Aqua­(6,6′-oxydipicolinato-κ2 O,N,N′,O′)copper(II)

Jingya Sun; Xiangdi Tong

doi:10.1107/S160053680905346X

. 2009 Dec 16;66(Pt 1):m70. doi: 10.1107/S160053680905346X

Aqua(6,6′-oxydipicolinato-κ² O,N,N′,O′)copper(II)

Jingya Sun ^a,^*, Xiangdi Tong ^a

PMCID: PMC2980167 PMID: 21579965

Abstract

In the title complex, [Cu(C₁₂H₆N₂O₅)(H₂O)], the Cu^II ion is in a slightly distorted square-pyramidal coordination environment with two N and two O atoms from a 6,6′-oxydipicolinate ligand occupying the basal plane and a water ligand in the apical site. The dihedral angle between the two pyridine rings is 5.51 (6)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link molecules into a two-dimensional network. In addition, weak intermolecular C—H⋯O and C=O(lone pair)⋯π(ring) interactions, with O⋯ring-centroid distances of 3.697 (4) and 3.094 (4) Å, provide additional stabilization.

Related literature

For intermolecular interactions, see: Choudhury et al. (2008 ▶). For the applications of picolinic acid compounds, see: Mann et al. (1992 ▶).

Experimental

Crystal data

[Cu(C₁₂H₆N₂O₅)(H₂O)]
M _r = 339.74
Monoclinic,
a = 7.2487 (16) Å
b = 21.055 (4) Å
c = 8.2269 (17) Å
β = 110.201 (9)°
V = 1178.4 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.89 mm⁻¹
T = 296 K
0.40 × 0.35 × 0.30 mm

Data collection

Siemens SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.519, T _max = 0.602
6790 measured reflections
2074 independent reflections
1806 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.110
S = 1.18
2074 reflections
190 parameters
H-atom parameters constrained
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.37 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1996 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶) and SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680905346X/lh2964sup1.cif

e-66-00m70-sup1.cif^{(15.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680905346X/lh2964Isup2.hkl

e-66-00m70-Isup2.hkl^{(102KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8⋯O4ⁱ	0.93	2.31	3.229 (4)	171
C9—H9⋯O2ⁱⁱ	0.93	2.42	3.331 (4)	165
C4—H4⋯O6ⁱⁱⁱ	0.93	2.54	3.303 (4)	140
O6—H6B⋯O4^iv	0.85	1.97	2.772 (3)	157
O6—H6A⋯O2^v	0.85	2.01	2.807 (3)	156

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

supplementary crystallographic information

Comment

Picolinic acid compounds play an vital role in the development of coordination chemistry related to catalysis, magnetism and molecular architectures (Mann et al., 1992). As part of our studies on the synthesis and characterization of these types of compounds, we report here the synthesis and crystal structure of the title compound (I).

The molecular structure of the title compound (I) is shown in Fig. 1. The Cu^II ion is in a slightly distorted square-pyramidal coordination environment with two N and two O atoms from a 6,6'-oxydipicolinato ligand occupying the basal plane and one water ligand in the apical site. The dihedral angle between the two pyridine rings is 5.51 (6)°. The delocalization of electrons within the carboxylate groups is reflected in the C═O lengths. In the crystal structure, there are intermolecular O—H···O hydrogen bonds involving the carboxyl oxygen atoms and coordinated water molecules (Fig. 2) forming a two-dimensional network (see Table 1 for hydrogen bond geometries). In addition to weak intermolecular C-H···O interactions, further stabilization appears to be provided by weak C=O(lone pair)···π(ring) stacking interactions (Choudhury et al., 2008). The relevant distances are C12—O4···Cg1ⁱ = 3.697 (4) Å, Cg1 is the centroid of the ring defined by the atoms N1/C7-C11 [symmetry code: (i) -x, -y, 2-z] and the angle C12—O4···Cg1ⁱ is 98.95 (34)°; C1—O2···Cg2ⁱⁱ = 3.094 (4) Å, Cg2 is the centroid of the ring defined by the atoms N2/C2-C6 [symmetry code: (ii) 0.5+x, 0.5-y, 0.5+z] and the angle C1—O2···Cg2ⁱⁱ is 115.48 (4)° (see Fig. 3).

Experimental

All reagents were available commercially and were used without further purification. 6,6'-Oxydipicolinic acid (260 mg) was added to 1 mmol (132 mg) of CuCl₂ in 10 ml of water. The suspension was stirred for 4 h and filtered. After leaving the filtrate in air for one week, blue block-shaped crystals of (I) were formed. The crystals were isolated, washed with water three times and dried in a vacuum desicator using silica gel (Yield 75%). Elemental analysis: found C, 42.05; H, 2.96; N, 8.18%; calc. for C₁₂H₈CuN₂O₆; C, 42.17; H, 2.95; N, 8.20%.