Cu(II) and Co(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole: Synthesis and study

Article abstract of DOI:10.1134/S1070328406050010

The Cu(II) and Co(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole (L) of the composition CuLA₂ · H₂O (A = Cl ^-, Br^-), CuL₂A₂ (A = Cl^-, Br^-, NO₃^-), CoL₂A₂ · nH₂O (A = Cl^-, n = 1; A = NCS^-, n = 0) are synthesized. In these complexes, the ligand L is coordinated to a metal in monodentate mode through the heterocyclic N(1) atom. The Cu: L = 1: 1 complexes have binuclear structures with the anions acting as bridges, whereas the M: L = 1: 2 complexes are mononuclear. Both ferro- and antiferromagnetic exchange interactions are detected for the synthesized complexes. Pleiades Publishing, Inc., 2006.

Full text of DOI:10.1134/S1070328406050010

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2006, Vol. 32, No. 5, pp. 309–320. © Pleiades Publishing, Inc., 2006.
Original Russian Text © M.B. Bushuev, A.V. Virovets, D.Yu. Naumov, Yu.G. Shvedenkov, L.A. Sheludyakova, V.N. Elokhina, E.G. Boguslavsky, L.G. Lavrenova, 2006, published in
Koordinatsionnaya Khimiya, 2006, Vol. 32, No. 5, pp. 323–335
Cu(II) and Co(II) Complexes
with 3,5-Diphenyl-4-amino-1,2,4-triazole: Synthesis and Study
M. B. Bushueva, A. V. Virovetsa, D. Yu. Naumova, Yu. G. Shvedenkova, L. A. Sheludyakovaa,
V. N. Elokhinab, E. G. Boguslavskya, and L. G. Lavrenovaa
a
Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, pr. Akademika Lavrent’eva 3,
Novosibirsk, 630090 Russia
b
Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received April 18, 2005
Abstract—The Cu(II) and Co(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole (L) of the composition
CuLA2 · H2O (A = Cl–, Br–), CuL2A2 (A = Cl–, Br–, NO3– ), CoL2A2 · nH2O (A = Cl–, n = 1; A = NCS–, n = 0)
are synthesized. In these complexes, the ligand L is coordinated to a metal in monodentate mode through the
heterocyclic N(1) atom. The Cu : L = 1 : 1 complexes have binuclear structures with the anions acting as
bridges, whereas the M : L = 1 : 2 complexes are mononuclear. Both ferro- and antiferromagnetic exchange
interactions are detected for the synthesized complexes.
DOI: 10.1134/S1070328406050010
The synthesis of transition metal complexes with
1,2,4-triazoles is one of the developing directions in
NH2
coordination chemistry. The variety of modes in which
these ligands can be coordinated allows one to synthe-
size complexes with different compositions and struc-
tures [1]. In general, 1,2,4-triazoles, containing no sub-
stituents capable of coordinating or substituents in
positions 1 or 2 of a heterocycle, are coordinated to a
metal mainly as bidentate bridging ligands through the
cyclic N(1) and N(2) atoms and give oligo- or polynu-
clear compounds [1–7]. At the same time, 3,5-disubsti-
tuted and 3,4,5-trisubstituted 1,2,4-triazoles, whose
substituents do not show tendency toward coordination,
most commonly form binuclear and trinuclear linear
and triangular complexes [8–15].
With the aim to study the effect of the volume of
substituents in positions 3 and 5 of a heterocycle on the
coordination mode of a ligand, composition and struc-
ture of complexes, we synthesized Co(II) and Cu(II)
complexes with 3,5-diphenyl-4-amino-1,2,4-triazole
(L), investigated their structures, spectral and magnetic
properties.
N
N
N
(L)
Synthesis of CuLCl2 · H2O (I) and CuLBr2 · H2O
(II). A hot solution of L (0.24 g, 1 mmol) in 15 ml of
ethanol was added to 10 ml of a hot ethanol solution
containing CuCl2 · 2H2O (0.17 g, 1mmol) or CuBr2
(0.22 g, 1 mmol). Then, 5 ml of hexane was added and
the reaction mixture was stirred with a magnetic stirrer
for 2–3 h. The solutions with precipitated complexes
were mixed for 1 h with gradual cooling to room tem-
perature. The precipitates were filtered off, washed
with ethanol, and dried in air. The yield of complex I
was 0.32 g (80%), complex II was formed in 70% yield
(0.34 g).
Single crystals of CuLCl2 · H2O were obtained by
slow crystallization of complex I from a solution in
acetonitrile.
EXPERIMENTAL
We used high-purity grade CuCl2 · 2H2O,
Cu(NO3)2 · 3H2O, and CuBr2; analytical grade CoCl2
and Co(NO3)2 · 6H2O; reagent grade NH4NCS;
3,5-diphenyl-4-amino-1,2,4-triazole was synthesized
by the procedure described in [16].
'
Single crystals of CuL2 Cl2 (I'), where L' is 3,5-
diphenyl-4-isopropylideneamino-1,2,4-triazole, were pre-
pared from a solution of complex I in acetone in the
309

