Bis(μ-4-methoxy­pyridine N-oxide-κ²O:O)bis­[dibromo­copper(II)]

In the binuclear centrosymmetric title compound, [Cu₂Br₄(C₆H₇NO₂)₂], two 4-methoxy­pyridine N-oxide ligands bridge two Cu atoms, conferring a square-planar geometry on Cu. Hydrogen bonds of the C—H...Br type lead to the formation of a sheet structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.014 Å
• R factor = 0.068
• wR factor = 0.153
• Data-to-parameter ratio = 15.1

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.296     0.565
            Tmin and Tmax expected:      0.227     0.525
            RR =      1.214
            Please check that your absorption correction is appropriate.
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       2.00 Ratio
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.18
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.93
PLAT213_ALERT_2_C Atom O1      has ADP max/min Ratio .............       3.60 prola
PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...         14

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.929
            Tmax scaled      0.525 Tmin scaled      0.275

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   8 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Bis(µ-4-methoxypyridine N-oxide-κ²O:O)bis[dibromocopper(II)]

Crystal data

[Cu2Br4(C6H7NO2)2]	F(000) = 660
Mr = 696.97	Dx = 2.450 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1100 reflections
a = 12.102 (3) Å	θ = 2.6–24.9°
b = 10.054 (3) Å	µ = 10.73 mm^−1
c = 7.767 (2) Å	T = 298 K
β = 90.962 (4)°	Prism, red
V = 944.9 (4) Å^3	0.15 × 0.12 × 0.06 mm
Z = 2

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1664 independent reflections
Radiation source: fine-focus sealed tube	1391 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.081
φ and ω scans	θmax = 25.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −14→14
Tmin = 0.296, Tmax = 0.565	k = −11→8
4667 measured reflections	l = −9→9

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.068	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.153	H-atom parameters constrained
S = 1.13	w = 1/[σ^2(Fo^2)] where P = (Fo^2 + 2Fc^2)/3
1664 reflections	(Δ/σ)max = 0.001
110 parameters	Δρmax = 1.18 e Å^−3
6 restraints	Δρmin = −0.90 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.57818 (9)	0.57752 (11)	0.13950 (15)	0.0254 (4)
Br2	0.77071 (9)	0.58993 (11)	0.16952 (14)	0.0377 (4)
Br1	0.53360 (9)	0.68205 (11)	0.39793 (13)	0.0376 (4)
N1	0.3333 (6)	0.5637 (7)	0.1655 (9)	0.0232 (18)
C1	0.2825 (8)	0.4740 (10)	0.2679 (12)	0.030 (2)
H4	0.3115	0.3889	0.2815	0.036*
O1	0.4236 (5)	0.5264 (7)	0.0789 (8)	0.0279 (15)
C3	0.1451 (7)	0.6368 (10)	0.3307 (11)	0.023 (2)
O2	0.0513 (6)	0.6635 (7)	0.4099 (9)	0.044 (2)
C5	0.2945 (7)	0.6877 (9)	0.1470 (11)	0.023 (2)
H1	0.3309	0.7476	0.0765	0.027*
C2	0.1884 (8)	0.5098 (11)	0.3511 (12)	0.033 (2)
H3	0.1531	0.4488	0.4215	0.039*
C6	0.0010 (11)	0.7900 (12)	0.3837 (15)	0.050 (3)
H5A	0.0496	0.8585	0.4259	0.075*
H6B	−0.0674	0.7936	0.4445	0.075*
H7C	−0.0133	0.8033	0.2629	0.075*
C4	0.2025 (8)	0.7265 (10)	0.2301 (12)	0.029 (2)
H2	0.1777	0.8137	0.2197	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0218 (7)	0.0233 (7)	0.0313 (7)	−0.0013 (5)	0.0060 (5)	−0.0102 (5)
Br2	0.0252 (7)	0.0423 (7)	0.0456 (7)	−0.0044 (5)	0.0013 (5)	−0.0066 (5)
Br1	0.0373 (7)	0.0385 (7)	0.0373 (6)	−0.0043 (5)	0.0071 (5)	−0.0173 (5)
N1	0.022 (5)	0.022 (5)	0.026 (4)	0.002 (3)	0.004 (3)	−0.009 (3)
C1	0.041 (6)	0.019 (5)	0.030 (5)	−0.001 (5)	0.011 (4)	0.006 (4)
O1	0.014 (3)	0.032 (4)	0.039 (4)	0.003 (3)	0.015 (3)	−0.014 (3)
C3	0.016 (5)	0.034 (6)	0.021 (5)	0.007 (4)	0.001 (4)	−0.006 (4)
O2	0.026 (4)	0.048 (5)	0.059 (5)	0.009 (4)	0.011 (4)	−0.005 (4)
C5	0.023 (5)	0.016 (5)	0.029 (5)	0.002 (4)	0.011 (4)	0.000 (4)
C2	0.033 (6)	0.034 (7)	0.032 (5)	−0.008 (5)	0.011 (4)	−0.004 (5)
C6	0.050 (3)	0.050 (3)	0.050 (3)	0.0007 (10)	0.0010 (10)	−0.0004 (10)
C4	0.029 (6)	0.024 (6)	0.034 (5)	0.008 (4)	0.003 (4)	−0.001 (4)

