Preparation, spectroscopic properties, and stability of water-soluble subphthalocyanines

Article abstract of DOI:10.1002/asia.200800369

A series of subphthalocyanines containing an axial pyridyl, amino, or carboxy group have been prepared. They undergo N-methylation or deprotonation readily to give a new series of water-soluble subphthalocyanines. All the compounds have been characterized

Full text of DOI:10.1002/asia.200800369

FULL PAPERS
DOI: 10.1002/asia.200800369
Preparation, Spectroscopic Properties, and Stability of Water-Soluble
Subphthalocyanines
Hu Xu and Dennis K. P. Ng*[a]
Abstract: A series of subphthalocya-
nines containing an axial pyridyl,
amino, or carboxy group have been
prepared. They undergo N-methylation
or deprotonation readily to give a new
series of water-soluble subphthalocya-
nines. All the compounds have been
characterized with various spectroscop-
ic methods and elemental analysis. The
molecular structure of the amino ana-
logue SPc(OCH2CH2NMe2) (6) has
also been determined by X-ray diffrac-
tion analysis. All these compounds are
essentially non-aggregated in DMF as
shown by the strong Q-band absorp-
tion. The low aggregation tendency of
these compounds also results in strong
fluorescence emission and high effi-
ciency in generating singlet oxygen. In
the presence of Cremophor EL, these
compounds also remain in the mono-
meric form in aqueous media and can
sensitize the formation of singlet
oxygen. The carboxy and carboxylate
derivatives exhibit a relatively higher
photostability than the amino and cat-
ionic pyridinium and ammonium coun-
terparts, making them potentially
useful as photosensitizers in aqueous
media.
Keywords: macrocycles · phthalo-
cyanines
·
sensitizers
·
singlet
oxygen · subphthalocyanines
Introduction
which can be tuned through rational chemical modification.
These characteristics render them to be applied as octupolar
nonlinear optical materials,[4] photovoltaic devices,[5] photo-
synthetic models for the study of photoinduced electron and
energy transfer processes,[6] colorimetric and fluorometric
molecular probes for cyanide and fluoride anions,[7] and pho-
tosensitizers for photodynamic therapy.[8] Subphthalocya-
nines therefore have emerged as a versatile class of func-
tional materials.
Although a substantial number of subphthalocyanine de-
rivatives have been reported,[1] water-soluble analogues
remain extremely rare. Application of these macrocycles in
the biomedical area is still under developed. van Lier and
co-workers reported the first water-soluble trisulfonated
subphthalocyanine, which was used to prepare several un-
symmetrical water-soluble phthalocyanine derivatives.[9]
Adachi and Watarai prepared a novel testosterone-conjugat-
ed subphthalocyanine, which served as a binding marker for
human serum albumin.[10] During the course of this investi-
gation, a tris(pyridinium) subphthalocyanine, which could
photodynamically inhibit the growth of Escherichia coli, was
reported.[8b] We describe herein a new series of subphthalo-
cyanines having a water-solubilizing axial group, including
their synthesis, general spectroscopic properties, and stabili-
ty, particularly in aqueous media. Upon irradiation, these
compounds can sensitize the formation of singlet oxygen,
and thus can find practical photosensitizing applications.
Subphthalocyanines are regarded as the lower homologues
of phthalocyanines.[1] The basic skeleton of these macrocy-
cles contains three diiminoisoindoline units N-fused around
a boron center adopting a cone-shaped structure. The early
impetus to this class of compounds stemmed from their use
in the ring-expansion reactions to prepare unsymmetrical
A3B-type phthalocyanines.[2] These nonselective reactions,
however, greatly depend on the characteristics of the start-
ing materials and the reaction conditions, which limit their
general synthetic utility.[3] Recently, emphasis has been
placed on their intriguing optical and electronic properties,
[a] Dr. H. Xu,+ Prof. D. K. P. Ng
Department of Chemistry and Center of Novel Functional Molecules
The Chinese University of Hong Kong
Shatin, N.T., Hong Kong (China)
Fax : (+852)2603 5057
E-mail: dkpn@cuhk.edu.hk
[+] Present address: Department of Chemistry and
Key Laboratory for Ultrafine Materials of Ministry of Education
East China University of Science and Technology
130 Meilong Road, Shanghai 200237 (China)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.200800369.
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Chem. Asian J. 2009, 4, 104 – 110

Results and Discussion
Synthesis and Characterization
A pyridinium group is a simple
hydrophilic moiety, which can
be introduced readily to the
subphthalocyanine core. As
shown in Scheme 1, treatment
of the commercially available
Scheme 2. Synthesis of subphthalocyanines 6 and 7.