310
BUSHUEV et al.
Table 1. Elemental analysis of Co(II) and Cu(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole
Content (found/calcd.), %
Compound
M
C
H
N
CuLCl2 · H2O (I)
C14H14N4Cl2CuO
CuLBr2 · H2O (II)
C14H14N4Br2CuO
CuL2Cl2 (III)
16.0/16.3
43.5/43.3
3.8/3.6
14.4/14.4
13.0/13.3
10.3/10.5
9.8/9.1
34.7/35.2
55.4/55.4
48.6/48.3
50.6/50.9
55.3/55.6
54.2/54.2
2.9/3.0
4.0/4.0
3.1/3.5
3.4/3.7
3.6/3.7
4.1/4.2
11.5/11.7
18.4/8.5
C28H24N8Cl2Cu
CuL2Br2 (IV)
16.1/16.5
21.3/21.2
22.0/21.6
18.0/18.1
C28H24N8Br2Cu
CuL2(NO3)2 (V)
C28H24N10CuO6
CoL2(NCS)2 (VI)
C30H24N10CoS2
CoL2Cl2 · H2O (VII)
C28H26N8Cl2CoO
9.4/9.6
8.4/9.1
9.2/9.5
presence of a small amount of DMF on slow evapora- tate was stirred for 1–2 h, the precipitate was filtered off
and washed with ethanol. The yield was 026 g (80%).
tion of a solvent.
Synthesis of CoL2Cl2 · H2O (VII). 0.24 g (1 mmol)
of L was dissolved in 15 ml of ethanol on heating and
10 ml of a hot ethanol solution containing CoCl2
(0.19 g, 1 mmol) was added. The precipitation of VII
from this solution was performed as in the case of com-
plex VI. The yield was 0.23 g (75%).
N
N
The metal content in the compounds obtained was
determined by complexometric titration after the sam-
ple digestion in a mixture of concentrated H2SO4 and
HClO4. The content of C, H, N was determined using
Carlo Erba analyzer and a standard procedure in
microanalysis laboratory of the Novosibirsk Institute of
Organic Chemistry, Siberian Division, Russian Acad-
emy of Sciences. The composition and the results of
analysis of complexes are given in Table 1. The content
of water was determined with Paulik-Paulik-Erdey
derivatograph by heating the samples (50 mg in weight)
in quartz crucibles in air (at a rate of 2.5 K/min with
Al2O3 (50 mg) used as a standard).
The diffuse reflection spectra were recorded on a
Unicam 700 A spectrophotometer at 340–2400 nm.
IR absorption spectra were measured on Scimitar
FTS 2000 and BOMEM MB-102 spectrometers at
4000–200 cm–1.
N
N
(L')
Synthesis of CuL2Cl2 (III) and CuL2Br2 (IV). The
complexes were synthesized by the procedures of pre-
paring complexes I and II using the following amount
of reagents: CuBr2 (0.11g, 0.5 mmol) or CuCl2 · 2H2O
(0.09 g, 0.5 mmol) and L (0.24 g, 1 mmol). Complex
III was formed in 60% yield (0.19 g), while complex
IV was formed in 75% yield (0.26 g).
Synthesis of CuL2(NO3)2 (V). Cu(NO3)2 · 3H2O
(0.24 g, 1 mmol) was dissolved in 10 ml of ethanol and
15 ml of a hot ethanol solution of L (0.24 g, 1 mmol)
was added. The reaction mixture was heated almost to
boiling, and 8 ml of hexane was added. A light blue pre-
cipitate was formed. The solution with the precipitate
was stirred for 0.5 h. The precipitate was filtered off and
washed with ethanol. The yield was 0.14 g (45%).
Synthesis of CoL2(NCS)2 (VI). 0.24 g (1 mmol) of
The EPR spectra of a powdered complex V were
L was dissolved on heating in 15 ml of ethanol and 5 ml recorded on a Varian E-109 radiospectrometer
of a hot ethanol solution containing Co(NO3)2 · 6H2O equipped with a signal digitizer and original software
(0.29 g, 1 mmol) and NH4NCS (0.15 g, 2 mmol) was for accumulation and preliminary processing of spec-
added. The solution obtained was heated for 2 h almost tra. The study was performed in the Q-range. In order
to boiling and then cooled to room temperature. A blue to calibrate the working frequency and the instrument
precipitate was formed. The solution with the precipi- sweep, the spectra of the complexes under consider-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

