The first dinuclear orotate complex: Syntheses, spectral, thermal and structural characterization of supramolecular orotate complexes of nickel(II) and copper(II) with 2-hydroxyethylpyridine

Article abstract of DOI:10.1016/j.molstruc.2008.02.029

Two novel orotate complexes, mononuclear [Ni(HOr)(H₂O)₂(etpy)]·H₂O (1) and dinuclear [Cu(μ-HOr)(etpy)]₂ (2) (etpy = 2-hydroxyethylpyridine, HOr^2- = dianionic orotate), have been prepared and characterized by elemental analyses, spectroscopic (IR, UV-vis), thermal, magnetic and single crystal X-ray diffraction studies. The mononuclear Ni(II) complex crystallizes in the triclinic space group P over(1, ?) and the dinuclear copper(II) complex crystallizes in the monoclinic space group P2₁/c. The mononuclear complex consists of individual units in which nickel(II) lies on the inversion center and has octahedral coordination by bidentate HOr^2-, bidentate etpy and two aqua ligands. The dinuclear copper(II) complex composed of a double-orotate bridge and bidentate etpy ligands. Each HOr^2- ligand simultaneously exhibits chelating bidentate and bridging coordination modes. HOr^2- is tricoordinated to one copper atom through N3 atom of pyrimidine ring, one oxygen atom of the carboxylate group as a bidentate ligand and to the other copper ion via the other oxygen of the carboxylate group. The structural units are joined into the framework by the hydrogen bonds in 1 and 2.

Full text of DOI:10.1016/j.molstruc.2008.02.029

Journal of Molecular Structure 889 (2008) 415–421
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
The first dinuclear orotate complex: Syntheses, spectral, thermal and structural
characterization of supramolecular orotate complexes of nickel(II) and
copper(II) with 2-hydroxyethylpyridine
a,*
a
a
b
Okan Zafer Ye ßs ilel , Aylin Mutlu , Cemil Ö g˘ retir , Orhan Büyükgüngör
a
Department of Chemistry, Faculty of Arts and Sciences, Eski ßs ehir Osmangazi University, 26480 Eski ßs ehir, Turkey
Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Kurupelit, Samsun, Turkey
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 24 October 2007
Received in revised form 21 February 2008
Accepted 21 February 2008
Available online 29 February 2008
Two novel orotate complexes, mononuclear [Ni(HOr)(H O) (etpy)]ꢀH O (1) and dinuclear [Cu(l-HOr)
2ꢁ
2
2
2
(
2
etpy)] (2) (etpy = 2-hydroxyethylpyridine, HOr = dianionic orotate), have been prepared and charac-
terized by elemental analyses, spectroscopic (IR, UV–vis), thermal, magnetic and single crystal X-ray
ꢀ
diffraction studies. The mononuclear Ni(II) complex crystallizes in the triclinic space group P1 and the
dinuclear copper(II) complex crystallizes in the monoclinic space group P2
1
/c. The mononuclear complex
consists of individual units in which nickel(II) lies on the inversion center and has octahedral coordina-
2ꢁ
tion by bidentate HOr , bidentate etpy and two aqua ligands. The dinuclear copper(II) complex com-
Keywords:
Orotate complexes
2ꢁ
posed of a double-orotate bridge and bidentate etpy ligands. Each HOr
ligand simultaneously
2
ꢁ
exhibits chelating bidentate and bridging coordination modes. HOr is tricoordinated to one copper
atom through N3 atom of pyrimidine ring, one oxygen atom of the carboxylate group as a bidentate
ligand and to the other copper ion via the other oxygen of the carboxylate group. The structural units
are joined into the framework by the hydrogen bonds in 1 and 2.
2
-Hydroxyethylpyridine
Dinuclear orotate complex
Dinuclear copper(II) complex
Ó 2008 Elsevier B.V. All rights reserved.
1
. Introduction
nitrogen and the adjacent carboxylate oxygen and to another oro-
3 2
tato anion at the exocyclic carbonyl oxygen. In the [Cu(HOr)(NH ) ]
Orotic acid has a great importance in the field of biological
[15] and [Cu(HOr)(phen)] [23] complexes, orotate is coordinated to
the copper ion through nitrogen atom of pyrimidine ring and oxy-
gen atom of carboxylate group as a chelate manner. The primary
coordination spheres about copper(II) were square–planer and
they were extended to octahedral coordination by exocyclic keto-
oxygens or other oxygen atom of carboxylate group of the symme-
try related complex units.
Following of our work on [24–28,39,42–45], we now are report-
ing on the preparation, spectral, thermal and structural character-
ization of orotate complexes of nickel(II) and copper(II) with
2-hydroxyethylpyridine (Scheme 1b).
activity, that is meaning vitamin B13 (Scheme 1) [1–5].