boronACHTUNGTRENNUNG(III) subphthalocyanine
chloride SPcCl (1) with 3- or
4-hydroxypyridine in toluene
gave the corresponding pyridyl
subphthalocyanine SPc
ACHTUNGTRNE(NUNG 3-OPy)
(2) or SPc
ACHTUNGTRENNUNG
Methylation of these com-
pounds with iodomethane in
chloroform proceeded smooth-
ly to afford the pyridinium
Scheme 3. Synthesis of subphthalocyanines 8–12.
subphthalocyanines
[SPcACHTUGNTREN(NUNG 3-
OPyMe)]I (4) and [SPc
G
In addition to these cationic subphthalocyanines, we also
prepared a series of anionic analogues for comparison using
the facile acid–base reaction. As depicted in Scheme 3, reac-
tion of 1 with 4-hydroxybenzoic acid in toluene gave the car-
boxy subphthalocyanine SPc(OC6H4CO2H) (8). Upon treat-
ment with a series of amines A including diethylamine, di-
propylamine, diisopropylamine, and tert-butylamine, this
compound underwent deproto-
These salts could be isolated readily by filtration, followed
by washing with chloroform and diethyl ether. Similarly,
treatment of 1 with 2-dimethylaminoethanol gave the amino
subphthalocyanine SPc(OCH2CH2NMe2) (6) in 35% yield,
which
underwent
methylation
to
afford
[SPc(OCH2CH2NMe3)]I (7) in 70% yield (Scheme 2).
nation readily to give the cor-
responding ammonium carbox-
ylates [HA]ACTHNUGTRENN[UG SPcCAHUTNGTRNE(NUNG OC6H4CO2)]
(9–12) in good yield. These
salts were purified readily by
filtration, followed by exten-
sive washing with nonpolar or-
ganic solvents.
Scheme 1. Synthesis of pyridinium subphthalocyanines 4 and 5.
All the new compounds (4–
12) were fully characterized
with various spectroscopic
methods and elemental analysis. For all of them, the
1H NMR spectra showed two typical AAꢁBBꢁ multiplets at
d=8.80–8.91 and 7.87–8.07 for the subphthalocyanine a and
b ring protons, respectively. The signals for the axial sub-
stituents were significantly shifted upfield owing to the
shielding by the subphthalocyanine ring current. The molec-
ular structure of SPc(OCH2CH2NMe2) (6) was also deter-
mined by X-ray diffraction analysis. Single crystals of this
compound were grown by layering hexane onto a chloro-
form solution. The compound crystallizes in the orthorhom-
bic system with a Pbca space group. As shown in Figure 1,
the boron center is tetra-coordinated with three isoindole ni-
trogen atoms in a cone-shaped macrocycle and an alkoxy
Abstract in Chinese:
À
group. The B O bond distance [1.422(4) ꢂ] and the average
À
B N bond distance [1.497(5) ꢂ] are comparable with those
in the ethoxy analogue SPc
ACHTUNGTNER(NUNG OEt) [1.418(5) and 1.512(5) ꢂ,
respectively].[12]
Chem. Asian J. 2009, 4, 104 – 110
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105

H. Xu and D. K. P. Ng
FULL PAPERS
pounds emit at 571–577 nm with a fluorescence quantum
yield (FF) of 0.04–0.10 relative to rhodamine B in EtOH
(FF =0.49)[13] (Table 1). Figure 2 shows the absorption and
fluorescence spectra of [tBuNH3]ACHTUNGTRNNEUG[SPcACHTUNTGRNE(NUGN OC6H4CO2)] (12) in
DMF, which are typical for all the other subphthalocyanines.
Figure 2. Electronic absorption (c) and fluorescence emission (b)
spectra of 12 in DMF (2.0 mm). The inset plots the Q-band absorbance at
563 nm versus the concentration of 12, showing that the Beer–Lambert
Law is followed.
Figure 1. Molecular structure of SPc(OCH2CH2NMe2) (6) showing the
30% probability thermal ellipsoids for all non-hydrogen atoms.
