New copper(II) and cobalt(II) complexes with the N,N′-Bis(antipyryl- 4-methyl)-piperazine (BAMP) ligand: Co2(BAMP)Cl4 and [Cu(BAMP)(H2O)](ClO4)2

Article abstract of DOI:10.1002/zaac.200400239

The syntheses and the crystal structures of the complexes Co ₂(BAMP)Cl₄ (1) and [Cu(BAMP)(H₂O)](ClO ₄)₂ (2) are reported. 1 crystallizes in the monoclinic space group C2/c with the unit cell dimensions a = 3129.7(4), b = 772.9(1), c - 1503.4(2) pm, β = 112.47(1)° and Z = 4. Cobalt(II) is surrounded in the fashion of a distorted tetrahedron built from the NO donor atoms of the BAMP ligand and two chloride anions. The copper compound 2 crystallizes in the monoclinic space group I2/a with unit cell dimensions of a = 2539.0(3), b = 1448.1(1), c = 1887.0(2) pm, β = 93.40(1)° and Z = 8. Copper(II) coordination can be described as a square-based pyramid with the N ₂O₂ donor atoms of the BAMP molecule forming the basal plane completed by a water molecule in the apical position. Spectroscopic (IR and UV-Vis) and conductivity data of the new complex compounds are presented.

Full text of DOI:10.1002/zaac.200400239

New Copper(II) and Cobalt(II) Complexes with the N,NЈ-Bis(antipyryl-4-
methyl)-piperazine (BAMP) Ligand: Co2(BAMP)Cl4 and
[Cu(BAMP)(H2O)](ClO4)2
Otilia Costisor*,a, Ingo Pantenburgb, Ramona Tudosea, and Gerd Meyerb
¸
a Timis¸oara / Romania, Institute for Chemistry
b Köln, Institut für Anorganische Chemie der Universität
Bei der Redaktion eingegangen am 26. Juni 2004.
Abstract. The syntheses and the crystal structures of the complexes
Co2(BAMP)Cl4 (1) and [Cu(BAMP)(H2O)](ClO4)2 (2) are re-
ported. 1 crystallizes in the monoclinic space group C2/c with the
unit cell dimensions a ϭ 3129.7(4), b ϭ 772.9(1), c ϭ 1503.4(2) pm,
β ϭ 112.47(1)° and Z ϭ 4. Cobalt(II) is surrounded in the fashion
of a distorted tetrahedron built from the NO donor atoms of the
BAMP ligand and two chloride anions. The copper compound 2
crystallizes in the monoclinic space group I2/a with unit cell dimen-
sions of a ϭ 2539.0(3), b ϭ 1448.1(1), c ϭ 1887.0(2) pm, β ϭ
93.40(1)° and Z ϭ 8. Copper(II) coordination can be described as
a square-based pyramid with the N2O2 donor atoms of the BAMP
molecule forming the basal plane completed by a water molecule
in the apical position. Spectroscopic (IR and UV-Vis) and conduc-
tivity data of the new complex compounds are presented.
Keywords: Copper; Cobalt; Mannich base
Neue Kupfer(II)- und Cobalt(II)-Komplexe mit dem BAMP-Liganden (N,NЈ-
Bis(antipyryl-4-methyl)-piperazin). Kristallstrukturen von Co2(BAMP)Cl4 und
[Cu(BAMP)(H2O)](ClO4)2
Inhaltsübersicht. Die Verbindungen Co2(BAMP)Cl4 (1) und [Cu-
(BAMP)(H2O)](ClO4)2 (2) wurden synthetisiert und durch Einkri-
stallröntgenstrukturanalyse charakterisiert. Der Co-Komplex kri-
stallisiert monoklin (C2/c, a ϭ 3129.7(4), b ϭ 772.9(1), c ϭ
1503.4(2) pm, β ϭ 112.47(1)° und Z ϭ 4). Das Co2ϩ-Ion ist verzerrt
tetraedrisch von den NO-Atomen des BAMP-Liganden und den
Chlorid-Ionen koordiniert. Die Cu-Verbindung 2 kristallisiert in
der monoklinen Raumgruppe I2/a mit acht Formeleinheiten in der
Elementarzelle (a ϭ 2539.0(3), b ϭ 1448.1(1), c ϭ 1887.0(2) pm,
β ϭ 93.40(1)°). Die N2O2-Donor-Atome des BAMP-Liganden bil-
den gemeinsam mit einem H2O-Molekül einen quadratisch-pyrami-
dablen Koordinationspolyeder um das Cu-Kation. An beiden Ver-
bindungen wurden spektroskopische (IR und UV-Vis) und Leitfä-
higkeits-Messungen durchgeführt.