Mono- and dianion of orotic acid are potential polydentate ligands.
The coordination may occur through the heterocyclic nitrogens of
the pyrimidine ring, the exocyclic carbonyl oxygens, and the
carboxylic group. The orotato anion may exhibit versatile coordi-
nating modes such as monodentate [6–12], bidentate [13–33],
bridging ligand [34–39] and counter anion [40–43]. To our knowl-
edge, so far the only one structural characterization of polymeric
copper–orotate complex has been reported [34] and X-ray crystal
structures of a few mononuclear copper(II) orotate complexes have
appeared in the literature [8,15,23,28,32,44,45]. Although orotic
acid has been studied extensively, both structurally and spectro-
scopically for many years [10–12], the dinuclear complexes of this
ligand have not been reported. In the polymeric orotate complex,
2
. Experimental
2.1. Preparation of the complexes
[
2 2 n
Cu(HOr)(H O) ] [34] the carboxylate group acts as a bridge be-
tween two metal atoms using its two oxygen atoms of carboxylate
group. By contrast, in polymeric Co(III) and Ni(II) complexes [30],
metal ions are coordinated to one orotato ligand at the N3 ring
A solution of etpy (0.44 g, 4 mmol) in ethanol (5 mL) was added
dropwise upon stirring to a solution of [Ni(HOr)(H
2
O)
4
]ꢀH
2
O [20]
(
0.61 g, 2 mmol) and [Cu(HOr)(H O) O [24] (0.62 g, 2 mmol)
2
4
]ꢀH
2
in distilled water (30 mL). The solution was heated to 60 °C in a
temperature-controlled bath and stirred for 5 h at 60 °C. Then the
reaction mixture was cooled to room temperature. The formed
*
Corresponding author. Tel.: +90 222 2393750; fax: +90 222 2393578.
E-mail address: yesilel@ogu.edu.tr (O.Z. Ye sß ilel).
0
022-2860/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2008.02.029

4
16
O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
Table 1
a
O
C
b
Crystal data and structure refinement for 1 and 2
1
2
OH
(
4)
Empirical formula
Formula weight (g mol
Crystal dimensions (mm)
Crystal system, space group
Color
Unit cell dimensions
C
12
H
17
N
3
O
8
Ni
C
24 22 6 2
H N O10Cu
(
3)
H
ꢁ1
)
389.97
681.56
(
5)
N
0.35 ꢂ 0.46 ꢂ 0.57
0.34 ꢂ 0.47 ꢂ 0.64
ꢀ
(
6)
(2)
Triclinic, P1
1
Monoclinic P2 /c
OH
Light-blue
Violet
O
N
H
(1)
O
N
a (Å)
b (Å)
c (Å)
a (°)
b (°)
c (°)
6.8688(5)
9.7596(8)
12.5138(10)
106.227(6)
99.553(6)
103.510(6)
758.77(10)
2
8.1099(9)
8.7365(16)
18.0608(17)
Scheme 1. Structures of the ligands: (a) Orotic acid (1,2,3,6-tetrahydro-2,6-dioxo-
-pyrimidinecarboxylic acid, H Or). (b) 2-Hydroxyethylpyridine, etpy.
4
3
98.919(8)
3
Volume (Å )
1264.2(3)
2
1.75
light-blue for Ni(II) complex and violet for Cu(II) complex crystals
were filtered and washed with 10 ml of water and ethanol and
Z
Absorption coefficient (mmꢁ1)
Data collection
1.75
STOE IPDS 2 diffractomer (x scan)
296(2)
0.5801, 0.7135
1.75, 27.95
dried in air. Found: C 35.84, H 4.39, N 10.73. Calcd. for C12
Ni: C 36.96, H 4.39, N 10.78% and found: C 42.51, H 3.32, N, 12.74.
Calcd. for C24 : C 42.29, H 3.25, N 12.33%.
17 3 8-
H N O
Temperature (K)
296(2)
0.3429, 0.5898
2.28–27.94
Tmin, Tmax
22 6 2
H N O10Cu
h Range (°)
Index ranges
h
k
l
ꢁ8 ? 9
ꢁ12 ? 12
ꢁ16 ? 16
14,682
2984
2784
ꢁ10 ? 10
ꢁ11 ? 11
ꢁ23 ? 23
17923
2482
2302
2
.2. Materials and measurements
All chemicals used were analytical reagent and were commer-
cially available. IR spectra were obtained with a Bruker Tensor 27
Reflections collected
Independent reflections
Reflections with I > 2r(I)
Absorption correction
ꢁ1
FT-IR spectrometer using KBr pellets in the 4000–400 cm range.
