A second monoclinic polymorph of 4,4′-[butane-1,4-diylbis(nitrilo­methyl­idyne)]dibenzonitrile

Kia, R.; Fun, H.-K.; Kargar, H.

doi:10.1107/S1600536808037537

organic compounds

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Volume 64| Part 12| December 2008| Page o2388

doi:10.1107/S1600536808037537

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A second monoclinic polymorph of 4,4′-[butane-1,4-diylbis(nitrilomethylidyne)]dibenzonitrile

Reza Kia,^a Hoong-Kun Fun ^a ^* and Hadi Kargar ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bDepartment of Chemistry, School of Science, Payame Noor University (PNU), Ardakan, Yazd, Iran
^*Correspondence e-mail: hkfun@usm.my

(Received 6 November 2008; accepted 12 November 2008; online 20 November 2008)

The asymmetric unit of the title Schiff base compound, C₂₀H₁₈N₄, contains one half-molecule, lying across a crystallographic inversion centre and adopting an E configuration with respect to the C=N bonds. The imino group is coplanar with the benzene ring with a maximun deviation of 0.096 (1) Å for the N atom. Within the molecule, the planar units are parallel but extend in opposite directions from the methylene bridge. In the crystal structure, neighbouring molecules are linked together by weak intermolecular C—H⋯N hydrogen bonds involving the cyano N atoms, forming R₂²(10) ring motifs.

Related literature

For general background, see: Casellato & Vigato (1977 ); Calligaris & Randaccio (1987 ). For related structures, see: Fun et al. (2008 ); Fun, Kia & Kargar (2008a ,b ); Fun & Kia (2008a ,b ). For bond-length data, see: Allen et al. (1987 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ).

Experimental

Crystal data

C₂₀H₁₈N₄
M_r = 314.38
Monoclinic, P 2₁ /n
a = 4.9958 (1) Å
b = 14.8164 (2) Å
c = 11.6633 (2) Å
β = 97.310 (1)°
V = 856.30 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 100.0 (1) K
0.39 × 0.29 × 0.28 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.891, T_max = 0.979
18411 measured reflections
4473 independent reflections
3659 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.135
S = 1.04
4473 reflections
109 parameters
H-atom parameters constrained
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2A⋯N2ⁱ	0.93	2.52	3.4037 (11)	158
Symmetry code: (i) -x+2, -y, -z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808037537/hk2569sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808037537/hk2569Isup2.hkl

checkCIF report

Comment top

The condensation of primary amines with carbonyl compounds yields Schiff base compounds (Casellato & Vigato, 1977); these are still one of the most prevalent mixed-donor ligands in coordination chemistry. In the past two decades, the syntheses, structures and properties of Schiff base complexes have stimulated much interest due to their noteworthy contributions in single molecule-based magnetism, materials science and the catalysis of many reactions such as carbonylation, hydroformylation, reduction, oxidation, epoxidation and hydrolysis (Casellato & Vigato 1977). In comparison to the Schiff base metal complexes, only a relatively small number of free Schiff base ligands have been characterized structurally (Calligaris & Randaccio, 1987). As an extension of our work (Fun et al., 2008; Fun, Kia & Kargar 2008a,b; Fun & Kia 2008a,b) on the structural characterization of Schiff base ligands, we reported herein the crystal structure of the title compound.

The asymmetric unit of the title compound contains one-half molecule (Fig. 1), lying across a crystallographic inversion centre and adopting E configurations with respect to the C═N bonds. The bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable with the related structure (Fun et al., 2008). The imino group is coplanar with the benzene ring, and the planar units are parallel but extend in opposite directions from the methylene bridge.

In the crystal structure, neighbouring molecules are linked together by weak intermolecular C-H···N hydrogen bonds (Table 1) involving the cyano N atoms, forming ten-membered rings with R₂²(10) ring motifs (Bernstein et al., 1995).

Related literature top

For general background, see: Casellato & Vigato (1977); Calligaris & Randaccio (1987). For related structures, see: Fun et al. (2008); Fun, Kia & Kargar (2008a,b); Fun & Kia (2008a,b). For bond-length data, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

The synthetic method has been described earlier (Fun, Kia & Kargar, 2008b). Single crystals suitable for X-ray analysis were obtained by evaporation of an ethanol solution at room temperature.

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, 2003).

Figures top

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry code: (A) -x, 1 - y, -z].
	Fig. 2. A partial packing diagram viewed down the a axis, showing R₂²(10) ring motifs. Hydrogen bonds are shown as dashed lines.

