Cu(NN)2Cl2 and Cu(NNN)Cl2 and HgCl 2 building blocks in the synthesis of coordination compoundsX-ray studies and magnetic properties

Article abstract of DOI:10.1016/j.jssc.2010.06.015

A series of complexes containing Cu(NN)₂Cl₂ (NN=bis(pyrazol-1-yl)methane (bpzm), bis(3,5dimethylpyrazol-1-yl)methane (bdmpzm), 2,2-dipyridylamine (dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) and 2,2′-bipyridine (bipy)), Cu(NNN)Cl₂ (NNN=2,2′:6′,2″-terpyridine (terpy)) and HgCl₂ building blocks have been synthesized and structurally characterized. Increase in structural dimensionality is observed for [Cu(bpzm)₂][HgCl ₄], [Cu(dpa)₂][HgCl₃]₂ and [Cu(terpy)(μ-Cl)HgCl₃] compounds. No coordination polymers have formed in the case of bis(3,5dimethylpyrazol-1-yl)methane, 5,6-diphenyl-3-(2- pyridyl)-1,2,4-trazine and 2,2′-bipyridine. The [Cu(bpzm) ₂][HgCl₄] and [Cu(terpy)(μ-Cl)HgCl₃] complexes have been studied by magnetic measurements.

Full text of DOI:10.1016/j.jssc.2010.06.015

Journal of Solid State Chemistry 183 (2010) 2012–2020
Contents lists available at ScienceDirect
Journal of Solid State Chemistry
journal homepage: www.elsevier.com/locate/jssc
Cu(N–N)2Cl2 and Cu(N–N–N)Cl2 and HgCl2 building blocks in the synthesis of
coordination compounds—X-ray studies and magnetic properties
n
a
a
b
c
d
B. Machura a, , A. Switlicka , I. Nawrot , J. Mrozinski , R. Kruszynski , J. Kusz
´
´
a Department of Crystallography, Institute of Chemistry, University of Silesia, 9th Szkolna St., 40-006 Katowice, Poland
b Wroclaw University, F. Joliot-Curie 14 St., 50-383 Wroc!aw, Poland
c
˙
´
Department of X-ray Crystallography and Crystal Chemistry, Institute of General and Ecological Chemistry, Technical University of Lodz, 116 Zeromski St., 90-924 Ło´dz, Poland
d Institute of Physics, University of Silesia, 4th Uniwersytecka St., 40-006 Katowice, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of complexes containing Cu(N–N)2Cl2 (N–N¼bis(pyrazol-1-yl)methane (bpzm), bis(3,5di-
methylpyrazol-1-yl)methane (bdmpzm), 2,2-dipyridylamine (dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-
trazine (dppt) and 2,20-bipyridine (bipy)), Cu(N–N–N)Cl2 (N–N–N¼2,20:60,200-terpyridine (terpy)) and
HgCl2 building blocks have been synthesized and structurally characterized. Increase in structural
Received 22 March 2010
Received in revised form
15 June 2010
Accepted 21 June 2010
Available online 26 June 2010
dimensionality is observed for [Cu(bpzm)2][HgCl4], [Cu(dpa)2][HgCl3]2 and [Cu(terpy)(m-Cl)HgCl3]
compounds. No coordination polymers have formed in the case of bis(3,5dimethylpyrazol-1-
yl)methane, 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine and 2,20-bipyridine. The [Cu(bpzm)2][HgCl4] and
Keywords:
Heterobimetallic coordination polymer
Copper complexes
Mercury compounds
Chloride bridge
[Cu(terpy)(
m
-Cl)HgCl3] complexes have been studied by magnetic measurements.
& 2010 Elsevier Inc. All rights reserved.
X-ray
Magnetic measurements
1. Introduction
potentially bridging groups acting as ligands toward a second
metal ion; and (3) the use of exo-bidentate ligands, which is a
straightforward route towards high-dimensionality systems [9].
To date, numerous mononuclear metal coordination polymers
with various nuclearities, dimensionalities, or topologies of the
metallic centers have been successfully synthesized and char-
acterized. However, the chemistry of bimetallic coordination
polymers has received considerably less attention. During the past
decade, a series of very attractive mixed metal coordination
polymers have been obtained by using transition metal complex
cations and various cyanometallate or thiocyanometallate units.
The alteration of the metal center in M0Lnx+, [M00(CN)n]xꢀ or
[M00(SCN)n]xꢀ building blocks and the consequent adjustment of
the geometric, magnetic, and electronic properties, provides the
control and flexibility required to assemble solids with tunable
properties. Other approaches to mixed metal systems have
involved the linking of mixed metal polyoxometallates, which
leads to the incorporation of two metals into a single framework,
albeit on the same site [10–14].
The design and synthesis of homo- and hetero-metallic
coordination polymers is one of the most interesting topics in
current coordination chemistry and crystal engineering, Thanks to
unique structures, properties and reactivities a lot of hybrid
coordination polymers has been employed in catalysis, molecular
adsorption, molecular magnetism, nonlinear optics, luminescence
or model bioinorganic chemistry [1–6]. Intensive magnetostruc-
tural investigations of homo- and heteropolynuclear complexes
have contributed to the understanding of the factors governing
the sign and the magnitude of the intramolecular exchange
interactions between either identical or different paramagnetic
centers [6,7].
