright2008AmericanChemicalSociety.)
(a)
(b)
(c)
Figure3.14
Spin density distributionsof (a)
DTPLY
,(b)
TTPLY
,and(c)
HTPLY
. (a,c Reprinted with permission
from[10a].Copyright2007AmericanChemicalSociety.)
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