Introduction
ions with ligands containing the antipyrine moiety N,NЈ-
bis(4-antipyrylmethyl)-piperazine (BAMP) have been stud-
ied in our group [7], and some of them have been demon-
strated to exhibit antitumor activity in vitro [8].
As a continuation of the work in this field, we report here
on the synthesis, the structure, spectral and room tempera-
ture magnetic properties of binuclear Co2(BAMP)Cl4 (1)
and mononuclear [Cu(BAMP)(H2O)](ClO4)2 (2) which con-
tain the BAMP molecule as a bis-bidentate and tetradentate
ligand, respectively.
Mannich type reactions in the presence [1] or absence [2] of
metal ions are well developed. These kinds of ligands have
been designed with the aim to obtain binuclear metal com-
plexes with special magnetic and redox properties. Some
complexes can be considered as models of iron or copper
biosites [3]. Mannich bases with a polymeric structure have
been used as selective ion exchangers [4].
Mannich bases obtained from antipyrine and its deriva-
tives have been prepared with the aim to obtain antipyretic
and analgesic compounds [5]. Their complexes with certain
metal ions, including PtII and CoII, have been shown to act
as antitumor agents [6]. The formation of these complexes
with some oligo-elements may explain their pharmaceutical
activity. In this respect, complexes of some first row metal
Experimental Section
All chemicals have been purchased from commercial sources and
were used without further purification. Analytical data were ob-
tained by a Perkin-Elmer Model 240C elemental analyzer. Elec-
tronic spectra were recorded on a Perkin Elmer Lambda 12 spectro-
photometer, IR spectra by using KBr pellets on a BIO-RAD FTS
135 spectrometer. The magnetic susceptibilities were measured
at T ϭ 300 K with a Faraday balance using CuSO4·5H2O as the
calibrant. The molar magnetic susceptibility values were corrected
for the diamagnetism of the constituent atoms.
* Dr. Otilia Costis¸or
Institute for Chemistry Timis¸oara
Bd. Mihai Viteazu no. 24
RO Ϫ 1900 Timis¸oara, Romania
e-mail: ocostisor@acad-icht.tm.edu.ro
Z. Anorg. Allg. Chem. 2004, 630, 1645Ϫ1649
DOI: 10.1002/zaac.200400239
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
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O. Costis¸or, I. Pantenburg, R. Tudose, G. Meyer
Cu(BAMP)(ClO4)2 was synthesized according to the published
procedure [9]. BAMP has been obtained according to the Mannich
synthesis under the experimental conditions as reported pre-
viously [9].
Co2(BAMP)Cl4 (1): 0.46 g (2 mmol) of CoCl2 · 6H2O dissolved in
5 ml of EtOH was poured dropwise into a solution containing
0.486 g (1 mmol) of BAMP dissolved in 10 ml EtOH at 55 °C under
vigorous stirring. The blue reaction mixture was stirred for 120 min
at room temperature. The light blue microcrystalline precipitate of
the complex was collected by filtration, washed with ethanol and
dried over CaCl2. The product was recrystallysed from DMSO.
Light blue crystals suitable for X-ray analysis were thus obtained.
