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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

N-[(E)-Thio­phen-2-yl­methyl­­idene]-1,3-benzo­thia­zol-2-amine

aSchool of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
*Correspondence e-mail: akermanm@ukzn.ac.za

(Received 19 June 2012; accepted 4 July 2012; online 18 July 2012)

In the title thio­phene-derived Schiff base compound, C12H8N2S2, the thio­phene ring is slighty rotated from the benzothia­zole group mean plane, giving a dihedral angle of 12.87 (6)°. The largest displacement of an atom in the mol­ecule from the nine-atom mean plane defined by the non-H atoms of the benzothia­zole ring system is 0.572 (1) Å, exhibited by the C atom at the 3-position of the thio­phene ring. In the crystal, weak C—H⋯S hydrogen bonds involving the thio­phene group S atom and the 4-position thio­phene C—H group of a symmetry-related mol­ecule lead to an infinite one-dimensional chain colinear with the c axis. The structure is further stabilized by ππ inter­actions; the distance between the thia­zole ring centroid and the centroid of an adjacent benzene ring is 3.686 (1) Å. The crystal studied was an inversion twin with the ratio of components 0.73 (3):0.27 (3).

Related literature

For the synthesis and crystal structure of 2-amino­benzothia­zole, see: Ding et al. (2009[Ding, Q., He, X. & Wu, J. (2009). J. Comb. Chem. 11, 587-591.]). For crystal structures containing 2-amino­benzothia­zole derivatives, see: Garcia-Hernandez et al. (2006[Garcia-Hernandez, Z., Flores-Parra, A., Grevy, J. M., Ramos-Organillo, A. & Contreras, R. (2006). Polyhedron, 25, 1662-1672.]). For inhibitory properties against human cancer cell lines and general anti­tumor properties of benzothia­zole derivatives, see: Racane et al. (2001[Racane, L., Tralic-Kulenovic, V., Fiser-Jakic, L. & Boykin, D. W. (2001). Heterocycles, 55, 2085-2089.]); O'Brien et al. (2003[O'Brien, S. E., Browne, H. L., Bradshaw, T. D., Westwell, A. D. & Stevens, M. F. (2003). Org. Biomol. Chem. 1, 493-497.]). For anti­bacterial, anti­fungal, anti­tumor and anti­viral activites of benzthia­zoles, see: Yadav & Malipatil (2011[Yadav, S. K. & Malipatil, S. M. (2011). IJDDHR, 1, 42-43.]); Singh & Seghal (1988[Singh, S. P. & Seghal, S. (1988). Indian J. Chem. 27, 941-945.]); Pattan et al. (2005[Pattan, S. R., Suresh, C., Pujar, V. D., Reddy, V. V., Rasal, V. P. & Kotti, B. C. (2005). Indian J. Chem. Sect. B, 4, 2404-2408.]).

[Scheme 1]

Experimental

Crystal data
  • C12H8N2S2

  • Mr = 244.32

  • Monoclinic, P c

  • a = 10.7244 (5) Å

  • b = 4.6021 (2) Å

  • c = 11.1280 (5) Å

  • β = 100.367 (2)°

  • V = 540.25 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.46 mm−1

  • T = 100 K

  • 0.45 × 0.20 × 0.12 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.625, Tmax = 0.749

  • 14476 measured reflections

  • 7768 independent reflections

  • 7126 reflections with I > 2σ(I)

  • Rint = 0.033

Refinement
  • R[F2 > 2σ(F2)] = 0.033

  • wR(F2) = 0.085

  • S = 1.04

  • 7768 reflections

  • 145 parameters

  • 2 restraints

  • H-atom parameters constrained

  • Δρmax = 0.62 e Å−3

  • Δρmin = −0.36 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 2974 Friedel pairs

  • Flack parameter: 0.27 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C11—H11⋯S2i 0.95 2.92 3.517 (1) 122 (1)
Symmetry code: (i) [x, -y-1, z-{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

Benzothiazoles are naturally occurring molecules which consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. Their derivatives are abundantly distributed in nature and have been shown to have very interesting pharmacological activity, particularly antibacterial, antifungal, antitumor and antiviral properties (Yadav & Malipatil, 2011; Singh & Seghal, 1988; Pattan et al., 2005). The heterocyclic scaffold is readily substituted at the 2-position of the thiazole ring, allowing for derivatization.

