Poly[(μ3-5-bromo­nicotinato)(5-bromo­nicotinato)copper(II)]

Yang, J.; Chen, H.-J.

doi:10.1107/S1600536809038331

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 10| October 2009| Pages m1262-m1263

doi:10.1107/S1600536809038331

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Poly[(μ₃-5-bromonicotinato)(5-bromonicotinato)copper(II)]

Jun Yang ^a and Hong-Ji Chen ^a ^*

^aDepartment of Materials Science and Engineering, Jinan University, Guangzhou 510632, People's Republic of China
^*Correspondence e-mail: thjchen@jnu.edu.cn

(Received 28 August 2009; accepted 22 September 2009; online 30 September 2009)

The title coordination polymer, [Cu(C₆H₃BrNO₂)₂]_n, is composed of two structurally similar two-dimensional coordination polymers (twin layers). Both of them have the same chemical composition but they display different bond lengths and angles. In each layer, two N atoms and four carboxylate O atoms from the bridging 5-bromonicotinate ligands and four carboxylate O atoms from the terminal 5-bromonicotinate ligands bind to two Cu^II atoms to form a dinuclear paddle-wheel-like pattern. Adjacent paddle wheels are further linked by bridging 5-bromonicotinate groups to generate a two-dimensional coordination polymer; neighboring twin-like layers are finally stacked through π–π stacking interactions between adjacent pyridine rings [perpendicular distance of 3.626 (2) Å] in a `sandwich' manner, thus generating a three-dimensional supramolecular structure.

Related literature

For related literature on paddle-wheel secondary building units, see: Chen et al. (2006 ); Xue et al. (2007 ); Striegler & Dittel (2003 ); Ma & Moulton (2007 ); Banerjee et al. (2008 ); Saravanakumar et al. (2004 ). For similar structures, see: Yakovenko et al. (2009 ); Xue et al. (2007). For τ distortions of coordination polyhedra, see: Addison & Rao (1984 ).

Experimental

Crystal data

[Cu(C₆H₃BrNO₂)₂]
M_r = 465.55
Monoclinic, P 2₁ /c
a = 21.542 (4) Å
b = 11.746 (2) Å
c = 12.271 (2) Å
β = 104.31 (3)°
V = 3008.6 (9) Å³
Z = 8
Mo Kα radiation
μ = 6.78 mm⁻¹
T = 173 K
0.33 × 0.31 × 0.23 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ) T_min = 0.213, T_max = 0.305
15126 measured reflections
6502 independent reflections
4904 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.085
S = 1.03
6502 reflections
379 parameters
H-atom parameters constrained
Δρ_max = 1.40 e Å⁻³
Δρ_min = −1.34 e Å⁻³

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2005 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809038331/bg2298sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809038331/bg2298Isup2.hkl

checkCIF report

Comment top

Paddle-wheel secondary building units (SBUs) M₂(RCOO)₄ are useful building blocks for constructing complexes and 1D to 3D coordination polymers through bifunctional ligands. Research interest in these compounds with copper(II) paddle-wheel SBUs come from their structural diversity (Chen, et al., 2006; Xue et al., 2007) and potential applications in supramolecular medicinal chemistry (Ma & Moulton 2007), sugar discrimination (Striegler & Dittel 2003), molecular magnets (Banerjee et al., 2008; Saravanakumar et al., 2004; Yakovenko, et al., 2009), respectively. However, most reported Cu(II) complexes with paddle-whell secondary building units are constructed by mixed-ligands, either two kinds of organic ligands or one organic ligand and water molecules (Ma & Moulton 2007). 5-Bromonicotinic acid is a bifunctional ligand with two carboxylic oxygen atoms and one pyridyl nitrogen atom, and it can be coordinated to a metal centre in a variety of ways to create structural diversity. Here, we report a new two-dimentional coordination polymer with Cu(II) paddle-wheel SBUs formed from the organic ligand 5-Bromonicotinic acid and Cu(II) ions.

