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C. Öztürk et al. / Spectrochimica Acta Part A 86 (2012) 423–431
was further purified by chromatography over a silica gel column
using THF and then a mixture of CHCl3: MeOH (20/1 by volume)
as eluents. Yield = 0.035 g (18%). UV–Vis (DMSO): ꢄmax nm (log ε)
346 (4.46), 648 (4.05), 716 (4.71); (toluene): ꢄmax nm (log ε) 340
(4.41), 642 (4.00), 709 (4.62). FT-IR ꢃmax/cm−1 (KBr pellet): 3289
(N–H), 3060 (Ar–CH), 2933, 2838 (CH), 1606 (C C), 1582, 1501,
14761, 1349, 1252 (C–O–C), 1017, 740 (C–S–C). 1H NMR (CDCl3):
ı = 8.62–6.81 (24H, m, Ar–H), 4.12–3.68 (24H, m, CH3). Calc. for
(II) (3), oxo-titanium (IV) (4) and nickel (II) (5) phthalocya-
nines are prepared by template cyclotetramerization of newly
synthesized 3,4-dimethoxyphenylthio substituted phthalonitrile
(1). 2(3),9(10),16(17),23(24)-Tetra-substituted (peripheral posi-
tion) phthalocyanines can be synthesized from 4-substituted
conditions. The syntheses of complexes (3–5) were achieved by
treatment of 3,4-dimethoxyphenylthio substituted phthalonitrile
(1) with zinc (II) acetate, titanium (IV) butoxide or nickel (II) acetate
in dry 1-pentanol (Scheme 1). In this study, synthesized tetrakis-
3,4-dimethoxyphenylthio substituted phthalocyanine compounds
were obtained as isomer mixtures as expected. No attempt was
made to separate the isomers of complexes (2–5).
C64H50N8O8S4: C, 64.74; H, 4.24; N, 9.44; S, 10.80%. Found: C, 64.12;
H, 4.17; N, 9.89; S, 10.46%. MS (ESI-MS) m/z: Calc.: 1187.3; Found:
1187.2 [M]+.
2.5.3. 2(3),9(10),16(17),23(24)-Tetrakis-[3,4-
(dimethoxyphenylthio)]phthalocyaninato zinc (II) (3)
A mixture of compound (1) (0.20 g, 0.67 mmol), DBU (0.20 ml,
0.132 mmol) and Zn(OAc)2 (0.13 g, 0.67 mmol) in 2 ml 1-pentanol
was stirred and refluxed under argon atmosphere for 12 h. The
resulting green suspension was cooled and crude product was pre-
cipitated by addition of n-hexane. This product was purified with
column chromatography using THF and then CHCl3:MeOH (10/1
by volume) as eluents. Yield: 0.075 g (35%). UV–Vis (DMSO): ꢄmax
nm (log ε) 365 (4.97), 626 (4.74), 696 (5.39); (toluene): ꢄmax nm
(log ε) 355 (4.90), 619 (4.69), 688 (5.21). FT-IR ꢃmax/cm−1 (KBr pel-
let): 3062 (Ar–CH), 2933, 2838 (CH), 1582 (C C), 1606 (C C), 1501,
1460, 1436, 1394, 1348, 1311, 1229 (C–O–C), 929, 847, 815, 741
(C–S–C). 1H NMR (CDCl3): ı = 8.12–6.79 (24H, m, Ar–H), 3.85–374
(24H, m, CH3). Calc. for C64H48N8O8S4Zn: C: 61.45, H: 3.85, N: 8.95,
S: 10.25, Found C: 61.75, H: 3.91, N: 8.86, S: 10.31. MS (ESI-MS) m/z:
Calc.: 1250.80, Found: 1250.20 [M]+.
All of these new phthalocyanines (2–5) were purified by column
chromatography. They were obtained in a moderate yield (18% for
2, 35% for 3, 37% for 4 and 20% for 5) and were characterized by
elemental analysis together with the spectral data (1H NMR, FT-IR,
mass and UV–Vis spectroscopies). The characterization data of the
new compounds are consistent with the assigned formula as shown
in Section 2.
Generally, phthalocyanine complexes are insoluble in most
organic solvents; however introduction of substituents on the
ring increases the solubility. All studied phthalocyanine complexes
(2–5) exhibited excellent solubility in organic solvents such as
DCM, CHCl3, THF, toluene, DMF and DMSO.
The characteristic vibrations corresponding to
C N were
observed at 2230 cm−1 for compound 1 in the FT-IR spectrum. The
C–O–C vibrations and the thio ether (C–S–C) vibrations for com-
pound 1 were observed at 1277 cm−1 and 740 cm−1, respectively.
Aromatic C–H and aliphatic C–H vibrations occurred at 3078 cm−1
and between 2961 and 2834 cm−1 for the phthalonitrile (1), respec-
tively. The 1H NMR spectrum of the compound 1 showed signals
with ı ranging from 7.59 to 6.98 belonging to aromatic protons and
3.89 to 3.97 ppm belonging to aliphatic protons for compound 1.