Generally, the type and topology of the coordination polymers
depend on the metal element, valences and geometries needs of
the metal ion and functionality of the ligand [8].
In designing polynuclear complexes three important synthetic
strategies have been settled: (1) the use of compartmental
ligands, which usually leads to oligonuclear complexes; (2) the
building-block approach, consisting in the use of complexes with
Some multidimensional heteropolynuclear structures has been
also prepared in the reactions of HgX2 (X¼Cl, Br or CN) with
MLnCl2 (M¼Mn2+, Fe2+, Co2+, Ni2+, Cu2+; L¼neutral ligands). The
HgX2 moieties accept chloride ligands from the M(II) centers and
generate transition metal organoamine double salt mercurates
with several different structural motifs including one-dimen-
sional chains, 2D-layers and 3-D extended structures [15–20].
n Corresponding author.
E-mail addresses: basia@ich.us.edu.pl (B. Machura),
jmroz@wchuwr.chem.uni.wroc.p (J. Mrozin´ ski),
rafal.kruszynski@p.lodz.pl (R. Kruszynski).
0022-4596/$ - see front matter & 2010 Elsevier Inc. All rights reserved.
doi:10.1016/j.jssc.2010.06.015

B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
2013
The Hg(CN)2-based coordination polymers studied by Leznoff et al.
[20] represent unusual examples of mercury(II) (a diamagnetic d10
metal center) mediating a magnetic interaction.
Found: 23.68; H, 2.23; N, 15.62% Calc. for C14H16N8Cl4CuHg: C,
23.94; H, 2.30; N, 15.96%.
IR (KBr, cmꢀ1) 1641(w), 1519(m)
n(C¼Nbpzm) and
n(C¼Cbpzm).
As an extension of this research, we were keen to examine the
possibility of synthesis of coordination polymers in the reactions
HgCl2 with Cu(N–N)2X2 (where N–N¼bis(pyrazol-1-yl)methane
(bpzm), bis(3,5dimethylpyrazol-1-yl)methane (bdmpzm), 2,2-
dipyridylamine (dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine
(dppt) and 2,20-bipyridine (bipy)) and Cu(terpy)Cl2. From the
structural point of view, the used chelate ligands can be generally
divided into two groups. The first group includes bis(pyrazol-1-
yl)methane, bis(3,5dimethylpyrazol-1-yl)methane and 2,2-dipyr-
idylamine, and these ligands form a six-membered cycle of
boat conformation upon coordination to a transition metal.
5,6-Diphenyl-3-(2-pyridyl)-1,2,4-trazine, 2,20-bipyridine and 2,20:
60,200-terpyridine form an approximately planar five-membered
moiety when they coordinate to a central atom. In the case of
terpy two five-membered cycle are conjugated. The compounds
Cu(N–N)2X2 can be easily prepared by dissolving CuCl2 ꢁ 2H2O and
suitable ligand in methanol, and they have proven to be useful
building blocks in the synthesis of multidimensional coordination
polymers [21–24]. The geometry around the copper(II) ion in
Cu(N–N)2X2 compounds can be varied by changing the ligand. The
copper(II) complexes containing two bis(pyrazol-1-yl)methane
molecules are always octahedral, whereas the majority of the
others take form [Cu(L–L)2X]X, in which copper(II) atoms lie in
distorted five-coordinate environments of two chelate ligands and
unidentate X, but the distorted tetrahedral and octahedral
geometries are also possible [25]. By altering the cationic
copper(II)-ligand building block we have tried to study the factors
influencing the structures of the heterobimetallic species.
2.3. Preparation of [Cu(bdmpzm)2][Hg2Cl6] (2)
A procedure similar to that for 1 was used with HgCl2 (0.16 g;
0.60 mmol), CuCl2 ꢁ 5H2O (0.1 g; 0.59 mmol) and bis(3,5dimethyl-
pyrazol-1-yl)methane (0.245 g; 1.20 mmol). Violet crystalline
precipitate of 2 was collected in 80% yield.
Found: C, 24.15; H, 2.06; N, 10.53% Calc. for
C
22H32N8Cl6CuHg2: C, 24.33; H, 2.97; N, 10.32%.
IR (KBr, cmꢀ1
1613(w) and 1557(s)
(C¼Nbdmpzm
(C¼Cbdmpzm).
)
n
) and
n
2.4. Preparation of [Cu(dpa)2][HgCl3]2 (3a),
[Cu(dpa)2(H2O)2][Cu(dpa)2(HgCl4)2] (3b)
A procedure similar to that for 1 was used with HgCl2 (0.16 g;
0.60 mmol), CuCl2 ꢁ 5H2O (0.1 g; 0.59 mmol) and 2,2-dipyridyla-
mine (dpa) (0.105 g; 1.23 mmol). Brown precipitate was collected
in 90% yield and recrystallized from methanol. Dark red crystals of
[Cu(dpa)2][HgCl3]2 (3a) and green crystals of [Cu(dpa)2(H2O)2]
[Cu(dpa)2(HgCl4)2] (3b) were collected in 60% and 40% yield,
respectively. Crystals of 3a and 3b were separated using
microscope.
Found for 3a: C, 23.87; H, 1.75; N, 8.16% Calc. For
C20H18N6Cl6CuHg2: C, 23.55; H, 1.78; N, 8.24%.