Geometric parameters (Å, º)

Cu1—O1	1.989 (6)	C3—C4	1.387 (13)
Cu1—O1^i	1.992 (6)	C3—C2	1.389 (13)
Cu1—Br1	2.3368 (15)	O2—C6	1.424 (12)
Cu1—Br2	2.3411 (16)	C5—C4	1.353 (12)
N1—C5	1.339 (11)	C5—H1	0.9300
N1—O1	1.346 (9)	C2—H3	0.9300
N1—C1	1.356 (12)	C6—H5A	0.9600
C1—C2	1.367 (13)	C6—H6B	0.9600
C1—H4	0.9300	C6—H7C	0.9600
O1—Cu1^i	1.992 (6)	C4—H2	0.9300
C3—O2	1.328 (11)
O1—Cu1—O1^i	70.5 (3)	C4—C3—C2	118.1 (9)
O1—Cu1—Br1	95.15 (17)	C3—O2—C6	118.7 (9)
O1^i—Cu1—Br1	165.46 (18)	N1—C5—C4	120.4 (9)
O1—Cu1—Br2	165.45 (18)	N1—C5—H1	119.8
O1^i—Cu1—Br2	96.27 (18)	C4—C5—H1	119.8
Br1—Cu1—Br2	97.71 (5)	C1—C2—C3	120.2 (9)
C5—N1—O1	119.5 (7)	C1—C2—H3	119.9
C5—N1—C1	121.4 (8)	C3—C2—H3	119.9
O1—N1—C1	119.1 (8)	O2—C6—H5A	109.5
N1—C1—C2	119.4 (9)	O2—C6—H6B	109.5
N1—C1—H4	120.3	H5A—C6—H6B	109.5
C2—C1—H4	120.3	O2—C6—H7C	109.5
N1—O1—Cu1	125.3 (5)	H5A—C6—H7C	109.5
N1—O1—Cu1^i	125.1 (5)	H6B—C6—H7C	109.5
Cu1—O1—Cu1^i	109.5 (3)	C5—C4—C3	120.4 (9)
O2—C3—C4	124.8 (9)	C5—C4—H2	119.8
O2—C3—C2	117.1 (9)	C3—C4—H2	119.8
C5—N1—C1—C2	1.5 (14)	Br2—Cu1—O1—Cu1^i	−25.5 (10)
O1—N1—C1—C2	−177.5 (8)	C4—C3—O2—C6	3.9 (14)
C5—N1—O1—Cu1	75.9 (9)	C2—C3—O2—C6	−176.3 (8)
C1—N1—O1—Cu1	−105.0 (8)	O1—N1—C5—C4	178.7 (8)
C5—N1—O1—Cu1^i	−99.3 (8)	C1—N1—C5—C4	−0.3 (14)
C1—N1—O1—Cu1^i	79.7 (9)	N1—C1—C2—C3	0.0 (15)
O1^i—Cu1—O1—N1	−175.9 (9)	O2—C3—C2—C1	177.6 (9)
Br1—Cu1—O1—N1	6.6 (7)	C4—C3—C2—C1	−2.6 (14)
Br2—Cu1—O1—N1	158.6 (6)	N1—C5—C4—C3	−2.3 (14)
O1^i—Cu1—O1—Cu1^i	0.0	O2—C3—C4—C5	−176.4 (9)
Br1—Cu1—O1—Cu1^i	−177.5 (3)	C2—C3—C4—C5	3.7 (14)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H1···Br1^ii	0.93	2.92	3.744 (9)	148
C6—H6B···Br2^iii	0.96	2.90	3.790 (12)	156

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