CHIZHOVA et al.
1650
1
Electron absorption spectra of porphyrins 1 and 2 and Zn(II)
porphyrinates 3–6 in СHCl3, λ, nm (log ε)
6. In Н NMR spectrum of complex 6 signals of
pyrrole protons are absent.
Compound
Band I
Band II
Soret band
EXPERIMENTAL
no.
1
646 (4.05)
649 (3.94)
591 (4.10)
596 (3.97)
606 (3.88)
660 (4.07)
590 (4.15)
593 (4.01)
553 (4.33)
558 (4.37)
567 (4.15)
603 (4.17)
418 (5.76)
422 (5.63)
424 (5.54)
428 (5.67)
436 (5.51)
468 (5.42)
In this study we used 5,10,15,20-tetra(4-
bromophenyl)porphyrin produced by Porphychem and
aluminum oxide by Merck. Electron absorption spectra
were recorded on a spectrophotometer Cary-100. Mass
spectra were obtained on a mass spectrometer Maldi
2
3
4
1
5
Tof Shimadzu Biotech Axima Confidence. Н NMR
spectra were registered on a Bruker AV III-500
spectrometer in deuterochloroform. TLC analysis was
performed on Silufol plates, eluent chloroform-hexane,
2 : 1. Solvents purification was carried out as described
in [6].
6
Porphyrins exhibit their biological and catalytic
properties in complexes with metals. In the syntheses
of metalloporphyrins dimethylformamide [5] is usually
used. We synthesized complex Zn(II) 5,10,15,20-tetra-
(4-bromophenyl)porphyrinate 3 by reacting porphyrin
1 with zinc acetate in boiling mixture of chloroform–
DMF, 1 : 4.
2-Bromo-5,10,15,20-tetra(4-bromophenyl)por-
phyrin (2). To 0.04 g (0.043 mmol) of porphyrin 1 in
a mixture of 8 mL of СНСl3 and 2 mL of DMF was
added 0.0153 g (0.086 mmol) of NBS, the mixture was
stirred, heated till boiling, boiled at reflux for 5 min. In
the reaction mixture pyridine was added, the mixture
was cooled, water was added, organic layer was
separated, carefully washed with water, dried with
Na2SO4, evaporated to minimal quantity, chromato-
graphed on aluminum oxide eluting with a mixture
methylene chloride–hexane, 1 : 1, then with methylene
The bromination of Zn(II) 5,10,15,20-tetra(4-bro-
mophenyl)porphyrinate 3 with NBS (molar ratio 1 : 2)
in a mixture chloroform–DMF during 2 min results in
Zn(II) 2-bromo-5,10,15,20-tetra(4-bromophenyl)porphy-
rinate 4. In the reaction of complex 3 with NBS (molar
ratio 1 : 8) in a mixture chloroform–DMF during 10 min
Zn(II) 2,3,12,13-tetrabromo-5,10,15,20-tetra(4-bromo-
1
chloride. Yield 0.027 g (0.0267 mmol) (63%). Н
phenyl)porphyrinate
5
was mostly obtained.
NMR spectrum, δ, ppm: –2.95 s (2Н, NH), 7.87–7.95
m (8Н, НmPh), 8.02 m (2Н), 8.08 m (6Н, НоPh), 8.68–
8.75 m (2H), 8.78–8.84 m (2Н), 8.85 s (1Н), 8.88–8.91
s (2Нpyrr. ring).
Admixtures of bromoderivatives containing less than 4
bromine atoms were separated by column chromato-
graphy on aluminum oxide (eluent methylene chloride).
Further bromination of compound 5 with NBS (molar
ratio 1 : 8) in the mixture chloroform–DMF during
12 min results in Zn(II) 2,3,7,8,12,13,17,18-octabromo-
5,10,15,20-tetra(4-bromophenyl)porphyrinate 6.
Zn(II) 5,10,15,20-Tetra(4-bromophenyl)porphy-
rinate (3). 0.04 g (0.043 mmol) of porphyrin 1 and
0.079 g (0.43 mmol) of Zn(OAc)2 were dissolved in a
mixture of 8 mL of chloroform and 2 mL of DMF, the
reaction mixture was heated till boiling, boiled for 8 min,
then cooled, water was added, organic layer was sepa-
rated, washed with water, dried with Na2SO4, evapora-
ted to minimal quantity, chromatographed on aluminum
oxide eluting with methylene chloride, then with chloro-
form. Yield 0.034 g (0.0344 mmol) (80%), Rf 0.60. 1Н
NMR spectrum, δ, ppm: 7.93 d (8Н, НmPh, J 7.60 Hz),
8.10 d (8Н, НоPh, J 7.70 Hz), 8.97 s (8Нpyrr. ring). Mass
spectrum, m/z (Irel, %): 993.42 (4.7) [M]+, 837 (4.5),
619 (6.2), 485 (11.5), 457 (100), 441 (72.8).
The obtained compounds were characterized by
electron absorption, 1Н NMR, and mass spectra.
Characteristics of electron absorption spectra of
porphyrins 1 and 2 and Zn(II) porphyrinates in
chloroform are given in the table. At the introduction
of one bromine atom into the pyrrole ring of 1 a red
shift of bands in the electron absorption spectrum by
3–4 nm is observed. The Soret band of monobromo-
substituted Zn(II) porphyrinate 4 is shifted to the
longwave region by 4 nm, bands I and II are shifted by
5 nm compared to unsubstituted 3. Maximum red shift
of bands in electron absorption spectrum is observed in
the case of octabromo-substituted Zn(II) porphyrinate
Zn(II) 2-Bromo-5,10,15,20-tetra(4-bromophe-
nyl)prophyrinate (4). 0.02 g (0.0198 mmol) of
porphyrin 2 and 0.0363 g (0.198 mmol) of Zn(OAc)2
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 11 2015