Diaqua­bis(2-bromo­benzoato-κO)bis­(nicotinamide-κN 1)zinc(II)

Tuncer Hökelek; Hakan Dal; Barış Tercan; F Elif Özbek; Hacali Necefoğlu

doi:10.1107/S1600536809015645

. 2009 Apr 30;65(Pt 5):m607–m608. doi: 10.1107/S1600536809015645

Diaquabis(2-bromobenzoato-κO)bis(nicotinamide-κN ¹)zinc(II)

Tuncer Hökelek ^a,^*, Hakan Dal ^b, Barış Tercan ^c, F Elif Özbek ^d, Hacali Necefoğlu ^d

PMCID: PMC2977639 PMID: 21583825

Abstract

The title Zn^II complex, [Zn(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂], is centrosymmetric with the Zn atom on an inversion center. The molecule contains two 2-bromobenzoate (BB) and two nicotinamide (NA) ligands and two coordinated water molecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Zn atom 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 carboxyl group and the adjacent benzene ring is 31.14 (12)°, while the pyridine and benzene rings are oriented at a dihedral angle of 83.54 (5)°. In the crystal structure, O—H⋯O and N—H⋯O hydrogen bonds link the molecules into infinite chains. A weak C—H⋯π interaction is also present.

Related literature

For general backgroud to the properties of transition metal complexes with biochemically active ligands, see: Antolini et al. (1982 ▶); Bigoli et al. (1972 ▶); Krishnamachari (1974 ▶); Nadzhafov et al. (1981 ▶); Shnulin et al. (1981 ▶). For related structures, see: Hökelek et al. (1995 ▶, 1997 ▶, 2007 ▶, 2008 ▶); Hökelek & Necefoğlu (1996 ▶, 1997 ▶, 2007 ▶).

Experimental

Crystal data

[Zn(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂]
M _r = 745.68
Monoclinic,
a = 7.9111 (2) Å
b = 18.1604 (4) Å
c = 9.8345 (3) Å
β = 106.346 (1)°
V = 1355.80 (6) Å³
Z = 2
Mo Kα radiation
μ = 3.91 mm⁻¹
T = 100 K
0.43 × 0.33 × 0.24 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffctometer diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.230, T _max = 0.393
12839 measured reflections
3416 independent reflections
2948 reflections with I > 2σ(I)
R _int = 0.081

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.065
S = 1.06
3416 reflections
203 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.77 e Å⁻³
Δρ_min = −0.51 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: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809015645/xu2517sup1.cif

e-65-0m607-sup1.cif^{(18.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809015645/xu2517Isup2.hkl

e-65-0m607-Isup2.hkl^{(164.2KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Zn1—O1	2.1182 (13)
Zn1—O4	2.1647 (12)
Zn1—N1	2.1124 (14)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯O2ⁱ	0.83 (2)	2.10 (2)	2.870 (2)	155 (2)
O4—H41⋯O2ⁱⁱ	0.83 (3)	1.84 (3)	2.6339 (19)	159 (3)
C11—H11⋯Cg1ⁱⁱⁱ	0.93	2.87	3.600 (3)	136

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the C2–C7 ring.

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.

supplementary crystallographic information

Comment

Transition metal complexes with biochemically active ligands frequently show interesting physical and/or chemical properties, as a result they may find applications in biological systems (Antolini et al., 1982). The structural functions and coordination relationships of the arylcarboxylate ion in transition metal complexes of benzoic acid derivatives change depending on the nature and position of the substituent groups on the benzene ring, the nature of the additional ligand molecule or solvent, and the medium of the synthesis (Nadzhafov et al., 1981; Shnulin et al., 1981). Nicotinamide (NA) is one form of niacin and a deficiency of this vitamin leads to loss of copper from the body, known as pellagra disease. Victims of pellagra show unusually high serum and urinary copper levels (Krishnamachari, 1974). On the other hand, the nicotinic acid derivative N,N-diethylnicotinamide (DENA) is an important respiratory stimulant (Bigoli et al., 1972).

The structure determination of the title compound, (I), a zinc complex with two 2-bromobenzoate (BB), two nicotinamide (NA) ligands and two water molecules, was undertaken in order to determine the properties of the ligands and also to compare the results obtained with those reported previously.

Compound (I) is a monomeric complex, with the Zn atom on a centre of symmetry. It contains two BB, two NA ligands and two water molecules (Fig. 1). All ligands are monodentate. The four O atoms (O1, O4, and the symmetry-related atoms, O1', O4') in the equatorial plane around the Zn atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands (N1, N1') in the axial positions (Table 1 and Fig. 1).

The near equality of the C1—O1 [1.267 (2) Å] and C1—O2 [1.256 (2) Å] bonds in the carboxylate group indicates a delocalized bonding arrangement, rather than localized single and double bonds, and may be compared with the corresponding distances: 1.256 (6) and 1.245 (6) Å in [Mn(DENA)₂(C₇H₄ClO₂)₂(H₂O)₂], (II) (Hökelek et al., 2008), 1.265 (6) and 1.275 (6) Å in [Mn(C₉H₁₀NO₂)₂(H₂O)₄].2(H₂O), (III) (Hökelek & Necefoğlu, 2007), 1.260 (4) and 1.252 (4) Å in [Zn(DENA)₂(C₇H₄FO₂)₂(H₂O)₂],(IV) (Hökelek et al., 2007), 1.259 (9) and 1.273 (9) Å in Cu₂(DENA)₂(C₆H₅COO)₄, (V) (Hökelek et al., 1995), 1.279 (4) and 1.246 (4) Å in [Zn₂(DENA)₂(C₇H₅O₃)₄].2H₂O, (VI) (Hökelek & Necefoğlu, 1996), 1.251 (6) and 1.254 (7) Å in [Co(DENA)₂(C₇H₅O₃)₂(H₂O)₂], (VII) (Hökelek & Necefoğlu, 1997) and 1.278 (3) and 1.246 (3) Å in [Cu(DENA)₂(C₇H₄NO₄)₂(H₂O)₂], (VIII) (Hökelek et al., 1997). In (I), the average Zn—O bond length is 2.1415 (13) Å and the Zn atom is displaced out of the least-squares plane of the carboxylate group (O1/C1/O2) by -0.676 (1) Å. The dihedral angle between the planar carboxylate group and the benzene ring A (C2—C7) is 31.14 (12)°, while that between rings A and B (N1/C8—C12) is 83.54 (5)°.

In the crystal structure, intermolecular O—H···O and N—H···O hydrogen bonds (Table 2) link the molecules into infinite chains, in which they may be effective in the stabilization of the structure. There also exists a weak C–H···π interaction (Table 2).

Experimental

The title compound was prepared by the reaction of ZnSO₄.H₂O (0.89 g, 5 mmol) in H₂O (20 ml) and NA (1.22 g, 10 mmol) in H₂O (20 ml) with sodium 2-bromobenzoate (2.23 g, 10 mmol) in H₂O (50 ml). The mixture was filtered and set aside to crystallize at ambient temperature for 3 d, giving colorless single crystals.