Polymeric copper(II) complexes with 4-formyl-3-methyl-1-phenylpyrazol-5-one hetarylhydrazones: Synthesis and crystal structures

Article abstract of DOI:10.1134/S1070328413110079

4-Formyl-3-methyl-1-phenylpyrazol-5-one quinolin-2-yl- (H₂L ¹) and benzothiazol-2-ylhydra- zones (H₂L²) were synthesized and studied. Quantum-chemical modeling of possible tautomers of the hydra- zones was perfo

Full text of DOI:10.1134/S1070328413110079

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2013, Vol. 39, No. 12, pp. 849–856. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © L.D. Popov, S.I. Levchenkov, I.N. Shcherbakov, V.V. Minin, G.G. Aleksandrov, E.A. Ugolkova, V.V. Lukov, V.A. Kogan, 2013, published in Koordinatsionꢀ
naya Khimiya, 2013, Vol. 39, No. 12, pp. 743–750.
Polymeric Copper(II) Complexes with 4ꢀFormylꢀ3ꢀMethylꢀ1ꢀ
Phenylpyrazolꢀ5ꢀone Hetarylhydrazones:
Synthesis and Crystal Structures
,
L. D. Popova, S. I. Levchenkovb *, I. N. Shcherbakova, V. V. Mininc, G. G. Aleksandrovc,
E. A. Ugolkovac, V. V. Lukova, and V. A. Kogana
a Southern Federal University, RostovꢀonꢀDon, Russia
b Southern Scientific Center, Russian Academy of Sciences, RostovꢀonꢀDon, Russia
c Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
*eꢀmail: s.levchenkov@gmail.com
Received March 20, 2013
Abstract—4ꢀFormylꢀ3ꢀmethylꢀ1ꢀphenylpyrazolꢀ5ꢀone quinolinꢀ2ꢀylꢀ (H2L1) and benzothiazolꢀ2ꢀylhydraꢀ
zones (H2L2) were synthesized and studied. Quantumꢀchemical modeling of possible tautomers of the hydraꢀ
zones was performed. Copper(II) complexes of the general formula [Cu(HL)(ROH)]Y (R = CH3, C2H5;
Y = NO3, ClO4) were obtained and examined by IR and EPR spectroscopy, magnetochemistry, and Xꢀray
diffraction. Additional coordination through the N atom of the pyrazole ring enables the complex molecules
to form zigzag polymer chains linked by intermolecular hydrogen bonds.
DOI: 10.1134/S1070328413110079
INTRODUCTION
The yield of H2L1 was 1.17 g (68%),
Тm = 176°C.
Development of the coordination chemistry of
acylpyrazolones and their derivatives is due to their
high ligating ability and biological activity [1–5].
From the theoretical viewpoint, compounds of this
class are also interesting because of their plentiful tauꢀ
tomerism [1, 2, 6, 7]. Although complexes of acylhyꢀ
drazones and thiosemicarbazones of 4ꢀformylpyrazoꢀ
lones have been extensively examined [6, 8–12], the
ligating ability of 4ꢀformylpyrazolone hetarylhydraꢀ
zones remains poorly studied.
For C20H17N5O
anal. calcd., %: C, 69.96;
Found, %: C, 70.11;
H, 4.99;
H, 4.84;
N, 20.39.
N, 20.52.
1H NMR (DMSOꢀd6),
6.99 d (1H, H(3), quinoline,
ꢀPh, = 7.3 Hz), 7.203 s (1H, CH, azomethine),
7.34–7.40 m (3H, ꢀPh, H(8), quinoline), 7.66 t (1H,
H(7), quinoline, = 7.7 Hz), 7.81–7.86 m (2H, H(5),
H(6), quinoline), 7.99 d (2H, ꢀPh, = 7.8 Hz),
= 9.4 Hz), 12.83 s (1H,
δ
(ppm): 2.18 s (3H, Me),
= 9.4 Hz), 7.10 t (1H,
J
p
J
m
J
o
J
We obtained new ligand systems, namely,
4ꢀformylꢀ3ꢀmethylꢀ1ꢀphenylpyrazolꢀ5ꢀone quinoꢀ
linꢀ2ꢀylhydrazone (H2L1) and 4ꢀformylꢀ3ꢀmethylꢀ
1ꢀphenylpyrazolꢀ5ꢀone benzothiazolꢀ2ꢀylhydrazone
8.15 d (1H, H(4), quinoline,
NH), 17.67 s (1H, NH).