4,4'-[butane-1,4-diylbis(nitrilomethylidyne)]dibenzonitrile top

Crystal data top

C₂₀H₁₈N₄	F(000) = 332
M_r = 314.38	D_x = 1.219 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6822 reflections
a = 4.9958 (1) Å	θ = 2.2–39.9°
b = 14.8164 (2) Å	µ = 0.08 mm⁻¹
c = 11.6633 (2) Å	T = 100 K
β = 97.310 (1)°	Block, yellow
V = 856.30 (3) Å³	0.39 × 0.29 × 0.28 mm
Z = 2

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	4473 independent reflections
Radiation source: fine-focus sealed tube	3659 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 37.5°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −8→8
T_min = 0.891, T_max = 0.979	k = −24→25
18411 measured reflections	l = −19→18

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.135	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0727P)² + 0.1307P] where P = (F_o² + 2F_c²)/3
4473 reflections	(Δ/σ)_max < 0.001
109 parameters	Δρ_max = 0.55 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₂₀H₁₈N₄	V = 856.30 (3) Å³
M_r = 314.38	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 4.9958 (1) Å	µ = 0.08 mm⁻¹
b = 14.8164 (2) Å	T = 100 K
c = 11.6633 (2) Å	0.39 × 0.29 × 0.28 mm
β = 97.310 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	4473 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3659 reflections with I > 2σ(I)
T_min = 0.891, T_max = 0.979	R_int = 0.026
18411 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.135	H-atom parameters constrained
S = 1.04	Δρ_max = 0.55 e Å⁻³
4473 reflections	Δρ_min = −0.26 e Å⁻³
109 parameters

Special details top

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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

	x	y	z	U_iso*/U_eq
N1	0.01080 (11)	0.32548 (4)	0.04403 (5)	0.01925 (11)
N2	1.09394 (17)	−0.03532 (5)	0.17351 (7)	0.03381 (17)
C1	0.40142 (14)	0.18220 (4)	0.04338 (6)	0.01953 (12)
H1A	0.3066	0.1973	−0.0279	0.023*
C2	0.59829 (14)	0.11593 (5)	0.04968 (6)	0.02080 (12)
H2A	0.6360	0.0866	−0.0169	0.025*
C3	0.74003 (13)	0.09356 (4)	0.15748 (6)	0.01898 (11)
C4	0.68642 (13)	0.13779 (5)	0.25771 (6)	0.02032 (12)
H4A	0.7827	0.1231	0.3288	0.024*
C5	0.48772 (13)	0.20402 (4)	0.25021 (5)	0.01888 (11)
H5A	0.4503	0.2335	0.3168	0.023*
C6	0.34401 (12)	0.22663 (4)	0.14350 (5)	0.01610 (11)
C7	0.13465 (12)	0.29707 (4)	0.13917 (5)	0.01716 (11)
H7A	0.0919	0.3215	0.2080	0.021*
C8	−0.19246 (13)	0.39541 (4)	0.05029 (6)	0.02132 (12)
H8A	−0.1937	0.4135	0.1301	0.026*
H8B	−0.3694	0.3715	0.0221	0.026*
C9	−0.13397 (12)	0.47738 (4)	−0.02174 (6)	0.01933 (12)
H9A	−0.1314	0.4587	−0.1013	0.023*
H9B	−0.2785	0.5209	−0.0204	0.023*
C10	0.93805 (15)	0.02262 (5)	0.16554 (6)	0.02439 (14)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0200 (2)	0.0161 (2)	0.0217 (2)	0.00380 (17)	0.00313 (18)	0.00211 (17)
N2	0.0380 (4)	0.0346 (4)	0.0290 (3)	0.0179 (3)	0.0052 (3)	0.0058 (3)
C1	0.0237 (3)	0.0179 (2)	0.0164 (2)	0.0047 (2)	0.00064 (19)	0.00065 (19)
C2	0.0249 (3)	0.0188 (3)	0.0187 (3)	0.0055 (2)	0.0026 (2)	0.0003 (2)
C3	0.0188 (2)	0.0166 (2)	0.0215 (3)	0.00276 (18)	0.00223 (19)	0.00326 (19)
C4	0.0197 (2)	0.0220 (3)	0.0185 (3)	0.0020 (2)	−0.00060 (19)	0.0026 (2)
C5	0.0199 (2)	0.0200 (3)	0.0163 (2)	0.00113 (19)	0.00059 (18)	−0.00036 (19)
C6	0.0173 (2)	0.0140 (2)	0.0168 (2)	0.00002 (17)	0.00157 (17)	0.00093 (17)
C7	0.0183 (2)	0.0148 (2)	0.0187 (2)	0.00041 (17)	0.00331 (18)	−0.00005 (18)
C8	0.0179 (2)	0.0180 (2)	0.0289 (3)	0.00373 (19)	0.0065 (2)	0.0041 (2)
C9	0.0152 (2)	0.0177 (2)	0.0252 (3)	0.00334 (17)	0.00291 (19)	0.0039 (2)
C10	0.0252 (3)	0.0242 (3)	0.0238 (3)	0.0065 (2)	0.0032 (2)	0.0043 (2)