Yield: 0.7 g (93 %). Ϫ C28H34N6Cll4Co2O2 (746.27): calcd. C 45.06,
H 4.59, N 11.26, Cl 19.00, Co 15.79; found C 45.17, H 4.62, N
11.25, Cl 19.31, Co 15.73 %.
Figure 1 Mesomeric forms of the antipyrine fragment
copper(II) ion, created by the N2O2 donor atoms of a
BAMP molecule and by an oxygen atom of the neighboring
complex molecule in the apical position. In these terms, the
complex can be better described as a dimer. Surprisingly, in
the presence of MnCl2, the mononuclear species
[Cu(BAMP)(H2O)](ClO4)2 (2) crystallizes. The role of the
manganese(II) salt remains unclear.
Both complexes are stable in air, insoluble in most com-
mon organic solvents like alcohols, acetone, chloromethane,
or benzene, and soluble in DMSO, DMF or acetonitrile.
The molar conductivity values in these solvents indicate the
non-electrolytic nature of (1) while the value of 234 ΩϪ1
molϪ1cm2 for (2) in acetonitrile agrees well with those ex-
pected for 1 : 2 electrolytes [11].
UV/vis (DMSO) λmax (lgε) ϭ 615 nm (176), 670 nm (281), UV/vis (DMF):
λmax (lgε) ϭ 609 nm (389), 674 nm (618); ΛM (DMSO) ϭ 75 ΩϪ1 molϪ1
cm2, ΛM (DMF) ϭ 55 ΩϪ1 molϪ1 cm2. Ϫ IR (KBr): 1600, 1588, 1568, 1508,
1498, 1474, 1434, 1354, 1324, 1296, 1283, 1268, 1208, 1074, 972, 932, 868,
832, 764, 738, 694, 674, 646, 616, 608, 596 cmϪ1. Ϫ Far IR (polyethylene):
584, 564, 536, 520, 516, 504, 496, 472, 394, 380, 342 cmϪ1. Ϫ µ ϭ 4.65 µB.
[Cu(BAMP)(H2O)](ClO4)2 (2): 0.04 g (0.2 mmol) of MnCl2 · 4H2O
dissolved in 5 ml of a mixture of CH3OH : H2O ϭ 3 : 1 was poured
dropwise into a solution containing 0.15 g (0.2 mmol) of Cu-
(BAMP)(ClO4)2 dissolved in a 20 ml mixture of CH3OH : H2O ϭ
3 : 1 at 35 °C under vigorous stirring. The green reaction mixture
was stirred for 60 min at room temperature and after filtration,
light green crystals suitable for X-ray analysis were collected. Yield:
0.65 g (85 %). Ϫ C28H36N6Cl2CuO11 (767.07): calcd. C 43.84, H
4.73, N 10.96, Cl 9.24, Cu 8.28; found C 43.75, H 4.78, N 10.95,
Cl 9.31, Cu 8.31 %.
Spectral Characteristics
The absorption spectrum of (1) displays a single broad
band centered at 670 nm with a shoulder on the high energy
side. According to the literature this band is assigned to the
4T1 (P) ǟ 4A2 (F) transition characteristic for CoII in a
C2v environment [12]. The magnetic moment of 4.65 µB at
ambient temperature supports the distorted tetrahedral co-
ordination sphere in the CoII complex [13]. The electronic
spectra of the copper(II) complex (2) recorded on a freshly
prepared acetonitrile solution and nujol mull are very simi-
lar, proving that its structure is preserved in solution. The
single broad band centered at 709 nm with a shoulder on
the low energy side is typical for a square-planar CuN2O2
coordination geometry with one more weakly bound axial
ligand, supported also by the magnetic moment of 1.92 µB.