Found for 3b: C, 31.56; H, 2.52; N, 10.79% Calc. For
40H40N12O2Cl8Cu2Hg2: C, 31.35; H, 2.63; N, 10.97%.
C
IR of 3a (KBr, cmꢀ1) 3282(m)
(C¼Ndpa) and (C¼Cdpa).
IR of 3b (KBr, cmꢀ1) 3420(m)
(C¼Ndpa) and (C¼Cdpa).
n
(NH); 1630(s), 1584(s), 1519(s)
Here, we present synthesis and structural studies of the
following complexes [Cu(bpzm)2][HgCl4] (1), [Cu(bdmpzm)2]
[Hg2Cl6] (2), [Cu(dpa)2][HgCl3]2 (3a), [Cu(dpa)2(H2O)2][Cu(dpa)2
n
n
n
n
(NH); 1632(s), 1583(s), 1516(s)
n
(HgCl4)2] (3b), [Cu(dppt)2(m-Cl)HgCl3].H2O (4) and [Cu(bipy)2
(
m-Cl)2HgCl2] (5) and [Cu(terpy)(m-Cl)HgCl3] (6). Increase in
structural dimensionality is observed for 1, 3a and 6 compounds.
In the case of bis(3,5dimethylpyrazol-1-yl)methane, 5,6-diphenyl-
3-(2-pyridyl)-1,2,4-trazine and 2,20-bipyridine no coordination
polymers have formed. The compounds 1 and 6 have been studied
by magnetic measurements.
2.5. Preparation of [Cu(dppt)2(m-Cl)HgCl3] (4)
A procedure similar to that for 1 was used with HgCl2 (0.16 g;
0.60 mmol), CuCl2 ꢁ 2H2O (0.1 g; 0.59 mmol) and 5,6-diphenyl-3-
(2-pyridyl)-1,2,4-trazine (dppt) (0.37 g; 1.19 mmol). Green crys-
talline precipitate of 5 was collected in 75% yield.
Found: C, 45.64; H, 2.80; N, 10.62% Calc. For C40H30N8O
Cl4CuHg: C, 45.99; H, 2.89; N, 10.73%.
2. Experimental
IR (KBr, cmꢀ1) 1607(m), 1598(m), 1579(w)
n(C¼Ndppt) and
n(C¼Cdppt).
2.1. General procedure
2.6. Preparation of [Cu(bipy)2(
m-Cl)2HgCl2] (5)
The bis(pyrazol-1-yl)methane (bpzm) and bis(3,5dimethylpyr-
azol-1-yl)methane (bdmpzm) were synthesized according to the
literature methods [26]. The other reagents and solvents used to
the synthesis were purchased from commercial sources and all
manipulations were performed in air using materials as received.
Elemental analyses (C H N) were performed on a Perkin-Elmer
CHN-2400 analyzer.
A procedure similar to that for 1 was used with HgCl2 (0.16 g;
0.60 mmol), CuCl2 ꢁ 2H2O (0.1 g; 0.59 mmol) and 2,20-bipyridine
(0.19 g; 1.21 mmol). Green crystalline precipitate of
collected in 75% yield.
6 was
Found: C, 33.21; H, 2.32; N, 19.36% Calc. For C20H16N4Cl6CuHg:
C, 33.44; H, 2.25; N, 19.74%.
IR (KBr, cmꢀ1) 1599(s), 1575(m),
n(C¼Nbipy) and n(C¼Cbipy).
2.2. Preparation of [Cu(bpzm)2][HgCl4] (1)
2.7. Preparation of [Cu(terpy)HgCl4] (6)
HgCl2 (0.16 g; 0.60 mmol) was dissolved in water (20 ml) and
slowly added to the methanolic (20 ml) solution of CuCl2 ꢁ 2H2O
(0.1 g; 0.59 mmol) and bis(pyrazol-1-yl)methane (0.18 g;
1.22 mmol), and stirred at room temperature for 6 h. Blue
crystalline precipitate of [Cu(bpzm)2][HgCl4] (1) was filtered off
and dried in air. X-ray quality crystals of 1 were obtained by slow
recrystallization from methanol. Yield 85%.
A procedure similar to that for 1 was used with HgCl2 (0.16 g;
0.60 mmol), CuCl2 ꢁ 2H2O (0.1 g; 0.59 mmol) and 2,20:60,200-terpyr-
idine (terpy) (0.14 g; 0.60 mmol). Green crystalline precipitate of
6 was collected in 80% yield.
Found: C, 28.10; H, 1.79; N, 6.36% Calc. For C15H11N3Cl4CuHg:
C, 28.19; H, 1.73; N, 6.57%.

2014
B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
IR (KBr, cmꢀ1
(C¼Nterpy) and (C¼Cterpy).
)
1598(w), 1605(s), 1575(m) 1500(m),
scattering factors were those incorporated in the computer
programs.
n
n
2.9. IR and EPR spectra
2.8. Crystal structures determination and refinement
IR spectra were recorded on a Nicolet Magna 560 spectro-
photometer in the spectral range 4000–400 cmꢀ1 with the
samples in the form of KBr pellets.
The X-ray intensity data of 1, 2, 4 and 6 were collected on a
KM-4-CCD automatic diffractometer equipped with CCD detector
˚
and graphite monochromated MoK
a radiation (l¼0.71073 A).
