Hydrogen bonded networks and a self-assembled 1D water cluster in nickel(II) and copper(II)-orotate complexes

Article abstract of DOI:10.1016/j.poly.2010.06.011

Three Ni(II) and Cu(II)-orotate complexes with 1,3-propanediamine (pen) and N-methylethylenediamine (nmen), [Ni(HOr)(H₂O)₂(pen)] (1), [Cu₂(μ-HOr)₂(pen)₂] (2) and {[Cu(μ-HOr)(nmen)]·3H₂O}_n (3) (H₃Or = orotic acid) have been synthesized and characterized by thermal analysis, IR spectroscopy and single crystal X-ray diffraction techniques. In complex 1, the Ni(II) ion has a distorted octahedral geometry. The hydrogen bonds play an important role in the formation of the 3D polymeric structure of complex 1. The carboxylate groups interact with NH₂ groups of pen ligands, and HOr ligands are mutually hydrogen bonded to each other through the pyrimidine N and exocyclic O atoms, giving rise to R22(12) and R22(8) ring motives, respectively. Complex 2 consists of dimeric [Cu₂(μ-HOr)₂(pen) ₂] units in which the Cu(II) ions have square pyramidal coordination geometries with bridging oxygen atoms at the pyramid apex. The HOr ligands, linked by N-H···O hydrogen bonds, constitute centrosymmetric R22(8) rings through the plane (1 0 1). The hydrogen bonds between pen and HOr ligands result in R22(8) rings centered at (n + 1, 0, 1/2) (n = zero or integer). Complex 3 is a 1D coordination polymer, in which the orotate moiety acts as a bridging ligand in the structure. The [Cu(HOr)(nmen)] units are linked by carboxylate oxygen atoms of HOr, which result in a zigzag chain structure along the a axis. Two adjacent 1D coordination polymers are connected through π···π interactions. The lattice water molecules, forming a 1D water cluster, function as a glue to form a 3D supramolecular network through extended hydrogen bonding.

Full text of DOI:10.1016/j.poly.2010.06.011

Polyhedron 29 (2010) 2600–2608
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Hydrogen bonded networks and a self-assembled 1D water cluster in nickel(II)
and copper(II)-orotate complexes
a
b
c
Okan Zafer Yeßsilel a, , Hakan Erer , Gökhan Kaßstaßs , Ibrahim Kani
_
*
a Eskißsehir Osmangazi University, Faculty of Arts and Sciences, Department of Chemistry, 26480 Eskißsehir, Turkey
b Ondokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, 55139 Samsun, Turkey
c Anadolu University, Faculty of Sciences, Department of Chemistry, Eskißsehir, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Three Ni(II) and Cu(II)-orotate complexes with 1,3-propanediamine (pen) and N-methylethylenediamine
Received 1 June 2010
Accepted 8 June 2010
Available online 20 June 2010
(nmen), [Ni(HOr)(H2O)2(pen)] (1), [Cu2(
l
-HOr)2(pen)2] (2) and {[Cu(
l
-HOr)(nmen)]ꢀ3H2O}n (3)
(H3Or = orotic acid) have been synthesized and characterized by thermal analysis, IR spectroscopy and
single crystal X-ray diffraction techniques. In complex 1, the Ni(II) ion has a distorted octahedral geom-
etry. The hydrogen bonds play an important role in the formation of the 3D polymeric structure of com-
plex 1. The carboxylate groups interact with NH2 groups of pen ligands, and HOr ligands are mutually
hydrogen bonded to each other through the pyrimidine N and exocyclic O atoms, giving rise to R22ð12Þ
Keywords:
Water cluster
Orotate complexes
Orotic acid
and R2ð8Þ ring motives, respectively. Complex 2 consists of dimeric [Cu2(
l-HOr)2(pen)2] units in which
2
the Cu(II) ions have square pyramidal coordination geometries with bridging oxygen atoms at the pyra-
mid apex. The HOr ligands, linked by N–HꢀꢀꢀO hydrogen bonds, constitute centrosymmetric R22ð8Þ rings
through the plane (1 0 1). The hydrogen bonds between pen and HOr ligands result in R22ð8Þ rings cen-
tered at (n + 1, 0, 1/2) (n = zero or integer). Complex 3 is a 1D coordination polymer, in which the orotate
moiety acts as a bridging ligand in the structure. The [Cu(HOr)(nmen)] units are linked by carboxylate
oxygen atoms of HOr, which result in a zigzag chain structure along the a axis. Two adjacent 1D coordi-
Supramolecular structure
nation polymers are connected through
water cluster, function as a glue to form a 3D supramolecular network through extended hydrogen
p p interactions. The lattice water molecules, forming a 1D
ꢀꢀꢀ
bonding.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
hydrogen-bonding capabilities, depending on the metal coordina-
tion mode [8,11–19].
