SYNTHESIS AND SPECTRAL PROPERTIES OF OCTACYANOPYRAZINOPORPHYRAZINE
2683
the first band in the spectra of solutions of compounds
A
II–V in sulfuric acid suffers a red shift compared to its
value in organic solvents. The shift magnitude depends
on the complex-forming metal, that is well consistent
with the current understanding of the polarization of
chromophore framework at protonation. The
2
.0
1.5
V
coordination of Pzc(CN) H2 with the considered
metals in sulfuric acid solutions leads to a shift of 15,
8
1
0
.0
.5
II
IV
2
6 and 24 nm for copper, zinc, and cobalt complexes,
III
300
respectively (compared with the position in organic
solvents). This pattern is typical for the tetra-
areneporphyrazines aza-substituted at the periphery
0.0
00
2
400
500
600
700
800
λ, nm
[
13–16], since the introduction of electron-acceptor
Fig. 4. Electron absorption spectra of octacyanopor-
phyrazines, 17.5 M H SO
nitrogen atoms reducing the electron density in the
main chromophore leads to greater involvement of the
lone electron pairs of the nitrogen meso-atoms of the
macrocycle into conjugation, and thereby significantly
reduces their basicity.
2
2
.
C N . Calculated, %: C 53.33; N 46.67. IR spectrum
8 6
(KBr tablet), cm : 2252 (C = N).
–
1
Octacyanopyrazinoporphyrazine Pzc(CN) H ·
H O (II). 1 g of tetracyanopyrazine (I) was heated to
2
8
2
EXPERIMENTAL
4
2
00–210°C, and the resulting melt was kept at this
The IR spectra were recorded on an Avatar 360
ESP FT-IR spectrophotometer in KBr tablets, the
electron absorption spectra, on a Perkin Elmer Lambda
temperature for 5–10 min. The meet was cooled,
washed with distilled water, and the precipitate was
filtered off. The precipitate was chromatographed on
silica gel, compound II was eluted with acetone, the
eluate was evaporated to dryness. Yield of compound
II 82%. Found, %: C 47.39, 47.52; H 1.26, 1.29; N
2
0 spectrophotometer in rectangular quartz cells of 0.1
–4
to 1 cm thickness, the concentration of solutions 10
–6
–1
to 10 mol l . Elemental analysis was performed on
the analyzer CHNS-O Flash EA. The MALDI–TOF
mass spectra were obtained on a Ultraflex Bruker
Daltonics mass spectrometer. For preparation of solu-
tions were used organic solvents of chemically pure
grade and sulfuric acid of high purity grade. Purity of
the compounds obtained was checked by TLC on the
Merck Silica Gel 60 plates. The column chromato-
graphy was performed on the Merck silica gel 0.040–
41.47, 41.45; O 7.92, 7.95. C H N O . Calculated,
32 10 24 4
%
: C 48.36; H 1.26; N 42.32; O 8.06. MS (Maldi–
TOF), m/z 721 (calculated 722).
Octacyanopyrazinoporphyrazine metallocomplexes
Pzc(CN) M·nH O (III–V). A mixture of 0.18 g of
octacyanopyrazine I with 0.25 mmol of copper, cobalt
or zinc acetate, and a few drops of 1,8-diazabicyclo-
8
2
[
5,4,0]undecene-7 (DBU) was added to 15 ml of
0
.063 mm. The metal acetates prior to application to
sulfolane, and the resulting solution was kept at 135°C
for 2 h. The reaction mixture was cooled and poured
into water, the precipitate was filtered off. The
obtained metallocomplexes III–IV were chromato-
graphed on silica gel using acetone as eluent.
the syntheses were dried in a vacuum for 10 h at 110°C.
All solvents used in the work were purified by
standard techniques just before their application.
2
,3-Diiminosuccinonitrile was
obtained
by
oxidation of diaminomalenitrile with dichlorodicyano-
benzoquinone [17]. Yield 92%, mp 165–166°C.
Found, %: C 45.55, 45.69, H 1.90, 1.88; N 52.55,
Octacyanopyrazines are dark-green fine-crystalline
compounds with a metallic luster, not melting up to
4
00°C, soluble in acetone.
5
2.43. C H N . Calculated, %: C 45.28, H 1.88; N 52.83.
4 2 4
1
H NMR spec-trum (DMSO-d ), δ, ppm to HMDS:
Complex [C N Cu·3H O] (III). Yield 82%.
6
32 24
2
14.41 s (2H, NH).
Found, %: C 44.87, 44.92; H 0.75, 0.76; N 39.25,
3
9.31; O 7.40, 7.46. C H N O Cu. Calculated, %: C
32 6 24 3
Tetracyanopyrazine (I) was prepared by the
condensation of diiminosuccinononitrile with diamino-
malenitrile in trifluoroacetic acid [5]. Yield 69%, mp
4
5.85; H 0.71; N 40.12; O 7.58.
Complex [C N Zn·2H O] (IV). Yield 78%.
3
2
24
2
274–276°C. Found, %: C 53.21, 53.18; N 46.80, 46.75.
Found, %: C 45.97, 45.82; H 0.51, 0.55; N 40.10,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 12 2009