All these subphthalocyanines including the cationic and
anionic derivatives could not be completely dissolved in
water alone. However, by first dissolving the compounds in
DMF followed by dilution with water, all of them could
become soluble in water (with 0.1% (v/v) of DMF). Hence,
for all the measurements in aqueous media, the solutions
were prepared in this way. Figure 3 shows the absorption
Electronic Absorption and Photophysical Properties
The absorption spectra of 4–12 in DMF are very similar
showing the Soret B band at 293–305 nm, Q band at 561–
567 nm, together with a vibronic shoulder at 504–510 nm.
The data are compiled in Table 1. The very similar spectra
of these compounds indicate that the macrocyclic p system
is not perturbed by the axial ligand. By plotting the Q-band
absorbance versus the concentration, a linear relationship
was found for all these compounds, showing that they are
essentially non-aggregated under these conditions. Arising
from the low aggregation tendency, these compounds are
highly fluorescent. Upon excitation at 510 nm, these com-
spectra of [tBuNH3]ACHTNUTRGNEN[UG SPcAHCTUNGTERN(NUGN OC6H4CO2)] (12) in water, both in
the absence and presence of Cremophor EL. It can be seen
that the Q band is broad in water, suggesting that 12 is sig-
nificantly aggregated. In the presence of 0.05% (w/v) Cre-
mophor EL, the Q band sharpens and follows the Beer–
Lambert law as shown in the inset. These observations indi-
Table 1. Electronic absorption and photophysical data for 4-12.
[a,c]
[d]
Compound lmax [nm] (loge)[a]
lem [nm][a,b] FF
FD
4
5
6
7
8
9
10
11
12
303 (4.59) 508 (4.32) 566 (4.87) 575
0.09 0.61
0.08 0.66
0.04 0.41
0.10 0.59
0.10 0.62
0.10 0.56
0.10 0.58
0.09 0.60
0.10 0.57
305 (4.57) 510 (4.33) 567 (4.86) 577
294 (4.69) 504 (4.36) 561 (4.93) 571
302 (4.64) 505 (4.37) 562 (4.93) 575
293 (4.52) 505 (4.33) 561 (4.88) 573
293 (4.63) 504 (4.36) 561 (4.94) 572
293 (4.59) 504 (4.33) 561 (4.91) 572
294 (4.50) 504 (4.23) 561 (4.81) 572
293 (4.54) 504 (4.25) 563 (4.83) 572
[a] Measured in DMF. [b] Excited at 510 nm. [c] The fluorescence quan-
tum yields (FF) were determined with rhodamine B in EtOH (FF =0.49)
as reference. [d] The singlet oxygen quantum yields (FD) were deter-
mined in EtOH with rose bengal (FD =0.68) as reference. A color glass
filter cut-on 515 nm was used.
Figure 3. Electronic absorption spectra of 12 in water in the absence
(c) and presence of 0.05% (w/v) Cremophor EL (b) (both at
2.0 mm). The inset plots the Q-band absorbance at 564 nm versus the con-
centration of 12.
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Chem. Asian J. 2009, 4, 104 – 110

Preparation, Properties and Stability of Water-Soluble Subphthalocyanines
cate that Cremophor EL can effectively reduce the aggrega-
tion of 12. It is noteworthy that for the water-soluble sub-
phthalocyanine, which has three peripheral pyridinium
groups,[8b] it also requires 2% (w/v) sodium dodecyl sulfate
to generate the monomeric species in water. In the presence
of Cremophor EL, all the subphthalocyanines 4–12 show a
relatively strong fluorescence emission in water. The fluores-
cence quantum yields are in the range of 0.06–0.08. The ab-
sorption as well as the fluorescence emission data of these
compounds in water with 0.05% (w/v) Cremophor EL are
summarized in Table 2. Compared with the data recorded in
DMF, all the absorption and emission bands are slightly red-
shifted. For the anionic subphthalocyanines 9–12, the size of
the counter cations does not exert a significant influence on
these spectral properties.
The singlet oxygen quantum yields determined by the previ-
ously described method[14] are also listed in Table 1. All
these subphthalocyanines have similar FD values [0.56–0.66
relative
to
rose
bengal
(FD =0.68)][15]
except
SPc(OCH2CH2NMe2) (6), which has a slightly lower photo-
sensitizing efficiency (FD =0.41). It is likely that the amino
group of 6 acts as an electron donor, which reductively
quenches the singlet excited state leading to a lower fluores-
cence quantum yield (FF =0.04) and singlet oxygen quan-
tum yield.
Stability
The stability of these compounds in aqueous media was
then examined by monitoring the decrease in Q-band ab-
sorbance with time. Figure 5 shows the results for selected
Table 2. Electronic absorption and fluorescence emission data for 4–12
in water with 0.05% (w/v) Cremophor EL.