CU(II) AND CO(II) COMPLEXES
311
Table 2. Crystallographic parameters and summary of data collection for compounds I and I'
Value
Parameter
I
I'
Empirical formula
M
C28H28Cl4Cu2N8O2
777.46
C34H32Cl2CuN8
687.12
Crystal system
a, Å
Orthorhombic, Pbca
14.834(3)
Monoclinic, C2/c
26.776(4)
b, Å
11.7307(17)
17.464(4)
9.159(2)
c, Å
17.532(2)
β, deg
90
128.72(2)
V, Å3
3038.9(9)
3354.6(10)
4; 1.361
Z; ρ(calcd.), g/cm3
µ, cm–1
4; 1.699
1.794
2.672
F(000)
1576
1420
Crystal size, mm
Radiation (λ, Å)
Diffractometer (temperature)
2θmax, deg
0.48 × 0.36 × 0.04
MoKα (0.71073)
Enraf-Nonius CAD-4 (293)
50
0.30 × 0.12 × 0.08
CuKα (1.54178)
Syntex P21 (293)
114
Tmin–Tmax
0.866–1.134
2276/2276
214
0.501–0.815
Number of measured/independent reflections
Number of refined parameters
GOOF
2350/2257 (Rint = 0.0253)
205
0.718
1.035
R-factor, reflections with I > 2σ(I)
R-factor (on all reflections)
Residual peaks of electron density, e/Å3
R1 = 0.0423, wR2 = 0.1012 R1 = 0.0426, wR2 = 0.1057
R1 = 0.0603, wR2 = 0.1075 R1 = 0.0553, wR2 = 0.1132
0.713, –0.652
0.436, –0.370
ation were recorded together with the standard (magne- water molecules were localized from the Fourier differ-
sium oxide powder doped with Mn2+ ions (g = 2.003, ence synthesis and refined by imposing restrictions on
A = 86 G)). The EPR spectral parameters used further the N–H and O–H bonds. The remaining hydrogen
were obtained on modeling of the theoretical spectra atoms were calculated geometrically and refined in a
with the Simfonia (Bruker) program.
rigid body approximation.
The coordinates of non-hydrogen atoms and their
thermal parameters in structures I and I' are listed in
Table 3; selected bond lengths and bond angles are pre-
sented in Table 4.
X-ray powder diffraction analysis was carried out
on a PHILIPS-PW1700 diffractometer (CuKα radia-
tion, graphite monochromator, scintillation detector, at
a step of 0.02° in the range of 2θ from 5° to 50°. The
measurements were performed at room tempera-
ture with silicon powder as an external standard
(a = 5.4309 Å).
The magnetic properties of polycrystalline samples
of the complexes were studied on a MPMS-5S SQUID-
magnetometer (Quantum Design) at a temperature
interval of 2–300 K) and an external magnetic filed
strength of about 5 kOe. The molar magnetic suscepti-
bility (c) was calculated with the account for atomic
diamagnetism using Pascal additive scheme. The effec-
tive magnetic moment was calculated as
The structures of complexes I and I' were deter-
mined by X-ray diffraction analysis. The crystallo-
graphic parameters and summary of data collection are
given in Table 2. The absorption correction was applied
using azimuthal scan curves. The structures were
solved by the direct methods and refined by the full-
matrix least-squares method in anisotropic approxima-
µeff = [(3k/NAβ2)χT]1/2 ≈ (8χT)1/2
,
tion for non-hydrogen atoms with SHELX97 program where k is Boltzmann constant; NA is Avogadro num-
package [17]. The hydrogen atoms of imino groups and ber, and β is Bohr magneton.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

312
BUSHUEV et al.
Table 3. Coordinates of non-hydrogen atoms (×104) and equivalent thermal parameters (×103) in structures of complexes I and I'
Atom
x
y
z
Ueq, Å2
I
Cu(1)
Cl(1)
Cl(2)
O(1)
N(1)
N(2)
N(3)
N(4)
C(3)
C(5)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
5253(1)
5841(1)
6339(1)
6051(3)
4326(3)
3961(3)
2852(4)
3442(3)
3426(4)
4008(4)
4240(4)
4351(4)
4650(4)
4839(4)
4716(4)
4416(4)
2934(4)
2485(4)
2053(4)
2071(4)
2512(4)
2948(4)
8707(1)
9976(1)
7352(1)
9529(3)
7769(3)
8047(4)
5454(4)
6400(3)
7222(4)
6775(4)
6211(5)
6856(5)
6354(6)
5210(6)
4561(5)
5039(5)
7181(4)
8137(5)
8148(5)
7188(5)
6229(6)
6209(5)
I'
5411(1)
4250(1)
5248(1)
6123(2)
4912(3)
4205(3)
4587(3)
4566(2)
4003(3)
5127(3)
5843(3)
6500(3)
7165(3)
7186(4)
6539(4)
5870(3)
3285(3)
3030(3)
2327(3)
1876(3)
2122(3)
2822(3)
25(1)
31(1)
36(1)
28(1)
25(1)
27(1)
30(1)
23(1)
25(1)
24(1)
26(1)
36(2)
44(2)
47(2)
42(2)
31(1)
24(1)
33(2)
39(2)
39(2)
39(2)
31(1)
Cu(1)
Cl(1)
N(1)
N(2)
N(3)
N(4)
C(3)
C(5)
C(6)
5000
6062(1)
7648(1)
4558(3)
4601(3)
1616(3)
2717(3)
3490(4)
3441(4)
389(4)
7500
38(1)
70(1)
41(1)
45(1)
44(1)
39(1)
41(1)
37(1)
50(1)
79(2)
71(1)
43(1)
56(1)
70(1)
75(1)
75(2)
60(1)
39(1)
55(1)
64(1)
56(1)
49(1)
46(1)
4388(1)
4333(1)
4048(1)
3262(1)
3688(1)
3658(2)
4110(2)
3310(2)
2830(2)
3775(2)
3250(2)
3521(2)
3151(2)
2515(2)
2245(2)
2606(2)
4272(2)
4368(2)
4513(2)
4560(2)
4467(2)
4326(2)
6299(1)
7063(2)
7509(2)
5858(2)
6525(2)
7165(2)
6469(2)
6245(3)
5538(4)
7285(3)
7426(2)
8398(3)
8647(3)
7935(3)
6970(3)
6713(3)
5842(2)
5759(3)
5161(3)
4640(3)
4719(3)
5324(3)
C(7)
C(8)
–732(5)
–44(5)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
3071(4)
2880(5)
2413(6)
2109(6)
2320(6)
2796(5)
2996(4)
1536(4)
1133(5)
2158(5)
3606(4)
4035(4)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