Elemental analyses for C, H and N were performed using a Vario EL
III CHNS elemental analyzer. Magnetic susceptibility measure-
ments at room temperature were performed using a Sherwood Sci-
entific MXI model Gouy magnetic balance. The UV–vis spectra
were obtained for the aqueous solution of the complex (10 M)
with a Unicam UV2 spectrometer in the range 900–190 nm. Dia-
mond TG/DTA thermal analyzer were used to record simultaneous
TG, DTG and DTA curves in the static air atmosphere at a heating
Integration
Integration
0.50, ꢁ0.37
3
Largest diff. peak and hole (eÅ ) 0.39, ꢁ0.18
Final R indices I > 2r(I)
R
1
= 0.022,
wR = 0.058
int = 0.033
1.07
1
R = 0.025,
2
wR
int = 0.039
1.07
2
= 0.066
R indices (all data)
R
R
ꢁ3
Goodness-of-fit on F2
ꢁ1
rate of 10 K min in the temperature range 50–600 °C using plat-
3.2. IR spectra
inum crucibles.
The most significant frequencies in the IR spectra of the com-
plexes are given in Table 2 and Fig. 1, together with those of
2.3. Crystallographic analysis
H
3
OrꢀH
2
O [51], [Cu(HOr)(H
2
O)
4
]ꢀH
2
O [32] and [Ni(HOr)(H
2
O)
4
]ꢀH
2
O
Data collection was performed on a STOE IPDS II image plate
[32] for comparison. The strong and broad absorption bands at
3385 and 3372 cm
H O or etpy ligand, respectively. The bands at 3111 and
2
3122 cm are attributed to the NH stretching vibrations in HOr
ligand. The two weak close bands due to the m(CH) vibrations are
found at 2762–2959 cm
ꢁ1
detector using MoK
a
radiation (k = 0.71073 Å). Details of crystal
are attributed to the m(OH) vibrations of
data, data collection, structure solution and refinement are given
in Table 1. Data collections: Stoe X-AREA [46]. Cell refinement:
Stoe X-AREA [46]. Data reduction: Stoe X-RED [46]. The struc-
tures were solved by direct-methods using SIR97 [47] and aniso-
tropic displacement parameters were applied to non-hydrogen
ꢁ
1
2ꢁ
ꢁ1
.
A comparison between the carbonyl and carboxyl groups
2
atoms in a full-matrix least-squares refinement based on F
stretching vibration bands of H Or and its monodentate, bidentate
3
using SHELXL-97 [48]. Molecular drawings were obtained using
ORTEP III [49].
and tridentate complexes may provide important evidence for the
coordination of the orotate ligand. The carbonyl/carboxyl groups
appear as three main peaks at 1729 and 1719 [mC@O(acid) + mC(2)@O
]
ꢁ1
and 1700 cm
[mC(6)@O + mring
]
in the free orotic acid [51].
3
. Results and discussion
ꢁ1
Three carbonyl bands were observed at 1701 and 1639 cm for
3.1. UV–vis spectra and magnetic susceptibility
Table 2
The electronic spectrum of 1 in H
bands at 634 and 884 nm and the corresponding e values are 12
2
O exhibits two absorption
a
ꢁ1
IR spectral data of complexes (cm
)
ꢁ
1
ꢁ1
Assignment
1
2
H OrꢀH O
3 2
and 10 L mol cm , respectively. These values were assigned to
3
3
3
3
m
2
:
A
2g ? T1g and m
for 1 was calculated as 11,300 cm since D
50]. The UV–vis spectrum of 2 in H
band at 730 nm (e = 19 L mol cm ). These values were assigned
to a ? b
1
:
A
2g ? T2g d–d transitions. The D
0
values
for d complexes
2
O displays broad absorption
mOH
3385 m
3111 m
–
2945–2762 w
–
3372 m
3122 m
–
2959–2802 w
–
3241 sh
3154 m
3137 m
3099 s
ꢁ1
8
mN(1)
mN(3)
mCH
H
H
0 1
= m
[
ꢁ1
ꢁ1
mOHacid
[mC@O(acid) + mC(2)@O
2500 m, b
1
1
.
]
1634 vs, b
1679 vs
1621 vs
1462 m
513 w, 437 w
1729, 1719 vs
1700 vs
–
–
Complexes 1 and 2 exhibit magnetic moment values of 2.41 and
.10 BM which corresponds to two and one unpaired electrons,
respectively. However, this magnetic moment value is lower than
the spin only value for two unpaired electrons in Cu(II) complex
and indicates to antiferromagnetic effect.