[b]
Compound
lmax [nm] (loge)
lem [nm][a]
FF
4
5
6
7
8
9
10
11
12
305 (4.44)
306 (4.46)
304 (4.54)
304 (4.53)
306 (4.56)
306 (4.61)
306 (4.60)
307 (4.47)
307 (4.53)
510 (4.28)
567 (4.81)
568 (4.82)
566 (4.90)
566 (4.86)
564 (4.90)
564 (4.93)
564 (4.90)
563 (4.81)
564 (4.82)
577
578
576
576
574
574
574
574
574
0.07
0.06
0.07
0.08
0.08
0.08
0.07
0.08
0.08
511 (4.30)
507 (4.36)
507 (4.32)
510 (4.35)
509 (4.37)
510 (4.35)
510 (4.26)
508 (4.25)
[a] Excited at 510 nm. [b] The fluorescence quantum yields (FF) were de-
termined with rhodamine B in EtOH (FF =0.49) as reference.
Figure 5. Changes in the Q-band absorbance of 4 (stars), 6 (circles), 7 (di-
amond), 8 (squares), and 12 (triangles) in water with 0.05% (w/v) Cre-
mophor EL (all at 8.0 mm) with time, both in the absence (closed sym-
bols) and presence (open symbols) of light (l>515 nm, 118 mWcmÀ2).
The data were taken at 3 min intervals.
To evaluate the photosensitizing efficiency of these com-
pounds, the rates of decay of the singlet oxygen scavenger
1,3-diphenylisobenzofuran (DPBF), using these compounds
as the photosensitizers, were monitored spectroscopically (at
410 nm) and compared with that for rose bengal, which was
used as the reference. Figure 4 shows the results for selected
subphthalocyanines. All of them can generate singlet oxygen
and the efficiency is comparable with that of rose bengal.
subphthalocyanines both in the dark and under irradiation
with yellow light (l>515 nm). It can be seen that the ab-
sorbance of the carboxy subphthalocyanine 8 and carboxyl-
ate 12, as well as the other anionic subphthalocyanines 9–11
(data not shown) remains essentially unchanged in the ab-
sence of light showing that they are relatively stable in the
dark. However, the amino subphthalocyanine 6 and the cat-
ionic subphthalocyanines 4 and 7 (as well as 5, for which the
data are not shown) are relatively unstable. The absorbance
decreases by 10–32% in the first 12 min. Upon irradiation,
all the subphthalocyanines are unstable as shown by the de-
crease in the Q-band absorbance. For compounds 4–7, the
values drop by more than 95% in 12 min. In contrast, com-
pounds 8–12 show a relatively higher photostability. During
the first 12 min of illumination, the absorbance decreases by
only 31–35%. By extending the irradiation time to 21 min,
the values decrease further to 48–55%. These observations
clearly indicate that the carboxy subphthalocyanine 8 and
the carboxylates 9–12 are relatively more stable than the
amino subphthalocyanine 6 and the cationic analogues 4, 5,
and 7.
Figure 4. Comparison of the rates of decay of DPBF in EtOH as moni-
tored spectroscopically at 410 nm, using subphthalocyanines 4, 6–8, and
12 as the photosensitizers and rose bengal as the reference.
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H. Xu and D. K. P. Ng
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The efficiency of these subphthalocyanines in generating
singlet oxygen in water was also compared using a previous-
ly described method.[16] In this method, imidazole was used
to capture singlet oxygen to form a trans-annular peroxide
intermediate, which can induce the bleaching of 4-nitrosodi-
methylaniline (RNO) as monitored spectroscopically at
440 nm. All the subphthalocyanines 4–12 could not produce
singlet oxygen in the absence of light. Upon illumination,
photobleaching of RNO was observed showing that singlet
oxygen had been generated. Figure 6 shows the changes in
absorption spectra of these compounds in the presence of
RNO and imidazole in water upon irradiation. The absorb-
ance of RNO (at 440 nm) drops by 13–16% for compounds
4–7 and 21–25% for 8-12 in the first 12 min. Concomitantly,
the subphthalocyanine Q band (at ca. 560 nm) diminishes in
all cases, and the rate is much faster for the former series of
compounds. Extending the irradiation time could not induce
any further decrease in absorbance of RNO for compounds
4–7. However, for subphthalocyanines 8–12, the RNOꢁs ab-
sorbance at 440 nm further decreases to 32–39% in 21 min.