EPR spectra of compounds 1 and 6 were recorded at room
The X-ray intensity data of 3a, 3b and 5 were collected on a
Gemini Ultra diffractometer at room temperature using
graphite monochromated MoK radiation. Details concerning
temperature and 77 K on
a Bruker ESP 300 spectrometer
A
operating at X-band equipped with an ER 035 M Bruker NMR
gaussmeter and HP 5350B Hewlett-Packard microwave frequency
counter.
a
crystal data and refinement are given in Table 1. Lorentz,
polarization and absorption correction [27] were applied. The
structures were solved by the Patterson method and subsequently
completed by the difference Fourier recycling. All the non-
hydrogen atoms were refined anisotropically using full-matrix,
least-squares technique. The hydrogen atoms were treated as
‘‘riding’’ on their adjacent atoms and assigned isotropic
temperature factors equal 1.2 times the value of equivalent
temperature factor of the aromatic parent atoms and equal 1.5
times the value of equivalent temperature factor of the methyl
parent carbon atom. SHELXS97 [28], SHELXL97 [29] and SHELXTL
[30] programs were used for all the calculations. Atomic
2.10. Magnetic measurement
Variable-temperature magnetic measurements of polycrystal-
line samples of 1 and 6 were carried out with a Quantum Design
SQUID magnetometer (MPMSXL–5-type) at a magnetic field of
0.5 T over the temperature range 1.8–300 K. Correction are based
on subtracting the sample-holder signal and contribution wDia
estimated from Pascal constants [31] equal ꢀ330 ꢂ 10ꢀ6 cm3
moleꢀ1 for complex 1 and ꢀ284 ꢂ 10ꢀ6 cm3 moleꢀ1 for complex
Table 1
Crystal data and structure refinement for 1, 2, 3a, 3b, 4, 5 and 6 complexes.
1
2
3a
3b
4c
5
6
Empirical formula
C14H16N8Cl4CuHg C22H32N8Cl6CuHg2 C20H18N6Cl6 Cu
Hg2
C40H40Cl8N12O2Cu2Hg2 C40H30N8OCl4CuHg C20H16N4Cl4CuHg C15H11N3Cl4CuHg
Formula weight
Temperature (K)
702.28
150(2)
0.71073
1085.98
293(2)
1019.82
293(2)
1532.70
293(2)
1044.65
150(2)
718.30
293(2)
0.71073
639.20
293(2)
0.71073
0.71073
0.71073
0.71073
0.71073
˚
Wavelength (A)
Crystal system
Space group
Monoclinic
C2/c
Triclinic
Pꢀ1
Monoclinic
P2(1)/c
Triclinic
Pꢀ1
Monoclinic
P2(1)/c
Monoclinic
C2/c
Triclinic
Pꢀ1
Unit cell dimensions
a¼10.0397(3)
a¼9.3640(7)
a¼8.5400(17)
a¼8.9877(2)
a¼15.5148(7)
a¼21.3693(18)
a¼7.3187(9)
˚
(A, 1)
b¼14.7961(5)
c¼14.3794(5
b¼9.9892(9)
c¼14.7153(5
b¼21.0546(4)
c¼7.5037(15)
b¼11.2372(3)
c¼12.8652(3)
b¼16.0972(6)
c¼15.9348(6)
b¼9.1276(2)
b¼9.1689(13)
c¼13.4880(12)
c¼15.6161(15)
a
b
g
¼113.723(8)
¼101.397(6)
¼96.299(7)
a
b
g
¼78.981(2)
¼83.760(2)
¼77.313(2)
a
b
g
¼83.784(10)
¼81.715(9)
¼86.501(11)
b
¼94.381(3)
b
¼95.214(18)
b
¼93.537(4)
b¼131.660(15)
3
2129.80(12)
828.14(11)
1343.6(4)
1241.2(2)
3972.1(3)
2275.6(3)
889.44(18)
˚
Volume (A )
z
4
1
2
1
4
4
2
Density (calculated)
(mg/m3)
2.190
2.178
2.521
2.050
1.747
2.097
2.387
Absorption coefficient
8.718
1332
10.394
511
12.802
942
7.490
734
4.709
2044
8.158
1364
10.418
598
(mmꢀ1
)
F(000)
Crystal size (mm)
0.10 ꢂ 0.14 ꢂ 0.18 0.08 ꢂ 0.12 ꢂ 0.44 0.04 ꢂ 0.15 ꢂ 0.17 0.03 ꢂ 0.06 ꢂ 0.10
0.03 ꢂ 0.05 ꢂ 0.20 0.10 ꢂ 0.15 ꢂ 0.19 0.05 ꢂ 0.14 ꢂ 0.22
2.76 to 25.00
3.23 to 25.00
3.34 to 25.00
3.37 to 25.00
2.81 to 25.00
3.49 to 25.05
2.82 to 25.00
y
range for data
collection (1)
Index rangesz
ꢀ10rhr11
ꢀ17rkr17
ꢀ17rlr15
6914
ꢀ11rhr11
ꢀ11rkr6
ꢀ11rlr11
5141
ꢀ10rhr10
ꢀ25rkr24
ꢀ8rlr8
12,387
ꢀ10rhr10
ꢀ13rkr13
ꢀ15rlr15
23,810
ꢀ18rhr18
ꢀ10rkr19
ꢀ18rlr18
24,556
ꢀ25rhr25
ꢀ10rkr10
ꢀ18rlr18
10,301
ꢀ8rhr6
ꢀ10rkr10
ꢀ15rlr16
5459
Reflections collected
Independent
1882
2812
2353
4372 (Rint¼0.0289)
6961
2010
3001
reflections
(Rint¼0.0160)
99.9
(Rint¼0.0500)
96.7
(Rint¼0.0369)
99.8%
(Rint¼0.0551)
99.4
(Rint¼0.0247)
99.8
(Rint¼0.0219)
95.9
Completeness to 2
Max. and min.