J
IR (
1589 (C=N).
ν
, cm–1): 3390, 3188
ν(NH), 1640
ν(C=O),
(
H2L2),
[Cu(HL1)(EtOH)]NO3 (
II)
[Cu(HL2)(MeOH)]NO3
[Cu(HL2)(MeOH)]ClO4 (IV
and
their
copper(II)
complexes
ν
I
), [Cu(HL1)(EtOH)]ClO4
The yield of H2L2 was 0.96 g (55%),
Т
m = 198°C.
(
,
(
III),
and
).
For C18H15N5OS
anal. calcd., %: C, 61.88;
Found, %: C, 62.05;
H, 4.33;
H, 4.46;
N, 20.04.
N, 19.90.
EXPERIMENTAL
Synthesis of hydrazones H2L1 and H2L2
.
A hot soluꢀ
1H NMR (DMSOꢀd6),
7.09 t (1H, ꢀPh, = 7.8 Hz), 7.28–7.40 m (2H,
CHarom = 8.1 Hz), 7.50–7.65 m (5H, CHarom),
7.77 d (1H, CHarom = 7.5 Hz), 8.084 s (1H,
CHazomet), 12.20 s (1H, NH), 17.09 s (1H, NH).
IR ( (NH), 1632 (C=O),
, cm–1): 3408, 3185
1580 (C=N).
δ
(ppm): 2.49 s (3H, Me),
tion of 2ꢀhydrazinoquinoline or 2ꢀhydrazinobenꢀ
zothiazole (5 mmol) in ethanol (10 mL) was added to
a hot solution of 4ꢀformylꢀ3ꢀmethylꢀ1ꢀphenylpyraꢀ
zolꢀ5ꢀone (5 mmol) in ethanol (10 mL). The reaction
mixture was refluxed for 4 h and left overnight. The
precipitate that formed was filtered off and recrystalꢀ
lized from butanol–DMF (4 : 1).
p
J
,
J
,
J
ν
ν
ν
ν
849

850
POPOV et al.
Synthesis of complexes I and II. A solution of copꢀ
IR spectra (Nujol) were recorded on
per(II) nitrate or copper(II) perchlorate (1 mmol) in Varian Scimitar 1000 FTIR instrument in the 400–
a
methanol (10 mL) was added to a hot solution of the 4000 cm–1 range.
hydrazone H2L1 (1 mmol) in ethanol (20 mL). The
Specific magnetic susceptibility was measured
using the relative Faraday method in a temperature
reaction mixture was refluxed for 1 h. After cooling,
the precipitate that formed was filtered off and recrysꢀ
range from 77.4 to 300 K.
tallized from ethanol.
Xꢀray diffraction study of complexes I and IV was
performed on a Bruker Apex II diffractometer (Mo
The yield of complex
I was 0.23 g (45%), Тm >
K ,
α
250 С, μeff = 1.89 (300 K) and 1.88 μB (77.4 K).
°
radiation,
λ
= 0.71073 Å, graphite monochromator).
The collected set of reflection intensities was proꢀ
cessed with the SAINT [13] and SADABS programs
[14]. The structures were solved by the direct methods
2
For C22H22CuN6O5
anal. calcd., %: C, 51.4; H, 4.31; N, 16.4; Cu, 12.4.
Found, %: C, 51.7; H, 4.22; N, 16.0; Cu, 12.6.
and refined anisotropically on
by the fullꢀmatrix
Fhkl
leastꢀsquares method for nonꢀhydrogen atoms.
Hydrogen atoms were located geometrically and
IR (
1595 (С=N)
The yield of complex II was 0.19 g (35%), Тm
250 С, μeff = 1.85 (300 K) and 1.83 μB (77.4 K).
