Subphthalocyanine derivatives having a phosphorus group as an axial substituent

Article abstract of DOI:10.1246/bcsj.20110308

The synthesis and properties of novel subphthalocyanines having a phosphorus group as an axial substituent are reported. The excellent solubility of these materials may provide a good production method for optical films without impairing the excellent pro

Full text of DOI:10.1246/bcsj.20110308

Short Articles
Bull. Chem. Soc. Jpn. Vol. 85, No. 2, 245-247 (2012)
245
small half width in the 530-580 nm wavelength range and
sufficient light absorption properties.4
Subphthalocyanine Derivatives
Having a Phosphorus Group
as an Axial Substituent
Because a hydroxy group replaces a halogen in the axial
position on a centered-core boron and the subsequent reaction
for making an ether linkage with an alkyl or aryl group takes
place easily, there have been reports of several subphthalo-
cyanine derivatives with an alkoxy or an aryloxy group as an
axial substituent.5 In particular, we note the subphthalocyanines
with a trialkylsilyloxy group as an axial substituent in the study
of Torres on liquid crystalline properties.6 Peripheral substitu-
ents can generally improve the solubility of subphthalo-
cyanines in various organic solvents but they always affect
the Q-band absorption of the compound. On the other hand,
although axial substituents do not affect the Q-band absorption,
they are insufficiently stable to heat and/or light irradiation for
practical thin-film applications. In order to solve the problems
mentioned above, a large number of reports and patents,
including our recent work,7,8 have dealt with modified deriva-
tives of subphthalocyanines.
In this short article, we report the synthesis and properties of
novel subphthalocyanines having a phosphorus group as an
axial substituent and their excellent solubility; the axially
substituted phosphorus group does not cause any significant
changes in the peculiar properties, which is unique to the
subphthalocyanines without any peripheral substituents. By
using these subphthalocyanine derivatives with axial phospho-
rus group, we also tried to make functional optical films that are
resistant to light and heat, and have light absorptivity in specific
wavelength regions.9
Subphthalocyanine derivatives having the phosphorus group
as an axial substituent were synthesized from axially chloro-
substituted subphthalocyanine with phosphate or phosphonic
acid derivatives in fairly good yields and the synthetic
procedure is illustrated in Scheme 1.
The results of the reaction are summarized in Table 1. The
intensive synthetic procedure, 1H NMR, 13C NMR, IR spec-
troscopy, and FD-MS data of each derivative (Entries 1-9) are
available in the Supporting Information. The samples for the
measurement of the UV-vis spectra were prepared as follows:
10.0 mg of the obtained compound (Entries 1-9 and Refs. 1-4)
were completely dissolved in 100 mL of chloroform, and then
10 mL of the solution was diluted with chloroform to 100 mL
total volume. Subsequently, the solution was analyzed with a
spectrophotometer and the molar absorptivity was calculated
according to the Lambert-Beer equation. The UV-vis spectra
are depicted in Figure 1.
Yasuhiro Yamasaki* and Tomohiro Mori
Department of New Business, Orient Chemical Industries
Co., Ltd., 8-1 Sanra-Higashi-Machi, Neyagawa,
Osaka 572-8581
Received October 14, 2011
E-mail: y_yamasaki@orientchemical.com
The synthesis and properties of novel subphthalo-
cyanines having a phosphorus group as an axial substituent
are reported. The excellent solubility of these materials may
provide a good production method for optical films without
impairing the excellent properties peculiar to the original
subphthalocyanines.
Subphthalocyanines have been studied in an effort to apply
them to various commercial products such as pigments, thin
film chemical materials, information recording materials, and
light-emitting materials, however subphthalocyanines generally
have poor light resistance and poor solubility.1,2 Therefore,
when thin films are required, it is necessary to prepare a
pigment-dispersed liquid by dispersing the subphthalocyanines
into a solvent and then apply the liquid to form a thin film. The
thin film made from such pigment-dispersed liquid cannot
achieve sufficient transparency unless the subphthalocyanines
are pulverized into ultrafine particles smaller than 0.5 ¯m with
a very narrow particle size distribution.3 However, pulveriza-
tion increases the surface area and negatively affects light
resistance. Furthermore, it is difficult to prepare homogeneous
thin films if a liquid that containing a nondispersible pigment
is used.
In contrast, optical films such as functional optical thin films
having light absorption in specific wavelength regions, anti-
reflection films especially coated on marketable wide screen
display panels, such as plasma display panels and liquid crystal
display panels, color filters, optical recording media using light
in the blue laser region, and photoreceptors are required to have
It can be seen that the axial substituent did not affect much
the -max of the Q-band absorption, but peripheral substitution
OP(O)R2
Cl
2
R1
R1
CN
N
N
(i)
N
N
(ii)
R1
N
R1
N
B
B
N
N
R1
N
CN
N
N
N
R1
R1
Scheme 1. Synthetic route to the subphthalocyanine derivatives with an axially phosphorus substituent: (i) BCl3/xylene, reflux/2 h;
(ii) HO-P(O)R2 /ODCB, 180 °C/6 h.
2
Published on the web January 28, 2012; doi:10.1246/bcsj.20110308