transmission
y
(%)
99.7
0.421 and 0.227
0.428 and 0.230
0.531 and 0.138
0.804 and 0.594
0.870 and 0.757
0.439 and 0.242
0.603 and 0.195
Data/restraints/
parameters
1882/0/131
2812/0/182
2353/0/160
4372/0/305
6961/0/496
2010/0/137
3001/0/217
Goodness-of-fit on F2
Final R indices
1.047
1.036
1.051
1.024
0.911
1.096
1.012
R1¼0.0110
R1¼0.0433
R1¼0.0298
R1¼0.0167
R1¼0.0389
R1¼0.0275
R1¼0.0350
[I42s(I)]
wR2¼0.0280
R1¼0.0116
wR2¼0.1103
R1¼0.0489
wR2¼0.0743
R1¼0.0376
wR2¼0.0343
R1¼0.0211
wR2¼0.0987
R1¼0.0719
wR2¼0.0676
R1¼0.0314
wR2¼0.0940
R1¼0.0429
R indices (all data)
wR2¼0.0281
wR2¼0.1126
wR2¼0.0762
wR2¼0.0348
wR2¼0.1126
wR2¼0.0687
wR2¼0.0968
Largest diff. peak
0.467 and ꢀ0.356 3.788 and ꢀ0.970 1.453 and ꢀ1.989 0.337 and ꢀ0.535
4.463 and ꢀ0.885 0.412 and ꢀ1.402 2.110 andꢀ0.846
ꢀ3
˚
and hole (e A
)

B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
2015
6. The value 60 ꢂ 10ꢀ6 cm3 moleꢀ1 was used for the temperature-
dpa, dppt, bipy and terpy are observed in the range 1640–1500 cmꢀ1
.
independent paramagnetism of copper(II) center. The effective
The medium intensity bands at ꢃ3300 cmꢀ1 in the IR spectrum of
magnetic moment was calculated from the equation:
3a and 3b are assignable to n(NH) vibration of the coordinated
2,2-dipyridylamine [32].
1=2
meff ¼ 2:83ð
w
MTÞ ðB:M:Þ
Magnetization versus magnetic field measurements were
carried out at 2 K in the field range 0ꢀ5 T.
3.2. Crystal structure analysis
The crystallographic data of 1, 2, 3a, 3b, 4, 5 and 6 are
summarized in Table 1. The single-crystal X-ray diffraction
studies reveal that 1, 3a and 6 adopt supramolecular framework
structures, whereas the compounds 2, 3b, 4 and 5 are molecular
complexes. The short intra- and intermolecular contacts [33]
detected in the structures 1, 2, 3a, 3b, 4, 5 and 6 are collected in
Table 2.
3. Results and discussion
3.1. Preparation and infrared data
The compounds [Cu(bpzm)2][HgCl4] (1), [Cu(bdmpzm)2]
[Hg2Cl6] (2) [Cu(dppt)2(
-Cl)2HgCl2] (5) have been obtained in high yield and purity in
the reaction of aqueous solution of HgCl2 with a methanolic
solution of CuCl2 containing equivalents of bis(pyrazol-
1-yl)methane (bpzm), bis(3,5dimethylpyrazol-1-yl)methane
m-Cl)HgCl3] ꢁ H2O (4), [Cu(bipy)2
(
m
The compound 1 creates a one-dimensional zigzag chain along
¯
[101] crystallographic axis in which the adjacent units
2
[Cu(bpzm)2]2+ and HgCl24ꢀ are conjoined through the bridging
chloride ion (Fig. 1), and the intra-chain Cu?Hg, Cu?Cu and
(bdmpzm), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt), 2,20-
bipyridine (bipy), respectively. The reaction of HgCl2 with a
methanolic solution of CuCl2 containing 2 equivalents of 2,2-
dipyridylamine (dpa) leads to the formation of a mixture of
[Cu(dpa)2][HgCl3]2 (3a) and [Cu(dpa)2(H2O)2][Cu(dpa)2(HgCl4)2]
(3b). The complex [Cu(terpy)(m-Cl)HgCl3] (6) is a product of the
analogous reaction of HgCl2 with Cu(terpy)Cl2.
The selected frequencies observed in the IR spectra of 1–6
complexes are given in the Experimental part. The characteristic
bands of the C¼C and C¼N stretching modes of bpzm, bdmpzm,
˚
Hg?Hg contacts are 4.586, 9.078 and 9.172 A, respectively. The
polymer chains are connected via the intermolecular C–H?Cl
contacts (which can be classified as weak hydrogen bonds) to the
three dimensional net. The Cu(II) ions of 1 are six-coordinate and
the coordination geometry is best described as distorted
tetragonal bipyramid with chloride ions in the axial positions
and the equatorial plane defined by four nitrogen atoms of the
bis(pyrazol-1-yl)methane. The six-membered rings formed upon
coordination of bis(pyrazol-1-yl)methane molecules to the central
ion show a boat conformation with the copper and the carbon
atoms off the plane defined by the four nitrogen atoms. The Hg(II)
ions are tetrahedrally coordinated with four chloride ions and
each Hg(II) ion is bridged with two copper ions via the single
chloride bridge.
