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The crystal structure of the title compound, [Cu2Cl4(C9H7NO)2], has been determined from powder diffraction data. The crystals are built of dinuclear complex molecules, with a central four-membered Cu2O2 ring located about a crystallographic inversion centre, which involves two Cu atoms, each carrying two terminal chloro ligands each [Cu—Cl = 2.213 (8) and 2.222 (8) Å] and two O atoms of the quinoline N-oxide ligand. The Cu atom has a square-planar coordination, with considerable distortions due to the four-membered ring [O—Cu—O = 78 (1)° and Cl—Cu—Cl = 100.2 (3)°].
Supporting information
CCDC reference: 202286
Key indicators
- Powder unknown study
- T = 293 K
- Mean (Please check) = 0.000 Å
- R factor = 0.000
- wR factor = 0.000
- Data-to-parameter ratio = 0.0
checkCIF results
No syntax errors found
Structure: I
------------
ADDSYM reports no extra symmetry
Alert Level A:
RADNT_01 Alert A The radiation type should contain one of the following
* 'Cu K\a'
* 'Mo K\a'
* 'Ag K\a'
* neutron
* synchrotron
REFLT_03
_reflns_number_total not in the CIF
REFNR_01 Alert A Ratio of reflections to parameters is < 6 for a
centrosymmetric structure
sine(theta)/lambda 0.2961
Proportion of unique data used NaN
Ratio reflections to parameters 0.0000
THETM_01 Alert A The value of sine(theta_max)/wavelength is less than 0.550
Calculated sin(theta_max)/wavelength = 0.2961
General Notes
ABSMU_01 Radiation type not identified. Calculation of
_exptl_absorpt_correction_mu not performed.
3 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
0 Alert Level C = Please check
Compound (I) was prepared in polycrystalline form by mixing saturated ethanol solutions of quinoline N-oxide dihydrate (0.181 g, 1 mmol) and CuCl2·2H2O (0.171 g, 1 mmol). A yellow precipitate, which quickly turned black, was washed with ethanol and diethyl ether. It was then dried in air (yield: 58°). The electronic spectra of (I) were recorded using a Specord UV-Vis spectrometer in ethanol and in CH2Cl2. The IR spectra were measured in KBr using a Specord M-80 spectrometer.
X-ray powder diffraction patterns were obtained with two X-ray powder instruments, i.e. a Guinier-de Wolff camera and a DRON-4.07 diffraction system equipped with a standard resolution goniometer GUR-9 and scintillation counter. The first pattern was used for indexing and the second pattern was measured for structure solution and refinement. The powder was sprinkled on the sample to avoid preferred orientation. During the exposures, the specimen was spun in its plane to improve particle statistics. The unit-cell dimensions were determined using the indexing program TREOR (Werner et al., 1985) with M20 = 39 and F29 = 59 (0.0076, 65) using the positions of the first 66 peaks.
The correct solution was found in monoclinic space group P21/n. The structure was determined using the MRIA program (Zlokazov & Chernyshev, 1992), using grid search (Chernyshev & Schenk, 1998) and simulated annealing (Zhukov et al., 2001) techniques. The strength of the restraints was a function of interatomic separation and, for intramolecular bond lengths, corresponds to an r.m.s. deviation of 0.03 Å. An additional restraint was applied to the planarity of the quinoline N-oxide fragment. Isotropic atomic displacement parameters were refined for Cu and Cl, and an overall Uiso parameter was used for the rest of non-H atoms. H atoms were placed in geometrically calculated positions and allowed to refine using bond restraints, with a common isotropic displacement parameter Uiso(H) fixed at 0.051 Å2. The diffraction profiles are shown in Fig. 2.
Data collection: local program; cell refinement: LSPAID (Visser, 1986); data reduction: local program; program(s) used to solve structure: MRIA (Zlokazov & Chernyshev, 1992); program(s) used to refine structure: MRIA; molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: MRIA, SHELXL97 (Sheldrick, 1997) and PARST (Nardelli, 1983).