246
Bull. Chem. Soc. Jpn. Vol. 85, No. 2 (2012)
© 2012 The Chemical Society of Japan
Table 1. The Reaction Yields of [B(R1 subpc){OP(O)R2 }] with the -max and Molar Absorptivity (¾)
3
2
¹4
[B(R1 subpc){OP(O)R2 }]
-
max
/nm
¾ © 10
3
2
Entry
R1
R2
Ph
O-Ph
O-n-Bu
Ph
O-n-Bu
Ph
O-Ph
Ph
O-n-Bu
Cl
Cl
Cl
Cl
Yield/%a)
/dm3 mol¹1 cm
¹1
1
2
3
4
5
6
7
8
9
H-
H-
H-
t-Bu-
67.4
64.4
34.3
23.3
18.8
57.6
46.9
56.0
40.0
(34.0)b)
(27.9)b)
(44.0)b)
(34.2)b)
564.0
564.5
562.5
570.5
568.0
586.0
586.5
584.5
584.0
565.0
570.0
587.5
586.0
7.69
6.96
7.78
8.74
7.62
7.12
8.20
7.24
9.95
5.10
5.10
5.82
7.58
t-Bu-
isopentyl-S-
isopentyl-S-
Ph-S-
Ph-S-
H-
t-Bu-
isopentyl-S-
Ph-S-
Ref. 1
Ref. 2
Ref. 3
Ref. 4
a) The yields are for the second step in Scheme 1. b) The yields in parentheses are for the first step in Scheme 1.
120000
Entry 1
Entry 2
Entry 3
100000
Entry 4
Entry 5
Entry 6
Entry 7
Entry 8
Entry 9
Ref. 1
Ref. 2
Ref. 3
Ref. 4
80000
60000
40000
20000
0
250
300
350
400
450
500
550
600
650
700
Wavelength λ/nm
750
Figure 1. The UV-vis spectra of [B(R1 subpc){OP(O)R2 }]: the measurements were carried out in CHCl3.
3
2
apparently resulted in red shift, the extent of which depends on
the substituents. This may cause problems when a thin-filmed
device requires its absorption at about 560 nm for Entries 1, 2,
and 3.
the present subphthalocyanine derivative, which is a coloring
dyestuff for a thin film obtained in its solid state, was produced
as follows: 0.5 g of [B(R1 subpc){OP(O)R2 }] and 1.0 g of
polycarbonate were added into 68.5 g of cyclohexanone and
30 g of butan-2-one, stirred and dissolved to obtain a coating
solution. The obtained coating solution was applied on 1 mm
thick glass plate using an automatic film applicator.
It can be seen that both axial and peripheral substituents can
indeed improve the solubility in MEK to make a thin film and
even for the derivatives without peripheral substituents, the
solubility of the derivative with R2 = O-Bu (Entry 3) was
surprisingly enhanced more than 10 wt % and the solubility of
the derivative with R2 = Ph or O-Ph (Entries 1 and 2) was
more than 0.3 wt %. Their solubility should be enough to make
a thin-filmed device from a coating solution compared to that
of [B(subpc)Cl] (Ref. 1: 0.003 wt % means almost insoluble).
3
2
In any case, the synthetic procedure for derivatives without
peripheral substituents is advantageous from the viewpoint of
industry, and it can be also seen that their molar absorptivity
was enhanced by the axial substituents compared to those
of the corresponding axially chloro-substituted subphthalo-
cyanine. These facts reduce the required volume of the solution
containing a functional dyestuff, i.e., the subphthalocyanines,
for making a thin film and reduce the production cost.
We have also investigated the solubility of [B(R1 subpc)-
3
{OP(O)R2 }] in butan-2-one (MEK) as well as the Haze value,
2
light resistance, and heat resistance for a thin film solid state.
The results are summarized in Table 2. A thin film containing