Table 2
Hydrogen bonds for 1, 2, 3a, 3b, 4, 5 and 6 complexes.
D
A
H?A
D?A
D–H?A
1
C(1)
C(3)
C(7)
C(7)
2
Cl(1)#1
Cl(2)#2
Cl(2)#3
Cl(1)#4
2.74
2.83
2.59
2.63
3.471(2)
3.527(2)
3.430(2)
3.555(2)
137.0
133.0
145.0
160.0
C(11)
3a
Cl(3)#5
2.64
3.583(8)
164.0
N(2)
C(1)
3b
Cl(2)#6
Cl(4)#7
2.36
2.81
3.313(5)
3.674(7)
162.0
156.1
O(1)
O(1)
O(1)
N(3)
N(3)
N(5)
N(5)
C(1)
C(17)
4
Cl(3)
2.28
2.69
2.51
2.25
2.56
2.50
2.42
2.79
2.72
3.188(3)
3.434(3)
2.956(4)
2.956(4)
3.394(3)
3.177(2)
3.253(3)
3.528(3)
3.606(4)
152.0
152.0
116.0
135.0
155.0
132.0
154.0
137.0
158.0
Cl(1)
N(3)
O(1)
Cl(1)#7
Cl(4)
Cl(2)#8
Cl(2)#9
Cl(3)#10
O(1)
C(8)
C(27)
C(36)
5
Cl(4)
2.43
2.80
2.69
2.77
3.263(19)
3.657(8)
3.609(8)
3.692(8)
180.0
153.00
171.0
170.0
Cl(3)
Cl(2)#11
Cl(3)
C(1)
C(3)
C(4)
C(7)
6
Cl(2)#12
Cl(1)#13
Cl(2)#14
Cl(2)#15
2.68
2.82
2.78
2.79
3.366(6)
3.731(8)
3.692(5)
3.669(8)
131.0
168.0
166.0
159.00
C(2)
C(7)
C(9)
Cl(1)#16
Cl(4)#17
Cl(2)#18
2.76
2.77
2.67
3.685(9)
3.672(8)
3.544(8)
171.0
163.0
156.0
#1: 1/2+x, ꢀ1/2+y, z; #2: 2ꢀx, y, 1/2ꢀz; #3: 3/2ꢀx, 1/2ꢀy, ꢀz; #4: 1+x, y, z; #7:
ꢀx, 1ꢀy, 1ꢀz; #5: ꢀx, 1ꢀy, 1ꢀz; #6: x, 3/2ꢀy, 1/2+z; #7: ꢀx, ꢀy, 2ꢀz; #8: ꢀx,
ꢀy, 1ꢀz; #9: ꢀx,1ꢀy, 2ꢀz; #10: x, ꢀ1+y, z; #11: ꢀx, 1ꢀy, 2ꢀz; #12: ꢀx, y,
1/2ꢀz; #13: 1/2ꢀx, 1/2+y, 1/2ꢀz; #14: 1/2ꢀx, 1/2ꢀy, 1ꢀz; #15: 1/2ꢀx, 1/2ꢀy,
1ꢀz; #16: ꢀ1ꢀx, ꢀy, 1ꢀz; #17: ꢀ1+x, 1+y, z; #18: ꢀx, 1ꢀy,ꢀz.
Fig. 1. The 1D structure of 1 viewed along crystallographic a-axis. Color codes:
orange, Cu; pink, Hg; green, Cl; purple, N; gray, C; white, H. (For interpretation of
the references to color in this figure legend, the reader is referred to the web
version of this article.)

2016
B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
The crystal structure of 2 consists of [Cu(bdmpzm)2]2+ cations
units bridged by two Cl(3) atoms with distorted tetrahedral
coordination for Hg and a four-membered Hg2Cl2 ring.
and [Hg2Cl6]2ꢀ anions in a molar ratio 1:1 connected via the
intermolecular C–H?Cl contacts to the one-dimensional chains
extending along crystallographic [001] axis (Fig. 2). Similar to 1,
bis(3,5-dimethylpyrazol-1-yl)methane molecules bind to the
The polymer net of 3a creates 2,3-c two nodal net with
described by {83}2{8} Schlafli symbol [34]. Considering each of
metal atoms as a separate independent point node leads to
extended point symbols [8(2)] and [8.8.8], respectively, for Cu and
Hg ions. In case of considering of polymer as an uninodal net with
centers located at net binding points (Hg ions), the net is
expressed by {63} Schlafli symbol corresponding to 3-c uninodal
net described by [6.6.6] extended point symbol.