ν
, cm–1): 3377
ν
(OH), 3193 (NH), 1625,
ν
ν
.
refined using a riding model (
U
iso(H) = nUiso(C)
,
>
where = 1.5 for the methyl C atoms and
n
n
= 1.2 for
°
the other C atoms). All calculations were performed
with the SHELX program package [15]. The molecuꢀ
lar geometry of the complexes was analyzed using the
PLATON program [16].
For C22H22CuN5O6Cl
anal. calcd., %: C, 47.9; H, 4.02; N, 12.7; Cu, 11.5.
Found, %: C, 48.3; H, 4.00; N, 12.9; Cu, 11.7.
Crystallographic parameters and the data collecꢀ
tion and refinement statistics for structures
I and IV
are summarized in Table 1. Selected bond lengths and
bond angles are given in Table 2; hydrogen bond
parameters are given in Table 3. The atomic coordiꢀ
nates and thermal parameters have been deposited
with the Cambridge Crystallographic Data Centre
(nos. 909689 (I) and 909690 (IV); deposit@ccdc.cam.
ac.uk or http://www.ccdc.cam.ac.uk).
IR (
1595 (C=N).
ν
, cm–1): 3461
ν
(OH), 3191 ν(NH), 1621,
ν
Synthesis of complexes III and IV. A solution of
copper(II) nitrate or copper(II) perchlorate (1 mmol)
in methanol (10 mL) was added to a suspension of the
hydrazone H2L2 (1 mmol) in hot methanol (20 mL).
The hydrazone dissolved immediately. The reaction
mixture was refluxed for 3 h. After cooling, the precipꢀ
itate that formed was filtered off and washed with
methanol.
Quantumꢀchemical DFT computations were perꢀ
formed using the hybrid exchangeꢀcorrelation funcꢀ
tional B3LYP [17–19] and the extended splitꢀvalence
basis set 6ꢀ311G+(d,p) with the Gaussian’03 program
The yield of complex III was 0.18 g (35%), Тm
250 С. μeff 1.90 (300 K) and 1.91 μB (77.4 K).
>
[20]. The results of the calculations were visualized
and graphically represented with the Chemcraft proꢀ
gram [21].
°
For C19H18CuN6O5S
anal. calcd., %: C, 45.1; H, 3.59; N, 16.6; Cu, 12.6.
Found, %: C, 44.8; H, 3.67; N, 17.0; Cu, 12.3.
EPR spectra were recorded on a Bruker Eꢀ680X
ELEXSYS radio spectrometer in the X range at room
temperature. The stable diphenylpicrylhydrazyl radiꢀ
cal was used as a standard. The parameters of the spin
Hamiltonian were determined by minimizing an error
functional for the best fit of a theoretical spectrum to
the experimental one:
IR (
1595 (С=N).
The yield of complex IV was 0.16 g (30%), Тm
250 μeff = 1.87 (300 K) and 1.87 μB (77.4 K).
ν
, cm–1): 3460
ν
(OH), 3220 (NH), 1620,
ν
ν
>
°С,
N
2
,
)
F =
Y T −YiE
1
N
(1)
(
i
∑
i=1
For C19H18ClCuN5SO6
anal. calcd., %: C, 42.0; H, 3.34; N, 12.9; Cu, 11.7.
Found, %: C, 42.6; H, 3.45; N, 12.4; Cu, 11.5.
E
where
is the array of experimental EPR signal
Yi
intensities for a constant magnetic field strength (
Н
)
T
, cm–1): 3479
ν
(OH), 3230
ν
(NH), 1617, 1597
increment,
ties calculated at the same field strengths
the number of points.
are the theoretical EPR signal intensiꢀ
Yi
IR (
(C=N).
1H NMR spectra were recorded on a Varian
Unity 300 spectrometer (300 MHz) in the pulse Fouꢀ
rier transform mode in DMSOꢀd6 with HMDS as the described in [22]. A sum of the Lorentzian and Gausꢀ
internal standard. sian functions was used as a function for line shapes
ν
Н, and N is
ν
Theoretical EPR spectra were modeled as
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
No. 12
2013

POLYMERIC COPPER(II) COMPLEXES
851
[23]. According to relaxation theory [24], the line
RESULTS AND DISCUSSION
widths were given by the formula
Compounds H2L1 and H2L2 as well as other
4ꢀformylꢀ3ꢀmethylꢀ1ꢀphenylpyrazolꢀ5ꢀone hydraꢀ
zones can exist as a number of tautomers. These can be
divided into two groups: pyrazolone and hydroxypyraꢀ
zole tautomers, the former being more stable in the
majority of cases [6, 25].
