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Acta Cryst. (2010). E66, m1473    [ doi:10.1107/S1600536810042789 ]

{6,6'-Diethoxy-2,2'-[4,5-dimethyl-o-phenylenebis(nitrilomethylidyne)]diphenolato}copper(II)

A. Jamshidvand, H. Kargar, R. Kia and M. N. Tahir

Abstract top

In the title complex, [Cu(C26H26N2O4)], the CuII ion lies on a crystallographic twofold rotation axis and is coordinated in a slightly distorted square-planar environment. The dihedral angle between the central benzene ring and each of the two symmetry-related outer benzene rings is 5.1 (2)°. The crystal structure is stabilized by intermolecular [pi]-[pi] interactions with centroid-centroid distances in the range 3.466 (2)-3.6431 (16) Å.

Comment top

Schiff base complexes are one of the most important stereochemical models in transition metal coordination chemistry, with the ease of preparation and structural variations (Granovski et al., 1993). Metal derivatives of the Schiff bases have been studied extensively, and Ni(II) and Cu(II) complexes play a major role in both synthetic and structural research (Elmali et al., 2000; Blower et al., 1998).

The molecular structure of the title compound is shown in Fig. 1. The asymmetric unit comprises half of a Schiff base complex. The bond lengths (Allen et al., 1987) and angles are within the normal ranges. The geometry around the CuII ion is slightly distorted square-planar for which the coordination is a N2O2 donor set of the Schiff base ligand. The dihedral angle between the mean planes of the centeral aromatic ring with the two symmetry-related outer rings is 5.1 (2)°. The crystal structure is stabilized by intermolecular π–π interactions [Cg1···Cg3i = 3.594 (2)Å, (i) -x, 1 - y, -z; Cg2···Cg2i = 3.6431 (16)Å, Cg2···Cg3i = 3.466 (2)Å, Cg1, Cg2, and Cg3 are the centroids of Cu1/N1/C8/C8A/N1A, C1–C6, and Cu1/O1/C1/C6/C7/N1, respectively.

Related literature top

For background to Schiff base–metal complexes, see: Granovski et al. (1993); Blower et al. (1998); Elmali et al. (2000). For standard bond lengths, see: Allen et al. (1987).

Experimental top

The title compound was synthesized by adding bis(3-ethoxysalicylidene)-4,5- dimethyl phenylenediamine (2 mmol) to a solution of CuCl2.4H2O (2 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for half an hour. The resultant solution was filtered. Dark-green single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by slow evaporation of the solvents at room temperature over several days.