The formation of the two-dimensional structure of 3a can be
explained as follows: the chloride ligands migrate from Cu(II)
center to HgCl2 to form a HgCl3ꢀ anions, which form a 1-D chain of
[HgCl3]nnꢀ along the [001] crystallographic axis with Hg(1)–Cl(4)
Cu(II) ion forming two six-membered cycles with
a boat
conformation. However, in this case the cations and anions
remain isolated, probably due to the presence of the bulky methyl
group in the coordinated bdmpzm ligands. The distance from the
Cu(1) of [Cu(bdmpzm)2]2+ to the terminal chloride of the nearest
[Hg2Cl6]2ꢀ anion is equal to 5.247 A. The centrosymmetric
˚
dinuclear anion [Hg2Cl6]2ꢀ contains two bent Cl(1)-Hg(1)-Cl(2)
˚
bond lengths of 2.6634(14) A, and such chains are further bridged
by [Cu(dpa)2]2+ cations into a 2-D layer extending along crystal-
lographic (100) plane (Fig. 3). The polymer sheets of 3a
are connected via the intermolecular N–H?Cl hydrogen bonds
to the three dimensional net, and the presence of C–H?Cl
intramolecular hydrogen bonds provide additional stabilization to
the polymer net. Each Cu(II) ion of 3a is six-coordinate and its
coordination geometry is best described as distorted tetragonal
bipyramid with chloride ions in the axial positions and the
equatorial plane defined by four nitrogen atoms of the 2,2-
dipyridylamine. Likewise as bis(pyrazol-1-yl)methane, the
coordinated 2,2-dipyridylamine molecules form with the central
atom two six-membered cycles with a boat conformation.
Fig. 4 presents the cell packing of 3b viewing along [100]
crystallographic direction. The Cu(1) and Cu(2) central ions of 3b
are six-coordinate and their coordination geometries are the best
described as distorted tetragonal bipyramids with equatorial
planes defined by four nitrogen atoms of the 2,2-dipyridylamine.
The Cu(1) coordination sphere is completed by two water
molecules in the apical positions, whereas the Cu(2) center links
two tetrahedrally coordinated mercury ions HgCl24ꢀ through a
single chloride bridge. The presence of medium strength and
weak hydrogen bonds within structure of 3b leads to formation of
three-dimensional network linking cations and anions.
The perspective drawing of 4 with atomic numbering is shown
in Fig. 5. The Cu(1) ion is five-coordinate coordinated by four N
donors from the two dppt ligands and chloride anion. The angular
structural index parameter
t [35] expressed here as the difference
between the bond angles N(8)–Cu(1)–N(4) and N(2)–Cu(1)–N(6)
divided by 60 has a value of 0.52. Compared with the ideal values
Fig. 2. The cell packing of 2.
Fig. 3. The 2D structure of 3a viewed along crystallographic a-axis. Color codes: orange, Cu; pink, Hg; green, Cl; purple, N; gray, C; white, H. (For interpretation of the
references to color in this figure legend, the reader is referred to the web version of this article.)

B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
2017
of 1 for an equilateral bipyramid and 0 for a square pyramid, the
t
bridge the Cu(II) and Hg(II), and the Cu?Hg separation equal to
3.832 A indicates that there is no metal–metal bonding between
the two metal centers. The Cu(II) coordination geometry is best
˚
descriptor of the examined structure suggests a stereochemistry
intermediate between equilateral-bipyramidal and square-
pyramidal. The medium strength intermolecular O–H?N hydro-
gen bond in structure 4 links water molecule and complex cation.
An additional weak C–H?Cl intramolecular hydrogen bonds link
these moieties to dimers. Beside mentioned, in the structure
of 4 exist some short intramolecular interactions, which can be
classified as a weak hydrogen bonds.
described as
a distorted octahedron with two cis-oriented
molecules of 2,20-bipyridine and two chloride ions completing
the coordination sphere. The four-coordinated Hg(II) center has a
distorted seesaw coordination geometry with structural index
parameter t4 ¼ ð3601ꢀðaþbÞ=1411Þ equal to 0.78 [36].
The structure 6 reveals a one-dimensional chain motif of
[Cu(terpy)HgCl4]n that runs parallel to the [100] crystallographic
axis, and the intra-chain Cu?Hg and Cu?Cu contacts are 3.923
X-ray crystal structure of 5 reveals a simple molecular complex
in which the coordinatively unsaturated HgCl2 unit is bound to
the chloride ligands of Cu(bipy)2Cl2 (Fig. 6). The chloride ligands
˚
and 7.319 A, respectively (Fig. 7). The polymer chains of 6 are
connected via the intermolecular C–H?Cl contacts (which can be
classified as weak hydrogen bonds) to the three-dimensional nets.
Each Cu(II) atom is connected with two mercury ions through a
single chloride bridge. The Hg(II) center is four-coordinated by Cl
ions and the angular structural index parameter t4 equal to 0.72
indicates a distorted square-pyramidal coordination geometry
around Hg(II) ions [36]. The Cu(II) center is five-coordinated by
three N donors from the terpy ligand and two chloride anions. The
angular structural index parameter
t [35] equal to 0.01 indicates a
square-pyramidal coordination geometry around Cu(II) ions with
the three N atoms of terpy ligand and one chloride ligand in the
basal square plane.
The Cu–N, Cu–Cl and Cu–O distances of the examined
structures fall within the normal range, and they are in good
agreement with the bond lengths found in the related structures
˚
[37–41]. The Hg–Cl bond lengths are in the range of 2.29–3.19 A
confirmed for chloro complexes of Hg(II) [16–20].
3.3. EPR spectra
The EPR powder spectra of the complex 1 recorded in the
X-band indicates single line only, at room temperature with
parameter gaverage¼2.07 and poorly resolved line at 77 K with
g ¼2.07 and gO¼2.22. The EPR powder spectra of the complex 6
?