ΔH = α + βmI + γmI2,
(2)
where mI is the projection of the nuclear spin onto the
magnetic field vector and and are parameters.
In the minimization procedure, factors, hyperfine
α,
β,
γ
g
constants, and line widths and shapes were varied.
Ph
O
Ph
O
N
H
N
H
N
N
N
N
N
N
H
N
H
N
H3C
H3C
(H2L1a)
(H2L1b)
Ph
Ph
O
O
N
N
H
H
N
S
S
N
N
N
N
N
N
H
N
H3C
H3C
H
(H2L2a)
(H2L2b)
To determine the most stable species for the hydraꢀ
The organic ligand in complex I is monodeprotoꢀ
zones H2L1 and H2L2, we effected quantumꢀchemical nated and coordinated in a tridentate fashion. The
calculations of the geometry and total energies of all coordination polyhedron of the copper atom is a disꢀ
possible tautomers in vacuo and in solutions (CHCl3 torted trigonal bipyramid (Fig. 1). The equatorial
and DMSO). The pyrazolone tautomers H2L1a (quiꢀ plane is made up of the O(2) atom of the coordinated
nolone) and H2L2a (benzothiazolone) proved to be ethanol molecule, the azomethine N(3) atom, and the
always most stable. The second pyrazolone tautomer N(4B) atom of the pyrazole ring of an adjacent comꢀ
H2L1b is less stable than H2L1a in vacuo and in CHCl3 plex molecule. The apical positions are occupied by
and DMSO by 0.95, 0.62, and 0.05 kcal/mol, respecꢀ the O(1) atom and the quinoline N(1) atom. The Cu
tively. For H2L2, the energy difference between these atom deviates from the equatorial plane by only
tautomers is much larger: 3.00, 2.56, and 0.009 Å toward the O(1) atom. The sixꢀmembered
1.89 kcal/mol, respectively.
chelate ring is virtually planar; the largest deviation
from the meanꢀsquare plane is 0.040 Å (C(12)). The
fiveꢀmembered chelate ring adopts an envelope conꢀ
formation, with the copper atom deviating from the
meanꢀsquare plane of the other four atoms by 0.141 Å.
Both chelate rings are virtually coplanar with the quinꢀ
oline moiety. The monodeprotonated tridentate
organic ligand is nearly planar; the dihedral angle
between the meanꢀsquare planes of the pyrazole and
quinoline rings is 10.25°. The planes of the phenyl and
pyrazole rings make an angle of 55.04°.
According to the calculated energies, both pyraꢀ
zolone tautomers H2L1a and H2L1b could coexist in
DMSO. However, 1H NMR spectra provide evidence
that the quinoloneꢀpyrazolone species H2L1а is the
main tautomer in this case as well, because the couꢀ
pling constant for the H(3) and H(4) protons of the
quinoline moiety is 9.5 Hz. For the quinoline tauꢀ
tomer H2L1b, this constant would be ~8 Hz.
The lowestꢀenergy hydroxypyrazole tautomers of
the hydrazones H2L1 and H2L2 are less stable in vacuo
than H2L1a and H2L2a by 2.59 and 3.88 kcal/mol,
respectively. In CHCl3 and DMSO, the energy differꢀ
ence increases substantially: 5.89 and 6.64 kcal/mol
Because the coordination polyhedron of the Cu
atom comprises the N atom of an adjacent molecule,
the mononuclear species form infinite zigzag polymer
chains along the crystallographic axis
y in the crystal
for H2L1 and 7.25 and 8.28 kcal/mol for H2L2
.