These results (for selected subphthalocyanines) are depicted
in Figure 7. Thus, it can be concluded that the carboxy sub-
phthalocyanine 8 and the anionic analogues 9–12 are more
effective singlet oxygen generators in aqueous media, proba-
bly as a result of their higher photostability.
Conclusions
In summary, a series of subphthalocyanines with an axial
pyridyl, amino, or carboxy group have been prepared by
typical ligand-substitution reactions. Upon methylation or
Figure 6. Changes in absorption spectra of mixtures containing 4–12 (8.0 mm), 0.05% (w/v) Cremophor EL, RNO (25.0 mm), and imidazole (6.3 mm) in
water upon irradiation (l>515 nm) with time. The spectra were taken at 3 min intervals. The relative rates of decay of RNO and the photosensitizer can
be compared by monitoring the decrease in absorbance at 440 and 564–568 nm, respectively.
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Preparation, Properties and Stability of Water-Soluble Subphthalocyanines
SPc(OCH2CH2NMe2) (6): A mixture of SPcCl (1) (ca. 90%, 200 mg,
0.42 mmol) and a large excess of 2-dimethylaminoethanol (1 mL) in tolu-
ene (5 mL) was heated under reflux overnight. After cooling, the vola-
tiles were removed under reduced pressure. The residue was then loaded
onto a silica-gel column and eluted with CH2Cl2/MeOH [changing gradu-
ally from 40:1 (v/v) to 20:1 (v/v)]. The crude product obtained was fur-
ther purified by size exclusion chromatography with Bio-Beads S-X1
beads using THF as the eluent. The final product was obtained as a violet
solid by recrystallization from acetone/hexane (70 mg, 35%). 1H NMR
(300 MHz, CDCl3): d=8.83–8.87 (m, 6H; SPc-Ha), 7.88–7.92 (m, 6H;
SPc-Hb), 1.70 (s, 6H; Me), 1.54 (t, J=6.3 Hz, 2H; CH2), 1.41 ppm (t, J=
6.3 Hz, 2H; CH2); 13C{1H} NMR (75.4 MHz, CDCl3): d=151.5, 130.9,
129.6, 122.0, 59.5, 57.0, 45.3 ppm; HRMS (ESI): m/z calcd for
C28H23BN7O: 484.2052 [M+H]+; found: 484.2052; elemental analysis:
calcd (%) for C28H22BN7O: C 69.58, H 4.59, N 20.29; found: C 69.10,
H 5.11, N 20.07.
Figure 7. Changes in absorbance of RNO at 440 nm with time {initial
[RNO]=25.0 mm} using subphthalocyanines 4 (stars), 6 (circles), 7 (dia-
mond), 8 (squares), and 12 (triangles) as the photosensitizers (all at 8 mm)
in water with 0.05% (w/v) Cremophor EL, both in the absence (closed
symbols) and presence (open symbols) of light (l>515 nm,
118 mWcmÀ2). The data were taken at 3 min intervals ([imidazole]=
6.3 mm).
AHCTUNGRTEN[GUNN SPc(OCH2CH2NMe3)]I (7): A mixture of 6 (10 mg, 0.02 mmol) and a
large excess of iodomethane (1 mL) in chloroform (10 mL) was stirred at
room temperature for 30 min. A large amount of diethyl ether (50 mL)
was then added. The precipitate formed was collected by filtration,
washed with diethyl ether, and then dried in vacuo to afford 7 as a violet
solid (9 mg, 70%). 1H NMR (300 MHz, CDCl3): d=8.86–8.89 (m, 6H;
SPc-Ha), 7.94–7.97 (m, 6H; SPc-Hb), 2.85 (vt, J=4.5 Hz, 2H; CH2), 2.71
(s, 9H; Me), 1.88 ppm (br s, 2H; CH2); 13C{1H} NMR (75.4 MHz,
CDCl3): d=151.5, 130.8, 130.2, 122.3, 66.0, 54.2, 53.5 ppm; HRMS (ESI):
m/z calcd for C29H25BN7O: 498.2208 [MÀI]+; found: 498.2214; elemental
analysis: calcd (%) for C29H26BIN7O1.5 (7·0.5H2O): C 54.92, H 4.13,
N 15.46; found: C 55.01, H 4.58, N 15.09.
deprotonation, these compounds can be converted readily
to the corresponding cationic or anionic analogues, all of
which possess a reasonably high solubility in water. With a
cone-shaped macrocycle and an axial substituent, these com-
pounds are essentially non-aggregated in solution and show
a high efficiency in generating singlet oxygen. The carboxy
and carboxylate derivatives exhibit a relatively higher pho-
tostability, making them potentially useful as photosensitiz-
ers in aqueous media.
