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ISSN: 2056-9890

Crystal structure of 3-[2-(1,3-thia­zol-2-yl)diazen-1-yl]pyridine-2,6-di­amine monohydrate

aDepartment of Chemistry, Faculty of Science, Naresuan University, Muang, Phitsanulok 65000, Thailand, bDepartment of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand, and cMaterials and Textile Technology, Faculty of Science and Technology, Thammasat University, Khlong Luang, Pathum Thani 12121, Thailand
*Correspondence e-mail: ratanonc@nu.ac.th

Edited by M. Weil, Vienna University of Technology, Austria (Received 13 February 2018; accepted 22 March 2018; online 27 March 2018)

In the title hydrated azo compound, C8H8N6S·H2O, the two aromatic groups are close to coplanar with the dihedral angle between the mean planes of the thia­zole and pyridine rings being 2.9 (2)°. The organic mol­ecule adopts an E configuration with respect to the double bond of the azo bridge. In the crystal, mol­ecules are linked by (amine)N—H⋯N(pyridine), (amine)N—H⋯O(water) and (water)O—H⋯N(thia­zole) hydrogen bonds along with ππ inter­actions involving pairs of thia­zole rings and pairs of pyridine rings. The plane-to-plane distance between two parallel mol­ecules is 3.7856 (4) Å and corresponds to the length of the a axis. In this way, a layer structure parallel to (010) is formed. The layers are linked by weak C—H⋯S hydrogen bonds, eventually resulting in a three-dimensional network.

1. Chemical context

Azo compounds are one of the most important organic dyes used in industrial applications to colour various consumer goods such as leather, plastics and cosmetics (Kaur et al., 2018[Kaur, B., Kaur, N. & Kumar, S. (2018). Coord. Chem. Rev. 358, 13-69.]). The main characteristic of these compounds is the chromophore of the azo group (–N=N–), which is responsible for the color of the dyes. Compounds with an aromatic thia­zolylazo moiety are a subclass of azo dyes, which contain the thia­zole group on one side of the azo linkage and are important ligands in coordination chemistry (Kaim, 2001[Kaim, W. (2001). Coord. Chem. Rev. 219-221, 463-488.]). In this regard, zinc complexes with polydentate chelating thia­zolylazo ligands have been prepared as luminescence probes for selectively sensing phosphates (Hens et al., 2015[Hens, A., Mondal, P. & Rajak, K. K. (2015). Polyhedron, 85, 255-266.]). Recently, Piyasaengthong et al. (2015[Piyasaengthong, A., Boonyalai, N., Suramitr, S. & Songsasen, A. (2015). Inorg. Chem. Commun. 59, 88-90.]) reported the synthesis of a gold(III) complex of 3-(2′-thia­zolylazo)-2,6-di­amino­pyridine and investigated its pepsin inhibition.

[Scheme 1]

We report here the crystal structure of 3-(2′-thia­zolylazo)-2,6-di­amino­pyridine monohydrate, C8H8N6S·H2O, (I)[link], obtained through the diazo­tization of 2-amino­thia­zole followed by a coupling reaction with 2,6-di­amino­pyridine (Montelongo et al., 1982[Montelongo, F. G., Díaz, V. G. & González, C. R. T. (1982). Microchem. J. 27, 194-199.]).

2. Structural commentary

The mol­ecular entities of (I)[link] with atom labelling are presented in Fig. 1[link]. The organic mol­ecule has an E configuration with respect to the azo bridge (–N2=N3–), and is essentially planar with an r.m.s deviation of the fitted non-hydrogen atoms being 0.033 Å. The amine N5 and N6 atoms are 0.044 (2) and −0.059 (3) Å, respectively, out of this plane. The thia­zole ring (C1–C3, N1, S1) makes a dihedral angle of 2.9 (2)° with the pyridine ring (C4–C8, N4). An intra­molecular N5—H5A⋯N2 hydrogen bond is observed (Table 1[link]), showing an S(6) ring motif.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C2—H2⋯S1i 0.93 3.02 3.665 (3) 128
N5—H5A⋯N2 0.86 (1) 2.03 (3) 2.645 (4) 128 (3)
N5—H5A⋯O1 0.86 (1) 2.59 (2) 3.314 (4) 143 (3)
N5—H5B⋯N4ii 0.86 (1) 2.14 (1) 2.998 (4) 172 (3)
N6—H6A⋯O1ii 0.86 (1) 2.27 (2) 3.048 (4) 151 (4)
N6—H6B⋯O1iii 0.86 (1) 2.13 (1) 2.988 (4) 177 (4)
O1—H1A⋯N1 0.84 (1) 2.13 (3) 2.923 (4) 158 (6)
O1—H1B⋯N2iv 0.84 (1) 2.31 (2) 3.143 (4) 170 (9)
Symmetry codes: (i) [x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]; (ii) -x+1, -y+1, -z+1; (iii) x-1, y, z+1; (iv) x+1, y, z.
[Figure 1]
Figure 1
The mol­ecular structure of the organic entity and the water mol­ecule in compound (I)[link], with the atom labelling and displacement ellipsoids drawn at the 50% probability level.

