Synthesis of novel covalently linked dimeric phthalocyanines

Article abstract of DOI:10.1002/ejoc.200600733

We report the syntheses of the dimeric homonuclear Pcs 9a and 9b and of the dimeric heteronuclear Pc 9c, starting from the unsymmetrical phthalocyanines 7a and 7b, each containing a phenolic OH group in one of its substituents. Compounds 9a and 9b were ob

Full text of DOI:10.1002/ejoc.200600733

FULL PAPER
DOI: 10.1002/ejoc.200600733
Synthesis of Novel Covalently Linked Dimeric Phthalocyanines
Aleksey Lyubimtsev,[a] Sergej Vagin,[a] Sergej Syrbu,[a] and Michael Hanack*[b]
Keywords: Statistical condensation / Phthalonitriles / Phthalocyanines / Alkylation / Metal complexes
We report the syntheses of the dimeric homonuclear Pcs 9a
and 9b and of the dimeric heteronuclear Pc 9c, starting from
the unsymmetrical phthalocyanines 7a and 7b, each contain-
ing a phenolic OH group in one of its substituents. Com-
pounds 9a and 9b were obtained by single-step alkylations
of 7a and 7b with 1,6-dibromohexane or, in better yields, by
coupling of Pcs 7a and 7b with the bromoalkyl-derivatized
Pcs 8a and 8b, while 9c was prepared by treatment of 8a
with Pc-Ni complex 7b. The dimeric Pcs 9a–9c show strong
cofacial intramolecular association in solution.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
ocyanine of the A3B type with one functional group active
for a nucleophilic substitution. This group can be either an
alkyl or an aryl substituent containing, for example, a free
hydroxy group. Subsequently this A3B-type Pc can be
treated with 4-nitrophthalonitrile to give a Pc substituted
with a phthalonitrile group. Condensation of this with
phthalonitriles affords the corresponding dimeric products.
The advantage of this method is its applicability to the
synthesis of both symmetrical and asymmetrical (for in-
stance heteronuclear) systems, while the same approach also
offers the possibility of synthesizing mixed porphyrin-
phthalocyanine systems.[16,17] However, application of the
statistical condensation as the last step in this synthetic
route results in low yields of the final products.
A compound containing an active group such as a hy-
droxy moiety – such as, for example, the Pcs 7a or 7b
(Scheme 2) – can be used directly for dimerization through
a bifunctional spacer. In our current research this approach
has been applied to the synthesis of the dimeric phthalocy-
anines 9a, 9b, and 9c (Scheme 3), linked through mixed
alkyl–aryl spacers in order to avoid the second statistical
cross-condensation step as described above. This method is
distinguished by its simplicity and also provides an oppor-
tunity for synthesis of heteronuclear and/or heteroleptic di-
meric systems and allows the extent and character of the
spacer group to be varied easily.
Introduction
Multinuclear phthalocyanine (Pc) systems, like their mo-
nomeric symmetrically and unsymmetrically substituted Pc
counterparts, have recently attracted much attention be-
cause of their potential applications as semiconductors,
nonlinear optical materials, and catalysts.[1] The synthesis of
multinuclear phthalocyanine compounds has also provided
new information contributing to the study of phthalocyan-
ine aggregation.