The thiophene ring of the title compound (I) is not in the same plane as the 1,3-benzothiazole moiety, with a dihedral angle of 13.6 (1)° relative to the benzthiazole ring. This out-of-plane rotation of the thiophene results in the carbon atom in the 3-position of the thiophene ring (C10) sitting 0.572 (1) Å from the 9-atom mean plane defined by all non-hydrogen atoms of the benzthiazole ring system. The C8—N2 bond distance of 1.290 (1) Å and the C7—N2—C8 bond angle of 118.12 (7)° emphasize the sp2 hybridization of the imino nitrogen atom (refer to Figure 1 for the atom numbering scheme). An (E)-configuration about the imine bond is observed for this Schiff base moiety.

The structure exhibits both hydrogen bonding and π···π interactions. The distance between the centroid of the benzene ring and the centroid of the thiazole ring of an adjacent molecule is 3.686 (1) Å. In addition to the π···π interactions there are non-classical hydrogen bonds between the thiophene sulfur atom, S2, and the thiophene hydrogen atom H11 of an adjacent molecule. This hydrogen bond links the molecules into infinite, one-dimensional hydrogen-bonded chains, which are co-linear with the c-axis. The adjacent, hydrogen-bonded molecules are not both in the same plane, the 24-atom mean planes of two adjacent molecules make an angle of 75.9 (1)° to each other. Although the hydrogen bonds are not likely very strong as they are only marginally shorter than the sum of the van der Waals radii (0.066 Å), these intermolecular interactions can stabilize the lattice.

Related literature top

For the synthesis and crystal structure of 2-aminobenzothiazole, see: Ding et al. (2009). For crystal structures containing 2-aminobenzothiazole derivatives, see: Garcia-Hernandez et al. (2006). For inhibitory properties against human cancer cell lines and general antitumor properties of benzothiazole derivatives, see: Racane et al. (2001); O'Brien et al. (2003). For antibacterial, antifungal, antitumor and antiviral activites of benzthiazoles, see: Yadav & Malipatil (2011); Singh & Seghal (1988); Pattan et al. (2005).

Experimental top

A mixture of 2-aminobenzothiazole (1.27 g; 8.45 mmol) and thiophene-2-carbaldehyde (0.92 ml; 10.2 mmol) in methanol (50 ml) was heated to reflux for 24 h. The resulting orange solution was allowed to cool to room temperature and concentrated by rotary evaporation under reduced pressure. Dry toluene (45 ml) was added to the solution and heated to reflux with a Dean and Stark apparatus for an additional 24 h. Upon cooling the title compound was isolated as brown, needle-shaped crystals.

Refinement top

The positions of all C-bonded hydrogen atoms were calculated using the standard riding model of SHELXL97 (Sheldrick, 2008) with C—H(aromatic) distances of 0.93 Å and Uiso = 1.2Ueq(C).

Structure description top

Benzothiazoles are naturally occurring molecules which consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. Their derivatives are abundantly distributed in nature and have been shown to have very interesting pharmacological activity, particularly antibacterial, antifungal, antitumor and antiviral properties (Yadav & Malipatil, 2011; Singh & Seghal, 1988; Pattan et al., 2005). The heterocyclic scaffold is readily substituted at the 2-position of the thiazole ring, allowing for derivatization.

The thiophene ring of the title compound (I) is not in the same plane as the 1,3-benzothiazole moiety, with a dihedral angle of 13.6 (1)° relative to the benzthiazole ring. This out-of-plane rotation of the thiophene results in the carbon atom in the 3-position of the thiophene ring (C10) sitting 0.572 (1) Å from the 9-atom mean plane defined by all non-hydrogen atoms of the benzthiazole ring system. The C8—N2 bond distance of 1.290 (1) Å and the C7—N2—C8 bond angle of 118.12 (7)° emphasize the sp2 hybridization of the imino nitrogen atom (refer to Figure 1 for the atom numbering scheme). An (E)-configuration about the imine bond is observed for this Schiff base moiety.

The structure exhibits both hydrogen bonding and π···π interactions. The distance between the centroid of the benzene ring and the centroid of the thiazole ring of an adjacent molecule is 3.686 (1) Å. In addition to the π···π interactions there are non-classical hydrogen bonds between the thiophene sulfur atom, S2, and the thiophene hydrogen atom H11 of an adjacent molecule. This hydrogen bond links the molecules into infinite, one-dimensional hydrogen-bonded chains, which are co-linear with the c-axis. The adjacent, hydrogen-bonded molecules are not both in the same plane, the 24-atom mean planes of two adjacent molecules make an angle of 75.9 (1)° to each other. Although the hydrogen bonds are not likely very strong as they are only marginally shorter than the sum of the van der Waals radii (0.066 Å), these intermolecular interactions can stabilize the lattice.