SPc(OC6H4CO2H) (8):
A mixture of SPcCl (1) (ca. 90%, 110 mg,
0.23 mmol) and 4-hydroxybenzoic acid (128 mg, 0.93 mmol) in toluene
(5 mL) was heated under reflux overnight. After cooling, the volatiles
were removed under reduced pressure, then the residue was loaded onto
a silica-gel column and eluted with CHCl3/MeOH [changing gradually
from 40:1 (v/v) to 20:1 (v/v)]. The crude product obtained was further
purified by size exclusion chromatography with Bio-Beads S-X1 beads
using THF as the eluent. The final product was obtained as a violet solid
by recrystallization from CHCl3/hexane (33 mg, 27%). 1H NMR
(300 MHz, [D6]DMSO): d=12.49 (br s, 1H; COOH), 8.83–8.87 (m, 6H;
SPc-Ha), 7.99–8.02 (m, 6H; SPc-Hb), 7.34 (d, J=7.8 Hz, 2 H C6H4),
5.36 ppm (d, J=7.8 Hz, 2H; C6H4); 13C{1H} NMR (75.4 MHz,
[D6]DMSO): d=167.6, 157.5, 152.2, 131.7, 131.2, 131.1, 124.7, 123.0,
119.6 ppm; HRMS (ESI): m/z calcd for C31H18BN6O3: 533.1528 [M+H]+;
found: 533.1526; elemental analysis: calcd (%) for C31H18BN6O3.5
(8·0.5H2O): C 68.78, H 3.35, N 15.52; found: C 68.42, H 3.54, N 15.38.
Experimental Section
General
Experimental details regarding the purification of solvents and instru-
mentation are described elsewhere.[17] The pyridyl subphthalocyanines 2
and 3 were prepared as described.[11]
AHCUTNERTG[GUNNN Et2NH2]ACHTNURGTEG[NNUN SPcCAHTUNGTREN(NUGN OC6H4CO2)] (9): To a solution of 8 (6.0 mg, 0.011 mmol)
in chloroform (3 mL) was added a large excess of diethylamine (0.5 mL).
The resulting mixture was stirred at room temperature for 10 min, then a
large amount of hexane (15 mL) was added to give a precipitate. The
violet product was collected by filtration and washed with hexane
(5.5 mg, 81%). 1H NMR (300 MHz, CDCl3): d=8.83–8.86 (m, 6H; SPc-
Ha), 7.89–7.92 (m, 6H; SPc-Hb), 7.42 (d, J=8.1 Hz, 2H; C6H4), 5.35 (d,
J=8.1 Hz, 2H; C6H4), 2.81 (q, J=7.2 Hz, 4H; CH2), 1.18 ppm (t, J=
7.2 Hz, 6H; Me); 13C{1H} NMR (75.4 MHz, CDCl3): d=172.0, 155.3,
151.3, 130.9, 130.6, 129.9, 128.7, 122.2, 118.3, 41.7, 11.5 ppm; HRMS
(ESI): m/z calcd for C31H16BN6O3: 531.1382 [MÀEt2NH2]À; found:
531.1398; elemental analysis: calcd (%) for C35H30BN7O4 (9·H2O):
C 67.43, H 4.85, N 15.73; found: C 67.59, H 5.24, N 15.34.
Synthesis
ACHTUNGTRENNUNG[SPcACHTUNGTRENNUNG(3-OPyMe)]I (4): A mixture of SPcCAHTNUGTRENN(UNG 3-OPy) (2) (23 mg, 0.047 mmol)
and a large excess of iodomethane (1 mL) in chloroform (10 mL) was
heated under reflux for 1 h. After cooling, the solid was collected by suc-
tion filtration and washed successively with chloroform and diethyl ether
to give the product as a violet solid (19 mg, 64%). 1H NMR (300 MHz,
[D6]DMSO): d=8.85–8.88 (m, 6H; SPc-Ha), 8.22 (d, J=6.0 Hz, 1H; Py-
H), 8.02–8.05 (m, 6H; SPC-Hb), 7.54–7.59 (m, 2H; Py-H), 6.25 (d, J=
8.7 Hz, 1H; Py-H), 3.87 ppm (s, 3H; Me); 13C{1H} NMR (75.4 MHz,
[D6]DMSO): d=152.2, 152.0, 138.8, 138.4, 133.6, 130.9, 130.8, 128.2,
122.6, 47.9 ppm; HRMS (ESI): m/z calcd for C30H19BN7O: 504.1739
[MÀI]+; found: 504.1741; elemental analysis: calcd (%) for
C30H19BIN7O: C 57.08, H 3.03, N 15.53; found: C 56.89, H 3.51, N 15.55.
