Complexes of Cu(II) and Pd(II) with 2-R-1,3,11,11c-tetraazacyclopenta[c] phenanthrenes

Article abstract of DOI:10.1134/S1070363210010184

Paramagnetic complexes CuL¹SO₄?0.5H ₂O, CuL²SO₄?2H₂O and diamagnetic Pd(HL²)Cl₃ (L¹ = 2-methyl-1,3,11,11c-tetraazacyclopenta[c]phenanthrene complex (L²

Full text of DOI:10.1134/S1070363210010184

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 1, pp. 133–136. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © S.B. Larionov, L.I. Myachina, E.G. Boguslavskii, R.V. Andreev, G.I. Borodkin, V.E. Shubin, 2010, published in Zhurnal Obshchei
Khimii, 2010, Vol. 80, No. 1, pp. 139–142.
Complexes of Cu(II) and Pd(II)
with 2-R-1,3,11,11с-Tetraazacyclopenta[c]phenanthrenes
S. B. Larionova, L. I. Myachinaa, E. G. Boguslavskiia,
R. V. Andreevb, G. I. Borodkinb, and V. E. Shubinb
a Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences,
pr. Akad. Lavrent’eva 3, Novosibirsk, 630090 Russia
e-mail: lar@che.nsk.su
b Vorozhtsov Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Received March 26, 2009
Abstract―Paramagnetic complexes CuL1SO4·0.5H2O, CuL2SO4·2H2O and diamagnetic Pd(HL2)Cl3 (L1 =
2-methyl-1,3,11,11с-tetraazacyclopenta[c]phenanthrene complex (L2 = 2-phenyl-1,3,11,11с-tetraazacyclopenta-
[c]phenanthrene) were synthesized. The most probable structure of the complexes was suggested on the basis
of the IR and ESR spectra. Coordination units of paramagnetic complexes contain N atoms of the bidentate
cycle-forming ligands, L1 and L2 molecules. The square PdCl3N unit of the diamagnetic complex includes the
N atom of the triazole fragment of the monodentate ligand, (HL2)+ cation.
DOI: 10.1134/S1070363210010184
Complexes of metals with nitrogen heterocycles
form one of the most studied classes of coordination
compounds. Of great interest are those nitrogen hetero-
cycles which can play the role of bidentate cycle-
forming ligands due to their structure. Widely known
ligands of such type are 2,2'-dipyridyl and 1,10-
phenanthroline containing two pyridine fragments [1–
4]. These heterocycles are classical analytical reagents.
Coordination compounds with these ligands have
various functional properties. In particular, copper
complexes with 1,10-phenanthroline have nonlinear
optical properties [5]. Heteroligand complexes of
lanthanides containing 1,10-phenanthroline are promising
luminescent materials [6]. Complexes with nitrogen
heterocycles with two different heterocyclic fragments
attract appreciable attention of researchers [7–10].
Complexes of Pd(II) and Pt(II) with triazolopyrimidine
were synthesized, and anticancerogenic activity of the
platinum complexes was studied [10].
N
N
N
N
R
R = Me (L1), Ph (L2).
the reactions of CuSO4 with L1 and L2 (the mole ratio
Cu:L = 1:2) in the EtOH–H2O medium. The values of
μeff for paramagnetic complexes I and II equal to 1.85
and 2.2 BM, respectively, point to the d9 electron
configuration of the Cu2+ ion.
In the IR spectrum of free L1 bands at 1633, 1594,
and 1535 cm–1 are observed, which can be assigned to
the stretching vibrations of conjugated С=С and С=N
bonds. In the IR spectrum of complex I there are also
three bands in the range of 1640–1500 cm–1 (1636,
1598, and 1549 cm–1). The shift of bands in the
spectrum of complex I in comparison to the spectrum
of L1 points to the coordination of nitrogen atoms of
ligand L1 to the ion Cu2+, where L1 is apparently a
bidentate cycle-forming ligand. Such coordination
mode results in the formation of the hexatomic chelate
cycle CuC2N3. The intensive split band at 1192 and
1175 cm–1 and the band at 1079 cm–1 in the IR
The aim of this work was to synthesize and study
complexes of Cu(II) (an intermediate acid according to
Pearson) and Pd(II) (a soft acid according to Pearson)
with 2-R-1,3,11,11с-tetraazacyclopenta[c]phenanthrenes
L1 and L2 containing pyridine and 1,2,4-triazole fragments.
