Synthesis and spectral properties of porphyrazines with unsymmetrical structure based on 3,6-dipentoxyphthalodinitrile and 1,2-diphenylfumarodintrile

Article abstract of DOI:10.1134/S1070363209050272

Porphyrazines of unsymmetrical structure of A₃B, ABAB and AABB types were prepared by random condensation of 3,6-dipentyloxyphthalodinitrile (A component) with 1,2-diphenylfumarodinitrile (B component), and their spectral properties were invest

Full text of DOI:10.1134/S1070363209050272

ISSN 1070-3632, Russian Journal of General Chemistry, 2009, Vol. 79, No. 5, pp. 1024–1028. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © N.E. Galanin, G.P. Shaposhnikov, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 5, pp. 852–856.
Synthesis and Spectral Properties of Porphyrazines
with Unsymmetrical Structure Based
on 3,6-Dipentoxyphthalodinitrile
and 1,2-Diphenylfumarodintrile
N. E. Galanin and G. P. Shaposhnikov
Ivanovo State Chemical Technological University,
pr. Engel’sa 7, Ivanovo,153000 Russia
e-mail: ttoc@isuct.ru
Received November 18, 2008
Abstract―Porphyrazines of unsymmetrical structure of А3В, АВАВ and ААВВ types were prepared by
random condensation of 3,6-dipentyloxyphthalodinitrile (A component) with 1,2-diphenylfumarodinitrile (B
component), and their spectral properties were investigated.
DOI: 10.1134/S1070363209050272
Substituted porphyrazines with unsymmetrical
structure nowadays are intensively studied. This is
related to the fact that the presence in a molecule of
both electron-donor and electron-acceptor substituents
simultaneously leads to a polarized electronic structure
[1], and such compounds are promising for application
in non-linear optics [2, 3]. Moreover, the unsym-
metrical porphyrazines containing long alkyl sub-
stituents or bulky triphenylmethyl groups often possess
the properties of liquid crystals [4–6]. The features of
molecular and electronic structure of unsymmetrically
substituted porphyrazine provide a possibility of their
application to nano technology [7].
as A component is chosen 3,6-dipentoxyphthalo-
dinitrile (I), as B component 1,2-diphenylfumaro-
dinitrile (II).
The choice of compound I is defined by the
presence in its structure of two bulky pentoxy sub-
stituents that hinder sterically the formation of sym-
metrical octapentoxyphthalocyanine [13] and thus
increase the process selectivity. Dinitrile I is obtained
by alkylation of 3,6-dihydroxyphthalodinitrile (III)
with 1-bromopentane in DMF in the presence of
K2CO3.
OH
OC5H11
CN
CN
CN
K2CO3
Among the numerous tetrapyrrole derivatives a
great interest present the porphyrazines of unsym-
metrical structure containing phenyl substituents or
condensed benzene rings in the pyrrole fragments [8–
10] owing to their specific electronooptical properties.
The aim of this work is the development of methods
for the synthesis of unsymmetrical phenyl-substituted
porphyrazines containing strong electron-donor sub-
stituents in a fused benzene fragment, and the study of
spectral properties of the synthesized compounds.
+ BrC5H11
CN
OC5H11
OH
III
I
Compound I is a white powder, well soluble in
benzene and chloroform and poorly soluble in DMF
and acetone. Its composition and structure are
confirmed by elemental analysis, data of vibration and
1H NMR spectroscopy, and mass-spectrometry.
For the synthesis of porphyrazines of such structure
the most often the method is used of random
condensation of two ortho-dicarboxylic acid nitriles in
the presence of a template agent [11, 12]. In this work
The IR spectrum of compound I contains a band at
2936 cm–1 that corresponds to vibrations of С–H bonds
in alkyl substituents, a band at 2304 cm–1 charac-
1024

