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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 5| May 2012| Page o1406
doi:10.1107/S1600536812015243

2-Amino-3-[(E)-(2-hy­dr­oxy-3-methyl­benzyl­­idene)amino]­but-2-ene­di­nitrile

Elham S. Aazama* and Orhan Büyükgüngörb

aDepartment of Chemistry, Girls Section, King Abdulaziz University, PO Box 6171, Jeddah 21442, Saudi Arabia, and bOndokuz Mayıs University, Arts and Sciences Faculty, Department of Physics, 55139-Samsun, Turkey
*Correspondence e-mail: wayfield8@yahoo.com

(Received 3 April 2012; accepted 6 April 2012; online 18 April 2012)

The title compound, C12H10N4O, is a Schiff base obtained from the condensation of diamino­maleonitrile and 2-hy­droxy-3-methyl­benzaldehyde. The mol­ecule is roughly planar, with an r.m.s. deviation of 0.0354 Å, and adopts the phenol–imine tautomeric form. An intra­molecular O—H⋯N hydrogen bond involving the O—H group and the azomethine N atom generates an S(6) ring. In the crystal, there are two N—H⋯N hydrogen bonds.

Related literature

For the biological properties of Schiff bases see: Da Silva et al. (2011[Da Silva, C. M., Da Silva, D. L., Modolo, L. V., Alves, R. B., De Resende, M. A., Martins, C. V. B. & De Fátima, Â. (2011). J. Advert. Res. 2, 1-8.]) and for their use in coordination chemistry, see: Aazam et al. (2011[Aazam, E. S., Ng, S. W. & Tiekink, E. R. T. (2011). Acta Cryst. E67, m314-m315.]); Kargar et al. (2009[Kargar, H., Jamshidvand, A., Fun, H.-K. & Kia, R. (2009). Acta Cryst. E65, m403-m404.]); Yeap et al. (2009[Yeap, C. S., Kia, R., Kargar, H. & Fun, H.-K. (2009). Acta Cryst. E65, m570-m571.]). For graph-set notation, see: Bernstein et al., (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For related structures, see: Aazam & Büyükgüngör (2010[Aazam, E. S. & Büyükgüngör, O. (2010). Acta Cryst. E66, o2587-o2588.]); Hökelek et al. (2000[Hökelek, T., Kiliç, Z., Isiklan, M. & Toy, M. (2000). J. Mol. Struct. 523, 61-69.]); Odabaşoğlu et al. (2005[Odabąsogˇlu, M., Albayrak, C. & Büyükgüngör, O. (2005). Acta Cryst. E61, o425-o426.]); Rivera et al. (2006[Rivera, A., Ríos-Motta, J. & León, F. (2006). Molecules, 11, 858-866.]).

[Scheme 1]

Experimental

Crystal data

  • C12H10N4O

  • Mr = 226.24

  • Monoclinic, P 21 /c

  • a = 6.9041 (6) Å

  • b = 11.8791 (7) Å

  • c = 14.0282 (11) Å

  • β = 101.600 (7)°

  • V = 1127.02 (15) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.76 × 0.48 × 0.03 mm
Data collection

  • Stoe IPDS 2 diffractometer

  • Absorption correction: integration (X-RED32; Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.]) Tmin = 0.949, Tmax = 0.996

  • 16504 measured reflections

  • 2336 independent reflections

  • 1700 reflections with I > 2σ(I)

  • Rint = 0.054
Refinement

  • R[F2 > 2σ(F2)] = 0.059

  • wR(F2) = 0.132

  • S = 1.14

  • 2336 reflections

  • 168 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.15 e Å−3

  • Δρmin = −0.16 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O1—H1⋯N1 0.88 (3) 1.83 (3) 2.643 (2) 153 (3)
N2—H2A⋯N4i 0.89 (3) 2.40 (3) 3.156 (3) 142 (2)
N2—H2B⋯N3ii 0.88 (3) 2.26 (3) 3.098 (3) 159 (2)
Symmetry codes: (i) [-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}].