Refinement top

All hydrogen atoms were positioned geometrically with C-H = 0.93-0.97 Å and included in a riding model approximation with Uiso (H) = 1.2 or 1.5 Ueq (C). A rotating group model was applied to the methyl groups.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 40% probability displacement ellipsoids and the atomic numbering. Symmetry code for the unlabled atoms: -x, y, -z + 1/2
[Figure 2] Fig. 2. Part of the crystal structure viewed approximately along the b-axis showing π–π stacking interactions as dashed lines.
{6,6'-Diethoxy-2,2'-[4,5-dimethyl-o- phenylenebis(nitrilomethylidyne)]diphenolato}copper(II) top
Crystal data top
[Cu(C26H26N2O4)]F(000) = 1028
Mr = 494.03Dx = 1.294 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2273 reflections
a = 14.9755 (7) Åθ = 2.5–27.5°
b = 15.8803 (7) ŵ = 0.89 mm−1
c = 12.2264 (6) ÅT = 296 K
β = 119.285 (2)°Block, green
V = 2536.0 (2) Å30.27 × 0.21 × 0.11 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3157 independent reflections
Radiation source: fine-focus sealed tube1910 reflections with I > 2σ(I)
graphiteRint = 0.049
φ and ω scansθmax = 28.3°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		h = −16→20
Tmin = 0.982, Tmax = 0.992k = 0→21
3157 measured reflectionsl = −16→0
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)] = 0.066Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.147H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0549P)2 + 4.1197P]
where P = (Fo2 + 2Fc2)/3
3157 reflections(Δ/σ)max = 0.001
152 parametersΔρmax = 0.43 e Å−3
0 restraintsΔρmin = −0.46 e Å−3
Crystal data top
[Cu(C26H26N2O4)]V = 2536.0 (2) Å3
Mr = 494.03Z = 4
Monoclinic, C2/cMo Kα radiation
a = 14.9755 (7) ŵ = 0.89 mm−1
b = 15.8803 (7) ÅT = 296 K
c = 12.2264 (6) Å0.27 × 0.21 × 0.11 mm
β = 119.285 (2)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3157 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)		1910 reflections with I > 2σ(I)
Tmin = 0.982, Tmax = 0.992Rint = 0.049
3157 measured reflectionsθmax = 28.3°
Refinement top
R[F2 > 2σ(F2)] = 0.066H-atom parameters constrained
wR(F2) = 0.147Δρmax = 0.43 e Å−3
S = 1.05Δρmin = −0.46 e Å−3
3157 reflectionsAbsolute structure: ?
152 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
Cu10.00000.51186 (3)0.25000.0401 (2)
O10.06365 (19)0.42620 (14)0.2039 (2)0.0464 (6)
N10.0519 (2)0.60241 (16)0.1905 (3)0.0401 (7)
O20.1286 (2)0.28916 (14)0.1524 (3)0.0591 (8)
C10.1134 (3)0.4353 (2)0.1421 (3)0.0395 (8)
C20.1501 (3)0.3619 (2)0.1111 (3)0.0444 (9)
C30.2022 (3)0.3667 (3)0.0445 (4)0.0548 (10)
H3A0.22710.31770.02720.066*
C40.2178 (3)0.4435 (3)0.0029 (4)0.0590 (11)
H4A0.25140.4457−0.04400.071*
C50.1843 (3)0.5156 (3)0.0305 (4)0.0531 (10)
H5A0.19580.56700.00280.064*
C60.1315 (3)0.5138 (2)0.1013 (3)0.0411 (8)
C70.0998 (3)0.5921 (2)0.1269 (3)0.0449 (9)
H7A0.11450.64030.09540.054*
C80.0270 (3)0.6835 (2)0.2165 (3)0.0436 (9)
C90.0525 (3)0.7599 (2)0.1837 (4)0.0544 (10)
H9A0.08810.76010.13920.065*
C100.0264 (3)0.8356 (2)0.2158 (4)0.0621 (13)
C110.0545 (4)0.9164 (3)0.1760 (5)0.0899 (18)
H11A0.09250.95160.24810.135*
H11B−0.00670.94510.11690.135*
H11C0.09570.90410.13760.135*
C120.1611 (3)0.2112 (2)0.1270 (4)0.0537 (10)
H12A0.23520.20950.16710.064*
H12B0.13360.20440.03730.064*
C130.1234 (4)0.1426 (3)0.1764 (5)0.0774 (14)
H13A0.14900.08960.16590.116*
H13B0.04990.14190.13130.116*
H13C0.14690.15210.26380.116*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0526 (4)0.0263 (3)0.0492 (4)0.0000.0309 (3)0.000
O10.0652 (17)0.0318 (12)0.0572 (16)0.0001 (11)0.0415 (15)0.0021 (11)