For the synthesis and crystal structure of 2-aminobenzothiazole, see: Ding et al. (2009). For crystal structures containing 2-aminobenzothiazole derivatives, see: Garcia-Hernandez et al. (2006). For inhibitory properties against human cancer cell lines and general antitumor properties of benzothiazole derivatives, see: Racane et al. (2001); O'Brien et al. (2003). For antibacterial, antifungal, antitumor and antiviral activites of benzthiazoles, see: Yadav & Malipatil (2011); Singh & Seghal (1988); Pattan et al. (2005).

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: WinGX (Farrugia, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A thermal ellipsoid plot of (I). Ellipsoids are rendered at the 50% probability level.
[Figure 2] Fig. 2. The one-dimensional, hydrogen-bonded chains of (I). Viewed along the a-axis. Hydrogen bonds are shown as dotted lines.
N-[(E)-Thiophen-2-ylmethylidene]-1,3-benzothiazol-2-amine top
Crystal data top
C12H8N2S2F(000) = 252
Mr = 244.32Dx = 1.502 Mg m3
Monoclinic, PcMo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2ycCell parameters from 7126 reflections
a = 10.7244 (5) Åθ = 1.9–46.7°
b = 4.6021 (2) ŵ = 0.46 mm1
c = 11.1280 (5) ÅT = 100 K
β = 100.367 (2)°Neelde, yellow
V = 540.25 (4) Å30.45 × 0.20 × 0.12 mm
Z = 2
Data collection top
Bruker APEXII CCD
diffractometer
7768 independent reflections
Radiation source: fine-focus sealed tube7126 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
φ and ω scansθmax = 46.7°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
h = 2121
Tmin = 0.625, Tmax = 0.749k = 99
14476 measured reflectionsl = 2122
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)] = 0.033H-atom parameters constrained
wR(F2) = 0.085 w = 1/[σ2(Fo2) + (0.0462P)2 + 0.0113P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
7768 reflectionsΔρmax = 0.62 e Å3
145 parametersΔρmin = 0.36 e Å3
2 restraintsAbsolute structure: Flack (1983), 2974 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.27 (3)
Crystal data top
C12H8N2S2V = 540.25 (4) Å3
Mr = 244.32Z = 2
Monoclinic, PcMo Kα radiation
a = 10.7244 (5) ŵ = 0.46 mm1
b = 4.6021 (2) ÅT = 100 K
c = 11.1280 (5) Å0.45 × 0.20 × 0.12 mm
β = 100.367 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
7768 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
7126 reflections with I > 2σ(I)
Tmin = 0.625, Tmax = 0.749Rint = 0.033
14476 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.033H-atom parameters constrained
wR(F2) = 0.085Δρmax = 0.62 e Å3
S = 1.04Δρmin = 0.36 e Å3
7768 reflectionsAbsolute structure: Flack (1983), 2974 Friedel pairs
145 parametersAbsolute structure parameter: 0.27 (3)
2 restraints
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
S10.784499 (18)0.45575 (5)0.332022 (16)0.01350 (4)
S20.443816 (19)0.29395 (6)0.120085 (18)0.01726 (4)
N10.84951 (6)0.36879 (17)0.11966 (6)0.01280 (9)
N20.66346 (7)0.11200 (17)0.15758 (6)0.01375 (10)
C41.11614 (8)0.8815 (2)0.21064 (8)0.01636 (12)
H41.18520.96700.18080.020*
C51.03822 (8)0.68618 (19)0.13798 (7)0.01428 (11)
H51.05370.63640.05910.017*
C60.93578 (7)0.56279 (17)0.18281 (7)0.01178 (10)
C70.76580 (7)0.29951 (17)0.18671 (7)0.01226 (10)
C80.63195 (8)0.02760 (18)0.04564 (7)0.01376 (11)
H80.67830.09350.01420.017*
C90.52640 (7)0.16652 (18)0.01185 (7)0.01283 (10)
C100.47648 (8)0.2709 (2)0.10331 (8)0.01632 (12)
H100.50910.22420.17490.020*