The complex compounds CuL1SO4·0.5H2O (I) and
СuL2SO4·2H2O (II) were obtained with high yields by
133

134
LARIONOV et al.
1
2
1
2
10000
11000 12000 13000
14000 15000
10000 11000 12000 13000 14000
15000
H, Gs
H, Gs
Fig. 2. (1) Experimental and (2) theoretical ESR spectra of
complex II in Q range. Narrow lines in the high-field part
of the spectrum correspond to the Mn2+ ion of a standard
sample.
Fig. 1. (1) Experimental and (2) theoretical ESR spectra of
complex I in Q range.
spectrum of compound I belong to the ν3 vibrations of
a coordinated SO42– anion [11]. Apparently this ion also
functions as a bidentate cycle-forming ligand. The
band at 1002 cm–1 corresponds to the ν1 vibration of
the SO42– anion. The wide band with a maximum at
3483 cm–1 belongs to a crystal water molecule. These
results suggest that complex I contains the СuN2O2
unit formed due to the coordination of bidentate cycle-
forming ligands L1 and SO42–.
range of 3400–3600 cm–1, however at lower wave
numbers there is a wide absorption band of water with
a maximum at 3352 cm–1. Apparently, water molecules
are coordinated in complex II.
The ESR spectrum of complex II strongly differs
from the spectrum of complex I, being characteristic
for compounds containing two unpaired electrons
(Fig. 2). A satisfactory simulation of this spectrum is
reached with the following parameters: S 1, D 610 Gs,
Е 95 Gs, gx 2.18, gy 2.161, and gz 2.153 (gav 2.165).
The line width W is 80 Gs in the x and y directions and
100 Gs in the z direction. Such parameters suggest a
binuclear structure of complex II, where the
exchanging pairs of Cu2+ ions produce states with full
spins S 1 and S 0. The value of the fine structure
parameter D in the calculations for the model of
interacting point magnetic dipoles corresponds to the
Cu···Cu interionic distance of 3.5 Å. The values of g-
factors found by simulating the spectrum are non-
typical for mononuclear complexes of Cu2+ ions and have
an overestimated average value as compared to gav for
complex I. Apparently there are two {CuL2(H2O)2}2+
fragments in complex II, which are connected by two
bidentate bridging SO42– ions. Ions Cu2+ are included in
the composition of distorted octahedral CuN2O4 units
formed by N atoms of the bidentate cyclic L2 ligand, O
atoms of two water molecules, and bidentate bridging
SO42– ionic ligands.
This conclusion agrees with the ESR data. The ESR
spectrum of complex I (Fig. 1) is typical for magneto-
concentrated copper(II) complexes [12]. The spectrum
is characterized by the axial g-factor, and the hyperfine
structure (HFS) is averaged due to the exchange
interaction of unpaired electrons of Cu2+ ions. The
values of g-factors (g|| 2.279, g┴ 2.068, and gav 2.138)
are usual for the Cu2+ ion which is present in a CuN2O2
coordination unit. The anisotropy of the line (90/35 Gs)
width is proportional to the averaged HFS [12].