N10.0440 (18)0.0284 (15)0.0416 (17)0.0005 (12)0.0161 (15)0.0026 (12)
O20.084 (2)0.0334 (14)0.084 (2)0.0090 (13)0.0601 (18)0.0010 (13)
C10.041 (2)0.0384 (19)0.042 (2)−0.0003 (15)0.0224 (18)0.0007 (15)
C20.050 (2)0.045 (2)0.044 (2)0.0025 (17)0.0278 (19)−0.0011 (16)
C30.056 (3)0.057 (2)0.061 (3)0.002 (2)0.037 (2)−0.006 (2)
C40.058 (3)0.071 (3)0.066 (3)−0.005 (2)0.045 (2)−0.002 (2)
C50.057 (2)0.053 (2)0.052 (2)−0.0105 (19)0.029 (2)0.0052 (19)
C60.0423 (19)0.0403 (18)0.0402 (19)−0.0024 (16)0.0199 (16)0.0006 (16)
C70.049 (2)0.040 (2)0.042 (2)−0.0098 (16)0.0197 (19)0.0053 (16)
C80.048 (2)0.0262 (17)0.042 (2)−0.0007 (15)0.0111 (17)0.0014 (15)
C90.060 (3)0.0328 (19)0.054 (2)−0.0060 (18)0.015 (2)0.0081 (17)
C100.069 (3)0.0271 (19)0.053 (3)−0.0036 (18)0.001 (2)0.0032 (16)
C110.116 (4)0.032 (2)0.083 (4)−0.015 (2)0.019 (3)0.010 (2)
C120.055 (2)0.044 (2)0.064 (3)0.0131 (18)0.031 (2)−0.0042 (18)
C130.101 (4)0.039 (2)0.103 (4)0.011 (2)0.058 (3)0.000 (2)
Geometric parameters (Å, °) top
Cu1—O1i1.898 (2)C6—C71.419 (5)
Cu1—O11.898 (2)C7—H7A0.9300
Cu1—N1i1.938 (3)C8—C91.389 (5)
Cu1—N11.938 (3)C8—C8i1.406 (7)
O1—C11.303 (4)C9—C101.379 (5)
N1—C71.301 (5)C9—H9A0.9300
N1—C81.419 (4)C10—C10i1.404 (9)
O2—C21.361 (4)C10—C111.504 (5)
O2—C121.419 (4)C11—H11A0.9600
C1—C21.417 (5)C11—H11B0.9600
C1—C61.417 (5)C11—H11C0.9600
C2—C31.378 (5)C12—C131.484 (6)
C3—C41.385 (5)C12—H12A0.9700
C3—H3A0.9300C12—H12B0.9700
C4—C51.358 (5)C13—H13A0.9600
C4—H4A0.9300C13—H13B0.9600
C5—C61.430 (5)C13—H13C0.9600
C5—H5A0.9300
O1i—Cu1—O188.42 (14)N1—C7—H7A117.2
O1i—Cu1—N1i93.93 (11)C6—C7—H7A117.2
O1—Cu1—N1i174.47 (11)C9—C8—C8i119.1 (2)
O1i—Cu1—N1174.47 (11)C9—C8—N1126.1 (4)
O1—Cu1—N193.93 (11)C8i—C8—N1114.82 (19)
N1i—Cu1—N184.17 (17)C10—C9—C8121.6 (4)
C1—O1—Cu1127.2 (2)C10—C9—H9A119.2
C7—N1—C8122.0 (3)C8—C9—H9A119.2
C7—N1—Cu1124.8 (2)C9—C10—C10i119.4 (3)
C8—N1—Cu1113.1 (2)C9—C10—C11119.2 (4)
C2—O2—C12119.4 (3)C10i—C10—C11121.4 (3)
O1—C1—C2118.0 (3)C10—C11—H11A109.5
O1—C1—C6124.3 (3)C10—C11—H11B109.5
C2—C1—C6117.6 (3)H11A—C11—H11B109.5
O2—C2—C3124.8 (3)C10—C11—H11C109.5
O2—C2—C1114.0 (3)H11A—C11—H11C109.5
C3—C2—C1121.2 (3)H11B—C11—H11C109.5
C2—C3—C4120.7 (4)O2—C12—C13108.2 (3)
C2—C3—H3A119.6O2—C12—H12A110.1
C4—C3—H3A119.6C13—C12—H12A110.1
C5—C4—C3120.2 (4)O2—C12—H12B110.1
C5—C4—H4A119.9C13—C12—H12B110.1
C3—C4—H4A119.9H12A—C12—H12B108.4
C4—C5—C6121.0 (4)C12—C13—H13A109.5
C4—C5—H5A119.5C12—C13—H13B109.5
C6—C5—H5A119.5H13A—C13—H13B109.5
C1—C6—C7123.4 (3)C12—C13—H13C109.5
C1—C6—C5119.2 (3)H13A—C13—H13C109.5
C7—C6—C5117.3 (3)H13B—C13—H13C109.5
N1—C7—C6125.7 (3)
O1i—Cu1—O1—C1169.0 (3)C2—C1—C6—C7−179.4 (3)
N1—Cu1—O1—C1−6.0 (3)O1—C1—C6—C5−177.9 (3)
O1—Cu1—N1—C78.1 (3)C2—C1—C6—C50.7 (5)
N1i—Cu1—N1—C7−177.1 (4)C4—C5—C6—C1−0.6 (6)
O1—Cu1—N1—C8−175.5 (2)C4—C5—C6—C7179.5 (3)
N1i—Cu1—N1—C8−0.69 (17)C8—N1—C7—C6177.1 (3)
Cu1—O1—C1—C2−176.4 (2)Cu1—N1—C7—C6−6.9 (5)
Cu1—O1—C1—C62.2 (5)C1—C6—C7—N10.7 (6)
C12—O2—C2—C30.1 (6)C5—C6—C7—N1−179.4 (3)
C12—O2—C2—C1179.8 (3)C7—N1—C8—C9−2.6 (6)
O1—C1—C2—O2−0.6 (5)Cu1—N1—C8—C9−179.1 (3)
C6—C1—C2—O2−179.3 (3)C7—N1—C8—C8i178.5 (4)
O1—C1—C2—C3179.1 (3)Cu1—N1—C8—C8i2.0 (5)
C6—C1—C2—C30.5 (5)C8i—C8—C9—C100.2 (6)
O2—C2—C3—C4178.0 (4)N1—C8—C9—C10−178.7 (3)
C1—C2—C3—C4−1.7 (6)C8—C9—C10—C10i0.7 (7)
C2—C3—C4—C51.8 (7)C8—C9—C10—C11−179.0 (4)
C3—C4—C5—C6−0.6 (6)C2—O2—C12—C13−177.2 (4)
O1—C1—C6—C72.0 (6)
Symmetry codes: (i) −x, y, −z+1/2.
Acknowledgements top

HK and AJ thank PNU for financial support. RK thanks the Islamic Azad University and Professor H. M. Stoeckli-Evans for valuable help.

references
References top

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