[mC(6)@O + mring
mCOO
MAO, MAN
]
1481 m
476 w, 435 w
2
a
Abbreviations: sh, shoulder; w, weak; m, medium; s, strong; vs, very strong; b,
broad.

O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
417
Fig. 1. IR spectra of the complexes.
mono-deprotonated orotate ligand, [Co(H
2
Or)
for bis-deprotonated orotate ligand,
O [32], while the bis(bis-deprotonated) orotate
2
(H
2
O)
4
]ꢀ2 H
2
O [11],
ligands, (chaH)
[45], give two equally strong bands at 1654 and 1605 cm
In the IR spectra of 1 and 2, carbonyl/carboxyl stretching is
2
[Cu(HOr)
2
(cha)]ꢀ2H
2
O
(chaH = cyclohexylamine)
ꢁ1
ꢁ1
and 1685 and 1645 cm
Cu(HOr)(H O)
]ꢀH
.
[
2
4
2
Fig. 2. TG, DTG and DTA curves of 1.

4
18
O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
Fig. 3. TG, DTG and DTA curves of 2.
Fig. 4. The chemical structures of the complexes.
overlapped with the water bending and stretching vibration of
(H
2
O)
2
(etpy)]ꢀH
2
O decomposes in four stages (Fig. 2). The first
C@N of the pyridine ring and are broadened very strong absorption
stage between 80 and 131 °C corresponds to the endothermic
dehydration of the complex with a mass loss of 4.65% (calcd.
4.62%). The release of the two aqua ligands takes place in the sec-
ond stage (132–184 °C). The experimental mass loss of 9.67%
agrees well with the calculated mass loss of 9.24%. The decompo-
sition stage in the 185–263 °C range corresponds to removal of
ꢁ
1
ꢁ1
at 1634 cm for 1 and 1679 and 1621 cm for 2. The m(OHacid
)
ꢁ1
band at ca. 2500 cm in the free orotic acid completely disap-
peared and a new carboxylate band (mCOO) appeared at 1481 (1)
and 1462 (2) cm , indicating that the carboxylate group partici-
ꢁ1
pates in the coordination with the metal ions by deprotonation.
2
CH OH radical with an endothermic effect at 242 °C (found: 7.72,
3
.3. Thermal analysis
calcd. 8.07%). In the last stage, the exothermic degradation of pyr-
2ꢁ
idine and HOr ligands occurs in the 264–475 °C range with two
DTA peaks at 311 and 449 °C, and results in the formation of NiO
as an end product.
The thermal behavior of the nickel(II) and copper(II) complexes
was followed up to 600 °C in a static air atmosphere. [Ni(HOr)

O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
419
[
Cu(l-HOr)(etpy)]
2
shows a three stages weight loss (Fig. 3). The
first stage between 125 and 190 °C corresponds to the exothermic
removal of CH OH radical by giving endothermic effect
DTGmax = 171 °C, found 9.68, calcd. 9.11%). This type of behavior
2
(
in the saccharinato complexes with triethanolamine ligand has
been reported earlier [52]. The second stage is related to the
decomposition of remain etpy ligands with a mass loss of 27.24%
2
ꢁ
(
calcd. 27.03). The decomposition of the HOr ligands occur in
the third stage between 285 and 473 °C with the strong exothermic
peak of the DTA curve at 424 °C (found: 40.16, calcd. 40.52%). The
final decomposition product CuO was identified by IR spectroscopy
(
found: 77.08, calcd. 76.66%).
The proposed structures of the synthesized complexes which
are presented in Fig. 4, are consistent with each other in terms of
chemical, thermal and spectroscopic properties.
Fig. 5. Ortep III view of 1 with the atom numbering scheme.