(Fig. 2). The dihedral angle between the planes of the
Reactions of the hydrazones H2L1 and H2L2 with electronꢀdonating atoms O(1)N(3)N(1) in the neighꢀ
copper(II) nitrate and copper(II) perchlorate afforded boring mononuclear species is 64.71°. In the crystal of
the
[Cu(HL2)(ROH)]ClO4, respectively (R = C2H5
and CH3 III IV)). Complexes and IV were structurꢀ nitrate ion and the H(2
ally characterized by Xꢀray diffraction. mononuclear fragments (Table 3).
complexes
[Cu(HL1)(ROH)]NO3
and complex
I, II bonds involving the O(3) atom of the outerꢀsphere
and H(2 atoms of two
I, polymer chains are linked by hydrogen
(
)
(
,
I
C)
B)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
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2013

852
POPOV et al.
Table 1. Crystallographic parameters and the data collection and refinement statistics for structures I and IV
Value
Parameter
I
IV
M
514.00
0.09
Monoclinic
21/
543.43
0.12
Monoclinic
21/
Crystal dimensions, mm
Crystal system
Space group
0.15
×
×
0.05
0.28
×
×
0.07
P
n
P
n
a
, Å
, Å
11.635(2)
12.176(3)
15.065(3)
95.917(6)
2122.8(8)
4
11.1808(15)
12.5889(18)
15.123(2)
99.409(3)
2100.0(5)
4
b
c
, Å
β
V
Z
, deg
, Å3
ρcalcd, g/cm3
, mm–1
(000)
θmax, deg
Ranges of
1.608
1.719
μ
1.08
1.317
F
1060
1108
2
50.8
59.6
h
,
k
, and
l
indices
–12 <
–14 <
–18 <
h
k
l
< 14,
< 14,
< 18
–15 <
–17 <
–21 < l
h
k
< 12,
< 17,
< 12
Number of measured reflections
Number of unique reflections
15584
3891
14320
5901
Number of reflections with
I
≥
2σ(
I
)
1854
3558
Number of parameters refined
GOOF (for all reflections)
302
302
0.999
1.000
R1
wR2 (for all reflections)
Δρmax Δρmin
Å–3
(
I
> 2
σ
(
I
))
0.0739
0.1785
1.233/–0.997
0.0614
0.1609
1.509/–0.836
/
, e
Structure IV (Fig. 3) is similar to structure
close crystallographic parameters. The residue of
4ꢀformylꢀ3ꢀmethylꢀ1ꢀphenylpyrazolꢀ5ꢀone benꢀ
zothiazolꢀ2ꢀylhydrazone is monodeprotonated and
coordinated in a tridentate fashion. The coordination
polyhedron of the copper atom is a distorted trigonal
bipyramid. The equatorial plane is made up of the
I and has azomethine N(3) atom, and the N(5B) atom of the
pyrazole ring of an adjacent complex molecule. The
apical positions are occupied by the O(1) atom and the
N(1) atom of the benzothiazole ring.
As in complex I, additional coordination of the Cu
atom to the N atom of the pyrazole ring of an adjacent
molecule in complex IV enables its mononuclear speꢀ
O(2) atom of the coordinated methanol molecule, the cies to form infinite zigzag polymer chains along the
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
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2013

POLYMERIC COPPER(II) COMPLEXES
853
Table 2. Selected bond lengths and bond angles in the coorꢀ Table 3. Parameters of the intermolecular hydrogen bonds
dination polyhedra of the copper atoms in structures
IV
I
and in the crystals of complexes
I
and IV
*
*
Distance, Å
Angle
DHA,
deg
Bond
d
, Å
Bond
d
, Å
Hydrogen bond
D–H···A
I
D–H
H···A D···A
Cu(1)–N(3)
Cu(1)–N(1)
Cu(1)–N(4)i
1.980(6) Cu(1)–O(1)
1.985(6) Cu(1)–O(2)
2.102(6) O(1)–C(12)
IV
1.973(3) Cu(1)–O(1)
2.013(3) Cu(1)–O(2)
2.094(3) O(1)–C(10)
1.929(5)
2.121(6)
1.277(9)
I
O(2)–H(2C)⋅⋅⋅O(3S) 0.95 2.46 2.702(9)
⋅⋅⋅O(3S) i 0.88 1.90 2.757(9)
94
Cu(1)–N(1)
Cu(1)–N(3)
Cu(1)–N(5)i
1.931(3)
2.225(3)
1.278(5)
N(2)–H(2
B)
165
IV
Angle
ω
, deg
Angle
ω
, deg
N(2)–H(2
A
A
)
⋅⋅⋅O(4S) 0.88 2.18 2.951(5)
⋅⋅⋅O(3S) 0.88 2.26 3.048(5)
146
149
I
O(1)Cu(1)N(3) 92.5(2)
O(1)Cu(1)N(1) 171.7(2)
N(3)Cu(1)N(1) 81.0(3)
O(1)Cu(1)N(4)i 91.3(2)
N(3)Cu(1)N(4)i 131.3(3)
N(1)Cu(1)N(4)i 96.9(2)
O(1)Cu(1)O(2) 86.2(2)
N(3)Cu(1)O(2) 128.5(2)
N(1)Cu(1)O(2) 93.8(2)
N(4)iCu(1)O(2) 100.2(2)
N(2)–H(2
)
O(2)–H(2)⋅⋅⋅O(4S) ii 0.86 2.29 2.867(6)
125
i
ii
* The coordinates of the primed atoms: 1 –
1 – y, –z.