The design and synthesis of metal-directed supramolecular
frameworks have received much attention in coordination chemis-
try because of the interesting molecular topologies and potential
applications of these frameworks in catalysis, non-linear optics,
sensors and magnetism [1–5]. The non-covalent forces, including
Hydrogen-bonded water clusters have received much attention
because of their unusual properties and fundamental importance
[20–27]. The structural elucidation of discrete and polymeric water
clusters provides detailed knowledge of hydrogen-bonding, and
their fluctuations determined the properties of bulk water. Fur-
thermore, the synthesis and characterization of small and chain
water clusters are important for an understanding of the hydrogen
bonding interactions between water molecules in bulk water or ice
[20–22]. In the past decades, water clusters involving both rings
and one dimensional chains have been characterized in both theo-
retical and experimental studies [20,21,28]. Among these clusters,
infinite water chains are rare [20,28].
Recently, we have reported the synthesis and structures of
transition metal–orotate complexes with different aromatic
amines [15–19,29–32]. In the present paper, we describe the
syntheses, IR spectra, thermal studies (TG, DTG, DTA) and crystal
structures of orotate complexes of Cu(II) and Ni(II) with the 1,3-
propanediamine (pen) and N-methylethylenediamine (nmen)
ligands.
hydrogen bonds and
pꢀꢀꢀp interactions, have been used extensively
in the development of supramolecular chemistry [6–8]. Especially,
hydrogen bonding is a widely used interaction to generate supra-
molecular systems with a variety of novel structural features
[7,8]. Heterocyclic carboxylates have been used in the construction
of supramolecular coordination polymers [8–10]. Orotic acid (vita-
min B13, 2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic
acid, H3Or) has been widely studied in recent years as a polyfunc-
tional ligand [8,11–16]. Furthermore, coordinated HOr2ꢁ exhibits a
ligand surface with double DA (D: donor, A: acceptor) or triple ADA
* Corresponding author. Tel.: +90 2222393750; fax: +90 2222393578.
E-mail address: yesilel@ogu.edu.tr (O.Z. Yesßilel).
0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2010.06.011

O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
2601
Diffraction experiments were carried out at 296 K on a Bruker
Smart Apex CCD diffractometer using Mo radiation
2. Experimental section
K
a
(k = 0.71073 Å). The structures were solved by direct methods using
the program SHELXS97 [33]. All non-hydrogen atoms were refined
anisotropically by full-matrix least-squares methods [33]. All H
atoms, except those of NH2 groups in complex 3, were placed in
geometrically idealized positions and refined as riding atoms with
Uiso (H) = 1.2 Ueq (C, N) and Uiso (Hmethyl) = 1.5 Ueq (C). Program(s)
used to refine the structures: SHELXL97 [33]; molecular graphics:
Mercury [34] and PLATON/PLUTON [35]; software used to prepare mate-
rial for publication: WINGX [36]. Details of crystal data, data collec-
tion, structure solutions and refinements are given in Table 1.