3. Supra­molecular features

In the crystal of (I)[link], extensive (amine)N—H⋯N(pyridine), (amine)N—H⋯O(water) and (water)O—H⋯N(thia­zole) hydrogen bonds (Table 1[link]) are present. Together with ππ inter­actions involving pairs of thia­zole rings and pairs of pyridine rings with a plane-to-plane distance between two parallel mol­ecules of 3.7856 (4) Å, a layered structure parallel to the ac plane is formed (Fig. 2[link]). Weak C—H⋯S hydrogen bonds between adjacent thia­zole rings further consolidate the crystal packing, thus generating a three-dimensional network.

[Figure 2]
Figure 2
The unit-cell packing in (I)[link] , viewed approximately down [100]. The classical O—H⋯N, and N—H⋯O hydrogen bonds are shown as green dashed lines (see Table 1[link] for numerical details).

4. Database survey

A search of the Cambridge Structural Database (Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for compounds with the (E)-2-(pyridin-3-yldiazen­yl)thia­zole moiety gave no hits. However, structures of substituted thia­zolylazo derivatives were found, for example, 5-(di­ethyl­amino)-2-(2-thia­zolylazo)phenol (QAVNAD; Zhang et al., 2005[Zhang, G., Wang, S., Gan, Q., Zhang, Y., Yang, G., Shi Ma, J. & Xu, H. (2005). Eur. J. Inorg. Chem. pp. 4186-4192.]), 4-(2′-thia­zolylazo)pyrocatechol (TZAZPC; Apinitis, 1978[Apinitis, S. K. (1978). J. Struct. Chem. 19, 158-161.]), 1-(2-thia­zolylazo)-6-bromo-2-naphthol (TAZBRN10; Kurahashi et al., 1976[Kurahashi, M., Fukuyo, M., Shimada, A. & Kawase, A. (1976). Bull. Chem. Soc. Jpn, 49, 872-875.]) and 1-(2-thia­zolylazo)-2-naphthol (TAZNPL10; Kurahashi, 1976[Kurahashi, M. (1976). Bull. Chem. Soc. Jpn, 49, 2927-2933.]).

5. Synthesis and crystallization

2-Amino­thia­zole (1.0 g, 0.009 mol) was dissolved in 6 M hydro­chloric acid (16 ml) with sodium nitrite (0.7 g, 0.01 mol). The mixture was stirred at a temperature between 268 and 273 K while a solution of 2,6-di­amino­pyridine (1.0 g, 0.009 mol) in 40 ml of 4 M hydro­chloric acid was added. The reaction mixture was stirred for 1 h and then adjusted to pH 6.0 by 0.001 M sodium hydroxide. The red precipitate formed was filtered through suction and washed with water. Suitable crystals for X-ray analysis were grown by recrystallization using the vapor diffusion technique in a methanol-hexane mixture at 253 K [yield 1.12 g, 51%]. 1H NMR (400 MHz, 298 K, C2D6OS): δ 6.10 (d, m-ArH py, 1H), 7.39 (d, thia­zole-H, 1H), 7.55 (d, p-ArH py, 1H), 7.703 (d, thia­zole-H, 1H). Mass spec. (ESI) m/z 220.9 (M+), 136.2, 108.3, 81.4. IR–KBr (cm−1): 3335 (w), 3217 (w), 3082 (w), 1660 (s), 1631 (s), 1454 (m), 1292 (s), 1159 (m). Analysis calculated for C8H10N6OS: C, 43.64; H, 3.66; N, 38.16; 14.56. Found: C, 43.80; H, 3.79; N, 38.45; S,14.78.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. H atoms bonded to O and N atoms were located in difference-Fourier maps and refined with distance restraints of 0.84±0.02 Å with Uiso(H) = 1.5Ueq(O) and 0.86±0.02 Å with Uiso(H) = 1.2Ueq(N), respectively. The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.93 Å with Uiso(H) = 1.2Ueq(C).