x, –y, –
z;
1 –
x,
IV
O(1)Cu(1)N(1) 167.95(13) N(3)Cu(1)N(5)i 135.70(13)
O(1)Cu(1)N(3) 92.10(12) O(1)Cu(1)O(2) 86.38(12)
N(1)Cu(1)N(3) 79.99(13) N(1)Cu(1)O(2) 91.11(13)
O(1)Cu(1)N(5)i 95.49(12) N(3)Cu(1)O(2) 126.91(13)
crystallographic axis
into a 3D framework through the hydrogen bonds
N(2)–H(2 ⋅⋅⋅O(4S), N(2)–H(2 ⋅⋅⋅O(3S), and O(2)–
H(2)⋅⋅⋅O(4S) (Table 3). The dihedral angle between the
planes of the electronꢀdonating atoms O(1)N(3)N(1)
in the neighboring mononuclear species of complex IV
y (Fig. 4). The chains are united
A)
A)
N(1)Cu(1)N(5)i 96.52(13) N(5)iCu(1)O(2) 97.14(13)
i
* The symmetry operation codes are –
x
+ 1/2,
y
+ 1/2, –
z
+ 1/2
i
for
I
and –
x
+ 1/2,
y
+ 1/2, –z + 1/2 for IV.
O(2S)
N(1S)
H(2C)
O(1S)
N(5)
O(3S)
O(1)
O(2)
C(12)
N(4)
N(4B)
Cu(1)
N(1)
N(3)
N(2)
H(2B)
Fig. 1. Structure
I
with atomic thermal displacement ellipsoids (50% probability).
No. 12 2013
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39

854
POPOV et al.
Fig. 2. Polymer chains in the crystal of complex I (the nitrate ions and the hydrogen atoms are omitted).
O(2)
H(2)
N(5B)
O(1)
N(1)
C(10)
Cu(1)
N(4)
N(3)
N(5)
S(1)
N(2)
H(2
A
)
O(4S)
O(3S)
Cl(1)
O(1S)
O(2S)
Fig. 3. Structure IV with atomic thermal displacement ellipsoids (50% probability).
is somewhat smaller than that in complex
Nevertheless, the copper–copper distances in the
polymer chains of complexes
I
(
59.34°). compared to those for complex
I
are due to the bulkier
and the smaller one
equatorial substituent (EtOH) in
(MeOH) in IV, which produces a less “rigid” environꢀ
ment of the metal ion in the polymer matrix.
I
I
and IV are nearly the
same: 7.058 and 7.091 Å, respectively.
The EPR spectra (Fig. 5) of polycrystalline samples
The absence of a halfꢀfield signal for a forbidden
transition characteristic of exchangeꢀcoupled systems
of complexes
parallel and perpendicular orientations of the
with the following spin Hamiltonian parameters: g||
2.2215 and = 2.0862 for complex and || = 2.2520
= 2.0875 for complex IV. These spin Hamiltoꢀ
I
and IV show illꢀresolved lines in the
g
tensor
with the electron spin
exchange effects in complexes
netic exchange through a rather long chain of
S
= 1 suggests the absence of
and IV, though magꢀ
ꢀbonds
=
I
g
I
g
_
σ
|
and
g
|
has been repeatedly noted earlier for copper comꢀ
plexes [26, 27]. The conclusion about the absence of
magnetic exchange is confirmed by magnetochemical
_
nian parameters correspond to square planar Cu(II)
complexes with oxygen and nitrogen in the first coorꢀ
dination sphere. The wider EPR lines for complex IV data: the effective magnetic moments of complexes I–
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
No. 12
2013

POLYMERIC COPPER(II) COMPLEXES
855
Fig. 4. Polymer chains in the crystal of complex IV (the perchlorate ions and the hydrogen atoms are omitted).