2.1. Preparation of the complexes
A solution of orotic acid monohydrate (0.523 g, 3 mmol) in
water (25 mL) was added dropwise with stirring at 50 °C to a solu-
tion of Ni(CH3COO)2ꢀ4H2O (0.852 g, 3 mmol) or Cu(CH3COO)2ꢀH2O
(0.598 g, 3 mmol) in distilled water (25 mL). The solutions immedi-
ately became suspensions and were stirred for 4 h at 50 °C. Then
1,3-propanediamine (0.223 g, 3 mmol) and/or N-methylethylen-
ediamine (0.225 g, 3 mmol) in water (5 mL) was added dropwise
to these suspensions. The clear solutions that formed were stirred
for 2 h at 50 °C and then cooled to room temperature. The violet for
(1) and blue for (2 and 3) crystals that formed were filtered and
Table 2
Selected bond distances (Å), angles (°) and hydrogen bonding geometry for 1.
washed with 5 mL of water and dried in air. IR (KBr pellet,
m/
cmꢁ1) for 1: 3447 s, 3302 s, 2957 w, 2925 w, 2881 w, 2769 w,
1626 vs, 1560 sh, 1489m, 1396m, 1335 w, 1153 w, 1142 w, 1024
w, 933 w, 908 w, 804 w, 779 w, 669 w, 636 w, 586 w, 444 w. IR
Bond lengths (Å)
Ni1–N3
Ni1–N2
Ni1–O3
2.061(3)
2.062(3)
2.080(2)
Ni1–N4
Ni1–O1
Ni1–O2
2.092(3)
2.103(2)
2.153(3)
(KBr pellet,
m
/cmꢁ1) for 2: 3306 vs, 3269 vs, 3203m, 3096m,
Angles (°)
2949m, 2909m, 2892 w, 2796m, 1652 vs br, 1569 s, 1471 s, 1416
s, 1371 s, 1318 s, 1280m, 1186 s, 1142m, 1103 w, 1046 w, 1023
s, 940 s, 920 s, 850m, 797 s, 777 s, 708m, 675 w, 616 w, 532 w,
N3–Ni1–N2
N3–Ni1–O3
N2–Ni1–O3
N3–Ni1–N4
N2–Ni1–N4
O3–Ni1–N4
N3–Ni1–O1
N2–Ni1–O1
99.69(12)
179.01(10)
79.57(10)
91.66(13)
167.91(12)
89.03(11)
92.62(12)
90.13(10)
O3–Ni1–O1
N4–Ni1–O1
N3–Ni1–O2
N2–Ni1–O2
O3–Ni1–O2
N4–Ni1–O2
O1–Ni1–O2
88.05(10)
93.54(12)
93.13(13)
85.05(11)
86.15(11)
90.21(12)
173.05(11)
488m, 449m. IR (KBr pellet, m
/cmꢁ1) for 3: 3363 s, 3346 s, 3212
vs, 3172 vs, 2977 w, 2928 w, 2818 w, 1694 vs, 1656 vs, 1634 vs,
1576 s, 1481 s, 1473 s, 1377 s, 1322 s, 1135 w, 1076m, 1027 s,
966 w, 946 s, 805m, 768m, 702 w, 669 w, 586 w, 526 w, 443m.
D–HꢀꢀꢀA
d(HꢀꢀꢀA) (Å)
d(DꢀꢀꢀA) (Å)
<(DHA) (°)
N3–H3AꢀꢀꢀO3i
N4–H4BꢀꢀꢀO4ii
N1–H1ꢀꢀꢀO6iii
O1–H1BꢀꢀꢀO5iv
O2–H2BꢀꢀꢀO3ii
O2–H2AꢀꢀꢀO4i
O1–H1AꢀꢀꢀO5v
N3–H3BꢀꢀꢀO6
2.28
2.43
3.138(5)
3.298(5)
2.791(4)
2.759(3)
2.760(4)
2.756(4)
2.759(4)
2.862(4)
161
163
2.2. Materials and measurements
1.94(4)
1.915(19)
1.93(2)
1.918(19)
1.94(2)
2.16
171(3)
175(4)
159(4)
166(3)
165(4)
135
All chemicals used were analytical reagents and were commer-
cially purchased. IR spectra were obtained with a Perkin Elmer 100
FT-IR spectrometer using KBr pellets in the 4000–400 cmꢁ1 range.