Y. Yamasaki et al.
Bull. Chem. Soc. Jpn. Vol. 85, No. 2 (2012)
247
Table 2. The Solubility of [B(R1 subpc){OP(O)R2 }] in
Butan-2-one (MEK), the Haze Value, the Light and Heat
Resistance
film could be remarkably suppressed when the present
subphthalocyanine bearing the phosphorus group as an axial
substituent was used. The UV-vis spectra of the thin film
containing each derivatives (Entries 1-9) are available in the
Supporting Information.
3
2
Solubility in
MEK/wt %
Haze
Heat
Light
Entry
value resistance/% resistance/%
In summary, we report the synthesis and properties of novel
subphthalocyanines having a phosphorus group as an axial
substituent, and propose that their excellent solubility may
provide a good production method for optical thin-filmed
devices without impairing the properties peculiar to the original
subphthalocyanines. In a subsequent paper, we will describe
this and other recent work7,8 regarding subphthalocyanine
derivatives.
1
2
3
4
5
6
7
8
9
0.44
0.34
0.52
0.38
0.43
0.33
0.34
0.31
0.37
0.32
0.48
9.89
0.35
0.34
0.25
¹14.1
¹8.3
¹9.7
¹11.8
¹9.5
¹17.4
¹14.9
¹7.8
¹32.1
¹25.8
¹29.0
¹32.9
¹38.6
¹38.5
¹33.3
¹17.3
¹15.6
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
0.003
>10.0
>10.0
>10.0
¹9.4
Supporting Information
a)
Ref. 1
Ref. 2
Ref. 3
Ref. 4
¹52.8
¹27.1
¹21.2
¹17.8
®
Experimental details including synthetic procedures,
1H NMR, 13C NMR, IR spectroscopy, and FD-MS data of the
novel subphthalocyanines having a phosphorus group as an
axial substituent ([B(R1 subpc){OP(O)R2 }]; Entries 1-9), are
¹37.1
¹33.6
¹9.4
3
2
a) Measurement could not be carried out because only
inhomogeneous solution was obtained and accordingly non-
uniform thin films were obtained.
available electronically on the CSJ-Journal Web site. This
material is available free of charge on the web at http://www.
csj.jp/journals/bcsj/.
In the case of [B(subpc)Cl] (Ref. 1), the measurement of
light resistance could not be carried out because only an
inhomogeneous solution was obtained and accordingly non-
uniform thin films were produced (the Haze value for the film
that contained [B(subpc)Cl] (Ref. 1) was 9.89.). In contrast, the
Haze values were 0.52 and 0.38 for thin-films that contained
[B(subpc){OP(O)Ph2}] or [B(subpc){OP(O)(OPh)2}] (Entries
1 and 2) respectively. Taking this into consideration, it might
References
1
C. G. Claessens, D. González-Rodríguez, T. Torres, Chem.
Rev. 2002, 102, 835.
2
M. Geyer, F. Plenzig, J. Rauschnabel, M. Hanack, B.
del Rey, A. Sastre, T. Torres, Synthesis 1996, 1139.
3
4
5
T. Yanagimoto, N. Nishiyama, Japan Patent 4571138, 2010.
P. H. Berning, Appl. Opt. 1983, 22, 4127.
C. G. Claessens, D. González-Rodríguez, B. del Rey, T.
be feasible to produce thin films that contain [B(R1 subpc)-
3
Torres, G. Mark, H.-P. Schuchmann, C. von Sonntag, J. G.
MacDonald, R. S. Nohr, Eur. J. Org. Chem. 2003, 2547.
{OP(O)R2 }] to afford good Haze values in industrial coating
2
processes. Additionally, both heat and light resistance of thin
6
B. del Rey, M. V. Martínez-Díaz, J. Barberá, T. Torres,
films containing [B(subpc){OP(O)R2 }] were improved to
2
J. Porphyrins Phthalocyanines 2000, 4, 569.
some extend as shown in Table 2. This improvement might
be due to the molecular stability based on the energy and/or
structural difference between B-Cl and B-OP bond.7
Furthermore, we also confirmed by the UV-vis spectra that
the shift of the wavelength and broadening of the Q-band
absorption due to molecular association in the state of a thin
7
8
Y. Yamasaki, T. Mori, Chem. Lett. 2010, 39, 1108.
Y. Yamasaki, T. Mori, Bull. Chem. Soc. Jpn. 2011, 84,
1208.
9
2008.
T. Mori, Y. Yamasaki, Japan Patent Application 206016,