3
3
.4. Crystal structure of the complexes
Table 3
Geometric parameters (Å, °) for 1
.4.1. [Ni(HOr)(H
The molecular structure of [Ni(HOr)(H
2
O)
2
(etpy)]ꢀH
2
O
Ni1AN1
Ni1AN3
Ni1A O4
2.029(1)
2.073(1)
2.053(1)
Ni1AO5
Ni1AO6
Ni1AO7
2.112(1)
2.107(1)
2.091(1)
O)
2 2
(etpy)]ꢀH
2
O consists
of neutral molecules as shown in Fig. 5. Selected bond lengths
and angles together with the hydrogen bonding geometry are col-
lected in Table 3. The nickel(II) ion is coordinated by two aqua, one
etpy and one HOr ligands, exhibiting a distorted octahedral con-
figuration of the NiN
donor via nitrogen and oxygen atoms, creating a six-membered
chelate ring, while the HOr
through nitrogen atom of pyrimidine ring and oxygen atom of car-
boxylate group. The NiANetpy and NiAOetpy bonds distances are
2.0729 and 2.1120 Å, while the NiANHOr and NiAOHOr bond dis-
tances of 2.0292 and 2.0528 Å are comparable to those reported
N1ANi1AO4
N1ANi1AN3
O4ANi1AN3
N1ANi1AO7
O4ANi1AO7
N3ANi1AO7
N1ANi1AO6
O4ANi1AO6
79.73(5)
171.42(5)
93.57(5)
96.34(5)
172.47(5)
90.90(5)
90.08(5)
89.00(5)
N3ANi1AO6
O7ANi1AO6
N1ANi1AO5
O4ANi1AO5
N3ANi1AO5
O7ANi1AO5
O6ANi1AO5
95.20(5)
84.57(5)
85.69(5)
97.04(5)
89.86(5)
89.01(5)
171.88(5)
2ꢁ
2 4
O type. The etpy molecule acts as a bidentate
2ꢁ
also behavior bidentate ligand
Hydrogen-bond geometry (Å, °)
DAHꢀ ꢀ ꢀA
DAH
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
DAHꢀ ꢀ ꢀA
173(2)
171(2)
159(2)
167(2)
171(2)
156(2)
172(3)
170(3)
i
N2AH2ꢀ ꢀ ꢀO1
O5AH5ꢀ ꢀ ꢀO3
0.87(2)
0.80(2)
0.84(2)
0.85(2)
0.82(2)
0.80(2)
0.79(2)
0.82(2)
1.88(2)
1.932(6)
2.02(2)
2.12(2)
1.87(2)
1.88(2)
2.05(2)
2.02(2)
2.740(2)
2.728(2)
2.818(2)
2.952(2)
2.684(2)
2.631(2)
2.838(2)
2.831(2)
ii
2ꢁ
iii
for the corresponding mononuclear Ni(II) complexes of HOr
O6AH6Aꢀ ꢀ ꢀO2
iv
[27,29,30,44]. The NiAOetpy bond is also much longer than the
NiANetpy, NiANHOr and NiAOHOr bonds, and these results in
formation of an elongated octahedral geometry along the Oetpy
atom (Table 3). Both the HOr and etpy ligands are essentially
planar with r.m.s deviations from the best least-squares planes of
O6AH6Bꢀ ꢀ ꢀO7
O7AH7Aꢀ ꢀ ꢀO8
O7AH7Bꢀ ꢀ ꢀO1
O8AH8Aꢀ ꢀ ꢀO2
v
2ꢁ
ii
O8AH8Bꢀ ꢀ ꢀO4
Symmetry codes: (i) ꢁx + 1, ꢁy + 1, ꢁz; (ii) x ꢁ 1, y, z; (iii) ꢁx + 2, ꢁy + 1, ꢁz; (iv)
x + 1, ꢁy, ꢁz; (v) x ꢁ 1, y ꢁ 1, z.
0
.0122 and 0.0035 Å, respectively. The dihedral angles between
ꢁ
Fig. 6. Part of the crystal structure of 2, showing the formation of a hydrogen bonded R 2ð8Þ ring and p–p interaction (Cg3–Cg3 ). Symmetry codes: (i) 2 ꢁ x, 1 ꢁ y, ꢁz; (ii)
i
2
1
ꢁ x, 1 ꢁ y, ꢁz; (iii) ꢁ1 + x, y, z.

4
20
O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
Table 4
O(7)AH(7B)ꢀ ꢀ ꢀO(1), O(8)AH(8A)ꢀ ꢀ ꢀO(2) and O(8)AH(8B)ꢀ ꢀ ꢀO(4).
Geometric parameters (Å, °) for 2
There are also intramolecular hydrogen bonds between coordine
water molecules O7 and crystal water molecules O8, exocyclic
O1 atoms of orotate. All of these intermolecular interactions give
two-dimensional hydrogen-bonded network results (Table 3).
N1ACu1
N3ACu1
1.948(2)
1.971(2)
O4ACu1
O5ACu1
1.932(1)
1.939(2)
O4ACu1AO5
O4ACu1AN1
O5ACu1AN1
173.08(7)
83.33(6)
92.93(7)
O4ACu1AN3
O5ACu1AN3
N1ACu1AN3
94.03(6)
89.08(7)
173.59(7)
2 2 2
3.4.2. [Cu (HOr) (etpy) ] (2)
Hydrogen-bond geometry (Å, °)
The molecular view of [Cu
2 2 2
(l-HOr) (etpy) ] with atom number-
DAHꢀ ꢀ ꢀA
DAH
0.82(3)
0.86
Hꢀ ꢀ ꢀA
1.73(3)
2.01
Dꢀ ꢀ ꢀA
DAHꢀ ꢀ ꢀA
158(3)
156
ing scheme is shown in Fig. 7. The selected bond lengths and angles
together with the hydrogen bonding geometry are given in Table 4.