Data collection: X-AREA (Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2001[Stoe & Cie (2001). X-RED. Stoe & Cie, Darmstadt, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812015243/go2051sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812015243/go2051Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812015243/go2051Isup3.cml

checkCIF report


Comment top

Tetrameric HCN (diaminomaleonitrile, DAMN) is one of the most versatile reagents in organic chemistry. It has been used as a precursor for producing nucleotides and for synthesizing a wide variety of heterocyclic compounds. These compounds are important as synthetic intermediates and they are also used in pharmacology (Da Silva et al., 2011; Rivera et al., 2006).

Schiff bases derived from DAMN have also been used as versatile ligands in coordination chemistry (Aazam et al., 2011; Kargar et al., 2009; Yeap et al., 2009). There are two types of intra-molecular hydrogen bonds in Schiff bases, which may be stabilized either in keto-amine (N—H···O hydrogen bond) (Hökelek et al., 2000) or phenol-imine (N···H—O hydrogen bond) tautomeric forms (Odabaşoǧlu et al., 2005; Aazam & Büyükgüngör, 2010). The present X-ray investigation shows that the title compound is a Schiff base and exists in the phenol-imine form in the solid-state.

The molecular structure of the title compound is shown in Figure 1. An intramolecular O1—H1···N1 hydrogen bond, a characteristic hydrogen bond for Schiff bases, leads to the formation of a S(6) six-membered ring (Figure 1) (Bernstein et al., 1995).

The N2—H2A···N4i (i; -x, y - 1/2, -z + 1/2) and N2—H2B···N3ii (ii; x, -y + 3/2, z - 1/2) hydrogen bonds generate a C(5) zigzag chain running parallel to the b axis and a C(6) chain running parallel to the c axis, respectively, (Figure 2–3). The intersection of the C(5) and C(6) chains produce alternating R44(18) and R44(22) ring motives, (Figure 4), (Bernstein et al., 1995) which link the molecules into corrugated sheets which lie in the b,c plane. Details of the hydrogen bonds are given in Table 1.

Related literature top

For the biological properties of Schiff bases see: Da Silva et al. (2011) and for their use in coordination chemistry, see: Aazam et al. (2011); Kargar et al. (2009); Yeap et al. (2009). For graph-set notation, see: Bernstein et al., (1995). For related structures, see: Aazam & Büyükgüngör (2010); Hökelek et al. (2000); Odabaşoǧlu et al. (2005); Rivera et al. (2006). [SCHEME MISSING TWO N LABELS; ALSO REMOVE THE "(I)"]

Refinement top

The H atoms bonded to oxygen and nitrogen atoms were located in Fourier map and refined isotropically. Other hydrogen atoms were positioned geometrically and treated using a riding model, fixing bond lengths at 0.93 and 0.96 Å for CH (aromatic) and CH3, respectively. The displacement parameters of the H atoms were constrained with Uiso(H) = 1.2Ueq (aromatic and methyl C).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and atomic numbering.
[Figure 2] Fig. 2. Part of the crystal structure of the title compound, showing the formation of C(5) chains parallel to the b axis (i; -x, y - 1/2, -z + 1/2). Hydrogen bonds are indicated by dashed lines.
[Figure 3] Fig. 3. Part of the crystal structure of the title compound, showing the formation of C(6) chains parallel to the c axis (i; x, -y + 3/2, z - 1/2). Hydrogen bonds are indicated by dashed lines.
[Figure 4] Fig. 4. Part of the crystal structure of the title compound, showing the formation of R44(18) and R44(22) rings. Hydrogen bonds are indicated by dashed lines. (Symmetry codes as in Table 1)
2-Amino-3-[(E)-(2-hydroxy-3-methylbenzylidene)amino]but-2-enedinitrile top
Crystal data top
C12H10N4OF(000) = 472
Mr = 226.24Dx = 1.333 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 16504 reflections
a = 6.9041 (6) Åθ = 2.3–28.0°
b = 11.8791 (7) ŵ = 0.09 mm−1
c = 14.0282 (11) ÅT = 296 K
β = 101.600 (7)°Plate, brown
V = 1127.02 (15) Å30.76 × 0.48 × 0.03 mm
Z = 4
Data collection top
Stoe IPDS 2
diffractometer		2336 independent reflections
Radiation source: fine-focus sealed tube1700 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.054
rotation method scansθmax = 26.5°, θmin = 2.3°
Absorption correction: integration
(X-RED32; Stoe & Cie, 2002)		h = −8→8
Tmin = 0.949, Tmax = 0.996k = −14→14
16504 measured reflectionsl = −17→17
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.059H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.132 w = 1/[σ2(Fo2) + (0.0644P)2 + 0.0085P]
where P = (Fo2 + 2Fc2)/3
S = 1.14(Δ/σ)max < 0.001
2336 reflectionsΔρmax = 0.15 e Å−3
168 parametersΔρmin = −0.16 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.008 (2)
Crystal data top
C12H10N4OV = 1127.02 (15) Å3
Mr = 226.24Z = 4
Monoclinic, P21/cMo Kα radiation
a = 6.9041 (6) ŵ = 0.09 mm−1
b = 11.8791 (7) ÅT = 296 K
c = 14.0282 (11) Å0.76 × 0.48 × 0.03 mm
β = 101.600 (7)°
Data collection top
Stoe IPDS 2
diffractometer		2336 independent reflections
Absorption correction: integration
(X-RED32; Stoe & Cie, 2002)		1700 reflections with I > 2σ(I)
Tmin = 0.949, Tmax = 0.996Rint = 0.054
16504 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0590 restraints
wR(F2) = 0.132H atoms treated by a mixture of independent and constrained refinement
S = 1.14Δρmax = 0.15 e Å−3
2336 reflectionsΔρmin = −0.16 e Å−3
168 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.