Bands at 1635, 1594, 1534, and 1515 cm–1 corres-
ponding to the stretching vibrations of conjugated C=C
and C=N bonds are present in the IR spectrum of
coordinated L2. Positions of similar bands in the range
of 1640–1500 cm–1 in the IR spectrum of complex II
(1631, 1600, 1544, and 1516 cm–1) differ from those in
the spectrum of free L2, which points to the L2
coordination to the Cu2+ ion through N atoms. The
intensive split band at 1153 and 1135 cm–1 and the
band at 1042 cm–1 in the IR spectrum of compound II
can be assigned to the ν3 vibration of the coordinated
SO42– anion. The band at 969 cm–1 corresponds to the ν1
vibration. Unlike the IR spectrum of compound I
containing crystal water bands, the IR spectrum of
complex II does not contain an absorption band in the
The reaction of PdCL2 with L2 in ethanol acidified
by HCl yields a precipitate of diamagnetic compound
III with the composition C19H13Cl3N4Pd as determined
by the elemental analysis. The IR spectrum of
compound III in the high-frequency region essentially
differs from those of complexes I and II. First, there
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 1 2010

COMPLEXES OF Cu(II) AND Pd(II)
135
are no absorption bands in the range of 3800–3200 cm–1
that testifies to the absence of water in the composition
of complex III. Second, a band at 3120 cm–1 is
observed in the IR spectrum, which is absent from the
spectra of free L1 and L2 and from the spectra of
complexes I and II. We believe that the band at
3120 cm–1 is related to the stretching vibration of the
N–H bond. Apparently, the ion Pd2+ in complex III
coordinates not an L2 molecule, but its protonated form
as a monodentate ligand. Hence, the formula Pd(HL2)
Cl3 corresponds to complex III. Pyridine is a stronger
base (pKa 5.17) [13] than 1,2,4-triazole (pKa 2.45) [14].
We can assume that L2 is protonated at the N atom of
the pyridine fragment. Thus when the N atom of the
triazole fragment of the monodentate cation ligand
HL2+ and three Сl– ions are coordinated to the Pd2+ ion
the coordination unit PdCl3N is formed. According to
the diamagnetism of complex III, its symmetry is
close to square planar. It is possible that the band at
459 cm–1 is related to the Pd–N bond vibration. We
have assigned the bands at 330 and 318 cm–1 to the
vibrations of nonequivalent Pd–Cl bonds [15].
theoretical spectra using the Simfonia program
(Bruker).
Compounds L1 and L2 were synthesized according
to a scheme given in [16]. Reagents were of the
analytical or chemically-pure grade. Microanalyses
were fulfilled on Hewlett Packard 185 and Carlo Erba
1106 analyzers.
2-Methyl-1,3,11,11с-tetraazacyclopenta[c]phen-
anthrene. To a suspension of 0.30 mmol of 1-amino-
1,10-phenanthrolinium mesitylenesulfonate [17] in
0.4 ml of a 2 M KОН solution 0.4 ml of CH3CN was
added dropwise with stirring. The mixture was stirred
for 8 h at room temperature, and then diluted with
water (7 ml), and the reaction product was extracted by
СНCl3 (3×5 ml). The organic layer was dried with
Na2SO4, filtered, and then the solvent was distilled off.
The residue was chromatographed on a column
(sorbent Al2O3, eluent СНCl3). Yield 18 mg (26%).
1
Colorless powder, mp 175–176°С. H NMR spectrum
(CDCl3), ppm (JHH, Hz): 2.85 s (СН3), 7.68 d.d (Н9,
J 8.2, 4.3), 7.88 (Н5 or Н4, AB system, J 8.6), 7.93 (Н4
or Н5, AB system, J 8.6), 7.91 (Н7, AB system, J 9.2),
7.98 (Н6, AB system, J 9.2, 0.3), 8.35 d.d.d (Н8, J 8.2,
1.8, 0.3); 9.43 d.d (Н10, J 4.3, 1.8). 13С NMR spectrum
(CDCl3), ppm: 164.5, 151.7 (C2, C3a); 139.4, 130.3,
129.2, 124.1 (C5a, C7a, C11a, C11b); 150.7 (C10); 136.4,
130.5, 126.9, 125.6, 122.3, 116.3 (C4, C5, C6, C7, C8,
C9); 15.2 (CH3). Found: M 234.09145. C14H10N4.
Calculated: M 234.09054.
EXPERIMENTAL
1
13
The Н and C NMR spectra were recorded on an
AM-400 Bruker spectrometer (working frequency
400 MHz for Н and 100.6 MHz for 13С). The signals
1
of residual protons of CDCl3 (δН 7.24 ppm) were used
1
as the internal standard for Н and of C atoms of
13
CDCl3 (δC 76.9 ppm), for C. The mass spectra were
2-Phenyl-1,3,11,11с-tetraazacyclopenta[c]phen-
anthrene was synthesized analogously. Yield 34 mg
(36%). A sample was recrystallized from a benzene-
recorded on a Finnigan MAT-8200 device. The IR
spectra in the range 3800–200 cm–1 were recorded on
Specord 75 IR and Vertex 80 spectrophotometers.