Crystal data top
[Cu2Cl4(C9H7NO)2] | F(000) = 556 |
Mr = 559.02 | Dx = 1.767 Mg m−3 |
Monoclinic, P21/n | Melting point: 208(1) K |
a = 11.780 (3) Å | Fe Kα radiation, λ = 1.93728 Å |
b = 14.872 (5) Å | T = 293 K |
c = 6.061 (2) Å | Particle morphology: no specific habit |
β = 98.27 (2)° | black |
V = 1050.8 (6) Å3 | flat_sheet, 12 × 12 mm |
Z = 2 | |
Data collection top
X-ray powder diffraction system DRON-4.07 diffractometer | Data collection mode: reflection |
Radiation source: BSV-28, line-focus sealed tube | Scan method: step |
Pyrolitic graphite crystal monochromator | 2θmin = 10°, 2θmax = 70°, 2θstep = 0.1° |
Specimen mounting: The powder was sprinkled on the sample holder. | |
Refinement top
Refinement on Inet | 77 parameters |
Least-squares matrix: full with fixed elements per cycle | 1 constraint |
Rp = 0.064 | H-atom parameters constrained |
Rwp = 0.081 | w = 1/Ymeas2 |
Rexp = 0.029 | (Δ/σ)max = 0.02 |
χ2 = 7.840 | Background function: Chebyshev polynomial up to the 5th order |
601 data points | Preferred orientation correction: Spherical harmonics expansion (Ahtee et al., 1989) up to the 6th order |
Profile function: split-type pseudo-Voigt (Toraya, 1986) | |
Crystal data top
[Cu2Cl4(C9H7NO)2] | β = 98.27 (2)° |
Mr = 559.02 | V = 1050.8 (6) Å3 |
Monoclinic, P21/n | Z = 2 |
a = 11.780 (3) Å | Fe Kα radiation, λ = 1.93728 Å |
b = 14.872 (5) Å | T = 293 K |
c = 6.061 (2) Å | flat_sheet, 12 × 12 mm |
Data collection top
X-ray powder diffraction system DRON-4.07 diffractometer | Scan method: step |
Specimen mounting: The powder was sprinkled on the sample holder. | 2θmin = 10°, 2θmax = 70°, 2θstep = 0.1° |
Data collection mode: reflection | |
Refinement top
Rp = 0.064 | 601 data points |
Rwp = 0.081 | 77 parameters |
Rexp = 0.029 | H-atom parameters constrained |
χ2 = 7.840 | |
Special details top
Experimental. specimen was rotated in its plane |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cu | 0.6088 (3) | 0.4852 (3) | 0.3751 (5) | 0.048 (1)* | |
Cl1 | 0.6301 (5) | 0.3910 (4) | 0.0995 (12) | 0.074 (3)* | |
Cl2 | 0.7791 (6) | 0.5509 (5) | 0.4219 (9) | 0.081 (3)* | |
O1 | 0.4408 (15) | 0.4384 (10) | 0.384 (3) | 0.087 (3)* | |
N1 | 0.3980 (18) | 0.3627 (13) | 0.304 (4) | 0.087 (3)* | |
C2 | 0.330 (2) | 0.3629 (18) | 0.098 (5) | 0.087 (3)* | |
C3 | 0.286 (2) | 0.283 (2) | −0.002 (4) | 0.087 (3)* | |
C4 | 0.312 (2) | 0.2013 (19) | 0.107 (5) | 0.087 (3)* | |
C5 | 0.404 (2) | 0.1175 (16) | 0.427 (4) | 0.087 (3)* | |
C6 | 0.471 (2) | 0.1138 (17) | 0.636 (5) | 0.087 (3)* | |
C7 | 0.517 (2) | 0.194 (2) | 0.735 (4) | 0.087 (3)* | |
C8 | 0.492 (2) | 0.2761 (16) | 0.627 (4) | 0.087 (3)* | |