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 > σ(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
C10.2927 (3)0.39788 (16)0.57527 (14)0.0412 (5)
C20.2741 (3)0.30861 (18)0.50843 (15)0.0451 (5)
C30.2980 (3)0.19643 (18)0.53978 (17)0.0507 (5)
C40.3421 (3)0.1774 (2)0.63866 (19)0.0579 (6)
H40.35810.10360.66090.069*
C50.3637 (3)0.2639 (2)0.70634 (17)0.0597 (6)
H50.39510.24800.77260.072*
C60.3382 (3)0.3731 (2)0.67447 (16)0.0518 (5)
H60.35140.43130.71960.062*
C70.2734 (4)0.1024 (2)0.4671 (2)0.0730 (7)
H7A0.37350.10810.42870.088*
H7B0.14520.10730.42540.088*
H7C0.28600.03150.50060.088*
C80.2653 (3)0.51404 (16)0.54458 (14)0.0426 (5)
H80.27850.56980.59200.051*
C90.2013 (3)0.65633 (15)0.42752 (14)0.0393 (5)
C100.1644 (3)0.68409 (16)0.33180 (14)0.0405 (5)
C110.2178 (3)0.74210 (17)0.50067 (15)0.0461 (5)
C120.1464 (3)0.80158 (18)0.30383 (15)0.0482 (5)
N10.2236 (2)0.54359 (13)0.45456 (11)0.0405 (4)
N20.1385 (3)0.61018 (17)0.25795 (15)0.0563 (5)
H2A0.112 (4)0.538 (3)0.2695 (19)0.077 (8)*
H2B0.130 (4)0.637 (2)0.199 (2)0.076 (8)*
N30.2305 (3)0.80465 (17)0.56309 (15)0.0664 (6)
N40.1280 (3)0.89245 (17)0.27921 (17)0.0709 (6)
O10.2304 (3)0.32719 (15)0.41171 (12)0.0668 (5)
H10.217 (4)0.400 (3)0.405 (2)0.081 (9)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0386 (10)0.0447 (11)0.0419 (11)0.0035 (8)0.0116 (8)0.0071 (9)
C20.0471 (11)0.0469 (12)0.0413 (12)0.0045 (9)0.0090 (9)0.0061 (9)
C30.0485 (12)0.0429 (12)0.0594 (14)0.0028 (9)0.0076 (10)0.0095 (10)
C40.0520 (13)0.0504 (13)0.0705 (17)0.0023 (10)0.0108 (11)0.0236 (12)
C50.0649 (14)0.0679 (16)0.0466 (13)0.0040 (11)0.0120 (11)0.0215 (12)
C60.0563 (13)0.0597 (14)0.0417 (12)0.0015 (10)0.0149 (10)0.0064 (10)
C70.0825 (17)0.0444 (13)0.0863 (19)0.0090 (12)0.0027 (14)−0.0023 (13)
C80.0473 (11)0.0408 (11)0.0415 (12)0.0017 (8)0.0135 (8)0.0006 (9)
C90.0416 (10)0.0355 (10)0.0421 (11)−0.0004 (8)0.0113 (8)0.0004 (8)
C100.0430 (10)0.0345 (10)0.0436 (12)−0.0030 (8)0.0077 (8)0.0026 (8)
C110.0566 (13)0.0382 (11)0.0446 (12)0.0035 (9)0.0127 (10)0.0029 (10)
C120.0548 (12)0.0404 (12)0.0482 (12)−0.0029 (9)0.0072 (9)0.0055 (10)
N10.0450 (9)0.0367 (8)0.0411 (10)0.0015 (7)0.0114 (7)0.0039 (7)