Samples were prepared in the form of suspensions in
mineral and fluorinated oils. Magnetic susceptibility of
polycrystalline samples was measured by the Faraday
method at the room temperature.
1
hexane mixture, mp 211–212°С. H NMR spectrum
(CDCl3), ppm (JHH, Hz): 7.44–7.56 m (Н3', Н4', Н5'),
7.70 d.d (Н9, J 8.2, 4.2), 7.89 (Н5 or Н4, AB system,
J 8.6), 7.94 (Н4 or Н5, AB system, J 8.6), 8.01 (Н6 or
Н7, AB system, J 9.8), 8.02 (Н7 or Н6, AB system, J
9.8), 8.36 d.d (Н8, J 8.2, 1.7), 8.48–8.57 m (Н2', Н6'),
9.46 d.d (Н10, J 4.2, 1.8). 13С NMR spectrum (CDCl3),
ppm: 164.7, 152.2 (C2, C3a); 139.6, 131.0, 130.5, 129.2,
124.4 (C5a, C7a, C11a, C11b, C1'); 150.7 (C10); 136.2,
130.7, 129.9, 128.5, 127.7, 126.8, 125.8, 122.4, 116.7
(C4, C5, C6, C7, C8, C9, C2'-C6'); 15.2 (CH3). Found: M
296.10620. C19H12N4. Calculated: M 296.10619.
The ESR spectra were recorded on a Varian E-109
radiospectrometer equipped with a device for the
analog-digital signal transformation and with a special
software for the accumulation and primary treatment
of spectra. The study was carried out within the Q
range at the room temperature. Polycrystalline samples
were prepared by grinding a small amount of a
complex with MgO powder doped by Mn2+ ions in the
ratio 1:5000. The ESR spectrum of Mn2+ ions was used
for the calibration of the radiospectrometer working
frequency (g 2.003, a 86.6 Gs). The cited parameters
of the ESR spectra were obtained by the interpretation
of the spectra and were refined by the simulation of
CuL1SO4·0.5H2O (I). Warm (~50°С) solutions of
0.042 g of CuSO4·5H2O in ~0.7 ml of water and 0.079 g
of L1 in 1.5 ml of EtOH were mixed. A green
precipitate was formed on mixing, which was filtered
after 3 h, washed with EtOH and hexane, and dried in
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 1 2010

136
LARIONOV et al.
air. Yield 0.068 g (91%). IR spectrum, cm–1: 3483,
3098, 3073, 3044, 1636, 1598, 1549, 1483, 1446, 1387,
1377, 1192, 1175, 1079, 1002, 860, 676, 575, 478, 399,
328, 315. Found, %: C 41.7; H 2.7; N 13.4. C14H11Cu·
N4O4.5S. Calculated, %: C 41.7; H 2.75; N 13.9.
CuL2SO4·2H2O (II). Warm solutions of 0.050 g of
CuSO4·5H2O in 1 ml of water and 0.118 g of L2 in
3 ml of EtOH were mixed. On cooling the solution to
room temperature a yellow precipitate was formed,
which was treated in the same way as the precipitate of
complex I. Yield 0.118 g (~100 %). IR spectrum, cm–1:
3352, 3078, 1631, 1599, 1544, 1516, 1447, 1315,
1299, 1153, 1135, 1042, 969, 852, 739, 721, 693, 658,
574, 450, 416, 365, 331, 308, 302. Found, %: C 45.7;
H 3.0; N 11.2. С19H16CuN4O6S. Calculated, %: C 46.3;
H 3.2; N 11.5.