A Perkin–Elmer Diamond TG/DTA Thermal Analyzer was used to
record simultaneous TG, DTG and DTA curves in static air atmo-
sphere at a heating rate of 10 °C/min in the temperature range
40–700 °C using platinum crucibles.
Symmetry codes: (i) x + 1, y, z; (ii) ꢁx, ꢁy + 1, ꢁz; (iii) ꢁx + 1, ꢁy + 1, ꢁz + 1; (iv) x,
y ꢁ 1, z; (v) ꢁx, ꢁy + 1, ꢁz + 1.
Table 1
Crystal data and structure refinement parameters for complexes 1–3.
1
2
3
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C8H16N4NiO6
322.96
293(2)
0.71073 Mo K
triclinic
C16H24Cu2N8O8
583.51
293(2)
C16H24Cu2N8O8ꢀ3(H2O)
637.56
293(2)
a
0.71073 Mo K
a
0.71073 Mo K
triclinic
a
triclinic
ꢀ
ꢀ
ꢀ
P1
P1
P1
6.0330(10)
9.0650(13)
12.1227(19)
69.482(10)
89.502(10)
87.103(10)
620.10(17)
2
5.6113(5)
9.8402(8)
9.8522(8)
77.722(6)
76.262(5)
79.413(5)
511.24(8)
1
7.0447(8)
13.5017(15)
13.9819(16)
65.005(6)
88.326(6)
89.161(6)
1204.8(2)
2
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
Absorption coefficient (mmꢁ1
)
1.60
1.730
2.15
1.895
1.84
1.757
Dcalc (Mg mꢁ3
)
Crystal size (mm)
0.31 ꢂ 0.18 ꢂ 0.06
0.31 ꢂ 0.20 ꢂ 0.06
2.139–28.269
5103
0.23 ꢂ 0.11 ꢂ 0.04
2.756–28.285
12903
Theta range for data collection (°)
Measured reflections
Independent reflections
Absorption correction
Refinement method
Rint
–
5097
2790
2088
5890
Integration Stoe X-RED (Stoe and Cie, 2001)
Full-matrix least-squares on F2
0.048
0.061
0.163
0.97
0.016
0.017
0.035
0.091
1.06
R[F2 > 2
wR(F2)
r
(F2)]
0.024
0.067
1.19
Goodness-of-fit (GOF)on F2
0
1.73
0.42
0.99
D
D
qmax (e ÅAꢁ3
)
0
ꢁ1.71
ꢁ0.30
ꢁ0.77
q
min(e ÅAꢁ3
)

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O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
age Ni–O distance (2.112 Å) (Table 2). These values are comparable
3. Crystallographic analysis
3.1. Structure of [Ni(HOr)(H2O)2(pen)], 1
to those reported for mono-nuclear Ni(II) complexes of HOr2-
[11,12,15–17].
The crystal packing is achieved by inter-molecular hydrogen
bonds which play an important role in the formation of the 3D
supramolecular network of complex 1. Details of the hydrogen
bond geometries are provided in Supplementary Material (CCDC
No: 713625). It can be seen from Fig. 2 that the hydrogen bonds be-
tween the aqua ligands and the carboxylate group of HOr ligand
constitute edge-fused R22ð8Þ and R44ð12Þ rings in the ab plane. It is
also found that the carboxylate groups interact with the NH2
groups of pen ligands, and that HOr ligands are mutually connected
to each other by hydrogen bonds through the pyrimidine N and
exocyclic O atoms, giving rise to R22ð12Þ and R22ð8Þ ring motives,
respectively. The combined effect of these interactions results in
a step-shaped hydrogen bond pattern, as illustrated in Fig. 3.