CU(II) AND CO(II) COMPLEXES
Table 4. Basic bond lengths and bond angles in complexes I and I'*
313
I
Bond
Cu(1)–Cl(1)#1
d, Å
Bond
N(1)–C(5)
d, Å
2.3179(15)
2.6632(15)
2.2809(15)
1.969(4)
1.312(7)
1.300(6)
1.414(6)
1.378(6)
1.362(6)
1.452(7)
1.457(7)
Cu(1)–Cl(1)
Cu(1)–Cl(2)
Cu(1)–O(1)
Cu(1)–N(1)
Cl(1)–Cu(1)#1
N(1)–N(2)
N(2)–C(3)
N(4)–N(3)
N(4)–C(3)
N(4)–C(5)
C(3)–C(21)
C(5)–C(11)
1.965(4)
2.3179(15)
1.387(6)
Angle
ω, deg
Angle
ω, deg
Cl(1)#1Cu(1)Cl(1)
Cl(2)Cu(1)Cl(1)#1
Cl(2)Cu(1)Cl(1)
O(1)Cu(1)Cl(1)#1
O(1)Cu(1)Cl(1)
O(1)Cu(1)Cl(2)
92.95(5)
172.30(6)
93.61(5)
N(1)Cu(1)Cl(1)#1
N(1)Cu(1)Cl(1)
N(1)Cu(1)Cl(2)
N(1)Cu(1)O(1)
Cu(1)#1Cl(1)Cu(1)
89.84(13)
101.79(13)
92.76(13)
167.19(18)
87.05(5)
86.16(12)
90.58(12)
89.75(12)
I'
Bond
d, Å
Bond
d, Å
Cu(1)–Cl(1)#2
Cu(1)–Cl(1)
Cu(1)–N(1)
Cu(1)–N(1)#2
N(1)–N(2)
2.2170(12)
2.2170(12)
1.990(3)
1.990(3)
1.393(4)
1.308(4)
1.305(4)
1.372(4)
C(3)–C(31)
N(4)–C(5)
N(4)–N(3)
C(5)–C(51)
N(3)–C(6)
C(6)–C(7)
C(6)–C(8)
1.474(5)
1.364(4)
1.420(4)
1.469(5)
1.276(5)
1.500(5)
1.481(6)
N(1)–C(5)
N(2)–C(3)
C(3)–N(4)
Angle
ω, deg
Angle
ω, deg
Cl(1)#2Cu(1)Cl(1)
N(1)Cu(1)Cl(1)#2
N(1)#2Cu(1)Cl(1)#2
98.10(7)
140.49(8)
97.79(9)
N(1)Cu(1)Cl(1)
N(1)#2Cu(1)Cl(1)
N(1)Cu(1)N(1)#2
97.79(9)
140.49(8)
92.42(17)
#1
#2
* Symmetry transformations in I 1 – x, 2 – y, 1 – z and in I' 1 – x, y, 3/2 – z.
RESULTS AND DISCUSSION
1.5 : 1 and 1 : 1 (cCo ≈ 0.1 mol/l), have stoichiometric
ratio Co : L = 1 : 2. Attempts to obtain 1 : 4 complexes
of Co(II) chloride using excess ligand resulted in mix-
tures of 1 : 2 complexes and unreacted ligand. Unfortu-
nately, we could not synthesize Ni(II) chloride com-
plexes with L, because even with significant excess of
Ni salts (up to Ni : L = 6 : 1), the precipitate contained
unreacted ligand. The obtained compounds dissolve in
polar organic solvents (ethanol, acetonitrile) and are
decomposed with water.
The Cu(II) and Co(II) complexes with L were syn-
thesized by reacting the salts of corresponding metals
with ligand L in ethanol solutions with heating as
described above. At a molar ratio in a solution Cu : L =
1 : 1 (cCu ≈ 0.1 mol/l), the compounds of Cu(II) chlo-
rides and bromides with stoichiometric ratio Cu : L =
1 : 1 and the compound of Cu(II) nitrate with stoichio-
metric ratio Cu : L = 1 : 2 were obtained. The molar
ratio Cu : L = 1 : 2 in a solution resulted in the forma-
tion of 1 : 2 complexes. Complexes of Co(II), which
According to X-ray diffraction data, complex I is
were synthesized with the initial molar ratios Co : L = centrosymmetric dimer with bridging chloride ions
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