A
ACHUTNGTREN[NUG SPcACHUTNGTNER(NNGU OC6H4CO2)] (10): According to the previously mentioned
a
N
ACHTUNGTRENNUNG(4-OPyMe)]I (5): According to the previously mentioned procedure,
1H NMR (300 MHz, CDCl3): d=8.82–8.85 (m, 6H; SPc-Ha), 7.87–7.90
(m, 6H; SPc-Hb), 7.39 (d, J=8.4 Hz, 2H; C6H4), 5.35 (d, J=8.4 Hz, 2H;
C6H4), 2.68 (vt, J=7.8 Hz, 4H; CH2), 1.61 (sextet, J=7.5 Hz, 4H; CH2),
0.82 ppm (t, J=7.5 Hz, 6H; Me); 13C{1H} NMR (75.4 MHz, CDCl3): d=
172.4, 155.0, 151.3, 130.9, 130.4, 129.8, 129.6, 122.2, 118.2, 49.2, 19.7,
11.3 ppm; HRMS (ESI): m/z calcd for C31H16BN6O3: 531.1382
[MÀnPr2NH2]À; found: 531.1392; elemental analysis: calcd (%) for
C37H32BN7O3: C 70.15, H 5.09, N 15.48; found: C 70.61; H 5.53, N 15.28.
ACHTUNGTRENNUNG
give 5 (23 mg, 77%). 1H NMR (300 MHz, [D6]DMSO): d=8.88–8.91 (m,
6H; SPc-Ha), 8.23 (d, J=6.3 Hz, 2H; Py-H), 8.05–8.07 (m, 6H; SPc-Hb),
5.72 (d, J=6.3 Hz, 2H; Py-H), 3.80 ppm (s, 3H; Me); 13C{1H} NMR
(75.4 MHz, [D6]DMSO): d=165.9, 152.9, 147.5, 131.5, 131.2, 123.1, 116.3,
46.8 ppm; HRMS (ESI): m/z calcd for C30H19BN7O: 504.1739 [MÀI]+;
found: 504.1737; elemental analysis: calcd (%) for C30H21BIN7O2
(5·H2O): C 55.50, H 3.26, N 15.10; found: C 55.35, H 3.67, N 14.93.
Chem. Asian J. 2009, 4, 104 – 110
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
109

H. Xu and D. K. P. Ng
FULL PAPERS
ACHTUNGTRENNUNG[iPr2NH2]ACHTUNGTRENNUNG[SPcACHTUNGTRENNUNG(OC6H4CO2)] (11): According to the previously mentioned
Acknowledgements
procedure, subphthalocyanine 8 (10.0 mg, 0.019 mmol) was treated with
diisopropylamine (0.5 mL) to give 11 as a violet solid (10.0 mg, 84%).
1H NMR (300 MHz, [D6]DMSO): d=8.83–8.85 (m, 6H; SPc-Ha), 7.99–
8.01 (m, 6H; SPc-Hb), 7.28 (d, J=7.5 Hz, 2H; C6H4), 5.28 (d, J=7.5 Hz,
2H; C6H4), 2.92–3.00 (m, 2H; CH), 1.01 ppm (d, J=6.0 Hz, 12H; Me);
13C{1H} NMR (100.6 MHz, CDCl3): d=171.9, 154.7, 151.3, 130.9, 130.5,
130.3, 129.8, 122.2, 118.1, 45.8, 20.4 ppm; HRMS (ESI): m/z calcd for
C31H16BN6O3 531.1382 [MÀiPr2NH2]À; found: 531.1372; elemental analy-
sis: calcd (%) for C37H33BN7O3.5 (11·0.5H2O): C 69.17, H 5.18, N 15.26;
found: C 69.24, H 5.66, N 15.40.
This work was supported by a grant from the Research Grants Council
of the Hong Kong Special Administrative Region, China (Project No.
402607), and a strategic investments scheme administered by The Chi-
nese University of Hong Kong.