Selected bond lengths and angles together with the hydrogen
bonding geometries are given in Table 2. The nickel(II) complex
of HOr consists of discrete [Ni(HOr)(H2O)2(pen)] molecules in the
unit-cell. The Ni(II) ion has a distorted octahedral geometry
(Fig. 1), being different from the dimeric complex 2 in which the
Cu(II) ion has a square pyramidal coordination geometry. The Ni(II)
ion is chelated by the pen ligand through N atoms and by the oro-
tate anion through the carboxylate O and pyrimidine N atoms. The
octahedral geometry is completed by two trans aqua ligands in ax-
ial positions.
The Ni–N distances are close to each other, and the average va-
lue of the Ni–N distance (2.085 Å) is slightly shorter than the aver-
Fig. 1. The molecular structure of [Ni(HOr)(pen)(H2O)2] (1) with the atom labeling scheme.
Fig. 2. A view of the packing of 1, showing the centrosymmetric edge-fused R22ð8Þ and R44ð12Þ rings in the ab plane. Only relevant H atoms are included. Symmetry codes: (i)
x + 1, y, z; (iii) ꢁx + 1, ꢁy + 1, ꢁz + 1; (v) ꢁx, ꢁy + 1, ꢁz + 1.

O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
2603
Fig. 3. A partial view of the packing of 1, showing the formation of a step-shaped hydrogen bond pattern as well as edge-fused R22ð12Þ and R22ð8Þ rings. Unrelated H atoms and
aqua ligands are omitted for clarity. Symmetry codes: (i) x + 1, y, z; (ii) ꢁx, ꢁy+1, ꢁz; (iii) ꢁx + 1, ꢁy + 1, ꢁz + 1.
3.2. Structure of [Cu2(l-HOr)2(pen)2], 2
value of the Cuꢀ ꢀ ꢀCu distance (5.054 Å) indicates a weak interaction
between the copper centers in the dimeric units.
The molecular structure of complex 2 consists of dimeric
[Cu2( -HOr)2(pen)2] units (Fig. 4). In the structure, each Cu(II)
The Cu1–N2HOr (1.981 (2) Å) and Cu1–OHOr (1.958 (17) Å) bond
distances are similar to the corresponding values found in [Cu2-
l
ion has a square pyramidal coordination geometry with a bridging
oxygen atom at the pyramid apex [Cu1–O2 = 2.745 Å]. The basal
plane is formed by pyrimidine N and carboxylate O atoms of oro-
tate ligands and by two N atoms of chelating pen ligand. The low
(l-HOr)2(etpy)2] [17], [Cu(HOr)(H2O)2]n [13] and (chaH)2[Cu-
(HOr)2(cha)]ꢀ2H2O [15]. The Cu1–O2 bond distance of 2.745 Å is
significantly longer than the corresponding bond in [Cu(HOr)2-
(H2O)2]n (2.337(2) Å) [13] and [Cu2(l-HOr)2(etpy)2] (2.683(2) Å)
[17]. The deviation from an ideal square pyramidal geometry is
revealed by the bite of angles observed around the metal center:
N3–Cu1–N4 = 91.41(10)° and O1–Cu1–N2 = 82.76(8)° (Table 3).
The crystal packing in complex 2 is achieved via intra- and in-
ter-molecular hydrogen bonds (Fig. 5). Details of the hydrogen
bond geometries are provided in the Supplementary Material
(CCDC No: 713623). Hereafter, the graph-set notation [37] will
be employed to describe the hydrogen bond patterns. In the
extended structure (Fig. 5a), the orotate ligands are mutually con-
nected by N–Hꢀ ꢀ ꢀO hydrogen bonds, resulting in centrosymmetric
R22ð8Þ rings running through the plane (1 0 1). As is seen in Fig. 5b,
N4 of a pen ligand acts as a donor atom, via H4A, to the carboxylic
Table 3
Selected bond distances (Å), angles (°) and hydrogen bonding geometry for 2.
