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The title compound, [Cu2Br4(C5H4N2O3)2], is a centrosymmetric dimer that contains a central planar Cu2O2 rhombus with the O atom of the N-oxide group bridging two Cu atoms [Cu—O—Cu = 109.08 (19)° and O—Cu—O = 70.92 (19)°]. The two-dimensional sheet structure is built up via semi-coordinate intermolecular Cu...Br bonds [3.226 (1) and 3.810 (1) Å] and weak hydrogen bonding [C...Br = 3.733 (7), 3.781 (7) and 3.830 (7) Å].

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805005441/om6228sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805005441/om6228Isup2.hkl
Contains datablock I

CCDC reference: 270507

Key indicators

  • Single-crystal X-ray study
  • T = 297 K
  • Mean [sigma](C-C) = 0.010 Å
  • R factor = 0.044
  • wR factor = 0.114
  • Data-to-parameter ratio = 14.0

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density .... 3.08 PLAT220_ALERT_2_C Large Non-Solvent O Ueq(max)/Ueq(min) ... 3.00 Ratio PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 10 PLAT480_ALERT_4_C Long H...A H-Bond Reported H6A .. BR2 .. 3.06 Ang. PLAT480_ALERT_4_C Long H...A H-Bond Reported H2A .. BR1 .. 3.05 Ang. PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.21 Ratio
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 6 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 3 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: XS in SHELXTL (Bruker, 2001); program(s) used to refine structure: XL in SHELXTL; molecular graphics: XP in SHELXTL; software used to prepare material for publication: XCIF in SHELXTL.