The infrared spectra of the complexes show the charac-
teristic bands of the ligand. They support the involvement
of the antipyrine oxygen atom in the coordination in accord
with the mesomeric structures II and III in Figure 1. Thus,
the strong ν(CϭO) stretching vibration at 1669 in the spec-
trum of the free ligand disappears and a new band at 1208
for (1) and 1179 cmϪ1 for (2) appears as a result of the
reduction of the C-O bond order. The new band at
1568 cmϪ1 for (1) and 1556 cmϪ1 in the spectrum of (2) can
be assigned to a combination of the ν(CϭO) and ν(CϭN)
stretching modes [14] and is also in accord with the meso-
meric forms II and III (Fig. 1). Differences in the character-
istic frequencies of the piperazine bridge in the two com-
plexes can be noticed. For example, the bands at 1296, 1283
and 1268 cmϪ1 in the spectrum of (1), assigned to the wag-
UV/vis (DMSO): λmax (lgε) ϭ 374 nm (561), 709 nm (199), UV/vis (DMF):
λmax (lgε) ϭ 374 nm (625), 709 nm (224); ΛM (DMSO) ϭ 14 ΩϪ1 molϪ1
cm2, ΛM (DMF) ϭ 28 ΩϪ1 molϪ1 cm2. Ϫ IR (KBr): 3521, 1598, 1578, 1556,
1495, 1457, 1440, 1405, 1379, 1326, 1284, 1273, 1179, 1108, 1088, 1013, 965,
951, 847, 808, 766, 741, 698, 659, 624 cmϪ1. Ϫ Far IR (polyethylene): 598,
552m, 512, 495, 454, 376, 334 cmϪ1. Ϫ µ ϭ 1.92 µB.
Results and Discussion
The BAMP molecule has two kinds of donor atoms situ-
ated on each side of the piperazine bridge, i.e. a carbonyl
oxygen and a piperazine nitrogen atom. Subject to their do-
nor properties, their relatively flexible or rigid structure and
the symmetry of the BAMP molecule mono- and binuclear
complexes may be formed. Their actual structure depends
on the conformation of the piperazine moiety. Most stable
is the distorted chair conformation of the piperazine mol-
ecule. As a result, most BAMP complexes are homo- and
heterobinuclear of the general type MMЈ(BAMP) [7].
The binuclear complex Co2(BAMP)Cl4 (1) has been ob-
tained as suitable crystals for X-ray analysis for the first
time by the reaction of cobalt(II) chloride hexahydrate with
BAMP in a metal to ligand ratio of either 1 : 1 or 2 : 1 in
methanol followed by recrystallization of the crude product.
Only two mononuclear copper(II) complexes with the
BAMP ligand were reported so far [9, 10]. They contain the
BAMP unit as a tetradentate ligand through the N2O2 do-
nor atom set and the boat conformation of the piperazine
bridge. One of these complexes, Cu(BAMP)(ClO4)2, shows
a square-based pyramidal coordination geometry of the
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New Copper(II) and Cobalt(II) Complexes with the N,NЈ-Bis(antipyryl-4-methyl)-piperazine (BAMP) Ligand
Table 1 Crystal Data and Structure Refinement Parameters for Co2(BAMP)Cl4 (1), and [Cu(BAMP)(H2O)](ClO4)2 (2)
1
2
empirical formula
C28H34N6O2Cl4Co2
Co2(C28H34N6O2)Cl4
746.27
C28H36N6O11Cl2Cu