314
BUSHUEV et al.
(Fig. 1). Although there are two close N(1) and N(2) III and IV, the bands due to vibrations ν(M–Cl) and
atoms, the ligand molecule L is coordinated in mono- ν(M–Br) appear at 312 and 230 cm–1, respectively; in
dentate fashion to the metal atom. The coordination the spectrum of complex VII, the band characteristic of
polyhedron of the Cu atom is a distorted square pyra- vibrations ν(M–Cl) is observed at 320–280 cm–1. This
mid formed by two bridging and by one terminal chlo- fact suggests that these compounds do not contain
rine atoms, heterocyclic N(1) atom, and the O(1) atom bridging Cl atoms.
of coordinated water molecule. Phenyl rings point in
the same direction relative to triazole fragment. Com-
plexes I and II are isostructural. X-ray diffraction pat-
tern of complex II is indexed using X-ray diffraction
data for complex I. Indices of reflections calculated
with program [18] are given in Table 5. The unit cell
parameters for I and II were refined on the basis of
X-ray powder diffraction data and agree well with the
data found for single crystals (Table 6).
As in the initial compound I, triazole fragment in
complex I' is coordinated to a metal monodentately.
The coordination polyhedron of the Cu atom (on a two-
fold axis) is flattened tetrahedron, with cis-positions
occupied by pairs of chlorine and N(1) atoms of triazo-
le ring (Fig. 2). One of the reasons underlying flattening
of the coordination core could be large size of a ligand.
This structure is peculiar in that the phenyl ring, which
is located at maximum distance from the Cu atom, is
rotated about triazole plane.
Thus, when acetone is used as a solvent, it is bonded
to molecules L in the composition of complex I,
whereas the structure of “skeleton” of the compound is
changed in unusual way (Fig. 3). This reaction resulting
in complex I' is likely to occur due to increase in the
ligand volume and considerable change in its structure.
X-ray powder diffraction data for powder obtained
after complete removal of a solvent from I' indicate that
single crystals under study correspond to a total mass of
the product (Table 6). The amorphous component on
X-ray diffraction pattern indirectly confirms the pres-
ence of CuCl2 admixture, which agrees with the pro-
posed reaction scheme (Fig. 3).
In IR spectrum of a ligand, a band at 1525 cm–1 is
due to the stretching-deformation vibrations of triazole
ring, which is highly sensitive to coordination. In IR
spectra of all investigated complexes, this band is
shifted by 5–10 cm–1 toward high-frequency region,
which suggests coordination of heterocyclic N atoms
by a metal.
IR spectrum of complex V contains an intense band
due to absorption of the nitrate group split in two com-
ponents at 1475 and 1295 cm–1 (ν3) and corresponding
to vibrations ν4 (805 cm–1) and ν1 (1020 cm–1). The high
splitting of a band due to ν3 vibration and the presence
of a spectral component corresponding to ν1 vibration
suggest that the NO–3 ions in the complex have a dis-
torted geometry, probably, due to inner-sphere charac-
ter of the nitrate groups. In addition, the low-frequency
region contains bands at 327 and 294 cm–1 correspond-
ing to vibrations ν(M–O(NO–3 )) [19]. IR spectrum of
complex VI, containing the thiocyano group, exhibits
an intense band at 2080 cm–1 due to ν (NC) vibrations,
which is shifted toward high frequencies as compared
to its position in the spectrum of KNCS (2053 cm–1).
This allows one to assume that the NCS– ion in the
complex is coordinated to a metal through the N atom.
An additional argument in favor of this assumption is a
band at 317 cm–1 due to vibrations ν(M–N(NCS–)) [19].
In the high-frequency bands of IR spectra of isos-
tructural compounds I and II, the absorption bands are
observed due to ν(OH) vibrations of coordinated water
molecules (3380–3350 cm–1), which are lacking from
the spectra of the remaining complexes. In the complex
VII spectrum, the absorption bands at 3540–3460 cm−1
are characteristic of unbonded water molecules.
Note that a band due to the phenyl group vibrations
observed in IR spectrum of a ligand at 1600 cm–1 is
shifted in the spectra of all the studied complexes by
~20 cm–1 toward low frequencies, whereas the bands
due to ν(ëç) vibrations (3030 cm–1 in a ligand) shift by
10−30 cm–1 toward high-frequency region.
According to X-ray diffraction data, in complexes I
and II, the amino group is not coordinated by a metal.
In this case, the position of a band due to the stretching
vibrations ν(NH) in IR spectra of these complexes
remains almost unchanged as compared to the spec-
trum of a ligand. The same situation is observed in the
spectra of other complexes. Therefore, one can con-
clude that the amino group is not coordinated to a metal
in either complex.
In low-frequency region of IR spectra of all com-
plexes, the bands corresponding to vibrations ν(M–N)
appear at 280–230 cm–1, which is typical of complexes
with triazoles and tetrazoles. In the spectrum of com-
plex I, these bands are overlapped by intense absorp-
tion ν(M–Cl).
The diffuse reflection spectrum of complexes I and
II (Table 7) contains asymmetric band at 12900 cm–1.
In the case of I, the intense bands at 284 and It is known that the shift of a maximum of this band can
234 cm–1 are due to vibrations ν(M–Clterm) and be used as a spectral criterion while determining the
ν(M−Clbr), respectively. Similar bands corresponding coordination core geometry for Cu(II) pentacoordi-
to vibrations ν(M–Brterm) and ν(M–Brbr) are shifted in nated complexes and selecting the Cu2+ coordination
the spectrum of complex II toward low-frequency polyhedron between trigonal bipyramid and square
region as compared to the spectrum of complex I and pyramid [20]. For instance, the absorption band maxi-
appear at 219 and 205 cm–1. In the spectra of complexes mum in diffuse reflection spectra of the compounds
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

CU(II) AND CO(II) COMPLEXES
315
(a)
C(25)
C(15)
N(3)
C(26)
C(21)
C(16)
C(11)
C(24)
C(23)
C(14)
C(13)
N(4)
C(5)
C(3)
C(12)
C(22)
Cl(2)
N(1)
N(2)
Cu(1)
O(1)#
Cl(1)
O(1)
Cl(1)#
Cu(1)#
Cl(2)#
(b)
x
z
0
Fig. 1. (a) The structure of complex I and (b) packing of structural units in crystal.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