A series of linked Pc structures in which the spacer length
is systematically varied through a chain of one to five atoms
was studied to examine the effect of the linkage length on
the interaction between the two phthalocyanine terminal
structures. When a sufficient length of the linking moiety is
reached, a cofacial intramolecular association referred to as
“clamshell behavior” is observed, with a dynamic equilib-
rium existing between open and closed conformations.[2]
Examples of covalently linked dimeric phthalocyanines
containing spacer units have previously been reported by
Lever[3–7] and Torres.[8–10] The spacers in these dimeric
Pcs can be bis-alkoxy groups [e.g., –OCH2C(CH3)(R)-
CH2O–],[3–5] catechols with oxygen as bridging atoms,[6]
methylene chains of different lengths [e.g., –(CH2)n– with n
= 2,4],[6] alkynyl chains of varying lengths [e.g., –(CϵC)m–
with m = 1,2],[8,10] or double alkynyl chains with m = 2.[9]
Similar dimeric systems have also been prepared with por-
phyrins taken as macrocycles instead.[11–13] Like the dimeric
Pcs, these porphyrin-based systems are covalently linked
with alkyl or aryl groups through a meso carbon in a pil-
lared cofacial configuration[14] (Pacman-like systems).[15]
A first step in the synthesis of a covalently linked dimeric
Pc can, for example, be to obtain an unsymmetrical phthal-
Results and Discussion
For the synthesis of the dimeric Pcs 9a, 9b, and 9c
(Scheme 3) the routes shown in Scheme 1, 2, and 3 were
chosen. The unsymmetrical monofunctionalized phthalocy-
anines 7a and 7b (Scheme 2) used as starting materials for
9a–9c were prepared by statistical cross-condensation of the
newly prepared 4-(m-hydroxyphenoxy)phthalonitrile (3)
and 4,5-bis(3,5-di-tert-butylphenoxy)phthalonitrile (5).
Compound 3 was in turn obtained by treatment of 4-nitro-
[a] Ivanovo State University of Chemistry and Technology, Or-
ganic Chemistry Department,
F. Engels str. 7, 153460 Ivanovo, Russia
[b] Universität Tübingen, Institut für Organische Chemie,
Auf der Morgenstelle 18, 72076 Tübingen, Germany
2000
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Synthesis of Novel Covalently Linked Dimeric Phthalocyanines
FULL PAPER
phthalonitrile (1) with an excess of resorcine (2) in DMF in of all possible metal-free phthalocyanines, among which 6a
the presence of K2CO3 (see Scheme 1 and Exp. Sect.) and and 7a were dominant (Scheme 2). They were separated by
was separated from the also formed 4,4Ј-(m-phenylene- column chromatography with dichloromethane as eluent.
dioxy)bis(phthalonitrile) (4) by column chromatography.
Nickel complexes 6b and 7b were obtained as a mixture
by cross-condensation of phthalonitriles 3 and 5 in quino-
line in the presence of NiCl2 and catalytic amounts of am-
monium molybdate. Separation of the PcNis by column
chromatography with dichloromethane/hexane 7:3 as eluent
gave pure Pc 7b.
The UV/Vis spectra of 6a and 7a are consistent with
metal-free phthalocyanines and differ only slightly in the
intensities of their absorption bands (see Exp. Sect.).The
UV/Vis spectrum of 7b is typical for a metal phthalocyan-
ine, showing an unsplit Q-band (Figure 1), as in the case of
6b.
1
The H NMR spectra (CDCl3) of PcH2 7a and PcNi 7b
are very similar, each with a peak corresponding to the free
OH signal at δ ≈ 5 ppm and a multiplet of aromatic protons
in the resorcine moiety appearing in the 6.7–6.9 ppm re-
gion. The signal of the inner NH protons of 7a appears at
δ = –0.78 ppm and is absent in the spectrum of Ni complex
7b.
Treatment of 7a and 7b with excess 1,6-dibromohexane
in the presence of K2CO3, either in pure DMF or in a
DMF/THF mixture (1:1), resulted mainly in the formation
of the corresponding bromoalkyl derivatives 8a and 8b
(Scheme 3).
Scheme 1.
The bis(phthalonitrile) 4 might also have served as a pre-
Alkylation of the hydroxy groups in 7a or 7b did not
cursor for a dimeric phthalocyanine, but treatment of 4 with result in any significant change in the UV/Vis spectra; the
an excess of a substituted phthalonitrile (e.g., 5) did not main evidence for the structures of 8a and 8b follows from
result in the corresponding dimer.
their NMR and MALDI-TOF characteristics. The 1H
Condensation of 3 and 5 in a 1:3 ratio in hexanol in the NMR spectra of Pcs 8a and 8b exhibit no signals in the
presence of catalytic amounts of DBU resulted in a mixture 5 ppm region, which would be indicative of the presence of
Scheme 2.