O5AH5ꢀ ꢀ ꢀO1
N2AH2ꢀ ꢀ ꢀO2
2.508(2)
i
2.820(2)
1
The compound crystallizes in monoclinic P2 /c space group. Each
Symmetry codes: (i) 1 ꢁ x, 1 ꢁ y, ꢁz.
copper ion in 2 is coordinated by N atom of pyrimidine ring and
2
ꢁ
O atom of carboxylate from the chelating HOr ligand, N atom
of pyridine ring and O atom of ethanol group forming six-mem-
bered chelating etpy molecule in a square–planar arrangement.
The other carboxylate O atom further forms a weak bridge to the
adjacent Cu ion in the axial direction with a longer CuAO bond
(
2.683(2) Å). With this bridging carboxylate oxygen is linking the
second [Cu(HOr)(etpy)] unit, square pyramidal coordination geom-
etry is achieved around each copper with the formation of eight-
membered ring. Cuꢀ ꢀ ꢀCu separation of 5.086 Å indicates the very
weak interaction between two copper centers.
The bond lengths of CuAN(1)HOr and CuAO(4)HOr are 1.948(2)
and 1.932(2) Å, respectively. The CuAN(1)HOr and CuAO(4)HOr
bond distances are similar to the corresponding values found in
[
(
[
(
(
Cu(HOr)(H
HOr)
(cha)]ꢀ2H
45], [Cu(HOr)(H
HOr)(TEA)]ꢀH O, [1.952(2) and 1.944(2) Å] [27], [Cu(HOr)
ea) O [2.004(2) and 1.984(2) Å] [44]. The bridging CuAOacid
]ꢀ2H
2
O)
2
]
n
[1.975(2) and 1.948(2) Å] [34], (chaH)
O [1.980(3), 1.982(3) and 2.013(3), 2.208(3) Å]
O)(bipy)] [1.934(3) and 2.000(2) Å] [28], [Cu
2
[Cu
2
2
2
2
2
2
bond distance of 2.683(2) Å is significantly longer than the corre-
sponding bond in [Cu(HOr)(H O) [2.337(2) Å] [34]. In the cop-
Fig. 7. Ortep III view of 2 with the atom numbering scheme.
2
2 n
]
per(II) complex the two CAO bond lengths of the carboxylate
group of the HOr are quite different, 1.224(3) and 1.278(3) Å,
the pyrimidine ring of HOr2 and pyridine ring of etpy planes are
ꢁ
2ꢁ
6
5.73°.
The crystal packing of 1 is a composite of intermolecular hydro-
gen bonding and weak p–p interactions. A packing diagram of
with that bridge bonded to Cu(II) being the shorter. The CuANetpy
and CuAOetpy bond distances are 1.9705(16) and 1.9387(16) Å.
The internal geometries are as expected, with the bond lengths
NAC [within range of 1.3440(1) and 1.3524(3) Å]; CACetpy of pyri-
dine ring [within range of 1.3782(3) and 1.3715(3) Å] correspond-
ing exactly to typical double-bond lengths.
[
Ni(HOr)(H
2
O)
2
(etpy)]ꢀH
2
O is shown in Fig. 6. The NAH group
2
ꢁ
of HOr
give intermolecular hydrogen bonds with the car-
2
ꢁ
bonyl O1 atom of the neighboring HOr ligand (symmetry code:
2
x + 1, ꢁy + 1, ꢁz) and forms R2 ð8Þ ring. An intermolecular p–p
The crystal is mainly stabilized by so many strong intermolecu-
lar hydrogen bonds NAHꢀ ꢀ ꢀO. The details of hydrogen bonding
interaction contact occurs between the two symmetry-related
pyrimidine rings of the HOr2 ligand [Cg3ꢀ ꢀ ꢀCg3 3.5601(9) Å, (i):
ꢁ
i
2ꢁ
geometry are given in Table 4. Each of the HOr ligands is doubly
2
ꢁ x, 1 ꢁ y, ꢁz] (Fig. 6). The crystal is mainly stabilized by strong
H-bonded (DA:AD form) to a corresponding ligand of a neighboring
complex unit (Fig. 8). These DA:AD type hydrogen bonds involve
intermolecular H bonds O(6)AH(6A)ꢀ ꢀ ꢀO(2), O(7)AH(7A)ꢀ ꢀ ꢀO(8),
Fig. 8. The hydrogen bonding geometry of 2.