316
BUSHUEV et al.
Table 5. The values of 2θ, dhkl and reflection intensities calculated from experimental X-ray diffraction pattern for diffraction
maxima of complex II. The values of hkl are taken from X-ray diffraction data for complex I
2θexp
dhkl
I/I0 × 100%
hkl
2θexp
dhkl
I/I0 × 100%
hkl
9.99
10.72
11.60
11.86
13.77
14.00
14.82
15.50
16.73
17.19
17.74
18.84
19.01
19.64
19.97
20.44
20.87
21.11
21.47
21.75
22.16
23.28
23.58
23.77
24.23
24.47
24.95
25.29
25.64
25.84
26.83
27.21
27.60
28.11
28.77
29.06
29.47
29.86
30.22
30.79
31.18
31.49
31.66
8.8557
8.2536
7.6263
7.4624
6.4290
6.3256
5.9767
5.7174
5.3004
5.1591
4.9985
4.7105
4.6690
4.5199
4.4465
4.3458
4.2560
4.2089
4.1378
4.0868
4.0116
3.8205
3.7727
3.7433
3.6737
3.6382
3.5683
3.5211
3.4741
3.4479
3.3226
3.2767
3.2319
3.1742
3.1028
3.0722
3.0306
2.9923
2.9572
2.9037
2.8680
2.8406
2.8263
100.0
56.8
2.9
0 0 2
1 1 1
1 0 2
2 0 0
1 1 2
2 1 0
0 2 0
2 0 2
1 2 1
2 1 2
1 1 3
1 2 2
2 2 0
2 2 1
3 1 1
3 0 2
1 0 4
0 2 3
2 2 2
3 1 2
1 1 4
2 0 4
1 3 1
3 2 1
2 2 3
2 1 4
4 1 0
2 3 0
1 2 4
2 3 1
1 1 5
2 3 2
1 3 3
4 2 0
2 1 5
3 3 1
2 3 3
1 2 5
0 0 6
1 0 6
5 1 1
0 4 2
2 2 5
31.98
32.40
32.77
33.16
33.36
33.73
34.30
34.70
35.13
35.85
36.16
36.37
36.65
36.94
37.85
38.43
39.06
39.41
39.80
40.07
40.40
41.02
41.43
41.65
42.02
42.36
42.67
43.03
43.37
43.66
43.91
44.59
44.94
45.25
45.66
46.02
46.96
47.31
48.19
48.49
48.87
49.18
49.49
2.7988
2.7627
2.7326
2.7016
2.6855
2.6570
2.6140
2.5852
2.5545
2.5048
2.4837
2.4703
2.4518
2.4336
2.3766
2.3424
2.3059
2.2862
2.2647
2.2501
2.2327
2.2004
2.1793
2.1683
2.1502
2.1334
2.1191
2.1020
2.0862
2.0729
2.0617
2.0322
2.0168
2.0038
1.9869
1.9722
1.9347
1.9214
1.8883
1.8774
1.8637
1.8525
1.8418
2.0
16.7
7.6
4 2 3
2 3 4
4 3 0
4 3 1
2 1 6
0 2 6
1 2 6
4 2 4
3 3 4
2 2 6
0 4 4
3 4 2
1 1 7
5 1 4
5 3 1
1 5 1
6 2 0
6 2 1
2 5 1
5 1 5
2 2 7
1 0 8
6 0 4
4 3 5
3 3 6
2 0 8
3 2 7
6 3 1
1 4 6
4 1 7
2 3 7
3 0 8
6 1 5
4 3 6
5 2 6
1 5 5
1 1 9
2 5 5
4 1 8
0 2 9
1 2 9
1 5 6
5 2 7
20.9
10.2
1.5
6.0
0.8
25.2
11.3
12.7
6.7
3.4
44.1
6.9
17.6
13.4
18.6
22.2
2.2
2.5
7.5
2.9
3.4
1.7
16.1
15.9
3.4
21.2
16.7
5.7
4.4
3.7
2.9
12.9
1.2
12.8
11.2
1.8
10.1
5.4
5.2
3.7
8.2
12.5
12.5
5.3
3.0
36.3
29.4
25.7
10.7
37.7
16.2
4.5
2.1
1.3
2.0
3.2
7.9
5.7
1.8
0.9
2.4
3.8
5.3
2.5
26.3
9.7
8.4
3.5
13.9
1.8
2.8
5.6
34.3
9.4
2.6
5.7
10.0
5.4
3.2
2.2
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

CU(II) AND CO(II) COMPLEXES
317
12820 cm–1. The comparison with the literature data
[20] for Cu(II) complexes with a square coordination
core CuN2O2 makes suggest that the most high-energy
component in the spectrum under consideration is due
Table 6. The unit cell parameters in complexes I', I, and II
according to X-ray powder diffraction data
Compound
I'
I
II
Space group
C2/c
Pbca
Pbca
to d–d transition dz2
dx
.
2 – y2
a, Å
26.738(7)
9.148(3)
14.853(3)
11.735(4)
17.484(5)
14.975(3)
11.991(4)
17.784(6)
The number and positions of bands in diffuse reflec-
tion spectra of Co(II) complexes allows one to identify
them as compounds with tetrahedral or pseudotetrahe-
dral coordination core. Diffuse reflection spectrum of
complex VI contains three bands. The spectrum of
complex VII differs from that of complex VI. Thus,
near-IR region of complex VII contains three broad
bands corresponding to three components of the 4T1(F)
term, which indicates lowering of a chromophore sym-
metry from Td to C2v [20]. Therefore, a conclusion can
be made on a regular lowering in coordination core
symmetry from CoL2(NCS)2 (the CoN4 core) to
CoL2Cl2 · H2O (the CoN2Cl2 core). At the same time,
although the coordination cores have different compo-
sitions, the parameters of splitting in crystal field for
the complexes considered differ insignificantly and are
equal to ~4.7 × 103 cm–1. This is likely to be explained
by some symmetry distortion of coordination core in
these compounds.
b, Å
c, Å
17.498(8)
128.68(5)
β, deg
Table 7. Diffuse reflection spectra of complexes I–VII
Complex
ν
max, cm–1
Transition
∆ × 10–3, cm–1
I
II
III
12900
12900
21455
15060
21550
15060
IV
dz2
dx
2 – y2
4T1(P)
4T1
V
16530
VI
16950
8130
4655
16100
8620
7440
6130
4680
4A2
4A2
4A2
4A2
4.7
4.7
At a temperature interval of 10–300 K, the magnetic
susceptibility of all the studied Cu(II) complexes fol-
lows the Curie–Weiss law (χ = C/(T – θ)) (Table 8). The
low values of θ indicate the low efficiency of intermo-
lecular exchange channels.
4T2
4T1(P)
VII
At room temperature, the values of µeff for the
Cu(II) complexes lie in a range of 1.74–1.82 µB and are
close to the theoretical values of magnetic moment for
noninteracting spins S = 1/2 with effective g-factors
equal to 2.0–2.1. As the temperature decreases, the val-
ues µeff(T) for complexes II, III, and V decrease, while
they increase for complexes I and IV (Figs. 4, 5). Such
a magnetic behavior indicates that antiferromagnetic
exchange interaction predominate in compounds II,
III, and V, while in compounds I and IV, ferromagnetic
exchange interactions are predominant. The µeff(T) val-
ues for complex IV increase only up to 13 K, but with
further temperature lowering, they decrease. The
observed magnetic properties of compound IV are
most probably explained by the fact that it contains the
exchange clusters exhibiting ferromagnetic exchange
interactions. These exchange clusters show antiferro-
magnetic interactions, as a result of which µeff(T)
decreases at temperatures below 13 K.
4A2
4A2
4T1
4T2
under study is shifted to high frequencies. This means
that in both complexes, the coordination core configu-
ration is close to square pyramid.
The EPR spectrum of complex V was recorded with
the aim to obtain information on the structure of its
coordination core. The spectrum was typical of individ-
ual and almost noninteracting complex species. The
EPR spectral parameters of complex V (g|| = 2.295,
A|| = 160 G, g⊥ = 2.062) correspond to a square-planar
coordination core CuN2O2. The diffuse reflection spec-
tral data agree with the assumption of a square coordi-
nation of the ëu2+ ions. Indeed, diffuse reflection spec-
trum contains broad structurized asymmetric band with
Note that the exchange interactions observed in iso-
maxima at 16530 and 14490 cm–1 and shoulder at structural complexes I and II have different signs. As
Table 8. The Curie−Weiss equation parameters for complexes I–VII
Parameter
I
II
III
IV
V
VI
VII
C, (cm3 K mol–1)
θ, K
0.411
0.48
0.392
–2.18
0.410
–0.07
0.389
–3.31
0.411
1.54
2.311
–2.86
2.483
–1.41
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