Fig. 4. The cell packing of 3b viewing along the a direction. Color codes: orange,
Cu; pink, Hg; green, Cl; purple, N; gray, C; red, O; white, H. (For interpretation of
the references to color in this figure legend, the reader is referred to the web
version of this article.)
recorded in the X-band and indicate three single lines at 293 and
77 K with the g-parameters given in Table 3. This type of three
g-value signals is reasonable for the square-pyramidal symmetry
Fig. 5. The molecular structure of 4.

2018
B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
1.0
0.8
0.6
0.4
0.2
0.0
0
1
2
3
4
5
H (Tesla)
Fig. 8. The variation of the magnetization M versus the magnetic field H for
complex 1.
700
600
500
400
300
200
100
0
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Fig. 6. The molecular structure of 5.
0
50
100
150
200
250
300
T (K)
Fig. 9. Experimental magnetic data plotted as
complex 1.
wMT (o) and 1/wM
(ꢄ) versus T for
3.4. Magnetic properties
The variation of the magnetization M versus the magnetic field
H for complex 1 has been measured at 2 K and indicates linear
relation to ꢃ1 T and than continues Brillouin function (Fig. 8).
Value of magnetization 0.99 B.M. at 5 T evidences presence of one
unpaired electron in the complex molecule.
Magnetic properties of the complex 1 were determined over
the temperature range 1.8ꢀ300 K. Plots of reciprocal wMꢀ1¼f(T)
and wM T product versus T are given in Fig. 9. The value of wM T at
Fig. 7. The 1D structure of 6 viewed along crystallographic b-axis. Color codes:
300 K is equal 0.442 cm3 molꢀ1 K with effective magnetic
orange, Cu; pink, Hg; green, Cl; purple, N; gray, C; white, H.
moment 1.88 B.M. The values of Weiss constants
Y determined
from the relation wMꢀ1¼f(T) over the temperature range
1.8ꢀ300 K are equal to ꢀ0.05 K. This unusually low value of
Y
Table 3
EPR data of 6.
is characteristic for an isolated copper(II) magnetic center.
Magnetic properties of the complex 6 were determined in the
range 1.8–300 K. Plots of reciprocal wMꢀ1¼f(T) are given in Fig. 10.
Temperature (K)
g
The value of
w
MT at 300 K is equal 0.473 cm3 molꢀ1 K with
293
77
g1¼2.23
g1¼2.23
g2¼2.16
g2¼2.14
g3¼2.05
g3¼2.05
effective magnetic moment 1.95 B.M.
The relation wMꢀ1¼f(T) over the temperature range 50–300 K
indicate constant values of w
MTE0.48 cm3 molꢀ1 K. At the lower
temperatures (1.8–50 K) Weiss constant is equal ꢀ1.2 K as a
results of weak antiferromagnetic coupling copper centers
through [HgCl4]2ꢀ bridges.
that is found for the copper(II) sites. Up to liquid helium
temperature (4.2 K) EPR data indicated only signals typical for
monomeric centers.

B. Machura et al. / Journal of Solid State Chemistry 183 (2010) 2012–2020
2019
4. Conclusions
700
0.6
0.5
0.4
0.3
0.2
0.1
0.0
HgCl2 moiety accepts chloride ligands from the Cu(II) center of
Cu(N–N)2Cl2 (N–N¼bis(pyrazol-1-yl)methane (bpzm), bis(3,5di-
methylpyrazol-1-yl)methane (bdmpzm), 2,2-dipyridylamine
(dpa), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) and 2,2’-
bipyridine (bipy)) or Cu(N–N–N)Cl2 (N–N–N¼2,20:60,200-terpyri-
dine) and generates binulear or polynuclear complexes.
Increase in structural dimensionality is observed for [Cu(bpzm)2]
[HgCl4], [Cu(dpa)2][HgCl3]2 and [Cu(terpy)(m-Cl)HgCl3] compounds.
For the last one, the magnetic measurements reveal very weak
antiferromagnetic interaction of copper centers of the one-dimen-
sional chain [Cu(terpy)HgCl4]n.
600
500
400
300
200
100
0
0
50
100
150
200
250
300
T (K)
Supplementary data
Fig. 10. Experimental magnetic data plotted as
w
MT (o) and 1/wM
(
ꢄ) versus T for
complex 6. The solid line is the calculated curve for
vMT vs. T.
Supplementary data for C14H16N8Cl4CuHg, C22H32N8Cl6CuHg2,
C
C
20H18N6Cl6CuHg2, C40H40Cl8N12O2Cu2Hg2, C40H30N8OCl4CuHg,
20H16N4Cl4CuHg and C15H11N3Cl4CuHg are available from the
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK on request, quoting
the deposition numbers 769819–769825.
1.0
0.8
0.6
0.4
0.2
0.0
Acknowledgment
This work was supported by the Polish Ministry of Science and
Higher Education through Grant no. N N204 013936.
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N
b2g2
av eJ=kT
4kT
wCu
¼
where Hamiltonian with nearest neighbor interactions is equal
P
H ¼ ꢀ2J nSnSnþ1, J value characterizes intra-chain interactions, N
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vffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
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calc
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¼ 2:96 ꢂ 10ꢀ5
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n
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was the criterion used to determine the best fit.

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