C110.37091 (9)0.4557 (2)0.10202 (9)0.01923 (14)
H110.32480.54760.17270.023*
C31.09458 (8)0.9554 (2)0.32807 (9)0.01656 (12)
H31.14941.09010.37610.020*
C20.99466 (8)0.83477 (19)0.37474 (7)0.01491 (11)
H20.98030.88410.45400.018*
C10.91594 (7)0.63843 (17)0.30119 (7)0.01210 (10)
C120.34282 (9)0.4870 (2)0.01255 (10)0.01891 (14)
H120.27500.60260.03030.023*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.01409 (7)0.01617 (8)0.01111 (6)0.00243 (6)0.00462 (5)0.00251 (6)
S20.01686 (8)0.02164 (9)0.01432 (7)0.00281 (7)0.00559 (6)0.00148 (6)
N10.0128 (2)0.0148 (2)0.0111 (2)0.00094 (18)0.00313 (16)0.00076 (18)
N20.0137 (2)0.0151 (3)0.0127 (2)0.00233 (19)0.00298 (17)0.00149 (18)
C40.0137 (3)0.0163 (3)0.0195 (3)0.0015 (2)0.0040 (2)0.0025 (2)
C50.0129 (2)0.0164 (3)0.0143 (2)0.0002 (2)0.0044 (2)0.0016 (2)
C60.0117 (2)0.0121 (3)0.0117 (2)0.00034 (18)0.00274 (18)0.00046 (18)
C70.0132 (2)0.0131 (3)0.0107 (2)0.0009 (2)0.00263 (18)0.00112 (19)
C80.0142 (3)0.0150 (3)0.0125 (2)0.0025 (2)0.0037 (2)0.0016 (2)
C90.0126 (2)0.0142 (3)0.0122 (2)0.0008 (2)0.00370 (19)0.00131 (19)
C100.0152 (3)0.0208 (3)0.0138 (3)0.0033 (2)0.0047 (2)0.0044 (2)
C110.0140 (3)0.0229 (4)0.0211 (3)0.0032 (3)0.0041 (2)0.0073 (3)
C30.0140 (3)0.0156 (3)0.0195 (3)0.0028 (2)0.0012 (2)0.0005 (2)
C20.0147 (3)0.0147 (3)0.0151 (3)0.0013 (2)0.0020 (2)0.0022 (2)
C10.0119 (2)0.0123 (3)0.0122 (2)0.00014 (19)0.00249 (18)0.00036 (19)
C120.0143 (3)0.0185 (3)0.0249 (4)0.0031 (2)0.0062 (3)0.0015 (3)
Geometric parameters (Å, º) top
S1—C11.7279 (8)C6—C11.4152 (10)
S1—C71.7480 (7)C8—C91.4379 (11)
S2—C121.7111 (10)C8—H80.9500
S2—C91.7213 (8)C9—C101.3830 (11)
N1—C71.3058 (10)C10—C111.4183 (13)
N1—C61.3831 (10)C10—H100.9500
N2—C81.2904 (10)C11—C121.3694 (15)
N2—C71.3879 (10)C11—H110.9500
C4—C51.3844 (12)C3—C21.3880 (12)
C4—C31.4091 (13)C3—H30.9500
C4—H40.9500C2—C11.3966 (11)
C5—C61.4055 (11)C2—H20.9500
C5—H50.9500C12—H120.9500
C1—S1—C788.76 (4)C10—C9—S2111.59 (6)
C12—S2—C991.61 (4)C8—C9—S2120.57 (6)
C7—N1—C6109.46 (6)C9—C10—C11112.06 (8)
C8—N2—C7118.12 (7)C9—C10—H10124.0
C5—C4—C3121.06 (8)C11—C10—H10124.0
C5—C4—H4119.5C12—C11—C10112.47 (8)
C3—C4—H4119.5C12—C11—H11123.8
C4—C5—C6118.89 (7)C10—C11—H11123.8
C4—C5—H5120.6C2—C3—C4121.13 (8)
C6—C5—H5120.6C2—C3—H3119.4
N1—C6—C5125.08 (7)C4—C3—H3119.4
N1—C6—C1115.64 (7)C3—C2—C1117.74 (8)
C5—C6—C1119.28 (7)C3—C2—H2121.1
N1—C7—N2127.91 (7)C1—C2—H2121.1
N1—C7—S1116.87 (6)C2—C1—C6121.90 (7)
N2—C7—S1115.22 (6)C2—C1—S1128.84 (6)
N2—C8—C9119.77 (7)C6—C1—S1109.26 (6)
N2—C8—H8120.1C11—C12—S2112.27 (7)
C9—C8—H8120.1C11—C12—H12123.9
C10—C9—C8127.83 (7)S2—C12—H12123.9
C3—C4—C5—C60.46 (13)C8—C9—C10—C11179.24 (9)
C7—N1—C6—C5179.28 (8)S2—C9—C10—C110.19 (11)
C7—N1—C6—C10.46 (10)C9—C10—C11—C120.20 (13)
C4—C5—C6—N1178.98 (8)C5—C4—C3—C20.04 (14)
C4—C5—C6—C10.76 (12)C4—C3—C2—C10.22 (13)
C6—N1—C7—N2179.97 (8)C3—C2—C1—C60.10 (12)
C6—N1—C7—S11.01 (9)C3—C2—C1—S1179.40 (7)
C8—N2—C7—N112.23 (13)N1—C6—C1—C2179.17 (7)
C8—N2—C7—S1168.73 (7)C5—C6—C1—C20.60 (12)
C1—S1—C7—N11.00 (7)N1—C6—C1—S10.26 (9)
C1—S1—C7—N2179.84 (6)C5—C6—C1—S1179.98 (6)
C7—N2—C8—C9179.96 (7)C7—S1—C1—C2178.73 (8)
N2—C8—C9—C10177.50 (9)C7—S1—C1—C60.64 (6)
N2—C8—C9—S21.47 (12)C10—C11—C12—S20.12 (12)
C12—S2—C9—C100.10 (8)C9—S2—C12—C110.01 (8)
C12—S2—C9—C8179.23 (7)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···S2i0.952.923.517 (1)122 (1)
Symmetry code: (i) x, y1, z1/2.