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2001

A. Lyubimtsev, S. Vagin, S. Syrbu, M. Hanack
FULL PAPER
Scheme 3.
MALDI-TOF and UV/Vis, which confirmed their struc-
tures.
Compounds 9a and 9b were more easily synthesized by
coupling of the monomeric phthalocyanines 7a and 7b with
Pcs 8a and 8b, respectively. They were also obtained by
treatment of 7a or 7b with 0.5 equiv. 1,6-dibromohexane
either in DMF or in a DMF/THF mixture (1:1) with subse-
quent purification by column chromatography.
The UV/Vis spectra of dimeric Pcs 9a and 9b (Figure 2)
are different from the spectra of monomeric compounds 7a,
Figure 1. UV/Vis spectra (CH2Cl2) of 7a (solid line) and 7b (dashed
line).
7a and 7b, respectively. Two signals at approx. 4.0 and
3.3 ppm correspond to four alkyl protons, Hα and Hφ of
the bromohexyl fragments, whereas the signals of the other
six protons (2 Hβ, 2 Hγ, 2 Hδ), expected in the 1.88–
1.25 ppm region, are masked by the intense peaks of the
peripheral tert-butyl groups. In the spectrum of 8a the sig-
nals of the inner NH protons appear at –0.48 ppm.
The dimeric compounds 9a and 9b are also formed in
small quantities under the synthesis conditions. They were
separated by column chromatography and analyzed by line).
Figure 2. UV/Vis spectra (CH2Cl2) of 9a (dashed line) and 9b (solid
2002
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Synthesis of Novel Covalently Linked Dimeric Phthalocyanines
FULL PAPER
7b, 8a, and 8b. Compounds 9a and 9b each exhibit a more
intense absorption in the B-band region and a broad
pattern of the Q-band. The increased absorption at approx.
640 nm and 628 nm for 9a and 9b in CH2Cl2, and the inde-
pendence of the intensity ratios of the Q-band components
on the concentrations of 9a and 9b in solution indicate π–
π interactions between the macrocycles with a strong ten-
dency to co-facial orientation within the dimer molecules.
The 1H NMR spectra of dimeric phthalocyanines 9a and
9b each show a characteristic triplet in the area of 4 ppm,
corresponding to four alkyl protons Hα. In the metal-free
complex 9a the NH protons appear at approx. –0.69 ppm
(see Figure 3).
Figure 4. UV/Vis spectrum (CH2Cl2) of dimer 9c.
1
Figure 5. H NMR spectrum of heteronuclear dimeric phthalocy-
anine 9c.
Conclusions
The synthesis of the unsymmetrical substituted phthalo-
cyanines 7a and 7b, each containing one active (phenolic)
hydroxy group, is reported. These compounds were further
converted into dimeric phthalocyanine systems 9a, 9b, and
9c, exhibiting noticeable co-facial intramolecular interac-
tions of the Pc-macrocycles in their UV/Vis spectra in solu-
tion.
The method described for the synthesis of 9a–9c is easy
to carry out, proceeds with good yields, and represents a
convenient pathway to both homonuclear and heteronuc-
lear dimeric phthalocyanine compounds. Additionally, this
method allows the spacer group, metal cations, and periph-
eral substitution pattern to be varied for tuning of the prop-
erties of the dimers.
1
Figure 3. H NMR spectra of dimeric phthalocyanines 9a (a) and
9b (b) in CDCl3.
The heteronuclear dimeric phthalocyanine 9c was ob-
tained in good yield by treatment of 8a with an excess of
Pc-Ni complex 7b in DMF/THF in the presence of K2CO3
(see Exp. Sect.). Purification of Pc 9c was carried out by
column chromatography. As expected, its UV/Vis spectrum
is very similar to the superposed spectra of dimers 9a and
9b (see Figure 4).