318
BUSHUEV et al.
C(7)
C(6)
(a)
C(35)
N(3)
C(34)
C(33)
C(36)
C(53)
C(54)
C(52)
N(4)
C(8)
C(55)
C(31)
C(3)
C(51)
C(5)
C(56)
C(32)
Cl(1)
N(2) N(1)
Cu(1)
Cl(1)#
(b)
x
0
z
Fig. 2. (a) The structure of complex I' and (b) packing of structural units in crystal.
follows from X-ray diffraction and X-ray powder dif- sign of the exchange interaction in such dimeric mole-
fraction data, solid complexes I and II have dimeric cules significantly depend on a ratio between the
structures due to the bridging atoms of the correspond- CuHalCu angle and the Cu−Hal distance (φ/R0) [21].
ing halogens. The magnetic behavior of complex II is We estimated the exchange parameters of complexes I
also typical of the exchange-bonded dimers, since χ(T) and II using two-center exchange clusters within the
curve has maximum at 3.5 K (Fig. 4). The value and framework of approach suggested in [22]. The obtained
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

CU(II) AND CO(II) COMPLEXES
N
319
NH2
N
Ph
Ph
N
Ph
Cl
N
Ph
N
N
Cu
N
OH2
Cu
N
N
H3C
CH3
Cl
Cl
Ph
Cl
+ 2
+ CuCl2 + 4H2O
Cu
H2O
Cl
Cl
O
N
N
Ph
N
N
Ph
NH2
Ph
N
Fig. 3. The proposed scheme of reaction of complex I with acetone.
optimal exchange parameters (J) for I and II are equal prepared Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) com-
to +0.5 and –2 cm–1, respectively. The corresponding
theoretical curves are shown in Fig. 4 in solid lines. The
values φ/R0 = 32.7 and J = 0.5 cm–1 for complex I agree
with magnetic-structural correlation for an extensive
class of Cu(II) dimeric complexes with chloride
bridges [21].
plexes with 4-amino-1,2,4-triazole and 3,4,5-trisubsti-
tuted 1,2,4-triazole reveals the following tendencies.
Thus, the transition from 4-amino-1,2,4-triazole to
3,4,5-trimethyl-, 3,5-dimethyl-4-amino-, and 3,5-
diethyl-4-amino-1,2,4-triazoles [11, 13−15] is attended
by an increase in the M : L ratio in the composition of
complexes from 1 : 3 (which is characteristic of
4-amino-1,2,4-triazole) to 1 : 2, 3 : 4, 1 : 1, and 3 : 2.
The type of the ligand coordination remains unchanged
(bidentate-bridging (N(1), N(2)). The structure of the
complexes changes from chain-polymeric to binuclear,
trinuclear linear or trinuclear triangle structure due to
steric hindrances arising as a result of substituent intro-
duction in positions 3 and 5 of a heterocycle. On the
contrary, when going from 4-amino-1,2,4-triazole to
3,4,5-triamino-1,2,4-triazole [12] (when using substit-
uents of another nature, but of similar sizes), the M : L
The Co(II) complexes under study exhibit similar
pattern of µeff(T) functions (Fig. 6). At room tempera-
tures, µeff is equal to 4.29 and 4.49 µB for VI and VII,
respectively, which agrees with experimental data for
Co(II) complexes [23]. Further decrease in µeff(T) is
explained by antiferromagnetic intermolecular
exchange interactions. The parameters of Curie–Weiss
equation for complexes VI and VII are given in Table 8.
The comparison of the composition and structure of
the synthesized complexes with those of the previously
µ
, µB
eff
µ
, µB
eff
(a)
1
2
3
1.8
1.5
1.2
0.9
0.6
1.8
1.6
1.4
1.2
1.0
1
χ, ÒÏ3/ÏÓθ
0.06
(b)
2
0.05
0.04
0.03
0.02
0.01
0
10
20
30
40 T, K
0
50
100
150
T, K
200
250
300
0
50
100
150
T, K
200
250
300
Fig. 4. (a) The µ (T) function for (1) complex I and (2)
eff
Fig. 5. The µ (T) function for complexes (1) III, (2) IV,
complex II and (b) maximum on the χ(T) curve for complex
eff
II. The theoretical curves are shown in solid lines.
and (3) V.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006