C9 | 0.424 (2) | 0.2820 (18) | 0.416 (4) | 0.087 (3)* | |
C10 | 0.380 (2) | 0.2001 (19) | 0.317 (4) | 0.087 (3)* | |
H2 | 0.3132 | 0.4172 | 0.0207 | 0.051* | |
H3 | 0.2413 | 0.2844 | −0.1423 | 0.051* | |
H4 | 0.2811 | 0.1476 | 0.0447 | 0.051* | |
H5 | 0.3740 | 0.0646 | 0.3580 | 0.051* | |
H6 | 0.4883 | 0.0587 | 0.7066 | 0.051* | |
H7 | 0.5617 | 0.1921 | 0.8752 | 0.051* | |
H8 | 0.5236 | 0.3290 | 0.6935 | 0.051* | |
Geometric parameters (Å, º) top
Cu—O1 | 2.11 (2) | C7—C8 | 1.40 (4) |
Cu—O1i | 2.00 (2) | C9—N1 | 1.39 (3) |
Cu—Cl2 | 2.213 (8) | C9—C8 | 1.41 (3) |
Cu—Cl1 | 2.222 (8) | C9—C10 | 1.42 (4) |
O1—N1 | 1.30 (2) | C2—H2 | 0.94 |
C2—N1 | 1.38 (3) | C3—H3 | 0.93 |
C2—C3 | 1.40 (4) | C4—H4 | 0.93 |
C4—C3 | 1.40 (4) | C5—H5 | 0.93 |
C4—C10 | 1.40 (4) | C6—H6 | 0.93 |
C5—C6 | 1.40 (4) | C7—H7 | 0.93 |
C5—C10 | 1.41 (4) | C8—H8 | 0.94 |
C7—C6 | 1.40 (4) | | |
| | | |
O1i—Cu—O1 | 78 (1) | C5—C10—C9 | 121 (2) |
O1i—Cu—Cl1 | 169.2 (6) | C6—C5—C10 | 121 (2) |
O1—Cu—Cl2 | 168.8 (5) | C6—C7—C8 | 120 (3) |
O1i—Cu—Cl2 | 90.6 (5) | C7—C8—C9 | 122 (2) |
O1—Cu—Cl1 | 91.1 (5) | C8—C9—C10 | 117 (2) |
Cl2—Cu—Cl1 | 100.2 (3) | N1—C2—H2 | 120 |
Cui—O1—Cu | 101.8 (1) | C3—C2—H2 | 118 |
N1—O1—Cu | 126.3 (15) | C4—C3—H3 | 121 |
N1i—O1—O1 | 164.8 (5) | C2—C3—H3 | 120 |
N1—C9—C8 | 124 (2) | C3—C4—H4 | 120 |
N1—C9—C10 | 119 (2) | C10—C4—H4 | 120 |
N1—C2—C3 | 121 (2) | C6—C5—H5 | 120 |
O1—N1—C2 | 119 (2) | C10—C5—H5 | 119 |
O1—N1—C9 | 121 (2) | C5—C6—H6 | 120 |
C2—N1—C9 | 120 (2) | C7—C6—H6 | 120 |
C3—C4—C10 | 120 (2) | C6—C7—H7 | 120 |
C4—C3—C2 | 119 (3) | C8—C7—H7 | 120 |
C4—C10—C5 | 119 (2) | C7—C8—H8 | 120 |
C4—C10—C9 | 120 (2) | C9—C8—H8 | 118 |
C5—C6—C7 | 119 (2) | | |
| | | |
Cl1—Cu—O1—N1 | 20 (2) | Cu—O1—N1—C2 | −100 (2) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | [Cu2Cl4(C9H7NO)2] |
Mr | 559.02 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 11.780 (3), 14.872 (5), 6.061 (2) |
β (°) | 98.27 (2) |
V (Å3) | 1050.8 (6) |
Z | 2 |
Radiation type | Fe Kα, λ = 1.93728 Å |
Specimen shape, size (mm) | Flat_sheet, 12 × 12 |
|
Data collection |
Diffractometer | X-ray powder diffraction system DRON-4.07 diffractometer |
Specimen mounting | The powder was sprinkled on the sample holder. |
Data collection mode | Reflection |
Scan method | Step |
2θ values (°) | 2θmin = 10 2θmax = 70 2θstep = 0.1 |
|
Refinement |
R factors and goodness of fit | Rp = 0.064, Rwp = 0.081, Rexp = 0.029, χ2 = 7.840 |
No. of data points | 601 |
No. of parameters | 77 |
No. of restraints | ? |
H-atom treatment | H-atom parameters constrained |