In the 1H NMR, the four Hα alkyl protons of the hetero-
nuclear dimer 9c give two overlapping triplets in the 4 ppm
region (Figure 5). The characteristic singlet for the inner
NH protons of the metal-free macrocycle was observed in
the dimer at –0.98 ppm. In the MALDI-TOF spectra, none
of the synthesized dimers 9a–9c exhibited fragmentation:
only isotopic cluster peaks of molecular ions were observed,
which provides additional confirmation of the purities of
the synthesized Pcs 9a–9c.
Experimental Section
General: All solvents were dried by standard methods. Quinoline
was first purified on a column (basic alumina). Commercially avail-
able reagents were used as purchased. 4,5-Bis(3,5-di-tert-butylphen-
oxy)phthalonitrile (5) was prepared by a previously described pro-
cedure.[18] NMR spectra were recorded on a Bruker AC 250 spec-
trometer. The UV/Vis spectra were taken in CH2Cl2 with a Shim-
adzu UV-365 spectrometer and IR spectra with a Bruker Tensor 27.
Mass spectra (EI, MALDI-TOF) were obtained on a Finnigan
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A. Lyubimtsev, S. Vagin, S. Syrbu, M. Hanack
FULL PAPER
TSQ 70 MAT and a Bruker Autoflex spectrometer, and elemental
analyses on a Euro EA 3000.
anol, dried, and subjected to column chromatography on silica gel
with CH2Cl2/n-hexane (7:3) as eluent. The symmetrically substi-
tuted Pc 6b was eluted first, followed by the unsymmetrical PcH2
7b.
4-(m-Hydroxyphenoxy)phthalonitrile (3): A mixture of 4-nitro-
phthalonitrile (1, 1 g, 6 mmol), resorcine 2 (4 g, 36 mmol), and
K2CO3 (5.5 g, 0.04 mol) was heated to 85–90 °C with stirring in
anhydrous DMF (10 mL) for 1 h. After cooling, the reaction mix-
ture was filtered and the brown filtrate was added dropwise to
water (50 mL). The formed creamy colored precipitate was filtered
off and washed with water, and the mixture was subjected to col-
umn chromatography on silica gel with dichloromethane/acetoni-
trile (9:1), resulting in the elution of 4,4Ј-(m-phenylenedioxy)-
Compound 6b: Yield: 0.22 g (15.6%). 1H NMR (CDCl3, numbering
according to Scheme 2): δ = 8.94 (s, 8 H, H2), 7.22 (s, 8 H, H10),
7.09 (s, 16 H, H9), 1.3 (s, 144 H, H11) ppm. IR (KBr): ν = 2964,
˜
2905, 2869, 1608, 1588, 1533, 1459, 1418, 1363, 1297, 1275, 1246,
1198, 1145, 1095, 1055, 1002, 961, 903, 864, 837, 756, 729,
707 cm–1. UV/Vis (CH2Cl2): λmax (lgε) = 674.0 (5.40), 648.0 (sh),
608.0 (4.66), 391.0 (4.62), 305.0 nm (5.06). MS (MALDI-TOF): m/z
= 2203 [M]+.
bis(phthalonitrile) (4) (Rf
= 0.9) and subsequently 4-(m-hy-
1
droxyphenoxy)phthalonitrile (3, Rf = 0.6). The solvent was com-
pletely evaporated and products were dried under vacuum at 90 °C.