The title coordination polymer, twin-poly[copper(II) (η-N,O,O-5-bromonicotinato)(η-O,O-5-bromonicotinato)] (I), contains two similar, independent groups in the asymmetric unit consisting of two copper atoms (Cu1 and Cu2) and four 5-bromonicotinato ligands each. The coordination enviroments of the two copper atoms present a nearly perfect [CuO₄N] square pyramid geometry, characterized by τ factors (indicative of the distortion degree of such a coordination sphere, Addison & Rao, 1984), of 0.01 for Cu1 and 0.003 for Cu2. The bond lengths and angles around Cu1 and Cu2 are standard for a Jahn-Teller active square pyramidal Cu²⁺ ion, with basal Cu—O bond lengths ranging from 1.957 (3) Å to 1.979 (3) Å (1.952 (3)–1.976 (3) Å ) and a longer axial bond distance to the the ligand nitrogen atom of 2.150 (3) Å (2.164 (3) Å) for Cu1 (Cu2), respectively (Fig. 1).

As previously stated, each copper atom (Cu1 or Cu2) is located in a penta-coordinated geometry and is bonded by four oxygen atoms from carboxylate anions and one nitrogen atom from the axial ligand, which can also be considered as a molecular square when viewed along the axial direction. When four carboxylate groups of the ligands bridge to two asymmetric copper atoms in a syn-syn manner, a dinuclear paddle-wheel pattern is formed, with Cu—Cu distances of 2.6355 (10) Å for Cu1 and 2.6423 (10) Å for Cu2. These values are similar to those in the paddle-wheel copper(II) complex reported in Yakovenko, et al. 2009, but shorter than the corresponding ones in Xue et al. 2007.

When adjacent Cu1 paddle-wheels are bridged by the η-N,O,O-5-bromonicotinato groups, a layer motif (hereafter "A", [Cu1(η-N,O,O-5-bromonicotinato)(η-O,O-5-bromonicotinato)]_{n )}, is formed along (100). Similarly, those resulting from Cu2 generate another layer motif ( "B", [Cu2(η-N,O,O-5-bromonicotinato)(η-O,O-5-bromonicotinato)]_n) which lies parallel to the former (Fig. 2). Finally, both A and B layers contact along the c axial direction generating a new, twin-like coordination polymer (Fig. 3). Neighboring twin-like layers are further stacked via van der Waals interactions in a sandwich way extending the packing into a three-dimensional supramolecular structure. No significant hydrogen bonds were found in the crystal structure.

Related literature top

For related literature on paddle-wheel secondary building units, see: Chen et al. (2006); Xue et al. (2007); Striegler & Dittel (2003); Ma & Moulton (2007); Banerjee et al. (2008); Saravanakumar et al. (2004). For similar structures, see: Yakovenko et al. (2009); Xue et al. (2007). For τ distortions of coordination polyhedra, see: Addison & Rao (1984).

Experimental top

Copper nitrate trihydrate (0.4 mmol, 0.0966 g) in 10 ml water and 5-Bromonicotinic acid (0.4 mmol, 0.0808 g) were sealed in a Teflon-line autoclave and heated to 433 K for 72 h, after which the mixture was cooled down to room temperatureat at a rate of 5 K per hour. Blue single crystals suitable for x-ray crystallography analysis were obtained with a yield of 46 percent. IR (cm^-1, KBr): 3447m, 3057w, 1639vs, 1557 s, 1443vs, 1393vs, 1292 s, 1238w, 1178w, 1143m, 1024m, 904w, 877m, 781 s, 747vs, 685m, 497 s.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The coordination environment of Cu1 and Cu2 atoms in the title compound, showing displacement ellipsoids at the 35% probability level. Symmetry operator: i = 1-x, 1-y, 1-z; ii = 2-x, 1-y, -z;
	Fig. 2. A (100) view of the structure showing a twin two-dimensional coordination polymer, representing either layer A or layer B (Hydrogen and Bromine atoms are omitted for clarity).
	Fig. 3. A [001] view of the packing pattern of the twin layers.

Poly[(µ₃-5-bromonicotinato)(5-bromonicotinato)copper(II)] top

Crystal data top

[Cu(C₆H₃BrNO₂)₂]	Z = 8
M_r = 465.55	F(000) = 1784
Monoclinic, P2₁/c	D_x = 2.056 Mg m⁻³
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 21.542 (4) Å	θ = 2.4–27.0°
b = 11.746 (2) Å	µ = 6.78 mm⁻¹
c = 12.271 (2) Å	T = 173 K
β = 104.31 (3)°	Block, blue
V = 3008.6 (9) Å³	0.33 × 0.31 × 0.23 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	6502 independent reflections
Radiation source: fine-focus sealed tube	4904 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.031
ϕ and ω scans	θ_max = 27.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −27→15
T_min = 0.213, T_max = 0.305	k = −12→15
15126 measured reflections	l = −15→15

