metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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

aDepartment of Chemistry, School of Science, Payame Noor University (PNU), Ardakan, Yazd, Iran, bDepartment of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran, cX-ray Crystallography Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran, and dDepartment of Physics, University of Sargodha, Punjab, Pakistan
*Correspondence e-mail: zsrkk@yahoo.com, rkia@srbiau.ac.ir, dmntahir_uos@yahoo.com

(Received 9 October 2010; accepted 21 October 2010; online 30 October 2010)

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 ππ inter­actions with centroid–centroid distances in the range 3.466 (2)–3.6431 (16) Å.

Related literature

For background to Schiff base–metal complexes, see: Granovski et al. (1993[Granovski, A. D., Nivorozhkin, A. L. & Minkin, V. I. (1993). Coord. Chem. Rev. 126, 1-69.]); Blower et al. (1998[Blower, P. J. (1998). Transition Met. Chem. 23, 109-112.]); Elmali et al. (2000[Elmali, A., Elerman, Y. & Svoboda, I. (2000). Acta Cryst. C56, 423-424.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu(C26H26N2O4)]

  • Mr = 494.03

  • Monoclinic, C 2/c

  • a = 14.9755 (7) Å

  • b = 15.8803 (7) Å

  • c = 12.2264 (6) Å

  • β = 119.285 (2)°

  • V = 2536.0 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.89 mm−1

  • T = 296 K

  • 0.27 × 0.21 × 0.11 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.982, Tmax = 0.992

  • 31403 measured reflections

  • 3157 independent reflections

  • 1910 reflections with I > 2σ(I)

  • Rint = 0.049

Refinement
  • R[F2 > 2σ(F2)] = 0.066

  • wR(F2) = 0.147

  • S = 1.05

  • 3157 reflections

  • 152 parameters

  • H-atom parameters constrained

  • Δρmax = 0.43 e Å−3

  • Δρmin = −0.46 e Å−3

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


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 ππ 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.

Structure description 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 ππ 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.

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).

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 ππ 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 m3
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 mm1
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)
Graphite monochromatorRint = 0.049
φ and ω scansθmax = 28.3°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 1620
Tmin = 0.982, Tmax = 0.992k = 021
3157 measured reflectionsl = 160
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 Å3
0 restraintsΔρmin = 0.46 e Å3
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 mm1
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 reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0660 restraints
wR(F2) = 0.147H-atom parameters constrained
S = 1.05Δρmax = 0.43 e Å3
3157 reflectionsΔρmin = 0.46 e Å3
152 parameters
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)
H4A0.25140.44570.04400.071*
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*
H11B0.00670.94510.11690.135*
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, º) 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—C7179.4 (3)
N1—Cu1—O1—C16.0 (3)O1—C1—C6—C5177.9 (3)
O1—Cu1—N1—C78.1 (3)C2—C1—C6—C50.7 (5)
N1i—Cu1—N1—C7177.1 (4)C4—C5—C6—C10.6 (6)
O1—Cu1—N1—C8175.5 (2)C4—C5—C6—C7179.5 (3)
N1i—Cu1—N1—C80.69 (17)C8—N1—C7—C6177.1 (3)
Cu1—O1—C1—C2176.4 (2)Cu1—N1—C7—C66.9 (5)
Cu1—O1—C1—C62.2 (5)C1—C6—C7—N10.7 (6)
C12—O2—C2—C30.1 (6)C5—C6—C7—N1179.4 (3)
C12—O2—C2—C1179.8 (3)C7—N1—C8—C92.6 (6)
O1—C1—C2—O20.6 (5)Cu1—N1—C8—C9179.1 (3)
C6—C1—C2—O2179.3 (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—C10178.7 (3)
C1—C2—C3—C41.7 (6)C8—C9—C10—C10i0.7 (7)
C2—C3—C4—C51.8 (7)C8—C9—C10—C11179.0 (4)
C3—C4—C5—C60.6 (6)C2—O2—C12—C13177.2 (4)
O1—C1—C6—C72.0 (6)
Symmetry code: (i) x, y, z+1/2.

Experimental details

Crystal data
Chemical formula[Cu(C26H26N2O4)]
Mr494.03
Crystal system, space groupMonoclinic, C2/c
Temperature (K)296
a, b, c (Å)14.9755 (7), 15.8803 (7), 12.2264 (6)
β (°) 119.285 (2)
V3)2536.0 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.89
Crystal size (mm)0.27 × 0.21 × 0.11
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.982, 0.992
No. of measured, independent and
observed [I > 2σ(I)] reflections
3157, 3157, 1910
Rint0.049
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.066, 0.147, 1.05
No. of reflections3157
No. of parameters152
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.43, 0.46

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

 

Acknowledgements

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

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CSD CrossRef Web of Science Google Scholar
First citationBlower, P. J. (1998). Transition Met. Chem. 23, 109–112.  CrossRef CAS Google Scholar
First citationBruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationElmali, A., Elerman, Y. & Svoboda, I. (2000). Acta Cryst. C56, 423–424.  CSD CrossRef CAS IUCr Journals Google Scholar
First citationGranovski, A. D., Nivorozhkin, A. L. & Minkin, V. I. (1993). Coord. Chem. Rev. 126, 1–69.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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