In the mass spectrum of phthalonitrile compound (1) obtained by
the relatively soft GC–MS technique, the molecular ion peak was
observed at m/z 296 [M]+.
2.5.4. 2(3),9(10),16(17),23(24)-Tetrakis-[3,4-
(dimethoxyphenylthio)]phthalocyaninato oxotitanium (IV) (4)
The synthesis and purification of 4 was as outlined for 3, except
titanium(IV)butoxide(0.115 ml, 0.34 mmol)wasemployedinstead
of zinc acetate. The amounts of the other reagents were: compound
1 (0.2 g, 0.67 mmol) and DBU (0.10 ml) in 2 ml 1-pentanol. Yield:
0.078 g (37%). UV–Vis (DMSO): ꢄmax nm (log ε) 350 (4.73), 647
(4.53), 718 (5.39); (toluene): ꢄmax nm (log ε) 352 (4.79), 643 (4.61),
714 (5.44). FT-IR ꢃmax/cm−1 (KBr pellet): 3083 (Ar–CH), 2944, 2865
(CH), 1581 (C C), 1506, 1462, 1261 (C–O–C), 1019 (Ti O), 748
(C–S–C). 1H NMR (CDCl3): ı = 9.01–7.36 (24H, m, Ar–H), 3.99–3.82
(24H, m, CH3). Calc. for C64H48N8TiO9S4: C, 61.53; H, 3.87; N, 8.97;
S, 10.27%, Found: C, 62.39; H, 4.01; N, 9.06; S, 10.15%. MS (ESI-MS)
m/z: Calc.: 1250.8, Found: 1250.8 [M]+.
After conversion into phthalocyanines (2, 3, 4 and 5) the char-
acteristic sharp C N stretch at 2230 cm−1 for phthalonitrile 1
disappeared in the FT-IR spectra of phthalocyanine derivatives. The
FT-IR spectra of metal-free (2) and metallophthalocyanines (3, 4
and 5) are very similar. The significant difference is the presence of
N–H vibrations of the inner phthalocyanine core which are assigned
to a weak vibration at 3289 cm−1 for the metal-free compound.
The characteristic vibrations corresponding to the thioether groups
(C–S–C) were observed at 740 (for 2), 741 (for 3), 748 (for 4), and
751 cm−1 (for 5). The synthesized phthalocyanine complexes (2–5)
showed characteristic vibrations belong to ether groups (C–O–C)
at ca. ∼1250 cm−1, aromatic CH stretching at ca. 3062 cm−1 and
aliphatic CH stretching at ca. 2844–2950 cm−1. FT-IR bands at
1019 cm−1 correspond to Ti O vibration from the bond between
Ti and the axial oxygen ligand confirmed titanium phthalocyanine
(4) formation.
2.5.5. 2(3),9(10),16(17),23(24)-Tetrakis-[3,4-
(dimethoxyphenylthio)]phthalocyaninato nickel (II) (5)
The synthesis and purification of 5 was as outlined for 3,
except Ni(OAc)2 (0.11 g, 0.67 mmol) was employed instead of zinc
acetate. The amounts of the other reagents were compound 1 (0.2 g,
0.67 mmol) and DBU (0.10 ml) in 2 ml 1-pentanol. Yield: 0.045 g
(20%). UV–Vis (DMSO): ꢄmax nm (log ε) 296 (4.94), 625 (4.66), 687
(4.37); (toluene): ꢄmax nm (log ε) 303 (4.73), 619 (4.36), 687 (5.03).
FT-IR ꢃmax/cm−1 (KBr pellet): 3071 (Ar–CH), 2942, 2838 (CH), 1589
(C C), 1510, 1478, 1430, 1387, 1338, 1265 (C–O–C), 929, 847,
815, 751 (C–S–C). 1H NMR (CDCl3): ı = 9.15–7.28 (24H, m, Ar–H),
4.03–3.89 (24H, m, CH3). Calc. for C64H48N8NiO8S4: C, 61.79; H,
3.89; N, 9.01; S, 10.31%, Found: C, 62.39; H, 3.81; N, 9.17; S, 10.41%.
MS (ESI-MS) m/z: Calc.: 1244.06, Found: 1244.5 [M]+.
The 1H NMR spectra of tetra-substituted phthalocyanine
complexes (2–5) showed broad peaks when compared with
that of corresponding phthalonitrile derivative (1). It is likely
that broadness is due to both chemical exchange caused by
aggregation–disaggregation equilibrium in CDCl3 and the fact that
the product obtained in this reaction is a mixture of four positional
isomers which are expected to show chemical shifts which slightly
differ from each other for tetra substituted complexes (2–5). The
3,4-dimethoxyphenylthio substituted phthalocyanines were found
to be pure by 1H NMR with all the substituents and ring pro-
tons observed in their respective regions. The tetra substituted
phthalocyanines (2 to 5) showed the phthalocyanine ring protons
3.1. Synthesis and characterization
The synthetic route of novel phthalocyanines (2–5) is shown
in Scheme 1. Peripherally tetra-substituted metal free (2), zinc