Compound 7b: Yield: 0.2 g (12.5%). H NMR (CDCl3, numbering
according to Scheme 2): δ = 8.92–8.75 (m, 7 H, H2, 6 H1), 8.55 (s,
3
1 H, H4), 7.64 (d, J = 8.5 Hz, 1 H, H3), 7.34–7.11 (m), 6.88–6.70
1
Compound 3: Yield: 0.74 g (54%). H NMR ([D6]DMSO, number-
(m) (22 H, H5, H6, H7, H8, 12 H9, 6 H10), 5.15 (s, 1 H, HOH), 1.34–
ing according to Scheme 1): δ = 8.07 (d, 3J = 8.8 Hz, 1 H, H6),
1.29 (m, 108 H, H11) ppm. IR (KBr): ν = 3444 (OH), 2964, 2905,
4
3
4
˜
7.75 (d, J = 2.2 Hz, 1 H, H3), 7.36 (dd, J = 8.8 Hz, J = 2.2 Hz,
2869, 1608, 1589, 1533, 1460, 1421, 1362, 1352, 1297, 1277, 1246,
1198, 1138, 1096, 1056, 1002, 961, 903, 864, 756, 728, 707 cm–1.
UV/Vis (CH2Cl2): λmax (lgε) = 673.5 (5.40), 647.0 (sh), 606.5 (4.68),
382.5 (sh), 329.0 (sh), 305.5 nm (5.06). MS (MALDI-TOF): m/z =
1903 [M]+. Elemental analysis calcd. (%) for C122H140N8NiO8: C
76.91, H 7.41, N 5.88; found: C 76.63, H 7.49, N 5.89.
1 H, H5), 7.27 (t, J = 8.1 Hz, 1 H, H10), 6.71 (dd, J = 8.1 Hz, J
3
3
4
= 2.2 Hz, 1 H, H9), 6.58–6.51 (m, 2 H, H11, H8) ppm. IR (KBr): ν
˜
= 3372 (OH), 2252, 2231 (CϵN), 1602, 1566, 1479, 1421, 1340,
1310 1287, 1252, 1172, 1134, 975, 931, 882, 799, 693, 522 cm–1. MS
(electron ionization, EI): m/z (%) = 236.1 (100) [M]+, 208.1 (27),
179.1 (23), 65.2 (16), 39.2 (6). Elemental analysis calcd. (%) for
C14H8N2O2: C 71.18, H 3.41, N 11.86; found: C 70.94, H 3.29, N
11.89.
Alkylated Phthalocyanines 8a and 8b. General Method: Compound
7a or 7b (0.016 mmol) was mixed with excess 1,6-dibromohexane
in DMF (2 mL; for 7b in a 1:1 DMF/THF mixture) in the presence
of K2CO3 (0.02 g, 0.145 mmol). The mixture was heated to 50–
55 °C for 4 h. After cooling, the reaction product was added to
water/methanol (1:1, 20 mL), filtered off, washed thoroughly with
methanol, dried, and subjected to column chromatography on silica
gel with CH2Cl2/n-hexane (65:35) as eluent. Phthalocyanines 8a
and 8b were isolated as the largest fractions (second).
Compound 4: Yield: 0.07 g. IR (KBr): ν = 2232 (CϵN), 1568, 1563,
˜
1478, 1455, 1422, 1404, 1304, 1284, 1247, 1201, 1175, 1123, 1090,
1003, 980, 950, 917, 900, 888, 864, 851, 843, 792, 775, 720, 685,
525 cm–1. MS (electron ionization, EI): m/z (%): 362.1 (100) [M]+,
218.1 (14), 191.1 (41), 164.1 (26), 40.1 (15). Elemental analysis
calcd. (%) for C22H10N4O2: C 72.93, H 2.78, N 15.46; found: C
72.66, H 2.70, N 15.70.
1
Compound 8a: Yield: 0.021 g (65%). H NMR (CDCl3, numbering
Synthesis of 7a: 4-(m-Hydroxyphenoxy)phthalonitrile (3, 0.2 g,
0.84 mmol) and 4,5-bis(3,5-di-tert-butylphenoxy)phthalonitrile (5,
1.35 g, 2.52 mmol) were mixed with a catalytic quantity of DBU
under nitrogen in hexanol. The mixture was heated up to 170–
175 °C and was allowed to react for 16 h. After cooling, the reac-
tion product was added to methanol (50 mL) containing H2O
(0.5 mL), filtered off, washed thoroughly with methanol, dried, and
subjected to column chromatography on silica gel with CH2Cl2 as
eluent. The symmetrical Pc 6a was eluted first, followed by the
unsymmetrical PcH2 7a.
