856
IVANOVA et al.
1
Thus, chemical modification of tetra(4-tert-butyl)-
(5.28). H NMR spectrum (CDCl ), δ, ppm: ‒0.66 s (2H,
3
phthalocyanine to tetrakis[5,6-bis(4-tert-butylphenyl)-
pyrazino]porphyrazine increases the acidity by two orders
of magnitude and enhances fluorescence properties (more
than fivefold increase of the fluorescence quantum yield).
NH), 1.48 s (72H, t-Bu), 7.58 d (16H, m-H, J = 8.1 Hz),
8.05 d (16H, o-H, J = 8.1 Hz). Mass spectrum (MALDI-
TOF): m/z 1582.926 [M + 3H] .
+
Tetra(4-tert-butyl)phthalocyanine (2). A mixture
of 3.0 g (16.3 mmol) of 4-tert-butylphthalonitrile and
EXPERIMENTAL
0
.12 g (17.1 mmol) of lithium in 20 mL of anhydrous
quinoline was refluxed for 3 h. The mixture was cooled,
0 mLof concentrated aqueous HCl and 150 mLof water
1
The H NMR spectra were recorded on a Bruker
spectrometer. The mass spectra were obtained with a
ShimadzuAxima Confidence MALDI-TOF spectrometer.
The purity of the synthesized compounds was checked
by TLC on silica gel plates (layer thickness 0.5 mm,
Merck) using chloroform as eluent. The compounds were
purified and identified according to the recommendations
given in [17]. Spectrophotometric titration with solutions
of perchloric acid in acetonitrile (water content less
than 0.03%) was carried out using Varian Cary 100 and
SPEK SSP-715 spectrophotometers. The experimental
procedure and data processing were described in detail
in [18–24].
3
were added with stirring, and the precipitate was filtered
off, washed with water, and dried. The product was
dissolved in chloroform and subjected to chromatography
on aluminum oxide (activity grade III). The eluate was
evaporated, and compound 1 was precipitated with
methanol. Yield 0.8 g (36.2%), R 0.52 (CHCl –hexane,
f
3
3
: 1). Electronic absorption spectrum (CHCl ), λmax, nm
3
(
(
(
(
log ε): 342 (4.81), 603 (4.41), 645 (4.59), 664 (5.03), 701
1
5.10). H NMR spectrum (CDCl ), δ, ppm: ‒2.60 br.s
3
2H, NH), 1.90 m (36H, t-Bu), 8.15 m (4H, 5-H), 8.86 m
4H, 3-H), 9.16 m (4H, 6-H). Mass spectrum (MALDI-
+
5
,6-Bis(4-tert-butylphenyl)pyrazine-2,3-dicarbo-
TOF): m/z 739.156 [M] .
nitrile. A solution of 4.0 g (12.4 mmol) of 1,2-bis(4-
tert-butylphenyl)ethane-1,2-dione, 1.4 g (13.0 mmol) of
FUNDING
This study was performed under financial support by
the Russian Science Foundation (project no. 19-73-20079)
using the facilities of the Upper Volga Regional Center for
Physicochemical Studies.
2,3-diaminomaleonitrile, and 100 mg of p-toluenesulfonic
acid in 15 mL of methanol was refluxed for 3 h. The
mixture was cooled, and the precipitate was filtered
off, washed with methanol, and dried in air at room
1
CONFLICT OF INTEREST
The authors declare the absence of conflict of interest.
REFERENCES
temperature. Yield 4.2 g (85.9%). H NMR spectrum
(
CDCl ), δ, ppm: 1.35 s (18H, t-Bu), 7.41 d.t (4H, m-H,
3
J = 8.6, 2.1 Hz), 7.55 d.t (4H, o-H, J = 8.6, 2.1 Hz). Mass
+
spectrum (MALDI-TOF): m/z: 395.667 [M + H] .
1
2
3
4
5
. Berezin, B.D., Koordinatsionnye soedineniya porfirinov
i ftalotsianina (Coordination Compounds of Porphyrins
and Phthalocyanine), Moscow: Nauka, 1978.
Tetrakis{5,6-bis(4-tert-butylphenyl)pyrazino-
2,3-c]}porphyrazine (1). Metallic lithium, 50 mg
7.2 mmol), was dissolved on heating in 10 mL of
[
(
. Stepanov, B.I., Vvedenie v khimiyu i tekhnologiyu orga-
nicheskikh krasitelei (Introduction to the Chemistry and
Technology of Organic Dyes), Moscow: Khimiya, 1984.
ethylene glycol, 400 mg (1.01 mmol) of 5,6-bis(4-tert-
butylphenyl)pyrazin-2,3-dicarbonitrile was added, and
the mixture was refluxed for 3 h. The mixture was cooled,
and the precipitate was filtered off, washed with water,
and dried in air at 70°C. The product was dissolved
in chloroform, and the solution was acidified with
trifluoroacetic acid until the color changed from bluish
to green and subjected to silica gel chromatography using
chloroform–ethanol (99 : 1) as eluent. The eluate was
evaporated, and porphyrazine 1 was precipitated with
methanol, filtered off, and dried in air at 70°C. Yield
. Porfiriny: spektroskopiya, elektrokhimiya, primenenie
(Porphyrins: Spectroscopy, Electrochemistry, and Appli-
cation), Enikolopyan, N.S., Ed., Moscow: Nauka, 1987.
. Stillman, M.J. and Nyokong, T., Phthalocyanines: Prop-
erties and Applications, Leznoff, C.C. and Lever, A.B.P.,
Eds., New York: VCH, 1989, vol. 1, p. 133.
. Liu, Z., Zhang, X., Zhang, Y., and Jiang, J., Spectrochim.
Acta, Part A, 2007, vol. 67, no. 5, p. 1232.
7
0 mg (17.5%), R 0.85 (benzene–methanol, 30 : 1).
f
6. Nonlinear Optics of Organic Molecules and Polymers,
Nalwa, H.S. and Miyata, S., Eds., Boca Raton: CRC,
1997.
Electronic absorption spectrum (CHCl ), λmax, nm
3
(
log ε): 372 br (5.15), 473 br (4.83), 648 (5.18), 679
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 5 2020