In the title compound, [CuCl
2(C
9H
12N
2O)], the Cu
II atom is coordinated by two Cl
− anions and two N atoms of one
O-ethyl 3-methylpyridine-2-carboximidic acid molecule in a slightly distorted square-planar geometry, with Cu—N distances of 2.0483 (17) and 1.9404 (18) Å, and Cu—Cl distances of 2.2805 (10) and 2.2275 (14) Å. In addition, each Cu
II atom is connected by one Cl
− anion and the Cu
II atom from a neighbouring molecule, with Cu
Cl and Cu
Cu distances of 2.9098 (13) and 3.4022 (12) Å, respectively, and, therefore, a centrosymmetric dimer is formed. Adjacent molecular dimers are connected by π–π stacking interactions between pyridine rings to form a zigzag molecular chain. The molecular chains are also enforced by N—H
Cl and C—H
Cl interactions.
Supporting information
CCDC reference: 632918
2-Cyano-3-methylpyridine 0.2362 g (0.20 mmol) in absolute ethanol (5 ml) was mixed with CuCl2·2H2O (0.3409 g, 0.20 mmol) in absolute ethanol (5 ml) in a round-bottomed flask. The solution was heated and refluxed for 10 min and then cooled to room temperature. Single crystals of (I) were obtained in 3 d.
All H atoms were found in a difference Fourier map. The H atom bonded to atom N2 was refined with a bond length restraint of 0.835 (16) Å. The other H atoms were treated using a riding model, fixing the bond lengths at 0.96, 0.97 and 0.93 Å for methyl, methylene and aromatic H atoms, respectively. The displacement parameters of the H atoms were constrained at Uiso(H) = 1.2Ueq(C) for methylene and aromatic H atoms or 1.5Ueq(C) for methyl group H atoms.
Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC & Rigaku (2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999).
Dichloro(
O-ethyl 3-methylpyridine-2-carboximidic acid-
κ2N,
N')copper(II)
top
Crystal data top
[CuCl2(C9H12N2O)] | F(000) = 604 |
Mr = 597.29 | Dx = 1.706 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 9855 reflections |
a = 10.531 (5) Å | θ = 3.0–27.6° |
b = 10.274 (6) Å | µ = 2.31 mm−1 |
c = 11.012 (5) Å | T = 293 K |
β = 102.654 (15)° | Prism, blue |
V = 1162.5 (10) Å3 | 0.47 × 0.32 × 0.27 mm |
Z = 2 | |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 2378 reflections with I > 2σ(I) |
Detector resolution: 10.00 pixels mm-1 | Rint = 0.022 |
ω scans | θmax = 27.5°, θmin = 3.0° |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | h = −12→13 |
Tmin = 0.417, Tmax = 0.539 | k = −13→13 |
11146 measured reflections | l = −14→14 |
2644 independent reflections | |
Refinement top
Refinement on F2 | H atoms treated by a mixture of independent and constrained refinement |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0251P)2 + 0.5469P] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.023 | (Δ/σ)max = 0.001 |
wR(F2) = 0.058 | Δρmax = 0.28 e Å−3 |
S = 1.05 | Δρmin = −0.42 e Å−3 |
2644 reflections | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
142 parameters | Extinction coefficient: 0.0080 (6) |
1 restraint | |
Crystal data top
[CuCl2(C9H12N2O)] | V = 1162.5 (10) Å3 |
Mr = 597.29 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.531 (5) Å | µ = 2.31 mm−1 |
b = 10.274 (6) Å | T = 293 K |
c = 11.012 (5) Å | 0.47 × 0.32 × 0.27 mm |
β = 102.654 (15)° | |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 2644 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 2378 reflections with I > 2σ(I) |
Tmin = 0.417, Tmax = 0.539 | Rint = 0.022 |
11146 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.023 | 1 restraint |
wR(F2) = 0.058 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.28 e Å−3 |
2644 reflections | Δρmin = −0.42 e Å−3 |
142 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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cu1 | 0.364860 (19) | 0.04211 (2) | 0.89155 (2) | 0.03423 (9) | |
Cl1 | 0.40039 (4) | 0.25599 (4) | 0.89861 (5) | 0.04333 (13) | |
Cl2 | 0.55500 (4) | −0.01604 (5) | 0.83938 (5) | 0.04236 (12) | |
O1 | 0.15939 (12) | −0.28089 (12) | 0.93803 (13) | 0.0409 (3) | |
N1 | 0.16594 (13) | 0.05157 (14) | 0.85769 (14) | 0.0323 (3) | |
N2 | 0.32302 (14) | −0.13936 (15) | 0.91270 (16) | 0.0374 (3) | |
H2 | 0.3828 (19) | −0.191 (2) | 0.944 (2) | 0.058 (7)* | |
C1 | 0.10707 (16) | −0.06344 (16) | 0.86874 (15) | 0.0296 (3) | |
C2 | −0.02792 (16) | −0.07672 (18) | 0.84458 (16) | 0.0347 (4) | |
C3 | −0.09943 (17) | 0.0367 (2) | 0.8089 (2) | 0.0434 (4) | |
H3 | −0.1898 | 0.0333 | 0.7933 | 0.052* | |
C4 | −0.03978 (18) | 0.1524 (2) | 0.7963 (2) | 0.0468 (5) | |
H4 | −0.0887 | 0.2269 | 0.7712 | 0.056* | |
C5 | 0.09461 (18) | 0.15701 (18) | 0.82171 (18) | 0.0403 (4) | |
H5 | 0.1359 | 0.2355 | 0.8134 | 0.048* | |
C6 | −0.09872 (18) | −0.2024 (2) | 0.8521 (2) | 0.0475 (5) | |
H6A | −0.0789 | −0.2629 | 0.7925 | 0.071* | |
H6B | −0.1908 | −0.1864 | 0.8344 | 0.071* | |
H6C | −0.0718 | −0.2381 | 0.9343 | 0.071* | |
C7 | 0.20511 (16) | −0.16861 (17) | 0.90845 (16) | 0.0325 (4) | |
C8 | 0.25249 (19) | −0.38662 (19) | 0.9752 (2) | 0.0463 (5) | |
H8A | 0.318 | −0.3616 | 1.0479 | 0.056* | |
H8B | 0.2957 | −0.407 | 0.9083 | 0.056* | |
C9 | 0.1785 (2) | −0.5013 (2) | 1.0039 (2) | 0.0541 (5) | |
H9A | 0.2371 | −0.5729 | 1.0285 | 0.081* | |
H9B | 0.1141 | −0.5252 | 0.9314 | 0.081* | |
H9C | 0.1366 | −0.4801 | 1.0705 | 0.081* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.02352 (12) | 0.02903 (12) | 0.04855 (15) | −0.00192 (8) | 0.00448 (9) | 0.00088 (9) |
Cl1 | 0.0338 (2) | 0.0300 (2) | 0.0637 (3) | −0.00203 (16) | 0.0054 (2) | 0.00617 (19) |
Cl2 | 0.0334 (2) | 0.0431 (3) | 0.0538 (3) | 0.00002 (18) | 0.0165 (2) | −0.0029 (2) |
N1 | 0.0253 (7) | 0.0323 (8) | 0.0379 (7) | −0.0008 (5) | 0.0035 (6) | 0.0002 (6) |
N2 | 0.0257 (7) | 0.0295 (8) | 0.0542 (9) | 0.0000 (6) | 0.0026 (7) | 0.0022 (7) |
O1 | 0.0312 (6) | 0.0331 (7) | 0.0573 (8) | −0.0015 (5) | 0.0074 (6) | 0.0084 (6) |
C1 | 0.0269 (8) | 0.0322 (9) | 0.0296 (8) | −0.0015 (6) | 0.0057 (6) | −0.0015 (6) |
C2 | 0.0272 (8) | 0.0407 (10) | 0.0363 (9) | −0.0032 (7) | 0.0074 (7) | −0.0022 (7) |
C3 | 0.0243 (8) | 0.0507 (12) | 0.0531 (11) | 0.0029 (8) | 0.0040 (8) | 0.0007 (9) |
C4 | 0.0335 (9) | 0.0420 (11) | 0.0625 (13) | 0.0093 (8) | 0.0053 (9) | 0.0088 (9) |
C5 | 0.0335 (9) | 0.0334 (9) | 0.0527 (11) | 0.0009 (7) | 0.0068 (8) | 0.0058 (8) |
C6 | 0.0295 (9) | 0.0456 (11) | 0.0671 (13) | −0.0082 (8) | 0.0102 (9) | −0.0019 (10) |
C7 | 0.0297 (8) | 0.0309 (9) | 0.0350 (8) | −0.0026 (7) | 0.0032 (7) | −0.0020 (7) |
C8 | 0.0371 (9) | 0.0391 (11) | 0.0623 (12) | 0.0035 (8) | 0.0100 (9) | 0.0101 (9) |
C9 | 0.0483 (12) | 0.0409 (11) | 0.0722 (15) | −0.0008 (9) | 0.0108 (11) | 0.0116 (10) |
Geometric parameters (Å, º) top
C1—C2 | 1.394 (2) | C9—C8 | 1.485 (3) |
C3—C4 | 1.366 (3) | C9—H9A | 0.96 |
C3—C2 | 1.396 (3) | C9—H9B | 0.96 |
C3—H3 | 0.93 | C9—H9C | 0.96 |
C4—H4 | 0.93 | N1—C1 | 1.352 (2) |
C5—C4 | 1.382 (3) | N1—C5 | 1.328 (2) |
C5—H5 | 0.93 | N2—H2 | 0.835 (16) |
C6—C2 | 1.502 (3) | N2—C7 | 1.268 (2) |
C6—H6A | 0.96 | O1—C8 | 1.460 (2) |
C6—H6B | 0.96 | Cu1—N1 | 2.0480 (17) |
C6—H6C | 0.96 | Cu1—N2 | 1.9414 (18) |
C7—C1 | 1.492 (2) | Cu1—Cl1 | 2.2276 (14) |
C7—O1 | 1.318 (2) | Cu1—Cl2 | 2.2805 (10) |
C8—H8A | 0.97 | Cu1—Cl2i | 2.910 (1) |
C8—H8B | 0.97 | Cu1—Cu1i | 3.402 (1) |
| | | |
H6A—C6—H6B | 109.5 | C7—N2—H2 | 120.7 (17) |
H6A—C6—H6C | 109.5 | C7—N2—Cu1 | 117.98 (13) |
H6B—C6—H6C | 109.5 | C7—N2—H2 | 120.7 (17) |
H8A—C8—H8B | 108.5 | C7—O1—C8 | 117.45 (14) |
H9A—C9—H9B | 109.5 | C8—C9—H9A | 109.5 |
H9A—C9—H9C | 109.5 | C8—C9—H9B | 109.5 |
H9B—C9—H9C | 109.5 | C8—C9—H9C | 109.5 |
C1—C2—C3 | 115.89 (17) | C9—C8—H8A | 110.2 |
C1—C2—C6 | 124.83 (17) | C9—C8—H8B | 110.2 |
C1—N1—Cu1 | 114.39 (11) | O1—C7—C1 | 116.06 (15) |
C2—C1—C7 | 126.59 (16) | O1—C8—H8A | 110.2 |
C2—C3—H3 | 119.2 | O1—C8—H8B | 110.2 |
C2—C6—H6A | 109.5 | O1—C8—C9 | 107.39 (16) |
C2—C6—H6B | 109.5 | N1—C1—C2 | 122.46 (16) |
C2—C6—H6C | 109.5 | N1—C1—C7 | 110.95 (14) |
C3—C2—C6 | 119.27 (16) | N1—C5—C4 | 121.33 (18) |
C3—C4—C5 | 118.83 (18) | N1—C5—H5 | 119.3 |
C3—C4—H4 | 120.6 | N1—Cu1—Cl1 | 96.71 (4) |
C3—C4—C5 | 118.83 (18) | N1—Cu1—Cl2 | 152.39 (5) |
C4—C5—H5 | 119.3 | N2—C7—O1 | 127.29 (16) |
C4—C3—C2 | 121.56 (17) | N2—C7—C1 | 116.63 (16) |
C4—C3—H3 | 119.2 | N2—Cu1—N1 | 79.48 (6) |
C4—C5—H5 | 119.3 | N2—Cu1—Cl1 | 169.71 (5) |
C5—C4—H4 | 120.6 | N2—Cu1—Cl2 | 90.78 (5) |
C5—N1—C1 | 119.93 (15) | Cl1—Cu1—Cl2 | 96.73 (3) |
C5—N1—Cu1 | 125.60 (12) | Cu1—N2—H2 | 119.0 (17) |
C7—N2—Cu1 | 117.98 (13) | | |
| | | |
C1—C7—O1—C8 | 178.93 (15) | N2—C7—O1—C8 | −2.8 (3) |
C1—N1—C5—C4 | 0.7 (3) | N2—Cu1—N1—C1 | 1.47 (12) |
C2—C3—C4—C5 | −1.1 (3) | N2—Cu1—N1—C5 | −175.33 (17) |
C4—C3—C2—C1 | 1.2 (3) | O1—C7—C1—C2 | −8.9 (3) |
C4—C3—C2—C6 | −177.7 (2) | O1—C7—C1—N1 | 171.36 (15) |
C5—N1—C1—C2 | −0.5 (3) | Cu1—N1—C1—C2 | −177.52 (13) |
C5—N1—C1—C7 | 179.24 (16) | Cu1—N1—C1—C7 | 2.24 (17) |
C7—C1—C2—C3 | 179.83 (17) | Cu1—N1—C5—C4 | 177.38 (15) |
C7—C1—C2—C6 | −1.3 (3) | Cu1—N2—C7—O1 | −169.42 (14) |
C7—O1—C8—C9 | 179.84 (17) | Cu1—N2—C7—C1 | 8.8 (2) |
N1—C1—C2—C3 | −0.4 (3) | Cl1—Cu1—N1—C1 | −168.86 (11) |
N1—C1—C2—C6 | 178.38 (17) | Cl1—Cu1—N1—C5 | 14.34 (16) |
N1—C5—C4—C3 | 0.0 (3) | Cl1—Cu1—N2—C7 | 63.2 (3) |
N1—Cu1—N2—C7 | −5.81 (14) | Cl2—Cu1—N1—C1 | 72.50 (16) |
N2—C7—C1—N1 | −7.1 (2) | Cl2—Cu1—N1—C5 | −104.30 (16) |
N2—C7—C1—C2 | 172.65 (17) | Cl2—Cu1—N2—C7 | −159.81 (14) |
Symmetry code: (i) −x+1, −y, −z+2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···Cl1i | 0.84 (2) | 2.63 (2) | 3.4038 (19) | 154 (2) |
C3—H3···Cl2ii | 0.93 | 2.89 | 3.766 (2) | 158 |
Symmetry codes: (i) −x+1, −y, −z+2; (ii) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | [CuCl2(C9H12N2O)] |
Mr | 597.29 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 10.531 (5), 10.274 (6), 11.012 (5) |
β (°) | 102.654 (15) |
V (Å3) | 1162.5 (10) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.31 |
Crystal size (mm) | 0.47 × 0.32 × 0.27 |
|
Data collection |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.417, 0.539 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11146, 2644, 2378 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.058, 1.05 |
No. of reflections | 2644 |
No. of parameters | 142 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.28, −0.42 |
Selected geometric parameters (Å, º) topCu1—N1 | 2.0480 (17) | Cu1—Cl1 | 2.2276 (14) |
Cu1—N2 | 1.9414 (18) | Cu1—Cl2 | 2.2805 (10) |
| | | |
N1—Cu1—Cl1 | 96.71 (4) | N2—Cu1—Cl1 | 169.71 (5) |
N1—Cu1—Cl2 | 152.39 (5) | N2—Cu1—Cl2 | 90.78 (5) |
N2—Cu1—N1 | 79.48 (6) | Cl1—Cu1—Cl2 | 96.73 (3) |
| | | |
Cu1—N1—C5—C4 | 177.38 (15) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···Cl1i | 0.835 (16) | 2.634 (18) | 3.4038 (19) | 154 (2) |
C3—H3···Cl2ii | 0.93 | 2.89 | 3.766 (2) | 158 |
Symmetry codes: (i) −x+1, −y, −z+2; (ii) x−1, y, z. |
2-Cyano-3-methylpyridine is a useful intermediate in producing drugs and pesticides (Utsumi & Morii, 1997), but it is usually contaminated with by-products. As 2-chloro-5-methylpyridine can be separated from its isomer by forming a complex with CuCl2·2H2O (Xuan et al. 2003), we attempted to obtain pure 2-cyano-3-methylpyridine in the same way. To our surprise, we obtained the title compound, (I), instead of the desired product.
The molecular structure of (I) is shown in Fig. 1. The pyridine ring and methyl and imidate substituent groups are almost coplanar, and their bond lengths and angles are mormal. The CuII atom is coordinated by atoms N1 and N2 of one ethyl 3-methyl-2-pyridinecarboximidate and by atoms Cl1 and Cl2 in a slightly distorted square-planar geometry (Table 1). The Cu1—N1, Cu1—N2, Cu1—Cl1 and Cu1—Cl2 distances are 2.0480 (17), 1.9414 (18), 2.2276 (14) and 2.2805 (10) Å, respectively, which agree with the corresponding values for other CuII complexes (Ivashkevich et al., 2002; Zavalij et al., 2002; Xuan et al., 2003). The dihedral angle between the N1/Cu1/N2 and Cl1/Cu1/Cl2 planes is 26.96 (4)°. The CuII atom is almost in the pyridine ring plane, with a Cu1—N1—C5—C4 torsion angle of 177.38 (15)°.
Analysis of the supramolecular structure of (I) shows that, just as Br does (Chakrabarty et al., 2004), Cl2 also acts as a bridging atom. Each CuII atom is connected by another Cl2 anion and by a CuII atom from a neighbouring molecule (Fig. 2), with Cu1—Cl2i and Cu1—Cu1i [symmetry code: (i) −x + 1, −y, −z + 2] distances of 2.9098 (13) and 3.4022 (12) Å, respectively, and therefore a centrosymmetric dimer is formed. Because both Cu1—Cl2i and Cu1—Cu1i distances are longer than the sum of their covalent radii (2.27 and 2.56 Å, respectively; Standard reference?) and shorter than the sum of their van der Waals radii (4.07 and 4.64 Å, respectively; Standard reference?), there should be some weak interactions between these atoms which hold them together. This kind of Cu1—Cl2i interaction can also be regarded as a coordinate bond, as observed in similar compounds (Kostakis et al., 2006; Bernalte-Garcia et al., 2006), with Jahn–Teller distortion causing the Cu1—Cl2i distance to be longer than Cu1—Cl1 and Cu1—Cl2. In the present dimer, atoms Cu1, Cl2i, Cu1i and Cl2 are coplanar, with Cl2—Cu1—Cl2i and Cu1—Cl2—Cu1i angles of 99.07 and 80.93°. The Cl1, Cu1, Cu1i and Cl1i atoms are in another plane. The dihedral angle between these two planes is 86.31°.
In the packing diagram, it can be readily observed that there are two parallel pyridine rings between neighbouring dimers (Fig. 3), with the latter transposed by (- x, −y, −z + 2). The distance between these two ring centroids is 3.992 Å, the interplanar distance is 3.550 Å and the offset is 1.826 Å, so this may be regarded as a π–π interaction between these two rings (Cox & MacManus, 2003; Portilla et al., 2005). Thus, the molecular dimers are connected by π–π interactions and generate molecular chains.
Further analysis of the short contacts present in (I) shows that there are also N2—H2···Cl1ii and C3—H3···Cl2iii [symmetry codes: (iii) x − 1, y, z; (ii) − x + 1, −y, −z + 2] interactions in the same molecular chain, because both the H2···Cl1ii and H3···Cl2iii distances are shorter than 2.95 Å, and the N2—H2···Cl1ii and C3—H3···Cl2iii angles are larger than 140° (Brammer et al., 2001; Steiner, 1998; Aullon et al., 1998), and these enforce the molecular chain (Fig. 4, Table 2).