[Cu(C28H34N6O2)(H2O)](ClO4)2
767.07
formula mass
data collection
diffractometer
radiation
temperature /K
index range
STOE IPDS II
Mo-Kα (graphite monochromated, λ ϭ 71.073 pm)
293(2)
293(2)
Ϫ40 Յ h Յ 40
Ϫ9 Յ k Յ 9
Ϫ19 Յ l Յ 19
Ϫ30 Յ h Յ 30
Ϫ17 Յ k Յ 17
Ϫ22 Յ l Յ 22
rotation angle range
0° Յ ω Յ 180°; ψ ϭ 0°
0° Յ ω Յ 180°; ψ ϭ 0°
0° Յ ω Յ 180°; ψ ϭ 90°
0° Յ ω Յ 180°; ψ ϭ 90°
0° Յ ω Յ 180°; ψ ϭ 135°
∆ω ϭ 2°
270
5
120
1.9 Ϫ 54.8
38391
3761
0° Յ ω Յ 18°; ψ ϭ 135°
∆ω ϭ 2°
189
3
100
2.3 Ϫ 59.5
45345
6105
increment
no. of images
exposure time /min
detector distance /mm
2·θ range /deg
total data collected
unique data
observed data
Rmerg
1930
0.0923
3113
0.0871
absorption correction
transmission min / max
crystallographic data
crystal size /mm
colour, habit
crystal system
space group
a /pm
numerical, after crystal shape optimization [24, 25]
0.7835 / 0.9513
0.6681 / 0.8486
0.3 · 0.3 · 0.2
blue, column
monoclinic
C2/c (no. 15)
3129.7(4)
772.9(1)
1503.4(2)
112.47(1)
3.3606(7)
4
0.2 · 0.2 · 0.1
blue, polyhedron
monoclinic
I2/a (no. 15)
2539.0(3)
1448.1(1)
1887.0(2)
93.40(1)
6.9255(12)
8
1.471
0.850
3176
b /pm
c /pm
β /°
volume /nm3
Z
ρcalc /(g cmϪ3
µ /mmϪ1
F(000)
)
1.475
1.340
1528
structure analysis and refinement
refinement method
structure determination
no. of variables
Full-matrix least-squares on F2
SHELXS-97 [26] and SHELXL-93 [27]
438
259
R indexes [I>2σI]
R1 ϭ 0.0308
wR2 ϭ 0.0507
R1 ϭ 0.0821
wR2 ϭ 0.0577
0.761
R1 ϭ 0.0753
wR2 ϭ 0.2007
R1 ϭ 0.1270
wR2 ϭ 0.2231
0.886
R indexes (all data)
goodness of fit (Sobs
goodness of fit (Sall
)
)
0.761
0.886
largest difference map
hole / peak [e 10Ϫ6 pmϪ3
]
Ϫ0.693 / 0.278
Ϫ0.390 / 1.628
R1 ϭ ΣʈFoΗϪΗFcʈ / ΣΗFoΗ, wR2 ϭ [Σ w (ΗFoΗ2ϪΗFcΗ2)2 / Σ w (ΗFoΗ2)2]1/2, S2 ϭ [Σ w (ΗFoΗ2ϪΗFcΗ2)2 / (n-p)]1/2, with w ϭ 1 / [σ2 (Fo)2 ϩ (0,0246·P)2]
2
2
for (1) and w ϭ 1 / [σ2 (Fo)2 ϩ (0,1436·P)2] for (2), were P ϭ (Fo ϩ 2Fc ) / 3. Fc* ϭ k Fc [1ϩ0,001 · ΗFcΗ2 λ3 / sin(2θ)]Ϫ1/4
.
The H atoms for (1) were derived from the difference Fourier map. Hydrogen atoms for (2) were generated geometrically and allowed to
ride on their parent carbon atoms. The water molecule in (2) was refined without H atoms.
ing modes of the piperazine CH2 groups, occupy the same
positions as in the free ligand whereas the spectrum of (2)
shows a very weak shoulder at 1284 cmϪ1 and a well re-
solved band at 1273 cmϪ1. The band assigned to the pipera-
zine skeleton appears at 832 cmϪ1 for (1) and at 847 cmϪ1
for (2) compared with 830 cmϪ1 for the free ligand. The
stretching modes ν3 (1108 cmϪ1) and ν4 (624 cmϪ1) charac-
teristic for the uncoordinated perchlorate ion of Td sym-
metry can be observed in the IR spectrum of (2) [15]. In
the FIR spectra, the bands at 516 for (1) and 512 cmϪ1 for
(2) may be associated with the CuϪO bonds. The CuϪN
vibrations were identified at 394 for (1) and 454 cmϪ1 for
(2) [16].
