Preparation of 1,2-bis(3,4-dicyanophenoxymethyl)benzene and the binuclear zinc phthalocyanine derived from it

Article abstract of DOI:10.1070/MC2002v012n03ABEH001573

A method of synthesis of 1,2-bis(3,4-dicyanophenoxymethyl)benzene from the 1,2-bis(hydroxymethyl)benzene and 4-nitrophthalodinitrile is developed. Its tetramerization with Zn(OAc)₂·2H₂O gives a binuclear zinc phthalocyanine of a new type, containing four o-phenylidene bridges. The use of microwave heating decreases reaction time and increases yield.

Full text of DOI:10.1070/MC2002v012n03ABEH001573

Mendeleev Commun., 2002, 12(3), 96–97
Preparation of 1,2-bis(3,4-dicyanophenoxymethyl)benzene and the binuclear zinc
phthalocyanine derived from it
Alexander Yu. Tolbin,a Alexey V. Ivanov,b Larisa G. Tomilova*b and Nikolai S. Zefirovb
a Department of Chemistry, M. V. Lomonosov Moscow State University, 119992 Moscow, Russian Federation.
Fax: +7 095 939 0290; e-mail: tom@org.chem.msu.su
b Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region.
Fax: +7 095 785 7024
10.1070/MC2002v012n03ABEH001573
A method of synthesis of 1,2-bis(3,4-dicyanophenoxymethyl)benzene from the 1,2-bis(hydroxymethyl)benzene and 4-nitrophthalo-
dinitrile is developed. Its tetramerization with Zn(OAc)2·2H2O gives a binuclear zinc phthalocyanine of a new type, containing four
o-phenylidene bridges. The use of microwave heating decreases reaction time and increases yield.
The synthesis and study of binuclear phthalocyanines is one
of the priorities of modern phthalocyanine chemistry. Due to
interaction between phthalocyanine rings and a covalent bridge
between them, binuclear phthalocyanines can have specific
electro- and photocatalytic properties.1,2
Recently, the attention of investigators has been attracted to
binuclear phthalocyanines linked by only one bridge, called as
the clamshell.2 At the same time, the synthesis and properties of
binuclear phthalocyanines with a greater number of cross-links
are not described in the literature.
In order to obtain a new type of binuclear phthalocyanine, we
Scheme 2 Reagents and conditions: i, conc. H2SO4, NH4NO3, 0 °C; ii,
carried out the synthesis of 1,2-bis(3,4-dicyanophenoxymethyl)-
benzene 1 according to Scheme 1† by the common method1
of nucleophilic substitution of an activated nitro group in an
aromatic ring.
NH4OH, 20 °C; iii, POCl3, Py, 0 °C.
There are published data on the synthesis and properties of
binuclear phthalocyanines linked by one covalent bridge.1–3
Such phthalocyanines were synthesised by the interaction of bis-
phthalodinitriles with a large excess of phthalodinitrile or the
corresponding derivatives of o-phthalic acid. Under these con-
ditions, a large amount of monophthalocyanine was obtained as
a by-product.
To eliminate a possibility of the formation of phthalocyanines
with a different structure, we used only one phthalodinitrile
1 for the formation of binuclear phthalocyanine (Scheme 3).§
Phthalocyanine 4 was purified by TLC (Silufol UV-254, eluted
with MeOH, then CHCl3). It is readily soluble in the majority
of organic solvents. In the electronic absorption spectrum
(Figure 1), the Q-band occurs at 680 nm, characteristic of a D4h
symmetry, and the Sort-band at 352 nm. In the MALDI-TOF¶
MS spectrum (Figure 2) there is a peak of the molecular
ion 1692 (M+, the molecular weight of phthalocyanine 4 is
1692.392). As a peak with m/z 846 is absent in the mass
spectrum, we conclude that the side-strapped monophthalo-
cyanine is not present.
1,2-Bis(hydroxymethyl)benzene 2 has been previously syn-
thesised.3 4-Nitrophthalodinitrile 3 was obtained according to
Scheme 2. To obtain 4-nitrophthalimide, we used NH4NO3 in
concentrated H2SO4.‡ Stages ii and iii were made by published
methods,4,5 respectively.
Recently, we reported6 on the synthesis of mono- and bis-
phthalocyanines under microwave irradiation. The application
†
2.5
Reaction procedure: A mixture of 2 (2.67 g, 0.019 mol), 3 (8 g,
680
0.046 mol) and K2CO3 (2 g) in 100 ml DMSO was intensively stirred
for 15 h at 70 °C. After that, 2 g of K2CO3 was added and reaction was
continued for 15 h at the same temperature. Reaction was monitored by
TLC. Then the reaction mixture was poured into 500 ml of water, and
acetic acid was added to the mixture. The residue was filtered off,
flushed several times with water and recrystallised from EtOH. The
reaction product was dried in air at 70 °C. 6.22 g (84%) of compound 1
was obtained. Mp 229 °C. 1H NMR (CDCl3) d: 5.51 (d, 4H, CH2, J
5 Hz), 7.4–8.1 (m, 10H, Ar). IR, nmax/cm–1: 1275 (m), 1020 (w), 3100
(w), 1250 (m), 780 (w), 1610 (w), 2224 (w). MS, m/z: 390 (M+). Found
(%): C, 73.61; 73.70; H, 3.65, 3.72; N, 14.40, 14.52. Calc. for
C96H56N16O8Zn2 (%): C, 73.85; H, 3.59; N, 14.35.
2.0
1.5
1.0
0.5
0.0
352
613
‡
Reaction procedure: 28 g (0.19 mol) of phthalimide was added to 32 g
(0.4 mol) of NH4NO3 in 400 ml H2SO4 (d 1.84). Reaction mixture was
stirred for 2 h, then poured on ice (300 g). The product was filtered off
and flushed with water until neutral. The substance was dried in air
at 60 °C. After crystallization from ethanol, 22.5 g (58.6%) of pure
4-nitrophthalimide were obtained. Mp 200 °C (lit.,4 mp 200–202 °C). IR,
200
400
600
800
1000
l/nm
Figure 1 Absorption spectrum of 4 in CH2Cl2.
n
max/cm–1: 3340 (NH), 1710 (C=O).
– 96 –