3
according to Scheme 3): δ = 9.20 (d, J = 8.5 Hz, 1 H, H2), 9.07–
4
3
8.96 (m, 6 H, H1), 8.82 (d, J = 2.2 Hz, 1 H, H4), 7.79 (dd, J =
8.5 Hz, 4J = 2.2 Hz, 1 H, H3), 7.39–7.13 (m, 19 H, H6, 12 H9, 6
H10), 6.90 (dd, 3J = 8.1 Hz, 4J = 2.2 Hz, 1 H, H8), 6.83 (t, 4J =
2.2 Hz, 1 H, H5), 6.79 (dd, 3J = 8.1 Hz, 4J = 1.8 Hz, 1 H, H7), 3.99
3
3
(t, J = 6.3 MHz, 2 H, Hα), 3.36 (t, J = 6.6 Hz, 2 H, Hφ), 1.88–
1.25 (m, 116 H, 108 H11, 2 Hβ, 2 Hγ, 2 Hδ), –0.48 (s, 2 H,
HNH) ppm. IR (KBr): ν = 3444 (NH), 2963, 2869, 1608, 1588, 1467,
˜
1443, 1423, 1398, 1363, 1297, 1275, 1246, 1199, 1139, 1089, 1013,
961, 902, 866, 756, 707 cm–1. UV/Vis (CH2Cl2): λmax (lgε) = 702.0
(5.27), 668.0 (5.20), 639.5 (4.75), 607.0 (4.49), 400 (sh), 344.5 (4.99),
291.5 nm (4.88). MS (MALDI-TOF): m/z = 2011 [M]+. Elemental
analysis calcd. (%) for C128H153BrN8O8: C 76.43, H 7.67, N 5.57;
found: C 75.77, H 7.71, N 5.71.
Compound 7a: Yield: 0.22 g (14.2%). 1H NMR (CDCl3, numbering
3
according to Scheme 2): δ = 9.10 (d, J = 8.5 Hz, 1 H, H2), 9.01–
8.96 (m, 6 H, H1), 8.74 (s, 1 H, H4), 7.75 (d, 3J = 8.5 Hz, 1 H, H3),
7.35–7.14 (m), 6.90–6.71 (m, 22 H, H5, H6, H7, H8, 12 H9, 6 H10),
5.01 (s, 1 H, HOH), 1.38–1.32 (m, 108 H, H11), –0.78 (s, 2 H,
1
Compound 8b: Yield: 0.023 g (71%). H NMR (CDCl3, numbering
3
according to Scheme 3): δ = 8.95 (d, J = 8.4 Hz, 1 H, H2), 8.88–
HNH) ppm. IR (KBr): ν = 3442 (OH, NH), 2964, 2868, 1608, 1589,
˜
4
3
8.79 (m, 6 H, H1), 8.60 (d, J = 2.2 Hz, 1 H, H4), 7.66 (dd, J =
1500, 1467, 1443, 1423, 1398, 1364, 1317, 1297, 1276, 1246, 1198,
1137, 1089, 1013, 961, 902, 866, 757, 706 cm–1. UV/Vis (CH2Cl2):
λmax (lgε) = 702.0 (5.35), 667.5 (5.28), 640.5 (4.81), 606.0 (4.65),
400 (sh), 345.0 (5.6), 291.5 nm (4.95). MS (MALDI-TOF): m/z =
1847 [M]+. Elemental analysis calcd. (%) for C122H142N8O8: C
79.27, H 7.74, N 6.06; found: C 78.43, H 7.71, N 6.15.