Crystal structures
Co2(BAMP)Cl4 (1). The X-ray study reveals a binuclear
unit with the structure described by the basic configuration
of the BAMP molecule. Figure 2 shows a perspective view
of the complex unit and gives the numbering scheme of the
atoms. The molecule is centrosymmetric with the center of
inversion in the center of the piperazine bridge.
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O. Costis¸or, I. Pantenburg, R. Tudose, G. Meyer
Table 2 Selected internuclear distances /pm and angles /deg for
Co2(BAMP)Cl4 (1), and [Cu(BAMP)(H2O)](ClO4)2 (2)
Co2(BAMP)Cl4
Co1 Ϫ O7
Co1 Ϫ N3
Co1 Ϫ Cl1
Co1 Ϫ Cl2
N3 Ϫ C1
N3 Ϫ C2
C1 Ϫ C2
196.5(2)
212.0(2)
224.0(1)
222.7(1)
149.0(3)
148.5(3)
150.6(3)
O7 Ϫ Co1 Ϫ N3
Cl1 Ϫ Co1 Ϫ Cl2
O7 Ϫ Co1 Ϫ Cl1
Cl1 Ϫ Co1 Ϫ N3
Cl2 Ϫ Co1 Ϫ N3
N3 Ϫ C2 Ϫ C1
C2 Ϫ C1 Ϫ N3
C1 Ϫ N3 Ϫ C2
97.5(1)
113.2(1)
113.2(1)
104.8(1)
116.3(1)
111.5(2)
111.5(2
108.6(2))
[Cu(BAMP)(H2O)](ClO4)2
Cu1 Ϫ O1
Cu1 Ϫ O2
Cu1 Ϫ N1
Cu1 Ϫ N2
Cu1 Ϫ O3
N2 Ϫ C1
N2 Ϫ C3
N1 Ϫ C2
N1 Ϫ C4
C1 Ϫ C2
C3 Ϫ C4
195.5(4)
N2 Ϫ Cu1 Ϫ O1
O2 Ϫ Cu1 Ϫ N1
O2 Ϫ Cu1 Ϫ O1
N2 Ϫ Cu1 Ϫ N1
N2 Ϫ C3 Ϫ C4
N2 Ϫ C1 Ϫ C2
C3 Ϫ N2 Ϫ C1
C2 Ϫ N2 Ϫ C4
163.8(2)
164.2(2)
91.0(2)
194.2(4)
202.8(5)
206.5(6)
229.8(6)
146.2(9)
147.7(8)
148.3(8)
148.7(8)
152.5(9)
151.2(9)
Figure 3 The unit cell of Co2(BAMP)Cl4 (1) in a view along the
crystallographic b axis.
72.7(2)
107.4(6)
107.9(5)
108.1(5)
107.3(5)
Figure 4 Ellipsoid presentation of the [Cu(BAMP)(H2O)]2ϩ cation
in 2. Thermal ellipsoids represent 50 % probability. The labelling
of the atoms is as given in Table 2. All H atoms were omitted
for clarity.
Figure 2 Perspective view of the molecule Co2(BAMP)Cl4 (1) with
the atomic labeling sheme according to Table 2. The displacement
ellipsoids enclose a probability of 50 %. Symmetry-related atoms
are drawn as empty ellipsoids. H atoms have been omitted for
clarity.
tances are longer than those found for the free ligand
(125.0 pm). Furthermore, the distances between the atoms
in the pyrazolonic rings generally become shorter due to
coordination except for the C5ϪC17 (136.6 pm) bond
length which becomes longer. Comparing the torsion angles
of the pyrazolonic rings [18], we notice an increase of the
tendency to planarity on going from free BAMP to the co-
ordinated molecule. The observed differences support an
important contribution of the mesomeric structures II and
III (Fig. 1) which is also suggested by the IR spectra. The
aromatic rings of the ligands are planar within experimental
error and, as the view of the molecular packing along the
ac plane (Fig. 3) shows, the phenyl rings of the neighboring
molecules are arranged in a parallel manner with the dis-
tances between their ring centroids of 501.3 pm [19].