O.Z. Ye ßs ilel et al. / Journal of Molecular Structure 889 (2008) 415–421
421
the N2 atom of pyrimidine ring and carbonyl O2 atom
[15] P. Castan, T. Ha, Inorg. Chim. Acta 221 (1994) 173.
[16] I. Mutikainen, P. Lumme, Acta Crystallogr. B36 (1980) 2233.
i
[
N(2)AHꢀ ꢀ ꢀO(2) ;
N(2)ꢀ ꢀ ꢀO(2) = 2.820(2) Å,
Hꢀ ꢀ ꢀO(2) = 2.01 Å,
[
17] I. Mutikainen, R. Hämäläinen, M. Klinga, U. Turpeinen, Z. Kristallogr. 212
1997) 65.
N(2)AHꢀ ꢀ ꢀO(2) = 156°, (i) 1 ꢁ x, ꢁy, 1 ꢁ z] and generate centrosym-
metric edge-fussed four R22ð8Þ rings in two-dimensional network.
These two-dimensional supramolecular networks have only van
der Waals interactions do not have any CAHꢀ ꢀ ꢀp or pꢀ ꢀ ꢀp
interactions.
(
[18] I. Mutikainen, R. Hämäläinen, M. Klinga, O. Orama, U. Turpeinen, Acta
Crystallogr. C52 (1996) 2480.
[
[
19] T. Solin, K. Matsumoto, K. Fuwa, Bull. Chem. Soc. Jpn. 54 (1981) 3731.
20] M. Sabat, D. Zglinska, B. Jezowska-Trzebiatowska, Acta Crystallogr. B36 (1980)
1187.
[
[
[
[
21] I. Mutikainen, Inorg. Chim. Acta 136 (1987) 155.
22] X. Li, W. Bi, D. Yuan, R. Cao, Acta Crystallogr. E59 (2003) m470.
23] X. Li, R. Cao, W. Bi, D. Sun, M. Hong, Acta Crystallogr. E59 (2003) m228.
4
. Conclusion
_
24] H. I cß budak, H. Ölmez, O.Z. Ye sß ilel, F. Arslan, P. Naumov, G. Jovanovski, A.R.
Although a lot of orotato complexes both mononuclear and
polymeric are well known, quite surprisingly, up to now dinuclear
metal complexes of the orotate have not been reported. We have
Ibrahim, A. Usman, H.K. Fun, S. Chantrapromma, S.W. Ng, J. Mol. Struct. 657
(
2003) 255.
25] O.Z. Ye sß ilel, H. Pa sß ao g˘ lu, K. Akda g˘ , O. Büyükgüngör, Z. Anorg. Allg. Chem. 633
2007) 1731.
[
(
successfully synthesized the first dinuclear [Cu(l-HOr)(etpy)]
2
[26] O.Z. Ye sß ilel, F. Tezcan, H. Ölmez, H. Pa sß ao g˘ lu, O. Büyükgüngör, Z. Anorg. Allg.
Chem. 631 (2005) 2497.
2 2 2
and mononuclear [Ni(HOr)(H O) (etpy)]ꢀH O orotate complex
and characterized.
[
[
[
27] O.Z. Ye sß ilel, H. Ölmez, I. Ucar, A. Bulut, C. Kazak, Z. Anorg. Allg. Chem. 631
2005) 3100.
28] O.Z. Ye sß ilel, H. Olmez, H. Icbudak, O. Büyükgüngör, Z. Naturforsch. 60b (2005)
138.
29] M.J. Plater, M.R.J. Foreman, J.M.S. Skakle, R.A. Howie, Inorg. Chim. Acta 332
2002) 135.
[30] I. Mutikainen, Finn. Chem. Lett. (1985) 193.
(
1
Supplementary material
(
Crystallographic data for the structure reported here have been
deposited at the CCDC as supplementary data, CCDC No. 645539
for 1 and 645540 for 2. Copies of the data can be obtained on appli-
cation to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK. E-mail:
deposit@ccdc.-cam.ac.uk.
[
[
31] R. Hilal, Z.M. Zaky, S.A.K. Elroby, Spectrochim. Acta A 63 (2006) 740.
32] D. Michalska, K. Hernik, R. Wysoki n´ ski, B. Morzyk-Ociepa, A. Pietraszko,
Polyhedron 26 (2007) 4303.
[33] X. Li, R. Cao, D. Sun, Q. Shi, M. Hong, Y. Ling, Inorg. Chem. Commun. 5 (2002)
89.
34] T.T.B. Ha, A.M. Larsonneur-Galibert, P. Castan, J. Jaud, J. Chem. Crystallogr. 29
1999) 565.