8.4 Hz, J = 2.2 Hz, 1 H, H3), 7.36–7.11 (m), 6.90–6.75 (m, 22 H,
4
H5, H6, H7, H8, 12 H9, 6 H10), 3.98 (t, J = 6.2 Hz, 2 H, Hα), 3.36
3
(t, J = 6.9 Hz, 2 H, Hφ), 1.86–1.22 (m, 116 H, 108 H11, 2 Hβ, 2
3
Hγ, 2 Hδ) ppm. IR (KBr): ν = 2964, 2868, 1608, 1589, 1533, 1464,
˜
1421, 1363, 1297, 1276, 1246, 1198, 1139, 1116, 1056, 962, 903,
865, 755, 728, 707 cm–1. UV/Vis (CH2Cl2): λmax (lgε) = 674.0
(5.41), 646.0 (sh), 607.0 (4.71), 382.5 (sh), 329.0 (sh), 300.0 nm
(5.12). MS (MALDI-TOF): m/z = 2067 [M]+. Elemental analysis
calcd. (%) for C128H151BrN8NiO8: C 74.33, H 7.36, N 5.42; found:
C 74.52, H 6.98, N 5.89.
Synthesis of 7b: 4-(m-Hydroxyphenoxy)phthalonitrile (3, 0.2 g,
0.84 mmol) and 4,5-bis(3,5-di-tert-butylphenoxy)phthalonitrile (5,
1.35 g, 2.52 mmol) were mixed under nitrogen with NiCl2 (0.44 g,
3.36 mmol) in quinoline (4 mL). The mixture was heated up to
185–195 °C and was allowed to react for 16 h. After cooling, the
reaction product was added to methanol (50 mL) containing concd.
aqueous HCl (0.5 mL), filtered off, washed thoroughly with meth-
Synthesis of Homonuclear and Heteronuclear Dimeric Phthalocyan-
ines 9a, 9b, and 9c
2004
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Synthesis of Novel Covalently Linked Dimeric Phthalocyanines
FULL PAPER
3
Method A: Phthalocyanine 7a or 7b (0.05 g) and K2CO3 (0.01 g)
were added to a solution of 1,6-dibromohexane in DMF (0.012 ,
1 mL). The mixture was heated up to 50–55 °C and stirred for 48 h.
After cooling, the reaction product was added to water (10 mL),
filtered off, washed thoroughly with water and methanol, dried,
and subjected to column chromatography on silica gel with
CH2Cl2/n-hexane (65:35) as eluent. Phthalocyanines 9a and 9b were
isolated as first fractions.
2 H8, 24 H9, 12 H10), 4.02 (t, J = 6.2 Hz, 4 H, Hα), 1.85–1.21 (m,
224 H, 216 H11, 4 Hβ, 4 Hγ), –0.98 (s, 2 H, HNH) ppm. IR (KBr):
ν = 3443 (NH), 2963, 2868, 1607, 1588, 1532, 1465, 1421, 1385,
˜
1363, 1297, 1275, 1246, 1198, 1139, 1118, 1093, 1055, 1012, 961,
902, 865, 756, 706 cm–1. UV/Vis (CH2Cl2): λmax (lgε) = 699 (sh),
671.0 (5.18), 644.0 (5.07), 392.0 (sh), 331.0 (sh), 300.5 nm (5.17).
MS (MALDI-TOF): m/z = 3831 [M]+. Elemental analysis calcd.
(%) for C250H292N16NiO16·H2O: C 77.92, H 7.71, N 5.82; found: C
77.63, H 7.65, N 5.97.
Method B: Phthalocyanine 8 (0.025 mmol) and phthalocyanine 7
(0.05 mmol) were mixed with K2CO3 (0.1 mmol) in DMF (2 mL,
or DMF/THF 1:1). The mixture was heated up to 80–85 °C for
12 h. After cooling, the product was added to water (20 mL), fil-
tered off, washed thoroughly with water and methanol, dried, and
subjected to column chromatography on silica gel with CH2Cl2/n-
hexane (65:35) as eluent. Dimer 9a was obtained from PcH2 7a by
Method A in 89% yield. By starting from mononuclear phthalocy-
anines 8a and 7a in DMF, 9a was also obtained in 63% yield by
Method B.
