Diaqua­bis­(4-bromo­benzoato-κO)bis­(nicotinamide-κN 1)copper(II)

Hacali Necefoğlu; Füreya Elif Özbek; Vijdan Öztürk; Barış Tercan; Tuncer Hökelek

doi:10.1107/S1600536811021696

. 2011 Jun 11;67(Pt 7):m900–m901. doi: 10.1107/S1600536811021696

Diaquabis(4-bromobenzoato-κO)bis(nicotinamide-κN ¹)copper(II)

Hacali Necefoğlu ^a, Füreya Elif Özbek ^a, Vijdan Öztürk ^a, Barış Tercan ^b, Tuncer Hökelek ^c,^*

PMCID: PMC3151863 PMID: 21836889

Abstract

The asymmetric unit of the title mononuclear Cu^II complex, [Cu(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂], contains one half-molecule, the Cu^II atom being located on an inversion center. The unit cell contains two nicotinamide (NA), two 4-bromobenzoate (PBB) ligands and two coordinated water molecules. The four O atoms in the equatorial plane around the Cu^II ion form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxylate group and the adjacent benzene ring is 22.17 (16)°, while the pyridine ring and the benzene ring are oriented at a dihedral angle of 82.80 (6)°. In the crystal, N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. A weak C—H⋯π interaction is also observed.

Related literature

For literature on niacin, see: Krishnamachari (1974 ▶). For infomation on the nicotinic acid derivative N,N-diethylnicotinamide, see: Bigoli et al. (1972 ▶). For related structures, see: Hökelek et al. (1996 ▶, 2009a ▶,b ▶); Hökelek & Necefoğlu (1998 ▶, 2007 ▶); Necefoğlu et al. (2011 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

[Cu(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂]
M _r = 743.84
Triclinic,
a = 7.7072 (3) Å
b = 9.7536 (5) Å
c = 9.8471 (4) Å
α = 76.273 (2)°
β = 74.240 (2)°
γ = 85.024 (3)°
V = 691.86 (5) Å³
Z = 1
Mo Kα radiation
μ = 3.73 mm⁻¹
T = 100 K
0.41 × 0.38 × 0.35 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.236, T _max = 0.271
11758 measured reflections
3515 independent reflections
3172 reflections with I > 2σ(I)
R _int = 0.057

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.108
S = 1.13
3515 reflections
203 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.86 e Å⁻³
Δρ_min = −1.29 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811021696/su2279sup1.cif

e-67-0m900-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811021696/su2279Isup2.hkl

e-67-0m900-Isup2.hkl^{(168.8KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg is the centroid of the N1/C8–C12 pyridine ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯O2ⁱ	0.85 (3)	2.06 (3)	2.831 (2)	151 (3)
N2—H22⋯O3ⁱⁱ	0.88 (3)	2.03 (3)	2.893 (3)	166 (3)
O4—H41⋯O2ⁱⁱⁱ	0.87 (4)	1.86 (4)	2.718 (2)	167 (4)
O4—H42⋯O3^iv	0.78 (4)	2.17 (4)	2.911 (2)	159 (4)
C6—H6⋯O2^v	0.95	2.43	3.377 (3)	172
C4—H4⋯Cg^vi	0.95	2.63	3.581 (3)	176

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

The authors are indebted to Anadolu University and the Medicinal Plants and Medicine Research Centre of Anadolu University, Eskişehir, Turkey, for the use of X-ray diffractometer. This work was supported financially by the Scientific and Technological Research Council of Turkey (grant No. 108 T657).

supplementary crystallographic information

Comment

As a part of our ongoing investigations of transition metal complexes of nicotinamide (NA), one form of niacin (Krishnamachari, 1974), and/or the nicotinic acid derivative N,N-diethylnicotinamide (DENA), an important respiratory stimulant (Bigoli et al., 1972), the title compound was synthesized and its crystal structure is reported herein.

The asymmetric unit of the title mononuclear Cu^IIcomplex, (Fig. 1), contains one-half molecule. It consists of two nicotinamide (NA), two 4-bromobenzoate (PBB) ligands and two coordinated water molecules, all ligands coordinating in a monodentate manner. Atom Cu1 is located on an inversion center. The crystal structures of similar complexes of Cu^II, Co^II, Ni^II, Mn^II and Zn^II ions, [Cu(C₇H₅O₂)₂(C₁₀H₁₄N₂O)₂] (Hökelek et al., 1996), [Co(C₆H₆N₂O)₂(C₇H₄NO₄)₂(H₂O)₂] (Hökelek & Necefoğlu, 1998), [Co(C₉H₉O₂)₂(C₁₀H₁₄N₂O)₂(H₂O)₂] (Necefoğlu et al., 2011), [Ni(C₇H₄ClO₂)₂(C₆H₆N₂O)₂(H₂O)₂] (Hökelek et al., 2009a), [Mn(C₉H₁₀NO₂)₂(H₂O)₄].2H₂O (Hökelek & Necefoğlu, 2007) and [Zn(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂] (Hökelek et al., 2009b) have also been reported. In the copper(II) complex mentioned above the two benzoate ions coordinate to the Cu^II atom as bidentate ligands, while in the other structures all the ligands coordinate in a monodentate manner.

In the title complex, the four symmetry related O atoms (O1, O1', O4 and O4') in the equatorial plane around the Cu^II ion form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two symmetry related N atoms of the NA ligands (N1 and N1') in the axial positions. The near equalities of the C1—O1 [1.272 (3) Å] and C1—O2 [1.246 (3) Å] bonds in the carboxylate group indicate delocalized bonding arrangement, rather than localized single and double bonds. The Cu—O bond lengths are 1.9756 (16) Å (for benzoate oxygens) and 2.4199 (16) Å (for water oxygens), and the Cu—N bond length is 2.0116 (16) Å, close to standard values (Allen et al., 1987). The Cu atom is displaced out of the mean-plane of the carboxylate group (O1/C1/O2) by -0.5279 (1) Å. The dihedral angle between the planar carboxylate group and the adjacent benzene ring A (C2—C7) is 22.17 (16)°. The benzene A (C2—C7) and the pyridine B (N1/C8—C12) rings are oriented at a dihedral angle of A/B = 82.80 (6)°.

In the crystal, intermolecular N—H···O, O—H···O and C—H···O hydrogen bonds link the molecules into a three-dimensional network (Table 1). There also exists a weak C-H···π interaction (Table 1).

Experimental

The title compound was prepared by the reaction of CuSO₄.5H₂O (1.23 g, 5 mmol) in H₂O (20 ml) and NA (1.22 g, 10 mmol) in H₂O (20 ml) with sodium 4-bromobenzoate (2.23 g, 10 mmol) in H₂O (100 ml) at room temperature. The mixture was filtered and set aside to crystallize at ambient temperature for three weeks, giving blue single crystals.