SYNTHESIS AND SPECTRAL PROPERTIES OF PORPHYRAZINES
1025
terizing vibrations of cyano groups, bands at 1116 and
2,3,7,8-tetraphenyldi[(3,6-dipentoxy)benzo]porphyr-
azine (VI) (ААВВ). All these compounds were
isolated and purified by column chromatography.
Their composition and structure were elucidated by
means of elemental analysis, vibration, electronic, and
1H NMR spectroscopy.
1080 cm–1 that indicate the presence of С–О–С bonds.
1
In the H NMR spectrum of nitrile I at the most
downfield singlet at 7.38 ppm corresponds to the
resonance of two benzene ring protons, a multiplet in
the region of 4.19–4.01 characterizes the resonance of
four protons in the α-positions of alkyl groups, a multiplet
at 1.95–1.89 ppm corresponds to the resonance of four
protons in the β-positions, a multiplet at 1.49–1.24 ppm,
the resonance of eight protons in γ- and δ-positions,
and a singlet at 0.89 ppm, the resonance of six protons
of terminal methyl groups. In the mass spectrum of
compound I (ionization by electron impact) occurs a
peak of molecular ion, m/z 300 [М]+, and the peaks of
the products of its fragmentation: m/z 273 [M – HCN]+,
213 [M – OC5H11]+, and 126 [M – 2OC5H11]+.
In the IR spectra of porphyrazines IV–VI appear
selected several common bands. The bands in the
region of 3081–3076 cm–1 correspond to N–H vibra-
tions of endocyclic imino groups, the strong bands at
2954–2853 cm–1 correspond to vibrations of С–H
bonds in alkyl residues, the bands at 1731–1726,
1507–1488, 1271–1245 cm–1 characterize vibrations of
the bonds С=С and С=N in the macrocycles. The
bands in the region 1161–1148 cm–1 correspond to
vibrations of CAr–O bonds, and those at 1060–1058 cm–1,
to СAlk–О bonds.
Heating of the three-fold excess of nitrile I with
compound II in boiling 1-pentanol in the presence of
lithium 1-pentoxide followed by treatment with acetic
acid leads, in accordance Scheme 1, to the formation
of a mixture of 2,3-diphenyltri[(3,6-dipentoxy)benzo]
porphyrazine (IV) (А3В), 2,3,12,13-tetraphenyldi[(3,6-
dipentoxy)benzo]porphyrazine (V) (АВАВ) and
1
In the H NMR spectra of porphyrazines IV–VI
there are three groups of signals that characterize
resonance of the protons of endocyclic N–H groups,
pentoxide substituents, and the protons of benzene
rings, respectively. In going from compound IV to VI
the positions of the signals vary insignificantly, only
H11C5O
OC5H11
OC5H11
OC5H
11 N
N
(1) C5H11OH, C5H11OLi
(2) MeCO2H
N
N
CN
NC
Ph
Ph
Ph
Ph
+
NH
HN
CN
CN
N
N
OC5H11
OC5H11
H11C5O
OC5H11
I
II
IV
H11C5O
OC5H11
Ph
Ph
OC5H
11 N
N
N
N
N
N
N
N
Ph
Ph
Ph
Ph
+
NH
+
HN
NH
HN
Ph
Ph
N
N
N
N
OC5H11
H11C5O
OC5H11
H11C5O
OC5H11
V
VI
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 5 2009