Bond lengths (Å)
N2–Cu1
N3–Cu1
1.984(2)
1.981(2)
N4–Cu1
O1–Cu1
1.983(2)
1.958(2)
Angles (°)
O1–Cu1–N3
O1–Cu1–N4
N3–Cu1–N4
D–HꢀꢀꢀA
165.35(10)
89.09(9)
91.41(10)
d(HꢀꢀꢀA) (Å)
O1–Cu1–N2
N3–Cu1–N2
N4–Cu1–N2
d(DꢀꢀꢀA) (Å)
82.76(8)
98.02(9)
169.81(10)
<(DHA) (°)
N3–H3BꢀꢀꢀO4i
N4–H4AꢀꢀꢀO1ii
N4–H4BꢀꢀꢀN2i
N4–H4BꢀꢀꢀO4i
N1–H1ꢀꢀꢀO3iii
N3–H3AꢀꢀꢀO4
2.42(4)
2.58(4)
2.58(4)
2.62(3)
2.03(3)
2.08(4)
3.161(4)
3.109(3)
3.482(3)
3.330(3)
2.823(3)
2.849(3)
151(4)
129(4)
156(3)
130(3)
173(3)
149(3)
Fig. 4. The molecular structure of the dimeric complex [Cu2(l-HOr)2(pen)2] (2)
Symmetry codes: (i) x + 1, y, z; (ii) ꢁx + 2, ꢁy, ꢁz + 1; (iii) ꢁx, ꢁy, ꢁz.
along with the atom labeling scheme.

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O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
Fig. 5. The molecular packing of 2. H atoms not involved in hydrogen bonds are omitted for clarity.
Fig. 6. The one-dimensional chain structure of 3. H atoms not involved in hydrogen bonds are omitted for clarity.
O atom of an HOr ligand, producing a chain C(6) running through
the a axis and a centrosymmetric R22ð8Þ ring centered at (n + 1, 0,
1/2) (n = zero or integer). The exocyclic O atoms of HOr participate
in inter-molecular hydrogen bonds with N atoms of neighboring
pen ligands. This results in C(6) chains repeated through [1 0 0]
(Fig. 5c). It is also seen that N3–H3Bꢀ ꢀ ꢀO4i and N4–H4Bꢀ ꢀ ꢀ O4i
hydrogen bonds constitute R21ð7Þ rings along the a axis.
3.3. Structure of [Cu2(
l
-HOr)2(nmen)2]ꢀ3H2O, 3
Complex 3 has the same coordination geometry as that of com-
plex 2. However, complex 3 is a coordination polymer in which the
orotate moiety acts as a bridging ligand. The adjacent [Cu(HOr)(n-
men)] units are linked by carboxylate oxygen atoms of HOr, result-
ing in a zigzag chain structure along the a axis (Fig. 6). These chains

O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
2605
Fig. 7. A view of the 2D network of complex 2, formed by inter-molecular hydrogen bonds interlinking the zigzag chains. Only relevant H atoms are included. Symmetry
codes: (iv) x + 1, y, z; (v) ꢁx + 1, ꢁy, ꢁz + 2.
Fig. 8. The packing of complex 2, showing chain of edge-fused R22ð16Þ and R22ð18Þ rings. Only relevant H atoms are included. Symmetry codes: (i) ꢁx + 1, ꢁy + 1, ꢁz + 1; (v)
ꢁx + 1, ꢁy, ꢁz + 2.

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O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
Fig. 9. A view of the packing of complex 2, showing the R22ð20Þ ring pattern. Only relevant H atoms are included. Symmetry codes: (iii) ꢁx+2, ꢁy+1, ꢁz+1; (v) ꢁx+1, ꢁy,
ꢁz+2.
Table 4
Selected bond distances (Å), angles (°) and hydrogen bonding geometry for 3.
are inter-linked by moderate hydrogen bonds of the N–Hꢀ ꢀ ꢀO type
Bond lengths (Å)
(Figs. 7–9). Selected bond lengths and angles, together with the
N1–Cu1
N3–Cu1
N4–Cu1
N5–Cu2
N7–Cu2
1.9766(19)
1.989(2)
2.003(2)
2.012(2)
1.9689(19)
N8–Cu2
O1–Cu2
O2–Cu1
O5–Cu2
O6–Cu1i
1.988(2)
hydrogen bonding geometries, are given in Table 4.