ACHTUNGTRENNUNG[tBuNH3]ACHTUNGTRENNUNG[SPcACHTUNGTRENNUNG(OC6H4CO2)] (12): According to the previously mentioned
procedure, subphthalocyanine 8 (7.0 mg, 0.013 mmol) was treated with
tert-butylamine (0.5 mL) to give 12 as a violet solid (6.0 mg, 75%).
1H NMR (300 MHz, CDCl3): d=8.80–8.84 (m, 6H; SPc-Ha), 7.88–7.91
(m, 6H; SPc-Hb), 7.39 (d, J=8.4 Hz, 2H; C6H4), 5.35 (d, J=8.4 Hz, 2H;
C6H4), 1.08 ppm (s, 9H; Me); 13C{1H} NMR (75.4 MHz, [D6]DMSO): d=
169.3, 155.2, 152.2, 131.4, 131.1, 123.1, 118.9, 50.7, 29.2 ppm (some of the
signals are overlapped); HRMS (ESI): m/z calcd for C31H16BN6O3:
531.1382 [MÀtBuNH3]À; found: 531.1392; elemental analysis: calcd (%)
for C35H29BN7O3.5 (12·0.5H2O): C 68.41, H 4.76, N 15.96; found: C 68.41,
H 5.31, N 15.56.
[1] C. G. Claessens, D. Gonzꢃlez-Rodrꢄguez, T. Torres, Chem. Rev. 2002,
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X-ray Crystallographic Analysis of 6
Crystal data and details of data collection, and structure refinement are
given in Table 3. Data were collected on a Bruker SMART CCD diffrac-
tometer with an MoKa sealed tube (l=0.71073 ꢂ) at 293 K, using a w
scan mode with an increment of 0.38. Preliminary unit-cell parameters
were obtained from 45 frames. Final unit-cell parameters were obtained
by global refinements of reflections obtained from integration of all the
[6] See for example: a) D. Gonzꢃlez-Rodrꢄguez, T. Torres, D. M. Guldi,
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5706.
Table 3. Crystallographic data for subphthalocyanine 6.
6
Formula
Mr
C28H22BN7O
483.34
0.40ꢇ0.30ꢇ0.30
Orthorhombic
Pbca
15.611(3)
14.536(3)
21.001(4)
4765.6(15)
8
Crystal size [mm3]
Crystal system
Space group
a [ꢀ]
b [ꢀ]
c [ꢀ]
V [ꢂ3]
Z
F (000)
2016
1.347
0.086
1calcd [mgmÀ3
]
m [mmÀ1
]
q range [deg]
1.94 to 28.06
30832
5769 (Rint =0.0865)
334
0.0549
0.1256
[10] K. Adachi, H. Watarai, Anal. Chem. 2006, 78, 6840.
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Bull. Chem. Soc. Jpn. 1996, 69, 2559.
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[14] M. D. Maree, N. Kuznetsova, T. Nyokong, J. Photochem. Photobiol.
A 2001, 140, 117.
Reflections collected
Independent reflections
Parameters
R1 [I>2s(I)]
wR2 [I>2s(I)]
GOF
1.099
[15] R. W. Redmond, J. N. Gamlin, Photochem. Photobiol. 1999, 70, 391.
´
[16] I. Kraljic, S. El Mohsni, Photochem. Photobiol. 1978, 28, 577.
frame data. The collected frames were integrated using the preliminary
cell-orientation matrix. SMART software was used for collecting frames
of data, indexing reflections, and determination of lattice constants;
SAINT-PLUS for integration of intensity of reflections and scaling;[18]
SADABS for absorption correction;[19] and SHELXL for space group
and structure determination, refinements, graphics, and structure report-
ing.[20] CCDC 690351 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre at www.ccdc.cam.ac.uk/data_
request/cif.
[17] P.-C. Lo, C. M. H. Chan, J.-Y. Liu, W.-P. Fong, D. K. P. Ng, J. Med.
Chem. 2007, 50, 2100.
[18] SMART and SAINT for Windows NT Software Reference Manuals,
Version 5.0, Bruker Analytical X-ray Systems, Madison, WI, 1997.
[19] G. M. Sheldrick, SADABS - A Software for Empirical Absorption
Correction, University of Gçttingen, Germany, 1997.
[20] SHELXL Reference Manual, Version 5.1, Bruker Analytical X-ray
Systems, Madison, WI, 1997.
Received: September 24, 2008
Published online: November 4, 2008
110
www.chemasianj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 104 – 110