Selected geometric parameters (Å, º) topCu—O1 | 2.11 (2) | Cu—Cl2 | 2.213 (8) |
Cu—O1i | 2.00 (2) | Cu—Cl1 | 2.222 (8) |
| | | |
O1i—Cu—O1 | 78 (1) | Cl2—Cu—Cl1 | 100.2 (3) |
O1—Cu—Cl2 | 168.8 (5) | Cui—O1—Cu | 101.8 (1) |
O1—Cu—Cl1 | 91.1 (5) | N1—O1—Cu | 126.3 (15) |
| | | |
Cl1—Cu—O1—N1 | 20 (2) | Cu—O1—N1—C2 | −100 (2) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
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Heteroaromatic N-oxides are unique compounds due to the fact that the N—O group can act either as an electron-acceptor or an electron-donor, depending on compound structure and conditions. Molecular complexes of heteroaromatic N-oxides demonstrate a broad spectrum of biological activity (Ponomarenko, 1999). Moreover adducts of quinoline N-oxide with CuCl2 have interesting magnetic properties (Whyman et al., 1967).
The electronic spectrum of the title complex, (I), in ethanol is almost identical to the spectrum of quinoline N-oxide; however, in CH2Cl2, which is not capable of forming donor–acceptor bonds, a new band appears [379(2.83)] and bands decrease their intensities. Such an effect is probably caused by symmetrization of the structure of the complex (decreasing logε) and formation of new Cu—O bonds.
The intensities of the N—O bands in the IR spectra (1310 and 1272 cm−1) are decreased in (I) in comparison with the spectrum of the parent quinoline N-oxide. On the other hand, in agreement with the literature findings (Garvey et al., 1968), a new bands at 1175 cm−1, caused by the formation of a donor–acceptor bond between the O atom of quinoline N-oxide and Cu atoms, appears; the 343–336 cm−1 bands corresponding to the Cu–Cl bonds are also present.
The structure of the dimeric molecule consists of a binuclear complex with a central four-membered Cu2O2 ring, formed by two Cu atoms and two quinoline N-oxide O atoms (Fig. 1). The structure is similar to that of di-m-(pyridine oxide)-bis[dichlorocopper(II)] reported by Sager et al. (1967). The Cu atom has a distorted square-planar coordination formed by two terminal chloro ligands [Cu—Cl1 = 2.222 (8) Å and Cu—Cl2 = 2.213 (8) Å] and two bridging O atoms belonging to quinoline N-oxide ligands [Cu—O1 = 2.11 (2) Å and Cu—O1i 2.00 (2) Å; symmetry code: (i) 1 − x, 1 − y, 1 − z]. The distortions of the coordination are manifested in the O1—Cu—O1i and Cl1—Cu—Cl2 bond angles [78 (1) and 100.2 (3)°, respectively], which deviate significantly from 90°, as well as in the displacement of the Cu atom from the plane through its four ligands [0.21 (3) Å]. The plane of the Cu2O2 ring forms a dihedral angle of 90 (2)° with the quinoline fragment.