Acknowledgments
We thank the Deutscher Akademischer Austauschdienst (DAAD)
and the Ministry of Education and Science of the Russian Federa-
tion for financial support of this work (“Mikhail Lomonosov” Pro-
gram).
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Compound 9a: 1H NMR (CDCl3, numbering according to
3
Scheme 3): δ = 9.11 (d, J = 8.5 Hz, 2 H, H2), 9.00–8.96 (m, 12 H,
H1), 8.75 (d, 4J = 2.2 Hz, 2 H, H4), 7.74 (dd, 3J = 8.5 Hz, 4J =
2.2 Hz, 2 H, H3), 7.34–7.12 (m), 6.87–6.74 (m, 44 H, 2 H5, 2 H6, 2
3
H7, 2 H8, 24 H9, 12 H10), 4.00 (t, J = 6.3 Hz, 4 H, Hα), 1.82–1.24
(m, 224 H, 216 H11, 4 Hβ, 4 Hγ), –0.69 (s, 4 H, HNH) ppm. IR
(KBr): ν = 3451 (NH), 2963, 2869, 1608, 1588, 1467, 1443, 1423,
˜
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1397, 1363, 1297, 1274, 1247, 1199, 1139, 1089, 1012, 961, 902,
865, 759, 707 cm–1. UV/Vis (CH2Cl2): λmax (lgε) = 701.5 (5.16),
667.5 (5.20), 640.5 (5.02), 611.0 (sh), 393.5 (sh), 339.5 (5.10),
293.0 nm (5.00). MS (MALDI-TOF): m/z = 3776 [M]+. Elemental
analysis calcd. (%) for C250H294N16O16: C 79.46, H 7.84, N 5.93;
found: C 79.66, H 7.87, N 6.08.
Dimer 9b was prepared from PcNi 7b by Method A in 86% yield.
By Method B, starting from mononuclear phthalocyanines 7b and
8b in DMF/THF, 9b was obtained in 71% yield.
Compound 9b: 1H NMR (CDCl3, numbering according to
Scheme 3): δ = 8.81–8.64 (m, 14 H, 12 H1, 2 H2), 8.43 (d, 4J =
3
4
1.8 Hz, 2 H, H4), 7.56 (dd, J = 8.5, J = 1.8 Hz, 2 H, H3), 7.29–
7.11 (m), 6.97 (t, J = 2.2 Hz), 6.78–6.72 (m, 44 H, 2 H5, 2 H6, 2
4
H7, 2 H8, 24 H9, 12 H10), 4.05 (t, 4 H, Hα, 3J = 6.2 Hz), 1.87–1.27
(m, 224 H, 216 H11, 4 Hβ, 4 Hγ) ppm. IR (KBr): ν = 2963, 2868,
˜
1608, 1589, 1533, 1462, 1421, 1385, 1362, 1297, 1276, 1246, 1198,
1139, 1095, 1055, 962, 903, 864, 755, 707 cm–1. MS (MALDI-
TOF): m/z = 3891 [M]+. Elemental analysis calcd. (%) for
C250H290N16Ni2O16: C 77.14, H 7.51, N 5.76; found: C 77.63, H
7.60, N 6.02. UV/Vis (CH2Cl2): λmax (lgε) = 670.5 (5.15), 628.5
(5.11), 577.0 (sh), 383.0 (sh), 299.5 nm (5.26).
Dimeric heteronuclear phthalocyanine 9c was obtained from mo-
nonuclear phthalocyanines 8a and 7b by Method B in DMF/THF
in 70% yield.
Compound 9c: 1H NMR (CDCl3, numbering according to
Scheme 3): δ = 9.03–8.57 (m, 16 H, 12 H1, 2 H2, 2 H4), 7.72–7.61
(m, 2 H, H3), 7.29–7.12 (m), 6.90–6.73 (m, 44 H, 2 H5, 2 H6, 2 H7,
Received: August 18, 2006
Published Online: March 2, 2007
Eur. J. Org. Chem. 2007, 2000–2005
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2005