Mendeleev Commun., 2002, 12(3), 96–97
1692
1693
1694
1500
1000
500
1691
4
1690
1689
1695
1696
1697
1698
1685 1688 1690 1692 1694 1696 1698 1700
m/z
Figure 2 The molecular ion of 4.
of microwave irradiation considerably simplified the synthesis,
reducing the time of synthesis from several hours to several
minutes. The synthesis of binuclear phthalocyanine 4 was car-
ried out by irradiation of a homogeneous solution of compound
1 in o-DCB in the presence of two equivalents of Zn(OAc)2·2H2O
in a microwave oven (Samsung, model M1915NR). The irradi-
ation power varied from 100 to 400 W, time, from 5 to about
30 min. Experimentally, optimum conditions for the synthesis of
binuclear phthalocyanine were found. On the one hand, the full
conversion of bisphthalonitrile 1 took place, and, on the other
hand, a smaller formation of by-products, resulting in the
increased yield of the main product was observed. Thus, the
optimum conditions for the microwave synthesis of 4 are as
follows: irradiation power of 300 W and reaction time of 15 min.
The yield of phthalocyanine was 6.8%. Thus, the use of micro-
wave irradiation decreased the reaction time and increased the
yield of the binuclear phthalocyanine.
Scheme 3 Reagents and conditions: iv, DBU, isoamyl alcohol, Zn(OAc)2·2H2O,
o-DCB, 14 h, 180 °C.
References
1 S. Marcuccio, P. Svirskaya and S. Greenberg, Can. J. Chem., 1985, 63,
3057.
2 E. Dodsworth, A. B. P. Lever and P. Seymour, J. Phys. Chem., 1985, 89,
5698.
3 H. Becker, G. Domschke, E. Fanghänel, M. Fischer, K. Gewald, R. Mayer,
D. Pavel, H. Schmidt, K. Schwetlick, W. Berger, J. Faust, F. Gentz, R. Gluch,
K. Müller, K. Schollberg, E. Seiler and G. Zeppenfeld, Organikum, VEB
Deutscher Verlag der Wissenschaften, Berlin, 1990, vol. 2.
4 M. Bogert and L. Boroschek, J. Am. Chem. Soc., 1901, 23, 740.
5 H. Drew and D. Kelly, J. Chem. Soc., 1941, 10, 639.
6 E. G. Kogan, A. V. Ivanov, L. G. Tomilova and N. S. Zefirov, Mendeleev
Commun., 2002, 54.
This work was supported by the Russian Foundation for Basic
Research (grant no. 00-03-32658).
§
Reaction procedure: 55 mg of Zn(OAc)2·2H2O (0.25 mmol), 0.5 ml of
isoamyl alcohol and 0.3 ml of DBU were added to a solution of 0.2 g
(0.5 mmol) of compound 1 in 25 ml of o-dichlorobenzene. The mixture
was boiled in an atmosphere of argon for 14 h. After completion of the
reaction, the reaction mixture was filtered, and the residue on the filter
was repeatedly flushed with chloroform. The filtrate was evaporated and
the greasy residue was multiply flushed at first with methanol and then
with chloroform. The extracts were combined and evaporated to give
binuclear phthalocyanine 4 (4 mg, 1.84%). 1H NMR (CDCl3) d: 5.20 (m,
16H, OCH2), 7.2–7.8 (m, 40H, Ar). UV–VIS (CH2Cl2, lmax/nm): 352,
613, 680. MS, m/z: 1691 (M+). Found (%): C, 68.42; 68.53; H, 3.12,
3.04; N, 13.60, 13.70. Calc. for C96H56N16O8Zn2 (%): C, 68.13; H, 3.34;
N, 13.24.
¶
The sample was deposited on the matrix and analysed by an ionization
Received: 4th March 2002; Com. 02/1899
method during laser desorption.
– 97 –