N20.0836 (14)0.0420 (11)0.0416 (11)−0.0110 (10)0.0084 (9)0.0022 (9)
N30.0917 (15)0.0538 (12)0.0540 (12)0.0047 (10)0.0151 (11)−0.0096 (10)
N40.0901 (15)0.0433 (11)0.0779 (15)0.0048 (10)0.0134 (12)0.0155 (10)
O10.1120 (14)0.0444 (9)0.0415 (10)0.0164 (9)0.0098 (9)0.0023 (7)
Geometric parameters (Å, º) top
C1—C61.395 (3)C7—H7C0.9600
C1—C21.404 (3)C8—N11.286 (2)
C1—C81.447 (3)C8—H80.9300
C2—O11.348 (3)C9—C101.356 (3)
C2—C31.403 (3)C9—N11.392 (2)
C3—C41.378 (3)C9—C111.434 (3)
C3—C71.499 (3)C10—N21.342 (3)
C4—C51.386 (4)C10—C121.448 (3)
C4—H40.9300C11—N31.138 (3)
C5—C61.372 (3)C12—N41.133 (3)
C5—H50.9300N2—H2A0.89 (3)
C6—H60.9300N2—H2B0.88 (3)
C7—H7A0.9600O1—H10.88 (3)
C7—H7B0.9600
C6—C1—C2118.59 (18)H7A—C7—H7B109.5
C6—C1—C8119.22 (19)C3—C7—H7C109.5
C2—C1—C8122.19 (18)H7A—C7—H7C109.5
O1—C2—C3117.37 (19)H7B—C7—H7C109.5
O1—C2—C1121.37 (18)N1—C8—C1122.86 (18)
C3—C2—C1121.26 (19)N1—C8—H8118.6
C4—C3—C2117.4 (2)C1—C8—H8118.6
C4—C3—C7122.3 (2)C10—C9—N1119.49 (17)
C2—C3—C7120.3 (2)C10—C9—C11120.52 (17)
C3—C4—C5122.7 (2)N1—C9—C11119.99 (17)
C3—C4—H4118.7N2—C10—C9125.07 (19)
C5—C4—H4118.7N2—C10—C12115.50 (19)
C6—C5—C4119.2 (2)C9—C10—C12119.43 (18)
C6—C5—H5120.4N3—C11—C9175.5 (2)
C4—C5—H5120.4N4—C12—C10177.7 (2)
C5—C6—C1120.9 (2)C8—N1—C9121.38 (16)
C5—C6—H6119.6C10—N2—H2A118.9 (17)
C1—C6—H6119.6C10—N2—H2B117.7 (18)
C3—C7—H7A109.5H2A—N2—H2B123 (2)
C3—C7—H7B109.5C2—O1—H1105.2 (19)
C6—C1—C2—O1179.99 (18)C2—C1—C6—C5−0.2 (3)
C8—C1—C2—O10.3 (3)C8—C1—C6—C5179.5 (2)
C6—C1—C2—C30.8 (3)C6—C1—C8—N1179.86 (18)
C8—C1—C2—C3−178.93 (19)C2—C1—C8—N1−0.4 (3)
O1—C2—C3—C4−179.80 (19)N1—C9—C10—N22.9 (3)
C1—C2—C3—C4−0.6 (3)C11—C9—C10—N2−177.18 (19)
O1—C2—C3—C7−0.5 (3)N1—C9—C10—C12−178.38 (17)
C1—C2—C3—C7178.8 (2)C11—C9—C10—C121.5 (3)
C2—C3—C4—C5−0.2 (3)C1—C8—N1—C9−178.97 (18)
C7—C3—C4—C5−179.5 (2)C10—C9—N1—C8177.62 (18)
C3—C4—C5—C60.8 (3)C11—C9—N1—C8−2.3 (3)
C4—C5—C6—C1−0.5 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.88 (3)1.83 (3)2.643 (2)153 (3)
N2—H2A···N4i0.89 (3)2.40 (3)3.156 (3)142 (2)
N2—H2B···N3ii0.88 (3)2.26 (3)3.098 (3)159 (2)
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) x, −y+3/2, z−1/2.