2.3964(18)
1.9598(17)
1.9622(17)
2.3572(18)
In the extended structure, a 2D network in the ab plane is
formed by inter-molecular N–Hꢀ ꢀ ꢀO hydrogen bonds interlinking
the zigzag chains along the direction [1 0 0] (Figs. 7–9). Details of
hydrogen bond geometries are provided in the Supplementary
Material (CCDC: 713624). As is seen in Fig. 7, the amino atom N3
in the molecule at (x, y, z) acts as a hydrogen-bond donor, via
H3A, to the atom O6 in the molecule at (x + 1, y, z), while the atom
N3 at (x + 1, y, z), in turn, acts as a donor to O6 at (x, y, z). This
arrangement of hydrogen bonds along the a axis can be described
by the graph-set notation R22ð16Þ.
Angles (°)
O2–Cu1–N1
O2–Cu1–N3
N1–Cu1–N3
O2–Cu1–N4
N1–Cu1–N4
N3–Cu1–N4
O2–Cu1–O6ii
N1–Cu1–O6ii
N3–Cu1–O6ii
N4–Cu1–O6ii
83.48(7)
172.53(9)
101.56(9)
91.25(8)
164.77(9)
85.20(9)
91.86(7)
109.28(7)
81.30(9)
85.10(8)
O5–Cu2–N7
O5–Cu2–N8
N7–Cu2–N8
O5–Cu2–N5
N7–Cu2–N5
N8–Cu2–N5
O5–Cu2–O1
N7–Cu2–O1
N8–Cu2–O1
N5–Cu2–O1
83.63(7)
175.09(9)
100.15(9)
91.39(8)
165.37(9)
85.69(9)
90.36(7)
110.34(7)
85.38(10)
83.35(8)
Similarly, N8–H8Bꢀ ꢀ ꢀO7v hydrogen bonds form R22ð16Þ rings.
The interactions between the NH and carboxylate groups of
neighboring HOr ligands, and the interactions between the amino
group of nmen and the exocylic O atom of HOr generate a chain
of edge-fused R22ð16Þ and R22ð18Þ rings (Fig. 8). It is also seen that
the N4–H4ꢀ ꢀ ꢀO8v hydrogen bonds mutually connect zigzag chains,
resulting in centrosymmetric R22ð20Þ rings centered at (n + 1/2, n,
0) (n = 0 or integer) (Fig. 8). The crystal water molecules are in-
volved in hydrogen bonding with the carbonyl oxygen atoms
(O3, O4 and O7) of HOr ligands and water molecules (O9, O10
and O11). These hydrogen bonding interactions give rise to two
dimensional networks. Adjacent poly-nuclear chain are connected
to one another via O–HꢀꢀꢀO hydrogen bonds, forming an extended
C3 motif in the 1D chain. This water cluster plays an important
role in the stabilization of the crystal structure. The OꢀꢀꢀO dis-
tances are 2.783, 2.853 and 2.943 Å, and are longer than the cor-
responding value of 2.759 Å in ice [28] and less than the sum of
their van der Waals radii (3.04 Å). The two adjacent 1D coordina-
D–HꢀꢀꢀA
d(HꢀꢀꢀA) (Å)
d(DꢀꢀꢀA) (Å)
<(DHA) (°)
N2–H2ꢀꢀꢀO5iii
2.28(4)
2.13(7)
2.30(4)
2.40(4)
2.06(4)
2.56(4)
2.24(3)
2.14(4)
2.17(5)
2.01(6)
1.97(5)
2.46(4)
2.54(4)
1.81(5)
2.08(5)
3.046(3)
2.943(5)
3.008(3)
2.845(3)
2.876(3)
3.121(3)
3.068(3)
3.093(4)
2.887(4)
2.852(5)
2.795(4)
2.971(3)
3.179(4)
2.783(5)
2.813(4)
174(3)
167(7)
145(4)
115(4)
168(4)
137(4)
171(3)
177(4)
174(6)
172(5)
167(5)
128(4)
146(4)
173(4)
156(5)
O10–H10BꢀꢀꢀO9iv
N3–H3AꢀꢀꢀO3v
N3–H3AꢀꢀꢀO6ii
N4–H4ꢀꢀꢀO8vi
N5–H5ꢀꢀꢀO4iii
N6–H6ꢀꢀꢀO2vi
N8–H8BꢀꢀꢀO7vi
O9–H9AꢀꢀꢀO7vii
O9–H9BꢀꢀꢀO11viii
O10–H10AꢀꢀꢀO3iii
N3–H3BꢀꢀꢀO4
N3–H3BꢀꢀꢀO11
O11–H11BꢀꢀꢀO10
O11–H11AꢀꢀꢀO4
Symmetry codes: (i) x ꢁ 1, y, z; (ii) x + 1, y, z; (iii) ꢁx + 1, ꢁy + 1, ꢁz + 1; (iv) x, y + 1, z;
(v) ꢁx + 2, ꢁy + 1, ꢁz + 1; (ii) x + 1, y, z; (vi) ꢁx + 1, ꢁy, ꢁz + 2; (vii) ꢁx, ꢁy, ꢁz + 2; (viii)
xꢁ1, yꢁ1, z.

O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
2607
tion polymers are connected through
p
ꢀꢀꢀ
p
interactions. The lat-
tice water molecules, forming a 1D water cluster, function as glue
to form a 3D supramolecular network through extended hydro-
gen bonding (Fig. 10).
3.4. Thermal analyses
The thermal behaviors of the complexes are quite similar and
they show a three (1 and 3) or four (2) stage mass losses
(Fig. 11). The first stage between 109–165 °C for 1 and 43–
111 °C for 3 corresponds to the endothermic elimination of water
molecules, with an experimental mass loss of 11.22 and 8.45%,
respectively (calc. mass loss 11.15 and 8.47%). The removal of
N-donor ligands and decomposition of the orotate ligand occurs
in the following stage between 257–348 °C for 1, 273–313 °C
for 2 and 252–292 °C for 3. In the last stage, a strong exothermic
peak on the DTA curve (DTAmax = 354 (1), 475 (2) and 421 °C (3))
is associated with decomposition and burning of the remaining
organic part. The overall experimental mass loss, 76.92% for 1,
74.47% for 2 and 77.06% for 3, are in agreement with this stoi-
chiometry. The thermal decomposition product was identified
as NiO or CuO (calc. mass loss 76.87 for 1, 72.74% for 2 and
75.05% for 3).
4. Conclusion
In summary, new homo- di- and poly-nuclear orotate com-
plexes have been synthesized and characterized. In these com-
plexes, the orotate ligand acts as bidentate and tridentate
ligands. Moreover, complex 3 displays an interesting solid-state
structure, containing one dimensional water clusters. The crystal
structures of the complexes are stabilized by intra- and inter-
Fig. 10. (a) 3D network of 1 and (b) view of a C3 extended motif for 1, all hydrogen
atoms are omitted for clarity.
molecular O–HꢀꢀꢀO hydrogen bonds and
pꢀ ꢀ ꢀp interactions to form
3D supramolecular networks.
Fig. 11. TG, DTG and DTA curves of 3.

2608
O.Z. Yeßsilel et al. / Polyhedron 29 (2010) 2600–2608
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(1999) 565.
CCDC 713625, 713623 and 713624 contain the supplementary
crystallographic data for complexes 1, 2 and 3, respectively. These
data can be obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44)
1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
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Acknowledgement
The authors wish to acknowledge Anadolu University, Medici-
nal Plants, Drugs and Scientific Research Center (AUBIBAM) for
X-ray diffraction data collection.
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