Each cobalt atom is four-coordinate by NO atoms be-
longing to the BAMP molecule and two chloride anions
building, in total, a distorted tertrahedral surrounding. The
interatomic CoϪCl distances of 222.7 and 224.0 pm are
shorter than those found in the polymeric compound
Co(Ppz)Cl2 (Ppz ϭ piperazine) with 224.7(8) and 224.7 pm
[17]. Also, the bond length of 212.0 pm for the CoϪN dis-
tance is longer than found in the same polymeric compound
(204.2 Ϫ 206.4 pm). The CoϪO distance is 196.5 pm. The
angles around the cobalt(II) ion are spread over the range
97.5° (O7ϪCo1ϪN3) and 116.3 (N3ϪCo1ϪCl2). They de-
viate from the standard values and show a distorted tetra-
hedral environment. This may be caused by the repulsion
between the electronegative donor atoms.
The two cobalt atoms in one molecule are separated by
592.1 pm by a piperazine bridge which adopts a distorted
chair conformation. The structural data compare very well
with those found for the free ligand [9]. Due to the BAMP
coordination, a charge density delocalization occurs at the
antipyrine moieties. This fact is mirrored by changes in the
bond lengths of these fragments compared with those in the
free BAMP molecule. Thus, the C6ϪO7 (127.6 pm) dis-
[Cu(BAMP)(H2O)](ClO4)2 (2). The crystal structure of
the copper(II) complex (2) includes the mononuclear cation
[Cu(BAMP)(H2O)]2ϩ and two perchlorate anions. A view
of the molecule is shown in Figure 4 and the packing in the
crystallographic unit cell is given in Figure 5. The cop-
per(II) ion is fivefold coordinated by the N2O2 donor set of
the BAMP ligand forming a rather regular plane and the
oxygen atom of a water molecule in the apical position thus
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New Copper(II) and Cobalt(II) Complexes with the N,NЈ-Bis(antipyryl-4-methyl)-piperazine (BAMP) Ligand
Acknowledgements. This work was financially supported by the Ro-
manian Academy of Science and by the State of Nordrhein-
Westfalen / Universität zu Köln.
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Ghirvu, J. Nuno, An. Qium. 1977, 73, 1120.
[7] O. Costisor, A. Maurer, A. Tomescu, S. Policec, Bul. St. Tehn.
Inst. Pol. Timisoara, Ser. Chim. 1981, 26, 87; C. A. 1983, 99,
15418k; Bul. St. Tehn. Inst. Pol. Timisoara, Ser. Chim. 1981,
26, 93; C. A. 1983, 99, 32123c.
Figure 5 A projection of the non-hydrogen atoms of the salt [Cu-
(BAMP)(H2O)](ClO4)2 along the ab plane.
describing a square pyramidal environment. The metal ion
is disposed 22.6 pm above the basal plane [19] and the two
CuϪO (194.2 pm, 195.5 pm) distances as well as the two
CuϪN distances (202.8 pm, 206.5 pm) fall into the range
common for such complexes. The bite angle N1ϪCuϪN2
of 72.7(2), smaller as usual, and the different values of the
CuϪN distances account for the tension induced by the
presence of the two straps between the two adjacent nitro-
gen donors of the piperazine fragment. The piperazine
bridge adopts a distorted boat conformation with the bond
pair distances N2ϪC3 (147.7 pm) and N2ϪC1 (146.2 pm)
shorter than that of N1ϪC4 (148.7 pm) and N1ϪC2
(148.3 pm). Additionally, they are longer than the corre-
sponding distances in the free ligand [9]. The angles
C1ϪN2ϪC3 and C2ϪN1ϪC4 (108.1°, 107.3°) are com-
pressed when compared to the corresponding angles in the
free ligand (108.8° Ϫ 110.3°).
These changes along with structural data about the cop-
per(II) coordination sphere mirror the so-called “re-
inforced” effect induced by the piperazine bridge [20].