Pd(HL2)Cl3 (III). To a solution of 0.036 g of PdCl2
in a mixture of 1.5 ml EtOH and three drops of
concentrated HCl a solution of 0.059 g of L2 in 1.5 ml
of EtOH was added. The precipitate formed was
filtered off after ~4 h, washed with EtOH and hexane,
and dried in air. Yellow-pink powder. Yield 0.063 g
(62%). IR spectrum, cm–1: 3120, 3065, 1641, 1607,
1577, 1531, 1462, 1378, 890, 847, 785, 729, 715, 644,
563, 459, 415, 362, 330, 318, 262, 235. Found, %: C
45.0; H 2.6; Cl 20.9; N 10.7. С19H13Cl3N4Pd. Cal-
culated, %: C 44.7; H 2.6; Cl 20.85; N 11.0.
3. McWhinnie, W.R. and Miller, J.D., Adv. Inorg. Chem.
Radiochem., 1969, vol. 12, p. 135.
4. МсKenzie, E.D., Coord. Chem. Rev., 1971, vol. 6,
nos. 2–3, p. 187.
5. Yu, J.-H., Lü, Z.-L., Xu, J.-Q., Bie, H.-Y., Lu, J., and
Zhang, X., New. J. Chem., 2004, vol. 28, no. 8, p. 940.
6. Katkova, M.A., Vitukhnovskii, A.G., and Bochkarev, M.N.,
Usp. Khim., 2005, vol. 74, no. 12, p. 1293.
7. Ivashchenko, A.V., Garicheva, O.N., and Ivanova, T.N.,
Koord. Khim., 1983, vol. 9, no. 11, p. 1508.
8. Escrivà, E., Garcia-Lozano, J., Martínez-Lillo, J.,
Nuñez, H., Server-Carrio, J., Sato, L., Carrasco, R., and
Cano, J., Inorg. Chem., 2003, vol. 42, no. 25, p. 8328.
9. Aakeröy, C.B., Schultheiss, N., and Desper, J., Inorg.
Chem., 2005, vol. 44, no. 14, p. 4983.
10. Ruiz, J., Villa, M.D., Cutillas, N., Lopez, G., de Haro, C.,
Bautista, D., Mareno, V., and Valencia, L., Inorg.
Chem., 2008, vol. 47, no. 11, p. 4490.
11. Nakamoto, K. and McCarthy, J., Spectroscopy and
Structure of Metal Chelate Compounds, New York:
Wiley, 1968, p. 216.
12. Al’tshuler, S.A. and Kozyrev, B.M., Elektronnyi
paramagnitnyi rezonans (Electron Paramagnetic
Resonance), Moscow: Nauka, 1972, p. 442.
13. Brown, H.C. and Mihm, X.R., J. Am. Chem. Soc., 1955,
vol. 77, no. 7, p. 1723.
14. Hansen, L.D., Baca, E.J., and Scheiner, P., J. Hetero-
cyclic Chem., 1970, vol. 7, no. 4, p. 991.
ACKNOWLEDGMENTS
15. Comprehensive Inorganic Chemistry, Bailar, J.E.,
Emelèus, H.J., Nyholm, R., and Trotman-Dickenson, A.F.,
Eds., Oxford: Pergamon Press, 1973, vol. 3, p. 1284.
A.Yu. Vorob’ev took part in the experiments. The
authors are grateful to V.A. Daletskii for measuring
magnetic susceptibility and to L.A. Sheludyakov for
taking IR spectra.
16. Andreev, R.V. and Borodkin, G.I., Abstracts of Papers,
Trudy konferentsii “Organicheskii sintez v novom
stoletii” (Proc. Conf. “Organic Synthesis in the New
Century”), St. Petersburg: S.-Peterburg. Gos. Univ.,
2002, p. 64.
REFERENCES
1. Lindoy, L.F. and Livingstone, S.E., Coord. Chem. Rev.,
1967, vol. 2, no. 2, p. 173.
17. Takeuchi, H., Hayakawa, S., Tanahashi, T., Kabayashi, A.,
Adachi, T., and Higuchi, D., J. Chem. Soc., Perkin
Trans. 2, 1991, no. 6, p. 847.
2. König, E., Coord. Chem. Rev., 1968, vol. 3, no. 4,
p. 471.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 1 2010