1026
GALANIN, SHAPOSHNIKOV
changes occur in their relative intensity. In the
spectrum of porphyrazine IV the resonance of ten
protons in two phenyl substituents appear as a multi-
plet at 7.73–7.45 ppm, a multiplet at 7.19–7.03 ppm
characterizes the resonance of protons of benzene rings
in the isoindole fragments. A multiplet at 3.56–
3.50 ppm corresponds to the resonance of 12 protons
of methylene groups in the α-positions of six pentoxide
substituents, a multiplet at 2.01–1.97 ppm corresponds
to the resonance of 12 protons in the β-positions, a
multiplet at 1.48–1.33 ppm to the resonance of 24 pro-
tons in the γ- and δ-positions, a singlet at 0.97 ppm
characterizes the resonance of 18 protons of terminal
methyl groups. The resonance of two protons of
endocyclic imino groups is registered as a broad
singlet at –0.38 ppm
molecule to the acceptor one [14], which in this
particular case is diphenylpyrrole fragment. The Soret
band has a maximum at 342 nm. The comparison of
electron absorption spectrum of compound IV with
that of similar structure 2,3-di(m-trifluoromethyl-
phenyl)tribenzoporphyrazine [10] shows that the
introduction of electron-donor substituents to benzene
rings results in red shift of the long-wave Q band
maximum by 85 nm, the middle component suffers a
red shift by 64 nm, and the short-wave component
remains in the same region. This observation points to
the strong enhancing of HOMO energy at the
introducing pentoxide substituents to 3 and 6 positions
of isoindole fragments owing to significant contribu-
tion of atomic orbitals of the carbon atoms in these
positions to its formation [15]. Besides, polarization of
molecule of compound IV affects significantly its
spectral properties. Judging from the data of semi-
empirical AM1 quantum-chemical calculations, the
dipole moment of compound IV molecule is 8.54 D
that provides the observed value of the red shift of the
Q band long-wave component.
1
In the H NMR spectra of compounds V and VI
relative intensity grows of the resonance signals of the
protons in phenyl substituents and upfield shift occurs
of the signals of protons of endocyclic imino groups.
This fact indicates somewhat more planar structure of
compounds V and VI.
Electron absorption spectrum of compound V
(ABAB) (Fig. 1, curve 2) in the long-wave region
contains four bands with the maxima at 778, 717, 680,
and 640 nm. The increase in the number of bands
results from the fact that due to decrease in symmetry
of the macrocycle the two lowest molecular π* orbitals
are no more degenerate. In the spectrum of compound
VI (ААВВ) the number of bands in its electron
absorption spectrum diminishes (Fig. 1, curve 3). In
the long-wave region occur only two bands with the
maxima at 763 and 678 nm. In the region of 448 nm in
the spectra of compounds V and VI there are two
diffuse charge transfer bands and the Soret bands have
maxima at 344 and 335 nm.
Electron absorption spectra of compounds IV–VI
show strong absorption in the region of 778–633 nm
(Q bands) and in the region of 344–335 nm (Soret
bands).
In the spectrum of porphyrazine IV (А3В) (Fig. 1,
curve 1) the long-wave band is split into three
components with the maxima at 777, 718 and 633 nm.
The three-bands character of the spectrum in the long-
wave region is typical for the metal free porphyrazine
of А3В type, the most long-wave component of Q and
as well as diffuse band in the region of 413 nm are the
bands of charge transfer from the donor part of the
The data obtained fit well the Gouterman four
orbital model [16], assuming that the number of bands
in the electron absorption spectra of the unsym-
metrically substituted porphyrazine cis-isomers (ААВВ)
should be minimal, while that of the trans-isomer
(АВАВ) maximal. Just this picture is observed in our
case.
D
1.0
0.8
3
2
1
0.6
0.4
0.2
0.0
EXPERIMENTAL
The electronic absorption spectra of the obtained
compounds were registered on a Hitachi UV-2001
400
500
600 700
800 λ, nm
1
spectrophotometer, the H NMR spectra were taken
Electron absorption spectra (solvent chloroform): (1) com-
pound IV, (2) compound V, and (3) compound VI.
from solutions in CDCl3 on a Bruker АMD-200
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 5 2009