Experimental details

Crystal data
Chemical formulaC12H8N2S2
Mr244.32
Crystal system, space groupMonoclinic, Pc
Temperature (K)100
a, b, c (Å)10.7244 (5), 4.6021 (2), 11.1280 (5)
β (°) 100.367 (2)
V3)540.25 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.46
Crystal size (mm)0.45 × 0.20 × 0.12
Data collection
DiffractometerBruker APEXII CCD
Absorption correctionMulti-scan
(SADABS; Bruker, 2010)
Tmin, Tmax0.625, 0.749
No. of measured, independent and
observed [I > 2σ(I)] reflections
14476, 7768, 7126
Rint0.033
(sin θ/λ)max1)1.024
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.033, 0.085, 1.04
No. of reflections7768
No. of parameters145
No. of restraints2
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.62, 0.36
Absolute structureFlack (1983), 2974 Friedel pairs
Absolute structure parameter0.27 (3)

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), WinGX (Farrugia, 1999), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···S2i0.952.9223.517 (1)121.9 (1)
Symmetry code: (i) x, y1, z1/2.
 

Acknowledgements

We are grateful to the University of KwaZulu-Natal and the National Research Foundation of South Africa for funding.

References

First citationBruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDing, Q., He, X. & Wu, J. (2009). J. Comb. Chem. 11, 587–591.  Web of Science CrossRef PubMed CAS Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationGarcia-Hernandez, Z., Flores-Parra, A., Grevy, J. M., Ramos-Organillo, A. & Contreras, R. (2006). Polyhedron, 25, 1662–1672.  Web of Science CSD CrossRef CAS Google Scholar
First citationO'Brien, S. E., Browne, H. L., Bradshaw, T. D., Westwell, A. D. & Stevens, M. F. (2003). Org. Biomol. Chem. 1, 493–497.  Web of Science PubMed CAS Google Scholar
First citationPattan, S. R., Suresh, C., Pujar, V. D., Reddy, V. V., Rasal, V. P. & Kotti, B. C. (2005). Indian J. Chem. Sect. B, 4, 2404–2408.  Google Scholar
First citationRacane, L., Tralic-Kulenovic, V., Fiser-Jakic, L. & Boykin, D. W. (2001). Heterocycles, 55, 2085–2089.  CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSingh, S. P. & Seghal, S. (1988). Indian J. Chem. 27, 941–945.  Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationYadav, S. K. & Malipatil, S. M. (2011). IJDDHR, 1, 42–43.  Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds