Crystal structure of di­chlorido­bis­(methyl isonicotinate-κN)copper(II)

In the title compound, [CuCl₂(C₇H₇NO₂)₂], the square-planar-coordinated Cu^II ion lies on a centre of symmetry and is bonded to two monodentate methyl­isonicotinate ligands through their N atoms and by two chloride ligands. The mol­ecules pack in a herringbone pattern. Perpendicular to [100] there are weak inter­molecular C—H...Cl and C—H...O contacts. Along [100] there are infinite chains of edge-sharing octa­hedra linked through the chlorido ligands

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.036
• wR factor = 0.091
• Data-to-parameter ratio = 15.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.263 Check
PLAT910_ALERT_3_C Missing # of FCF Reflection(s) Below Th(Min) ...          7 Report
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1 Note

Alert level G
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.14 Ratio
PLAT794_ALERT_5_G Tentative Bond Valency for Cu1     (II)    .....       2.02 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

Isonicotinate is a versatile ditopic ligand that has been used for various applications. The copper(II) isonicotinate (Cu(4–C₅H₄N-COO)₂(H₂O)₄) coordination polymer has been explored as a sorbent in flow injection solid-phase extraction for determination of trace polycyclic aromatic hydrocarbons in environmental matrices [Zhou et al. (2006)]. The incorporation of both dinuclear (M₂) and mononuclear (M') units into molecular squares has been achieved by reacting a triply bonded Re₂(II,II) complex possessing two cis isonicotinate donor ligands with Pt(II) containing molecules with substitutionally labile cis trifluoromethanesulfonate groups [Bera et al. (2001)]. Quadruply bonded Mo₂⁴⁺ species having isonicotinate ligands bound through the carboxylate group have been designed to act as 'anglers' by luring metal-containing Lewis acids to bind to the N-pyridyl group [Cotton et al. (2007)]. The copper-isonicotinate metal-organic frameworks [Cu(INA)₂] (INA = isonicotinate) (MOFs) have been prepared simply by mixing and heating solid reactants without milling. The adsorption of fluorescein dye on the as-synthesized [Cu(INA)₂] has also been investigated [Tella et al. (2014)].

The molecular structure of the title compound possessing a crystallographic centre of inversion is depicted in Fig. 1. The first coordination sphere of the Cu1 centre consists of two nitrogen atoms, from the isoniconate ligands, at a distance of 2.025 (2) Å and two chlorido ligands at a distance of 2.2962 (7) Å. The various N1—Cu1—Cl1 angles are close to 90° resulting in a square-planar first coordination sphere of Cu1. By coordination of two additional chlorido ligands from adjacent complexes at a distance of 2.9215 (7) Å from the Cu1 centre, the coordination sphere is expanded to a distorted octahedron. The pyridine ring and the Cu1—Cl1 bond are not coplanar, but enclose an angle of 59.00 (9)°. The Cu—N1 bond and the plane of the pyridine ring deviate from coplanarity by an angle of 5.05 (11)°.

The herringbone pattern of the packing of the title compound is shown in Fig. 2. Perpendicular to [100] there are weak intermolecular C—H···Cl and C—H···O contacts with donor-acceptor distances of 3.517 (3) Å, 3.470 (4) Å and 3.298 (4) Å (C2···Cl1, C7···O2 and C7···O1, respectively). Along [100] there are infinite chains of edge-sharing octahedra linked through the chlorido ligands (Fig.3). This structural feature is found in many copper complexes consisting of two chlorido ligands and two pyridine derivatives, e.g. Vitorica-Yrezabel et al. (2011), Laing et al. (1971), Chen et al. (2006), Ge et al. (2006), Chen et al. (2011), Ma et al. (2010). Each bridging chlorido ligand has a short (2.2962 (7) Å) and a longer (2.9215 (7) Å) bond distance to the two adjacent Cu-centers. The bond angle at the bridging chloride ions is 92.03 (2)°. A consequence of the formation of the strands along [100] is π-stacking between adjacent pyridine rings. The average distance between the centres of gravity of adjacent rings is a = 3.7792 Å.

Related literature

For related structures, see: Vitorica-Yrezabal et al. (2011); Laing & Carr (1971); Chen & Mak (2006); Ge et al. (2006); Chen et al. (2011); Ma et al. (2010). For background to isonicotinate, see: Zhou et al. (2006); Bera et al. (2001); Cotton et al. (2007); Tella et al. (2014). For the synthesis of 4-(5-phenyl-1,3,4-oxadiazol-2-yl)pyridine, used in the preparation, see: Kangani & Day (2009).

S2. Experimental

The compound 4-(5-phenyl-1,3,4-oxadiazol-2-yl)pyridine (0.04 g, 0.18 mmol, synthesised by a previously reported method [Kangani et al. (2009)], and copper(II) chloride dihydrate (0.015 g, 0.09 mmol) were placed in the main arm of a branched tube. Methanol (13 ml) was carefully added to fill the arms, the tube was sealed and the reagent-containing arm immersed in an oil bath at 60 °C while the other arm was kept at ambient temperature. After two weeks, green, needle shaped crystals were deposited in the cooler arm. The crystals were filtered, washed with methanol and air dried. Yield 19% (7.0 mg).

S3. Refinement

All hydrogen atoms were positioned geometrically and treated as riding on their parent atoms (aromatic C—H = 0.95 Å, methyl C—H = 0.98 Å, U_iso(H) = 1.2U_eq(C, aromatic), U_iso(H) = 1.5U_eq(C, methyl)). The methyl group was allowed to rotate along the C–O bond to best fit the experimental electron density.

Computing details

Data collection: CrysAlis PRO (Oxford Diffraction, 2011); cell refinement: CrysAlis PRO (Oxford Diffraction, 2011); data reduction: CrysAlis PRO (Oxford Diffraction, 2011); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008, 2015); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of the title compound (ellipsoids drawn at the 30% probability level). Symmetry code: i = 1 - x, -y, 1 - z. Non-labelled non-hydrogen atoms have been generated by symmetry i.
	Fig. 2. The unit cell viewed along [100] (ellipsoids drawn at the 50% probability level). Intermolecular C—H···Cl and C—H···O contacts are indicated by dashed lines.
	Fig. 3. Infinite strands along [100] formed by intermolecular Cu—Cl bonds (thin bond diameter) (drawn at the 30% ellipsoid probability level).

Dichloridobis(methyl isonicotinate-κN)copper(II)

Crystal data

[CuCl2(C7H7NO2)2]	F(000) = 414
Mr = 408.71	Dx = 1.717 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 3.7792 (4) Å	Cell parameters from 1293 reflections
b = 29.891 (4) Å	θ = 4.5–26.3°
c = 7.0139 (8) Å	µ = 1.74 mm^−1
β = 94.036 (10)°	T = 173 K
V = 790.36 (16) Å^3	Rod, green
Z = 2	0.50 × 0.05 × 0.04 mm

Data collection

Oxford Diffraction Xcalibur 3 diffractometer	1617 independent reflections
Radiation source: fine-focus sealed tube	1404 reflections with I > 2σ(I)
Detector resolution: 15.9809 pixels mm^-1	Rint = 0.034
ω scans	θmax = 26.4°, θmin = 4.5°
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2011)	h = −4→4
Tmin = 0.775, Tmax = 1.000	k = −33→37
4265 measured reflections	l = −8→6

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.036	H-atom parameters constrained
wR(F^2) = 0.091	w = 1/[σ^2(Fo^2) + (0.0388P)^2 + 0.6044P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max < 0.001
1617 reflections	Δρmax = 0.53 e Å^−3
107 parameters	Δρmin = −0.69 e Å^−3

Special details

Experimental. Absorption correction: CrysAlisPro (Oxford Diffraction, 2011) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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 (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.5000	0.0000	0.5000	0.01825 (17)
Cl1	0.91406 (17)	0.03090 (2)	0.71647 (9)	0.01768 (18)
O2	0.3701 (7)	0.17679 (8)	−0.1593 (3)	0.0414 (7)
O1	0.1672 (6)	0.20909 (6)	0.0994 (3)	0.0291 (5)
N1	0.4707 (6)	0.05771 (7)	0.3486 (3)	0.0168 (5)
C1	0.5365 (7)	0.05831 (9)	0.1633 (4)	0.0180 (6)
H1	0.6172	0.0316	0.1070	0.022*
C2	0.4918 (7)	0.09617 (9)	0.0505 (4)	0.0197 (6)
H2	0.5444	0.0955	−0.0800	0.024*
C3	0.3693 (7)	0.13491 (9)	0.1308 (4)	0.0174 (6)
C4	0.3076 (8)	0.13494 (9)	0.3240 (4)	0.0188 (6)
H4	0.2278	0.1613	0.3837	0.023*
C5	0.3647 (8)	0.09584 (9)	0.4276 (4)	0.0202 (6)
H5	0.3272	0.0961	0.5601	0.024*
C6	0.3063 (8)	0.17503 (10)	0.0051 (4)	0.0236 (7)
C7	0.0886 (11)	0.24908 (11)	−0.0132 (5)	0.0384 (9)
H7A	0.3090	0.2613	−0.0577	0.058*
H7B	−0.0224	0.2714	0.0657	0.058*
H7C	−0.0739	0.2416	−0.1236	0.058*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0235 (3)	0.0123 (3)	0.0184 (3)	−0.00169 (19)	−0.0021 (2)	0.00175 (18)
Cl1	0.0186 (3)	0.0170 (4)	0.0175 (3)	−0.0002 (3)	0.0016 (3)	−0.0023 (2)
O2	0.0712 (19)	0.0277 (13)	0.0274 (13)	0.0115 (12)	0.0191 (13)	0.0092 (10)
O1	0.0465 (14)	0.0169 (11)	0.0239 (12)	0.0100 (10)	0.0035 (10)	0.0022 (9)
N1	0.0175 (12)	0.0144 (12)	0.0185 (12)	0.0009 (9)	0.0002 (9)	−0.0003 (9)
C1	0.0201 (14)	0.0150 (14)	0.0192 (14)	0.0007 (11)	0.0038 (11)	−0.0031 (11)
C2	0.0220 (15)	0.0190 (15)	0.0185 (14)	−0.0010 (11)	0.0048 (11)	−0.0006 (11)
C3	0.0169 (14)	0.0141 (14)	0.0210 (14)	−0.0016 (10)	0.0003 (11)	0.0010 (11)
C4	0.0212 (14)	0.0146 (14)	0.0211 (15)	0.0005 (11)	0.0043 (11)	−0.0029 (11)
C5	0.0242 (15)	0.0186 (14)	0.0184 (14)	−0.0006 (12)	0.0049 (12)	−0.0007 (11)
C6	0.0254 (16)	0.0192 (16)	0.0264 (17)	0.0002 (12)	0.0023 (13)	0.0000 (12)
C7	0.056 (2)	0.0217 (17)	0.037 (2)	0.0133 (16)	0.0034 (17)	0.0075 (14)