SYNTHESIS AND SPECTRAL PROPERTIES OF PORPHYRAZINES
1027
instrument (200 MHz, internal reference TMS), IR
spectra were registered on an Avatar 360 FT-IR
spectrophotometer in the region of 400–4000 cm–1
from thin films, the mass spectrum was registered on a
Varian Saturn 2000R chromato-mass sepctrometer.
Elemetal analysis was carried out on a FlashEA 1112
CHNS–O Analyzer.
(0.28), 718 (0.58), 676 sh., 633 (0.71), 413 (0.44), 342
(1.00). The IR spectrum, ν, cm–1: 3081, 2954, 2923,
2853, 1728, 1504, 1270, 1161, 1060, 807, 760, 722,
1
597. The H NMR spectrum, δ, ppm: 7.73–7.45 m
(10H), 7.19–7.03 m (6H), 3.56–3.50 m (12H), 2.01–
1.97 m (12H), 1.48–1.33 m (24H), 0.97 s (18H), –0.38
s (2H). Found, %: С 74.44; H 7.66; N 9.12.
С70H84N8О6. Calculated, %: С 74.18; H 7.47; N 9.89.
1,2-Diphenylfumarodinitrile III was prepared
along the procedure [17].
2,3,12,13-Tetraphenyldi[(3,6-dipentoxy)benzo]-
porphyrazine (V) (АВАВ), yield 0.06 g (34%), green
powder, well soluble in в benzene, chloroform, poorly
soluble in acetone. Rf 0.65 (Silufol, CHCl3). The elec-
tronic absorption spectrum (CHCl3), λmax., nm (D/Dmax.):
778 (0.34), 717 (1.00), 680 (0.82), 640 (0.80), 448
(0.39), 344 (0.96). The IR spectrum, ν, cm–1: 3079,
2948, 2855, 1731, 1496, 1271, 1161, 1050, 807, 722,
3,6-Dipentoxyphthalodinitrile (I). A mixture of
10 g (0.0625 mol) of 3,6-dihydroxyphthalodinitrile II,
45 ml (0.25 mol) of 1-bromopentane, 34.5 g (0.25 mol)
of K2CO3 and 50 ml of DMF was stirred at 100°С for
20 h, then cooled, diluted with 100 ml of water, and
the precipitate formed was filtered off, dried, and
recrystallized from DMF. Yield 18 g (96%), white
powder, mp 177°С. IR spectrum, ν, cm–1: 3096, 3032,
2936, 2304, 1528, 1416, 1336, 1220, 1116, 1080, 832.
The 1H NMR spectrum, δ, ppm: 7.38 s (2H), 4.19–4.01
m (4H), 1.95–1.89 m (4H), 1.49–1.24 m (8H), 0.89 s
(6H). The mass spectrum, m/z (Irel., %): 300 [М]+ (45),
273 [M – HCN]+ (52), 213 [M – OC5H11]+ (100), 126
[M – 2OC5H11]+ (88). Found, %: С 71.83; H 8.17; N
9.40. C18H24O2N2. Calculated, %: C 71.97; H, 8.05; N,
9.33.
1
597. The H NMR spectrum, δ, ppm: 7.75–7.42 m
(20H), 7.18–7.08 m (4H), 3.55–3.51 m (8H), 2.02–
1.96 m (8H), 1.49–1.30 m (16H), 0.96 s (12H), –0.77 s
(2H). Found, %: С 77.12; H 6.77; N 9.91. С68H70N8О4.
Calculated, %: С 76.81; H 6.64; N 10.54.
2,3,7,8-Tetraphenyldi[(3,6-dipentoxy)benzo]por-
phyrazine (VI) (ААВВ), yield 0.04 g (25%), green
powder, well soluble in в benzene, chloroform, poorly
soluble in acetone. Rf 0.54 (Silufol, CHCl3). The elec-
tronic absorption spectrum (CHCl3), λmax., nm (D/Dmax):
763 (1.00), 678 (0.89), 628 sh., 442 (0.34), 335 (0.99).
The IR spectrum, ν, cm–1: 3076, 2953, 2861, 17329,
Condensation of 3,6-dipentoxyphthalonitrile (I)
with 1,2-diphenylfumarodinitrile (III). To a boiling
solution of lithium 1-pentoxide in 1-pentanol prepared
by dissolving 0.1 g of lithium in 20 ml of anhydrous 1-
pentanol was charged 0.3 g (1.0 mmol) of compound I,
after 15-min reflux was added 0.08 g (0.3 mmol) of
compound III and boiling at reflux was continued for
4 h. The reaction mixture was cooled, 20 ml of acetic
acid and 30 ml of water was then added, the precipitate
separaterd was filtered off, washed on the filter with 30
ml of methanol, and dried. The product was dissolved
in benzene and subjected to chromatography on a
column with silica gel 60 (eluent benzene–hexane–
chloroform, 5:10:1 by volume). The mixture separated
1
1488, 1245, 1152, 1058, 809, 733, 591. The H NMR
spectrum, δ, ppm: 7.78–7.41 m (20H), 7.16–7.09 m
(4H), 3.54–3.49 m (8H), 2.10–1.98 m (8H), 1.48–1.35
m (16H), 0.97 s (12H), –0.81 s (2H). Found, %: С
76.55; H 6.98; N 9.85. С68H70N8О4. Calculated, %: С
76.81; H 6.64; N 10.54.
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