320
BUSHUEV et al.
3. Drabent, K. and Ciunik, Z., J. Chem. Soc., Chem. Com-
µ
, µB
eff
mun., 2001, no. 4, p. 1254.
2
4.5
4.0
3.5
3.0
4. Lavrenova, L.G., Larionov, S.V., and Grankina, Z.A.,
Izv. Sib. Otd. Akad. Nauk SSSR, Ser. Khim., 1979, no. 5,
p. 88.
5. Leonova, T.G., Lavrenova, L.G., Larionov, S.V., et al.,
Izv. Sib. Otd. Akad. Nauk SSSR, Ser. Khim., 1984, no. 1,
p. 82.
1
6. Lavrenova, L.G., Larionov, S.V., Grankina, Z.A., et al.,
Zh. Neorg. Khim., 1983, vol. 28, no. 2, p. 442.
7. Shakirova, O.G., Virovets, A.V., Naumov, D.Yu., et al.,
Inorg. Chem. Commun., 2002, vol. 5, no. 9, p. 690.
8. Rietmeijer, F.G., van Albada, G.A., De Graaf, R.A.G., et al.,
Inorg. Chem., 1985, vol. 24, no. 22, p. 3597.
0
50
100
150
T, K
200
250
300
9. Van Albada, G.A., De Graaf, R.A.G., Haasnoot, J.G., et al.,
Inorg. Chem., 1984, vol. 23, no. 10, p. 1404.
10. Antolini, L., Fabretti, A.C., Gatteschi, D., et al., Inorg.
Chem., 1990, vol. 29, no. 1, p. 143.
Fig. 6. The µ (T) function for complexes (1) VI and
eff
(2) VII.
11. Rietmeijer, F.G., Haasnoot, J.G., and den Hartog, A.J.,
Inorg. Chim. Acta, 1986, vol. 113, no. 2, p. 147.
12. Lavrenova, L.G., Larionov, S.V., Ikorskii, V.N., et al.,
ratio decreases to 1 : 4 and 1 : 6. Complexes with 1 : 6
stoichiometry are likely to have mononuclear structures
with monodentate function of a ligand, whereas 1 : 4
complexes are, probably, polynuclear with a ligand per-
forming both bidentate-bridging and monodentate
function. Probably, such a change in composition is
specified, in particular, by an increase in the number of
functional groups capable of forming hydrogen bonds.
Complexes with L differ significantly from compounds
considered. This difference consists, first of all, in mon-
odentate type of coordination of a given ligand
observed in all the complexes due to a large volume of
substituents in positions 3 and 5 of a triazole ring,
which brings about the structural changes in the com-
plexes. Thus, Co(II) and Cu(II) complexes with a ratio
M : L = 1 : 2 have mononuclear structure with tetrahe-
dral or distorted tetrahedral structure of the MN2A2
Zh. Neorg. Khim., 1987, vol. 32, no. 8, p. 1925.
13. Lavrenova, L.G., Baidina, I.A., Ikorskii, V.N., et al.,
Zh. Neorg. Khim., 1992, vol. 37, no. 3, p. 630.
14. Virovets, A.V., Podberezskaya, N.V., and Lavrenova, L.G.,
Zh. Strukt. Khim., 1997, vol. 38, no. 3, p. 532.
15. Yi, L., Zhao, B., Cheng, P., et al., Inorg. Chem., 2004,
vol. 43, no. 1, p. 33.
16. Bentiss, F., Langrence, M., and Barby, D., Tetrahedron
Lett., 2000, vol. 41, no. 10, p. 1539.
17. Sheldrick, G.M., SHELX97. Release 97-2, Göttingen
(Germany): Univ. of Göttingen, 1998.
18. Kraus, W., Nolze, G., Reck, G., et al., Powder Cell for
Windows. Version 2.4, Berlin: Federal Institute for Mate-
rials Research and Testing, 2000.
19. Nakomoto, K., Infrared Spectra of Inorganic and Coor-
dination Compounds, London: Wiley, 1963.
coordination core. The Cu(II) complexes with stoichio- 20. Lever, E. Inorganic Electronic Spectroscopy, Amster-
metric ratio M : L = 1 : 1, i.e., CuLA2 · H2O (A = Cl–,
dam: Elsevier, 1984, vol. 2.
Br−), have binuclear structure due to the bridging func-
tions of halide ions.
21. Hatfield, W.E., Magneto-Structural Correlations in
Exchange Coupled Systems, Willett R.D. and Reidel D.D.,
Eds., Dordrecht: Publishing Company, 1985, p. 555.
22. Ovcharenko, I.V., Shvedenkov, Yu.G., Musin, R.N., and
Ikorskii, V.N., Zh. Strukt. Khim., 1999, vol. 40, no. 1,
p. 36.
23. Rakitin, Yu.V., Interpretatsiya spektrov EPR koordinat-
sionnykh soedinenii (Interpretation of the EPR Spectra
of Coordination Compounds), Moscow: Nauka, 1993.
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RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 32 No. 5 2006