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.085	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0329P)² + 6.737P] where P = (F_o² + 2F_c²)/3
6502 reflections	(Δ/σ)_max = 0.002
379 parameters	Δρ_max = 1.40 e Å⁻³
0 restraints	Δρ_min = −1.34 e Å⁻³

Crystal data top

[Cu(C₆H₃BrNO₂)₂]	V = 3008.6 (9) Å³
M_r = 465.55	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 21.542 (4) Å	µ = 6.78 mm⁻¹
b = 11.746 (2) Å	T = 173 K
c = 12.271 (2) Å	0.33 × 0.31 × 0.23 mm
β = 104.31 (3)°

Data collection top

Bruker SMART CCD area-detector diffractometer	6502 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	4904 reflections with I > 2σ(I)
T_min = 0.213, T_max = 0.305	R_int = 0.031
15126 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.085	H-atom parameters constrained
S = 1.03	Δρ_max = 1.40 e Å⁻³
6502 reflections	Δρ_min = −1.34 e Å⁻³
379 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.36048 (3)	1.10765 (4)	0.45763 (4)	0.04098 (14)
Br2	0.22167 (2)	0.26934 (6)	0.04959 (4)	0.04929 (17)
Br3	0.65085 (2)	0.30249 (5)	−0.19347 (4)	0.04179 (15)
Br4	1.13503 (3)	0.60918 (5)	0.58445 (4)	0.05030 (18)
Cu1	0.48131 (2)	0.52244 (4)	0.59219 (4)	0.01204 (10)
Cu2	1.02261 (2)	0.48099 (4)	0.10871 (4)	0.01222 (10)
N1	0.46040 (15)	0.5444 (3)	0.7534 (3)	0.0155 (7)
N2	0.20763 (17)	0.4113 (4)	0.3472 (3)	0.0318 (9)
N3	1.04924 (15)	0.4524 (3)	0.2885 (3)	0.0158 (7)
N4	0.76951 (19)	0.2695 (4)	0.1228 (3)	0.0389 (10)
O1	0.39446 (13)	0.4902 (3)	0.5031 (2)	0.0261 (7)
O2	0.57262 (12)	0.5555 (3)	0.6502 (2)	0.0223 (6)
O3	0.49764 (14)	0.3579 (2)	0.6129 (2)	0.0223 (6)
O4	0.46875 (13)	0.6827 (2)	0.5418 (2)	0.0207 (6)
O5	1.04325 (13)	0.3262 (2)	0.0652 (2)	0.0179 (6)
O6	0.99585 (14)	0.6387 (2)	0.1185 (2)	0.0247 (7)
O7	0.93424 (13)	0.4281 (3)	0.0966 (2)	0.0231 (6)
O8	1.10483 (13)	0.5363 (2)	0.0872 (2)	0.0239 (7)
C1	0.48052 (18)	0.7079 (3)	0.4500 (3)	0.0157 (8)
C2	0.46378 (17)	0.8249 (3)	0.4044 (3)	0.0128 (7)
C3	0.42926 (18)	0.9003 (3)	0.4536 (3)	0.0176 (8)
H3B	0.4191	0.8821	0.5234	0.080*
C4	0.41056 (19)	1.0027 (3)	0.4004 (3)	0.0205 (9)
C5	0.42629 (19)	0.4721 (3)	0.7994 (3)	0.0198 (8)
H5A	0.4144	0.4051	0.7657	0.050*
C6	0.47896 (17)	0.6433 (3)	0.8054 (3)	0.0153 (8)
H6A	0.5027	0.6896	0.7725	0.050*
C7	0.38534 (18)	0.4560 (3)	0.4041 (3)	0.0169 (8)
C8	0.31838 (17)	0.4236 (3)	0.3453 (3)	0.0175 (8)
C9	0.30550 (19)	0.3730 (4)	0.2396 (4)	0.0241 (9)
H9A	0.3388	0.3606	0.2015	0.080*
C10	0.24266 (19)	0.3414 (4)	0.1909 (3)	0.0241 (9)
C11	0.19555 (19)	0.3611 (4)	0.2464 (4)	0.0249 (9)
H11A	0.1525	0.3381	0.2115	0.080*
C12	0.2679 (2)	0.4414 (4)	0.3946 (4)	0.0260 (9)
H12A	0.2769	0.4772	0.4672	0.080*
C13	0.89075 (18)	0.4275 (3)	0.0067 (3)	0.0176 (8)
C14	0.82826 (18)	0.3749 (3)	0.0129 (3)	0.0177 (8)
C15	0.77755 (19)	0.3685 (3)	−0.0817 (3)	0.0208 (9)
H15A	0.7803	0.4012	−0.1520	0.080*
C16	0.72308 (18)	0.3128 (4)	−0.0705 (3)	0.0226 (9)
C17	0.7203 (2)	0.2648 (4)	0.0305 (4)	0.0325 (11)
H17A	0.6817	0.2266	0.0354	0.080*
C18	0.8221 (2)	0.3253 (4)	0.1122 (4)	0.0301 (10)
H18A	0.8573	0.3313	0.1774	0.080*
C19	1.02976 (18)	0.2986 (3)	−0.0370 (3)	0.0152 (8)
C20	1.04662 (17)	0.1814 (3)	−0.0668 (3)	0.0132 (7)
C21	1.07623 (18)	0.1035 (3)	0.0149 (3)	0.0154 (8)
H21A	1.0841	0.1230	0.0950	0.050*
C22	1.09175 (19)	0.5010 (3)	0.4790 (3)	0.0191 (8)
C23	1.07778 (18)	0.5271 (3)	0.3658 (3)	0.0182 (8)
H23A	1.0892	0.6007	0.3428	0.080*
C24	1.03400 (17)	0.3506 (3)	0.3220 (3)	0.0151 (8)
H24A	1.0114	0.2988	0.2626	0.050*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0617 (3)	0.0352 (3)	0.0350 (3)	0.0291 (2)	0.0292 (2)	0.0086 (2)
Br2	0.0306 (3)	0.0809 (4)	0.0360 (3)	−0.0217 (3)	0.0076 (2)	−0.0310 (3)
Br3	0.0203 (2)	0.0719 (4)	0.0300 (3)	−0.0167 (2)	0.00016 (18)	−0.0005 (2)
Br4	0.0942 (5)	0.0338 (3)	0.0177 (2)	−0.0389 (3)	0.0040 (2)	−0.0080 (2)
Cu1	0.0157 (2)	0.0104 (2)	0.0101 (2)	−0.00042 (17)	0.00348 (17)	−0.00025 (17)
Cu2	0.0160 (2)	0.0096 (2)	0.0094 (2)	−0.00019 (17)	0.00013 (17)	−0.00022 (17)
N1	0.0182 (16)	0.0147 (18)	0.0131 (15)	−0.0002 (12)	0.0029 (13)	−0.0016 (13)
N2	0.0186 (19)	0.050 (3)	0.026 (2)	0.0006 (17)	0.0042 (15)	−0.0037 (18)
N3	0.0203 (17)	0.0119 (17)	0.0147 (16)	−0.0012 (12)	0.0031 (13)	0.0012 (12)
N4	0.032 (2)	0.060 (3)	0.027 (2)	−0.011 (2)	0.0113 (17)	0.008 (2)
O1	0.0174 (15)	0.0376 (19)	0.0224 (15)	−0.0036 (12)	0.0032 (12)	−0.0094 (13)
O2	0.0145 (14)	0.0315 (17)	0.0205 (15)	−0.0023 (12)	0.0034 (11)	−0.0019 (12)