IV at room temperature are somewhat higher than the coordinate axes,
S
= 1/2, Iz
,
Ix
,
and Iy are the projecꢀ
pure spin value and remain virtually unchanged on tions of the nuclear spin operator of the central atom
cooling to 77.4 K.
of the monomer onto the coordinate axes, I = 3/2.
The spin Hamiltonian parameters of the EPR
spectrum of a suspension of complex in CH2Cl2 are
as follows: z = 2.074, = 4.91 x = 2.145,
10–3 cm–1
= 9.93 y = 2.183, = 4.92
10–3 cm–1 10–3 cm–1.
The EPR spectrum obtained differs in spin Hamilꢀ
tonian parameters from the axially symmetrical specꢀ
trum of Cu(II) with the ground state of the cenꢀ
When dissolved in DMF, the complexes under
study decompose; in less polar dichloromethane, they
form suspensions, probably by degradation of the
polymer chain into mononuclear species. The EPR
I
g
A
g
×
, g
×
B
×
,
C
spectrum of a suspension of complex I (Fig. 6) differs
noticeably from the spectrum of its polycrystalline
sample. It can be described by a distorted (in a rhomꢀ
bic way) spin Hamiltonian with the hyperfine coupling
dx2 −y2
,
tral atom, for which g||
>
g
and
А
>
В. It rather correꢀ
⊥
ꢀ
ꢀ
ꢀ
sponds to the fairly uncommon
ground state of
dz2,
H solid = gzβH z S z + gxβH x S + gyβH y S
x
y
(3)
copper, for which
g > g|| and В < А. The ground state
⊥
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
+ AI S z + BI S + CI S ,
z
x
x
y
y
of Cu(II) changes when its square planar chelate ring
undergoes tetrahedral or other distortions. The type of
distortions occurring in this case cannot be specified
because we are unaware of the composition and strucꢀ
ture of a fragment formed by degradation of the polyꢀ
mer chain.
where gz
tensor,
fine structure tensor, the Sz
,
A
gx
,
and gy are the
and are the components of the hyperꢀ
Sx and Sy are the projecꢀ
z, x, y components of the
g
,
B
,
C
,
,
tions of the spin operator of the monomer onto the
To sum up, we obtained and studied 4ꢀformylꢀ3ꢀ
methylꢀ1ꢀphenylpyrazolꢀ5ꢀone hetarylhydrazones as
new ligand systems and performed quantumꢀchemical
modeling of their tautomeric species. A series of new
copper(II) complexes with these ligands were syntheꢀ
1
2
1
2
3000
3250
3500
3750
, G
H
2700
3000
3300
3600
H, G
Fig. 5. EPR spectra of polycrystalline samples of comꢀ
plexes ) and IV ) at 293 K.
Fig. 6.
(
1
) Experimental and (
2) theoretical EPR spectra of
I
(
1
(2
a suspension of complex I
in CH Cl at 293 K.
2
2
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
No. 12
2013

856
POPOV et al.
14. Sheldrick, G.M., SADABS. A Program for Exploiting the
Redundancy of AreaꢀDetector Xꢀray Data, Göttingen
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15. Sheldrick, G.M., Acta Crystallogr., Sect. A: Found.
Crystallogr., 2008, vol. 64, no. 1, p. 112.
sized, structurally characterized, and examined by
physicochemical methods. Because of additional
coordination through the N atom of the pyrazole ring,
these complexes form zigzag polymer chains.
16. Spek, A.L., J. Appl. Crystallogr., 2003, vol. 36, no. 1,
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Translated by D. Tolkachev
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 39
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2013