Bis(µ-4-nitropyridine N-oxide-κ2O:O)bis[bromocopper(II)] top
Crystal data top
[Cu2Br4(C5H4N2O3)2]F(000) = 1368
Mr = 726.92Dx = 2.640 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 5682 reflections
a = 10.044 (2) Åθ = 2.6–27.0°
b = 7.2816 (15) ŵ = 11.10 mm1
c = 25.006 (5) ÅT = 297 K
V = 1828.9 (6) Å3Plate, red
Z = 40.44 × 0.15 × 0.01 mm
Data collection top
Bruker–Siemens SMART APEX
diffractometer
1654 independent reflections
Radiation source: normal-focus sealed tube1400 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.080
Detector resolution: 8.3 pixels mm-1θmax = 25.2°, θmin = 1.6°
ω scansh = 1212
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
k = 88
Tmin = 0.081, Tmax = 0.898l = 3030
24047 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.114H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0511P)2 + 9.3212P]
where P = (Fo2 + 2Fc2)/3
1654 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 1.92 e Å3
0 restraintsΔρmin = 0.62 e Å3
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
xyzUiso*/Ueq
Br10.17741 (6)0.93850 (9)0.49303 (3)0.0350 (2)
Br20.04457 (8)0.73415 (11)0.37618 (3)0.0431 (3)
C20.1531 (6)0.6974 (9)0.6077 (3)0.0299 (14)
H2A0.22890.65520.59020.036*
C30.1637 (7)0.7895 (9)0.6555 (3)0.0326 (15)
H3A0.24640.81360.67080.039*
C40.0477 (6)0.8448 (9)0.6800 (3)0.0275 (14)
C50.0750 (6)0.8129 (9)0.6581 (3)0.0311 (15)
H5A0.15200.85000.67560.037*
C60.0817 (6)0.7257 (9)0.6101 (3)0.0287 (14)
H6A0.16370.70570.59380.034*
Cu10.05929 (8)0.67615 (11)0.46713 (3)0.0293 (3)
N10.0306 (5)0.6687 (7)0.5863 (2)0.0239 (11)
N20.0571 (7)0.9501 (10)0.7304 (2)0.0470 (17)
O10.0232 (4)0.5780 (6)0.53961 (17)0.0274 (10)
O20.0443 (6)0.9811 (11)0.7538 (3)0.074 (2)
O30.1644 (6)0.9959 (12)0.7455 (3)0.084 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0302 (4)0.0301 (4)0.0448 (4)0.0101 (3)0.0044 (3)0.0073 (3)
Br20.0592 (5)0.0346 (4)0.0354 (4)0.0096 (3)0.0068 (3)0.0072 (3)
C20.022 (3)0.034 (4)0.033 (4)0.000 (3)0.002 (3)0.002 (3)
C30.029 (4)0.033 (4)0.036 (4)0.007 (3)0.008 (3)0.001 (3)
C40.033 (3)0.024 (3)0.026 (3)0.001 (3)0.000 (3)0.001 (3)
C50.029 (3)0.032 (4)0.033 (4)0.004 (3)0.003 (3)0.003 (3)
C60.027 (3)0.025 (3)0.034 (4)0.001 (3)0.001 (3)0.003 (3)
Cu10.0313 (5)0.0269 (5)0.0299 (5)0.0102 (3)0.0004 (3)0.0016 (3)
N10.024 (3)0.021 (3)0.026 (3)0.006 (2)0.001 (2)0.001 (2)
N20.049 (4)0.063 (5)0.029 (3)0.005 (3)0.001 (3)0.010 (3)
O10.031 (2)0.029 (2)0.023 (2)0.0069 (19)0.0018 (18)0.0049 (18)
O20.054 (4)0.114 (6)0.053 (4)0.003 (4)0.006 (3)0.046 (4)
O30.054 (4)0.128 (7)0.068 (5)0.017 (4)0.008 (3)0.054 (5)
Geometric parameters (Å, º) top
Br1—Cu12.3403 (10)C6—N11.341 (8)
Br2—Cu12.3178 (11)C6—H6A0.9300
C2—N11.358 (8)Cu1—O11.982 (4)
C2—C31.376 (10)Cu1—O1i2.034 (4)
C2—H2A0.9300Cu1—Br1ii3.2261 (11)
C3—C41.377 (9)Cu1—Br1iii3.8103 (12)
C3—H3A0.9300N1—O11.343 (6)
C4—C51.369 (9)N2—O31.190 (8)
C4—N21.477 (9)N2—O21.196 (8)
C5—C61.359 (9)O1—Cu1i2.034 (4)
C5—H5A0.9300
N1—C2—C3119.2 (6)Br2—Cu1—Br198.93 (4)
N1—C2—H2A120.4O1—Cu1—Br1ii76.86 (13)
C3—C2—H2A120.4O1i—Cu1—Br1ii82.11 (13)
C2—C3—C4117.6 (6)Br2—Cu1—Br1ii110.31 (4)
C2—C3—H3A121.2Br1—Cu1—Br1ii88.09 (3)
C4—C3—H3A121.2O1—Cu1—Br1iii84.98 (13)
C5—C4—C3122.3 (6)O1i—Cu1—Br1iii115.93 (13)
C5—C4—N2119.2 (6)Br2—Cu1—Br1iii94.74 (4)
C3—C4—N2118.5 (6)Br1—Cu1—Br1iii69.07 (3)
C6—C5—C4118.6 (6)Br1ii—Cu1—Br1iii148.65 (3)
C6—C5—H5A120.7C6—N1—O1119.5 (5)
C4—C5—H5A120.7C6—N1—C2122.7 (5)
N1—C6—C5119.6 (6)O1—N1—C2117.9 (5)
N1—C6—H6A120.2O3—N2—O2124.2 (7)
C5—C6—H6A120.2O3—N2—C4118.3 (6)
O1—Cu1—O1i70.92 (19)O2—N2—C4117.4 (6)
O1—Cu1—Br2162.07 (13)N1—O1—Cu1127.4 (4)
O1i—Cu1—Br293.35 (12)N1—O1—Cu1i122.8 (3)
O1—Cu1—Br197.70 (13)Cu1—O1—Cu1i109.08 (19)
O1i—Cu1—Br1166.38 (13)
Symmetry codes: (i) x, y+1, z+1; (ii) x+1/2, y1/2, z; (iii) x, y+2, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6A···Br1iv0.932.893.733 (7)151
C6—H6A···Br2iv0.933.063.781 (7)136
C2—H2A···Br1ii0.933.053.830 (7)143
Symmetry codes: (ii) x+1/2, y1/2, z; (iv) x1/2, y+3/2, z+1.
 

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