Geometric parameters (Å, º) top

N1—C7	1.2714 (8)	C4—H4A	0.9300
N1—C8	1.4590 (8)	C5—C6	1.3962 (9)
N2—C10	1.1548 (9)	C5—H5A	0.9300
C1—C2	1.3851 (9)	C6—C7	1.4740 (8)
C1—C6	1.4015 (9)	C7—H7A	0.9300
C1—H1A	0.9300	C8—C9	1.5260 (9)
C2—C3	1.4019 (9)	C8—H8A	0.9700
C2—H2A	0.9300	C8—H8B	0.9700
C3—C4	1.3955 (10)	C9—C9ⁱ	1.5249 (13)
C3—C10	1.4382 (9)	C9—H9A	0.9700
C4—C5	1.3906 (9)	C9—H9B	0.9700

C7—N1—C8	117.13 (6)	C1—C6—C7	121.58 (5)
C2—C1—C6	120.53 (6)	N1—C7—C6	121.92 (6)
C2—C1—H1A	119.7	N1—C7—H7A	119.0
C6—C1—H1A	119.7	C6—C7—H7A	119.0
C1—C2—C3	119.30 (6)	N1—C8—C9	110.76 (5)
C1—C2—H2A	120.3	N1—C8—H8A	109.5
C3—C2—H2A	120.3	C9—C8—H8A	109.5
C4—C3—C2	120.75 (6)	N1—C8—H8B	109.5
C4—C3—C10	119.48 (6)	C9—C8—H8B	109.5
C2—C3—C10	119.75 (6)	H8A—C8—H8B	108.1
C5—C4—C3	119.36 (6)	C9ⁱ—C9—C8	112.85 (7)
C5—C4—H4A	120.3	C9ⁱ—C9—H9A	109.0
C3—C4—H4A	120.3	C8—C9—H9A	109.0
C4—C5—C6	120.49 (6)	C9ⁱ—C9—H9B	109.0
C4—C5—H5A	119.8	C8—C9—H9B	109.0
C6—C5—H5A	119.8	H9A—C9—H9B	107.8
C5—C6—C1	119.57 (6)	N2—C10—C3	178.58 (8)
C5—C6—C7	118.86 (5)

C6—C1—C2—C3	0.04 (10)	C2—C1—C6—C5	0.30 (10)
C1—C2—C3—C4	−0.57 (10)	C2—C1—C6—C7	−179.71 (6)
C1—C2—C3—C10	177.78 (6)	C8—N1—C7—C6	−179.98 (5)
C2—C3—C4—C5	0.76 (10)	C5—C6—C7—N1	174.67 (6)
C10—C3—C4—C5	−177.60 (6)	C1—C6—C7—N1	−5.31 (10)
C3—C4—C5—C6	−0.41 (10)	C7—N1—C8—C9	124.91 (7)
C4—C5—C6—C1	−0.12 (10)	N1—C8—C9—C9ⁱ	−62.65 (9)
C4—C5—C6—C7	179.90 (6)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···N2ⁱⁱ	0.93	2.52	3.4037 (11)	158

Symmetry code: (ii) −x+2, −y, −z.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₈N₄
M_r	314.38
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	4.9958 (1), 14.8164 (2), 11.6633 (2)
β (°)	97.310 (1)
V (Å³)	856.30 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.39 × 0.29 × 0.28

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.891, 0.979
No. of measured, independent and observed [I > 2σ(I)] reflections	18411, 4473, 3659
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.857

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.135, 1.04
No. of reflections	4473
No. of parameters	109
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.55, −0.26

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···N2ⁱ	0.93	2.52	3.4037 (11)	158

Symmetry code: (i) −x+2, −y, −z.

Acknowledgements

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund (grant No. 305/PFIZIK/613312). RK thanks Universiti Sains Malaysia for the award of a post-doctoral research fellowship. HK thanks PNU for financial support.

References

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. CrossRef Web of Science Google Scholar
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Calligaris, M. & Randaccio, L. (1987). Comprehensive Coordination Chemistry, Vol. 2, edited by G. Wilkinson, pp. 715–738. London: Pergamon. Google Scholar
Casellato, U. & Vigato, P. A. (1977). Coord. Chem. Rev. 23, 31–50. CrossRef CAS Web of Science Google Scholar
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Fun, H.-K. & Kia, R. (2008b). Acta Cryst. E64, m1116–m1117. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
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CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 12| December 2008| Page o2388

doi:10.1107/S1600536808037537

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

A second monoclinic polymorph of 4,4′-[butane-1,4-diylbis(nitrilo­methyl­­idyne)]dibenzo­nitrile

Related literature

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

A second monoclinic polymorph of 4,4′-[butane-1,4-diylbis(nitrilomethylidyne)]dibenzonitrile