Geometric parameters (Å, º)

Cu1—N1	2.025 (2)	C1—H1	0.9500
Cu1—N1^i	2.025 (2)	C2—C3	1.382 (4)
Cu1—Cl1	2.2962 (7)	C2—H2	0.9500
Cu1—Cl1^i	2.2962 (7)	C3—C4	1.391 (4)
Cu1—Cl1^ii	2.9215 (7)	C3—C6	1.498 (4)
Cu1—Cl1^iii	2.9215 (7)	C4—C5	1.385 (4)
O2—C6	1.196 (4)	C4—H4	0.9500
O1—C6	1.341 (3)	C5—H5	0.9500
O1—C7	1.452 (4)	C7—H7A	0.9800
N1—C1	1.340 (4)	C7—H7B	0.9800
N1—C5	1.341 (3)	C7—H7C	0.9800
C1—C2	1.385 (4)
N1—Cu1—N1^i	180.00 (6)	C3—C2—C1	118.9 (3)
N1—Cu1—Cl1	90.79 (7)	C3—C2—H2	120.6
N1^i—Cu1—Cl1	89.21 (7)	C1—C2—H2	120.6
N1—Cu1—Cl1^i	89.21 (7)	C2—C3—C4	118.8 (3)
N1^i—Cu1—Cl1^i	90.79 (7)	C2—C3—C6	118.4 (3)
Cl1—Cu1—Cl1^i	180.0	C4—C3—C6	122.8 (3)
N1—Cu1—Cl1^ii	90.70 (7)	C5—C4—C3	118.7 (3)
N1^i—Cu1—Cl1^ii	89.29 (7)	C5—C4—H4	120.7
Cl1—Cu1—Cl1^ii	87.97 (2)	C3—C4—H4	120.7
Cl1^i—Cu1—Cl1^ii	92.03 (2)	N1—C5—C4	122.7 (3)
N1—Cu1—Cl1^iii	89.30 (7)	N1—C5—H5	118.6
N1^i—Cu1—Cl1^iii	90.71 (7)	C4—C5—H5	118.6
Cl1—Cu1—Cl1^iii	92.03 (2)	O2—C6—O1	123.7 (3)
Cl1^i—Cu1—Cl1^iii	87.97 (2)	O2—C6—C3	124.6 (3)
Cl1^ii—Cu1—Cl1^iii	180.0	O1—C6—C3	111.7 (2)
C6—O1—C7	115.4 (2)	O1—C7—H7A	109.5
C1—N1—C5	118.1 (2)	O1—C7—H7B	109.5
C1—N1—Cu1	120.86 (18)	H7A—C7—H7B	109.5
C5—N1—Cu1	120.97 (19)	O1—C7—H7C	109.5
N1—C1—C2	122.8 (3)	H7A—C7—H7C	109.5
N1—C1—H1	118.6	H7B—C7—H7C	109.5
C2—C1—H1	118.6
C5—N1—C1—C2	−1.5 (4)	Cu1—N1—C5—C4	−173.5 (2)
Cu1—N1—C1—C2	174.6 (2)	C3—C4—C5—N1	−1.3 (4)
N1—C1—C2—C3	−1.0 (4)	C7—O1—C6—O2	1.3 (5)
C1—C2—C3—C4	2.3 (4)	C7—O1—C6—C3	−178.5 (3)
C1—C2—C3—C6	−177.2 (3)	C2—C3—C6—O2	−3.7 (5)
C2—C3—C4—C5	−1.2 (4)	C4—C3—C6—O2	176.8 (3)
C6—C3—C4—C5	178.3 (3)	C2—C3—C6—O1	176.1 (3)
C1—N1—C5—C4	2.7 (4)	C4—C3—C6—O1	−3.4 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···Cl1^iv	0.95	2.83	3.517 (3)	130
C7—H7B···O2^v	0.98	2.53	3.470 (4)	161
C7—H7C···O1^vi	0.98	2.58	3.298 (4)	130

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