O3	0.0369 (17)	0.0149 (15)	0.0186 (14)	0.0039 (12)	0.0136 (13)	0.0021 (12)
O4	0.0353 (17)	0.0144 (15)	0.0163 (14)	0.0052 (12)	0.0137 (12)	0.0061 (11)
O5	0.0270 (15)	0.0137 (14)	0.0112 (13)	0.0033 (11)	0.0016 (11)	−0.0041 (11)
O6	0.0450 (18)	0.0119 (15)	0.0146 (14)	0.0080 (13)	0.0023 (13)	0.0011 (11)
O7	0.0167 (14)	0.0336 (18)	0.0182 (15)	−0.0019 (12)	0.0032 (11)	−0.0022 (13)
O8	0.0197 (15)	0.0284 (18)	0.0199 (15)	−0.0079 (12)	−0.0018 (11)	0.0085 (12)
C1	0.0186 (19)	0.012 (2)	0.0155 (19)	−0.0014 (15)	0.0026 (15)	0.0005 (15)
C2	0.0133 (18)	0.015 (2)	0.0089 (17)	−0.0015 (14)	0.0002 (13)	0.0002 (14)
C3	0.020 (2)	0.017 (2)	0.0148 (19)	−0.0020 (15)	0.0037 (15)	0.0015 (16)
C4	0.026 (2)	0.017 (2)	0.022 (2)	0.0073 (16)	0.0133 (17)	−0.0017 (16)
C5	0.027 (2)	0.015 (2)	0.018 (2)	−0.0065 (16)	0.0073 (16)	−0.0065 (16)
C6	0.0158 (19)	0.013 (2)	0.0171 (19)	0.0023 (14)	0.0038 (15)	0.0000 (15)
C7	0.019 (2)	0.011 (2)	0.020 (2)	0.0009 (15)	0.0044 (16)	0.0032 (15)
C8	0.0137 (19)	0.018 (2)	0.019 (2)	0.0009 (15)	0.0003 (15)	0.0000 (16)
C9	0.019 (2)	0.029 (3)	0.024 (2)	−0.0038 (17)	0.0038 (17)	−0.0036 (18)
C10	0.020 (2)	0.030 (3)	0.020 (2)	−0.0046 (17)	0.0007 (17)	−0.0026 (18)
C11	0.017 (2)	0.031 (3)	0.025 (2)	−0.0019 (17)	0.0021 (17)	0.0012 (19)
C12	0.021 (2)	0.034 (3)	0.021 (2)	0.0016 (18)	0.0025 (17)	−0.0024 (19)
C13	0.020 (2)	0.0084 (19)	0.026 (2)	0.0012 (15)	0.0073 (17)	−0.0038 (16)
C14	0.020 (2)	0.013 (2)	0.020 (2)	−0.0019 (15)	0.0047 (16)	−0.0020 (16)
C15	0.021 (2)	0.016 (2)	0.025 (2)	−0.0002 (16)	0.0051 (17)	−0.0003 (17)
C16	0.016 (2)	0.027 (2)	0.023 (2)	−0.0009 (17)	0.0006 (16)	−0.0026 (18)
C17	0.025 (2)	0.041 (3)	0.033 (3)	−0.007 (2)	0.011 (2)	0.005 (2)
C18	0.025 (2)	0.046 (3)	0.018 (2)	−0.005 (2)	0.0044 (18)	0.001 (2)
C19	0.0194 (19)	0.0101 (19)	0.0167 (19)	−0.0020 (15)	0.0055 (15)	−0.0018 (15)
C20	0.0160 (18)	0.0079 (19)	0.0165 (19)	0.0006 (14)	0.0052 (14)	−0.0035 (14)
C21	0.022 (2)	0.015 (2)	0.0075 (17)	0.0018 (15)	0.0015 (14)	−0.0012 (14)
C22	0.028 (2)	0.016 (2)	0.0123 (18)	−0.0059 (16)	0.0021 (16)	−0.0051 (15)
C23	0.023 (2)	0.013 (2)	0.018 (2)	−0.0047 (15)	0.0039 (16)	−0.0005 (16)
C24	0.0185 (19)	0.0119 (19)	0.0139 (18)	0.0004 (15)	0.0019 (15)	0.0010 (15)

Geometric parameters (Å, º) top

Br1—C4	1.885 (4)	C3—C4	1.380 (5)
Br2—C10	1.881 (4)	C3—H3B	0.9600
Br3—C16	1.885 (4)	C4—C5ⁱⁱⁱ	1.394 (5)
Br4—C22	1.887 (4)	C5—C4^iv	1.394 (5)
Cu1—O1	1.957 (3)	C5—H5A	0.8971
Cu1—O2	1.958 (3)	C6—C2^iv	1.386 (5)
Cu1—O3	1.969 (3)	C6—H6A	0.9065
Cu1—O4	1.979 (3)	C7—O2ⁱ	1.257 (5)
Cu1—N1	2.150 (3)	C7—C8	1.494 (5)
Cu1—Cu1ⁱ	2.6355 (10)	C8—C12	1.385 (6)
Cu2—O6	1.952 (3)	C8—C9	1.390 (6)
Cu2—O8	1.965 (3)	C9—C10	1.389 (5)
Cu2—O7	1.973 (3)	C9—H9A	0.9601
Cu2—O5	1.976 (3)	C10—C11	1.375 (6)
Cu2—N3	2.164 (3)	C11—H11A	0.9599
Cu2—Cu2ⁱⁱ	2.6423 (10)	C12—H12A	0.9601
N1—C5	1.336 (5)	C13—O8ⁱⁱ	1.254 (5)
N1—C6	1.338 (5)	C13—C14	1.500 (5)
N2—C12	1.333 (5)	C14—C15	1.385 (6)
N2—C11	1.337 (5)	C14—C18	1.386 (6)
N3—C23	1.327 (5)	C15—C16	1.379 (6)
N3—C24	1.332 (5)	C15—H15A	0.9600
N4—C18	1.343 (6)	C16—C17	1.376 (6)
N4—C17	1.347 (6)	C17—H17A	0.9601
O1—C7	1.247 (5)	C18—H18A	0.9600
O2—C7ⁱ	1.257 (5)	C19—O6ⁱⁱ	1.254 (4)
O3—C1ⁱ	1.263 (5)	C19—C20	1.492 (5)
O4—C1	1.250 (4)	C20—C24^v	1.376 (5)
O5—C19	1.258 (4)	C20—C21	1.390 (5)
O6—C19ⁱⁱ	1.254 (4)	C21—C22^v	1.373 (5)
O7—C13	1.258 (5)	C21—H21A	0.9821
O8—C13ⁱⁱ	1.254 (5)	C22—C21^vi	1.373 (5)
C1—O3ⁱ	1.263 (5)	C22—C23	1.381 (5)
C1—C2	1.494 (5)	C23—H23A	0.9600
C2—C6ⁱⁱⁱ	1.386 (5)	C24—C20^vi	1.376 (5)
C2—C3	1.386 (5)	C24—H24A	0.9814