[35] D. Sun, R. Cao, Y. Liang, M. Hong, Y. Zhao, J. Weng, Aust. J. Chem. 55 (2002)
81.
5
[
(
Acknowledgement
6
[
[
36] W. Brockner, R. Branscheid, M. Gjikaj, A. Adam, Z. Naturforsch. 60b (2005) 175.
37] I. Bach, O. Kumberger, H. Schmidbaur, Chem. Ber. 123 (1990) 2267.
This work was supported by Eski ßs ehir Osmangazi University by
project No. 200619013.
[38] A. Wu, F.K. Zheng, X. Liu, Inorg. Chem. Commun. 9 (2006) 347.
[
[
39] O.Z. Ye sß ilel, O. Büyükgüngör, Solid State Sci. 9 (2007) 485.
40] L.R. Falvello, D. Ferrer, T. Soler, M. Tomás, Acta Crstallogr. C59 (2003)
m149.
References
_
[
41] A. Bulut, H. I cß budak, O.Z. Ye sß ilel, H. Ölmez, O. Büyükgüngör, Acta Crystallogr.
[
[
[
1] D.D. Genchev, Dokl. Bolg. Akad. Nauk 23 (1970) 435.
E59 (2003) m736.
2] J. Leberman, A. Kornberg, E.S. Simms, J. Biol. Chem. 215 (1955) 403.
3] N. Lalioti, C.P. Raptopoulou, A. Terzis, A. Panagiotopoulos, S.P. Perlepes, E.
Manessi-Zoupa, J. Chem. Soc., Dalton Trans. 8 (1998) 1327.
4] P. Castan, E. Colacio-Rodriguez, A.L. Beauchamp, S. Cros, S. Wimmer, J. Inorg.
Biochem. 38 (1990) 225.
5] H. Schmidbaur, H.G. Classen, J. Helbig, Angew. Chem. 102 (1990) 1122;
Angew. Chem., Int. Ed. Engl. 29 (1990) 1090.
6] G. Maistralis, A. Koutsodimou, N. Katsaros, Trans. Met. Chem. 25 (2000) 166.
7] D. Mentzafos, N. Katsaros, A. Terzis, Acta Crystallogr. C43 (1987) 1905.
8] D.J. Darenbourg, D.L. Larkins, J.H. Reibenspies, Inorg. Chem. 37 (1998) 6125.
9] X. Li, Q. Shi, D. Sun, W. Bi, R. Cao, Eur. J. Inorg. Chem. (2004) 2747.
[42] O.Z. Ye sß ilel, I. U cß ar, A. Bulut, H. Ölmez, O. Büyükgüngör, Z. Naturforsch. 61b
(2006) 147.
[43] O.Z. Ye sß ilel, H. Ölmez, C. Arıcı, Polyhedron 26 (2007) 3669.
[44] O.Z. Ye sß ilel, E. Sß ahin, Z. Anorg. Allg. Chem. 633 (2007) 1087.
[45] O.Z. Ye sß ilel, H. Pa sß ao g˘ lu, K. Akda g˘ , O. Büyükgüngör, Polyhedron 26 (2007)
2761.
[46] Stoe & Cie, X-AREA (Version 1.18), X-RED32 (Version 1.04), Stoe
Darmstadt, Germany, 2002.
[47] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C. Giacovazzo, A.
Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna, J. Appl. Crystallogr. 32
(1999) 115.
[48] G.M. Sheldrick, SHELXS97, SHELXL97. University of Göttingen, Germany, 1997.
[49] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
[
[
& Cie,
[
[
[
[
[
[
10] A. Karipides, B. Thomas, Acta Crystallogr. C42 (1986) 1705.
11] D.A. Kose, B. Zümreo g˘ lu-Karan, O. Sß ahin, O. Büyükgüngör, J. Mol. Struct. 789
(
2006) 147.
[50] D. Sutton, Electronic Spectra of Transition Metal Complexes, McGraw-Hill,
London, 1968. 208 pp..
[51] A. Hernanz, F. Billes, I. Bratu, R. Navarro, Biopolymers (Biospectroscopy) 57
(2000) 187.
[
[
[
12] M.S. Refat, J. Mol. Struct. 842 (2007) 24.
13] O. Kumberger, J. Riede, H. Schmidbaur, Chem. Ber. 124 (1991) 2739.
14] D. Burrows, D.M.P. Mingos, A.J.P. White, D.J. Williams, J. Chem. Soc., Dalton
Trans. (1996) 149.
[52] V.T. Yılmaz, Y. Topcu, A. Karada g˘ , Thermochim. Acta 383 (2002) 129.