The pyrazolonic rings of BAMP become more planar
compared to the free ligand, as in complex (1). Further, in
this case, the two phenyl rings of a BAMP molecule are
planar and disposed in a point-to-face, T-shape confor-
mation with the distances between atoms varying in the
range of 387.8 pm to 489.3 pm. According to Janiak [21],
this arrangement is a limiting form in aromatic interaction
of the type C-H···π.
[8] A. Stupariu, O. Costisor, E. Bedrosian, L. Radbea, E. Szabo,
Rev. Rom. Med. Veter. 1995, 5, 81.
[9] O. Costisor, R. Tudose, I. Pantenburg, G. Meyer, Z. Natur-
forsch. 2002, 57b, 1454.
[10] P. Weinberger, O. Costisor, R. Tudose, O. Baumgartner, W.
Linert, J. Mol. Struc. 2000, 519, 20.
[11] W.J. Geary, Coord. Chem. Rev. 1971, 7, 81.
[12] A.B.P. Lever, Inorganic Electronic Spectroskopy, Elsevier, Am-
sterdam, 1968, S. 350Ϫ359.
[13] B.N. Figgis, J. Lewis, Progress in Inorganic Chemistry, Intersci-
ence, New York, 1964, Vol. 6, S. 179.
[14] M. Hesse, H. Meier, B. Zeeh, Spektroskopische Methoden in
der Organischen Chemie, G. Thieme Verlag, Stuttgart, 1987.
[15] J.R. Ferraro, Low-Frequency Vibrations of Inorganic and Coor-
dination Compounds, Plenum Press, New York, 1971, S. 83.
[16] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, 4th Ed., J. Wiley, New York, 1986,
S. 328.
[17] M.-C. Suen, T.-C. Keng, J.-C. Wang, Polyhedron 2002, 21,
2705.
[18] Crystallographic data for the structures have been deposited
with the Cambridge Crystallographic Data Centre as sup-
plementary publication nos. CCDC-240385 for (1) and
CCDC-240386 for (2). Copies of the data can be optained,
free of charge, on application to CHGC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: ϩ44 1223 336033 or e-mail:
deposit@ccdc.cam.ac.uk).
[19] M. Nardelli, J. Appl. Crystallogr. 1995, 28, 659.
[20] K.P. Wainwright, Inorg. Chem. 1980, 19, 1396.
[21] C. Janiak, J. Chem. Soc., Dalton Trans. 2000, 3885.
[22] R. Vargas, J. Garza, A. Dixon, B.P. Hay, J. Am. Chem. Soc.
2000, 122, 4750; J. Calhorda, Chem. Commun. 2000, 801.
[23] H.W. Roesky, M. Andruh, Coord. Chem. Rev. 2003, 236, 91.
[24] X-RED 1.22, Stoe Data Reduction Program (C), Stoe & Cie
GmbH, Darmstadt, 2001.
A view of the unit cell (Fig. 5) shows a columnar arrange-
ment of the molecules. The atom H22 bonded to C22 (CH-
aromatic) and H9B bonded to C9 (CH3-pyrazolone) forms
Ϫ
a intramolecular hydrogen bond with atom O11 (ClO4
)
(259.7 pm) and atom O22 (ClO4Ϫ) (277.9 pm), respectively
[22]. The phenyl rings belonging to neighboring columns
are stacked with distances between their atoms falling in
the range between 387.5 pm and 390.5 pm. Thus, the forces
responsible for this arrangement can be descibed as inter-
molecular π-π interactions [23].
[25] X-Shape 1.06, Crystal Optimisation for Numerical Absorption
Correction (C), STOE & Cie GmbH, Darmstadt, 1999.
[26] G. M. Sheldrick, SHELXS-97, Program for Structure Analysis,
Univ. of Göttingen, Göttingen, 1998.
[27] G.M. Sheldrick, SHELXL-93, Program for Crystal Structure
Refinement, Univ. of Göttingen, Göttingen, 1993.
Z. Anorg. Allg. Chem. 2004, 630, 1645Ϫ1649
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