O1—Cu1—O2	167.78 (12)	N1—C5—H5A	119.1
O1—Cu1—O3	89.88 (13)	C4^iv—C5—H5A	119.5
O2—Cu1—O3	90.95 (12)	N1—C6—C2^iv	123.0 (4)
O1—Cu1—O4	88.36 (13)	N1—C6—H6A	116.4
O2—Cu1—O4	88.40 (12)	C2^iv—C6—H6A	120.7
O3—Cu1—O4	168.51 (11)	O1—C7—O2ⁱ	126.1 (4)
O1—Cu1—N1	98.55 (12)	O1—C7—C8	117.0 (3)
O2—Cu1—N1	93.55 (12)	O2ⁱ—C7—C8	116.9 (3)
O3—Cu1—N1	94.02 (11)	C12—C8—C9	118.3 (4)
O4—Cu1—N1	97.47 (11)	C12—C8—C7	121.3 (4)
O1—Cu1—Cu1ⁱ	86.23 (9)	C9—C8—C7	120.4 (3)
O2—Cu1—Cu1ⁱ	81.90 (9)	C10—C9—C8	117.7 (4)
O3—Cu1—Cu1ⁱ	80.33 (8)	C10—C9—H9A	121.1
O4—Cu1—Cu1ⁱ	88.23 (8)	C8—C9—H9A	121.2
N1—Cu1—Cu1ⁱ	172.64 (9)	C11—C10—C9	120.1 (4)
O6—Cu2—O8	89.09 (13)	C11—C10—Br2	119.6 (3)
O6—Cu2—O7	90.52 (13)	C9—C10—Br2	120.3 (3)
O8—Cu2—O7	168.27 (11)	N2—C11—C10	122.3 (4)
O6—Cu2—O5	168.22 (11)	N2—C11—H11A	118.9
O8—Cu2—O5	89.85 (12)	C10—C11—H11A	118.8
O7—Cu2—O5	88.14 (12)	N2—C12—C8	123.7 (4)
O6—Cu2—N3	95.31 (12)	N2—C12—H12A	118.3
O8—Cu2—N3	99.66 (12)	C8—C12—H12A	118.0
O7—Cu2—N3	92.04 (12)	O8ⁱⁱ—C13—O7	126.4 (4)
O5—Cu2—N3	96.44 (11)	O8ⁱⁱ—C13—C14	117.3 (3)
O6—Cu2—Cu2ⁱⁱ	82.01 (8)	O7—C13—C14	116.2 (4)
O8—Cu2—Cu2ⁱⁱ	85.86 (9)	C15—C14—C18	119.1 (4)
O7—Cu2—Cu2ⁱⁱ	82.48 (9)	C15—C14—C13	120.8 (4)
O5—Cu2—Cu2ⁱⁱ	86.21 (8)	C18—C14—C13	120.0 (4)
N3—Cu2—Cu2ⁱⁱ	173.85 (9)	C16—C15—C14	117.2 (4)
C5—N1—C6	118.8 (3)	C16—C15—H15A	121.5
C5—N1—Cu1	125.1 (3)	C14—C15—H15A	121.4
C6—N1—Cu1	115.9 (2)	C17—C16—C15	120.8 (4)
C12—N2—C11	117.8 (4)	C17—C16—Br3	118.9 (3)
C23—N3—C24	118.6 (3)	C15—C16—Br3	120.3 (3)
C23—N3—Cu2	125.9 (3)	N4—C17—C16	122.7 (4)
C24—N3—Cu2	115.5 (2)	N4—C17—H17A	118.7
C18—N4—C17	116.5 (4)	C16—C17—H17A	118.6
C7—O1—Cu1	120.4 (3)	N4—C18—C14	123.8 (4)
C7ⁱ—O2—Cu1	125.2 (3)	N4—C18—H18A	117.9
C1ⁱ—O3—Cu1	127.1 (2)	C14—C18—H18A	118.3
C1—O4—Cu1	117.7 (2)	O6ⁱⁱ—C19—O5	126.2 (4)
C19—O5—Cu2	119.7 (2)	O6ⁱⁱ—C19—C20	115.6 (3)
C19ⁱⁱ—O6—Cu2	125.9 (3)	O5—C19—C20	118.2 (3)
C13—O7—Cu2	124.3 (3)	C24^v—C20—C21	118.6 (3)
C13ⁱⁱ—O8—Cu2	120.8 (2)	C24^v—C20—C19	119.6 (3)
O4—C1—O3ⁱ	126.5 (4)	C21—C20—C19	121.8 (3)
O4—C1—C2	118.1 (3)	C22^v—C21—C20	117.5 (3)
O3ⁱ—C1—C2	115.2 (3)	C22^v—C21—H21A	122.2
C6ⁱⁱⁱ—C2—C3	118.6 (3)	C20—C21—H21A	120.3
C6ⁱⁱⁱ—C2—C1	119.2 (3)	C21^vi—C22—C23	120.7 (3)
C3—C2—C1	122.0 (3)	C21^vi—C22—Br4	120.0 (3)
C4—C3—C2	118.4 (4)	C23—C22—Br4	119.2 (3)
C4—C3—H3B	120.8	N3—C23—C22	121.4 (4)
C2—C3—H3B	120.8	N3—C23—H23A	119.5
C3—C4—C5ⁱⁱⁱ	119.9 (4)	C22—C23—H23A	119.2
C3—C4—Br1	121.4 (3)	N3—C24—C20^vi	123.2 (3)
C5ⁱⁱⁱ—C4—Br1	118.7 (3)	N3—C24—H24A	116.2
N1—C5—C4^iv	121.4 (4)	C20^vi—C24—H24A	120.5

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+2, −y+1, −z; (iii) x, −y+3/2, z−1/2; (iv) x, −y+3/2, z+1/2; (v) x, −y+1/2, z−1/2; (vi) x, −y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	[Cu(C₆H₃BrNO₂)₂]
M_r	465.55
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	173
a, b, c (Å)	21.542 (4), 11.746 (2), 12.271 (2)
β (°)	104.31 (3)
V (Å³)	3008.6 (9)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	6.78
Crystal size (mm)	0.33 × 0.31 × 0.23

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.213, 0.305
No. of measured, independent and observed [I > 2σ(I)] reflections	15126, 6502, 4904
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.640

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.085, 1.03
No. of reflections	6502
No. of parameters	379
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.40, −1.34

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2005), SHELXTL (Sheldrick, 2008).

Acknowledgements

This work was supported by the Natural Science Foundation of Guangdong Province (grant No. 0430064), People's Republic of China.

References

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