Experimental details

Crystal data
Chemical formulaC12H10N4O
Mr226.24
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)6.9041 (6), 11.8791 (7), 14.0282 (11)
β (°) 101.600 (7)
V (Å3)1127.02 (15)
Z4
Radiation typeMo Kα
µ (mm−1)0.09
Crystal size (mm)0.76 × 0.48 × 0.03
Data collection
DiffractometerStoe IPDS 2
diffractometer
Absorption correctionIntegration
(X-RED32; Stoe & Cie, 2002)
Tmin, Tmax0.949, 0.996
No. of measured, independent and
observed [I > 2σ(I)] reflections		16504, 2336, 1700
Rint0.054
(sin θ/λ)max (Å−1)0.628
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.059, 0.132, 1.14
No. of reflections2336
No. of parameters168
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.15, −0.16

Computer programs: X-AREA (Stoe & Cie, 2002), X-RED32 (Stoe & Cie, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.88 (3)1.83 (3)2.643 (2)153 (3)
N2—H2A···N4i0.89 (3)2.40 (3)3.156 (3)142 (2)
N2—H2B···N3ii0.88 (3)2.26 (3)3.098 (3)159 (2)
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) x, −y+3/2, z−1/2.
 

Acknowledgements

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the diffractometer (purchased under grant F. 279 of University Research Fund) and King Abdulaziz University and the Deanship of Scientific Research for financial support (grant No. 17–013/430).

References

First citationAazam, E. S. & Büyükgüngör, O. (2010). Acta Cryst. E66, o2587–o2588.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationAazam, E. S., Ng, S. W. & Tiekink, E. R. T. (2011). Acta Cryst. E67, m314–m315.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
 First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
 First citationDa Silva, C. M., Da Silva, D. L., Modolo, L. V., Alves, R. B., De Resende, M. A., Martins, C. V. B. & De Fátima, Â. (2011). J. Advert. Res. 2, 1–8.  CrossRef Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
 First citationHökelek, T., Kiliç, Z., Isiklan, M. & Toy, M. (2000). J. Mol. Struct. 523, 61–69.  Google Scholar
 First citationKargar, H., Jamshidvand, A., Fun, H.-K. & Kia, R. (2009). Acta Cryst. E65, m403–m404.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
 First citationOdabąsogˇlu, M., Albayrak, C. & Büyükgüngör, O. (2005). Acta Cryst. E61, o425–o426.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationRivera, A., Ríos-Motta, J. & León, F. (2006). Molecules, 11, 858–866.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationStoe & Cie (2001). X-RED. Stoe & Cie, Darmstadt, Germany.  Google Scholar
 First citationStoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.  Google Scholar
 First citationYeap, C. S., Kia, R., Kargar, H. & Fun, H.-K. (2009). Acta Cryst. E65, m570–m571.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
Volume 68| Part 5| May 2012| Page o1406
doi:10.1107/S1600536812015243
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