Table 2
Experimental details

Crystal data
Chemical formula C8H8N6S·H2O
Mr 238.28
Crystal system, space group Monoclinic, P21/n
Temperature (K) 296
a, b, c (Å) 3.7856 (4), 28.393 (3), 9.6324 (9)
β (°) 93.824 (3)
V3) 1033.02 (17)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.30
Crystal size (mm) 0.28 × 0.08 × 0.04
 
Data collection
Diffractometer Bruker D8 QUEST CMOS
Absorption correction Multi-scan (SADABS; Bruker, 2016[Bruker (2016). APEX3, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.644, 0.745
No. of measured, independent and observed [I > 2σ(I)] reflections 11837, 2100, 1670
Rint 0.054
(sin θ/λ)max−1) 0.630
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.061, 0.121, 1.17
No. of reflections 2100
No. of parameters 169
No. of restraints 6
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.33, −0.26
Computer programs: APEX3 and SAINT (Bruker, 2016[Bruker (2016). APEX3, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2014 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Supporting information


Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

3-[2-(1,3-Thiazol-2-yl)diazen-1-yl]pyridine-2,6-diamine monohydrate top
Crystal data top
C8H8N6S·H2OF(000) = 496
Mr = 238.28Dx = 1.532 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 3.7856 (4) ÅCell parameters from 4156 reflections
b = 28.393 (3) Åθ = 3.0–26.6°
c = 9.6324 (9) ŵ = 0.30 mm1
β = 93.824 (3)°T = 296 K
V = 1033.02 (17) Å3Needle, dark orange
Z = 40.28 × 0.08 × 0.04 mm
Data collection top
Bruker D8 QUEST CMOS
diffractometer
2100 independent reflections
Radiation source: microfocus sealed x-ray tube, Incoatec Iµus1670 reflections with I > 2σ(I)
GraphiteDouble Bounce Multilayer Mirror monochromatorRint = 0.054
Detector resolution: 10.5 pixels mm-1θmax = 26.6°, θmin = 3.6°
ω and φ scansh = 44
Absorption correction: multi-scan
(SADABS; Bruker, 2016)
k = 3535
Tmin = 0.644, Tmax = 0.745l = 1211
11837 measured reflections
Refinement top
Refinement on F2Primary atom site location: dual
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.061H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.121 w = 1/[σ2(Fo2) + (0.0131P)2 + 1.7616P]
where P = (Fo2 + 2Fc2)/3
S = 1.17(Δ/σ)max < 0.001
2100 reflectionsΔρmax = 0.33 e Å3
169 parametersΔρmin = 0.26 e Å3
6 restraints
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
S10.1445 (2)0.72666 (3)0.18385 (9)0.0377 (2)
N10.4021 (8)0.65791 (9)0.0492 (3)0.0356 (6)
N20.2953 (7)0.63596 (9)0.2749 (3)0.0317 (6)
N30.1805 (7)0.65155 (9)0.3905 (3)0.0310 (6)
N40.2611 (7)0.54434 (8)0.6116 (3)0.0299 (6)
N50.4246 (8)0.55257 (10)0.3899 (3)0.0379 (7)
N60.1041 (9)0.53404 (10)0.8343 (3)0.0437 (8)
C10.2378 (10)0.73517 (12)0.0133 (4)0.0415 (8)
H10.20220.76320.03550.050*
C20.3691 (10)0.69560 (12)0.0395 (4)0.0409 (8)
H20.43370.69390.13080.049*
C30.2931 (8)0.66920 (10)0.1706 (3)0.0303 (7)
C40.1707 (8)0.62052 (10)0.4978 (3)0.0284 (7)
C50.2873 (8)0.57206 (10)0.4993 (3)0.0279 (7)
C60.1248 (8)0.56226 (10)0.7246 (3)0.0306 (7)
C70.0081 (9)0.60975 (11)0.7330 (3)0.0342 (7)
H70.08450.62120.81340.041*
C80.0359 (8)0.63760 (11)0.6209 (3)0.0335 (7)
H80.03570.66890.62500.040*
O10.7912 (8)0.56959 (9)0.0910 (3)0.0489 (7)
H5A0.471 (9)0.5698 (10)0.320 (2)0.040 (10)*
H5B0.504 (9)0.5242 (6)0.397 (4)0.047 (11)*
H6A0.166 (10)0.5050 (5)0.826 (4)0.058 (12)*
H6B0.022 (10)0.5438 (12)0.910 (2)0.052 (12)*
H1A0.647 (12)0.5905 (15)0.062 (6)0.11 (2)*
H1B0.936 (19)0.584 (3)0.145 (8)0.23 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0472 (5)0.0283 (4)0.0375 (5)0.0039 (4)0.0011 (4)0.0003 (3)
N10.0457 (16)0.0316 (14)0.0299 (15)0.0034 (12)0.0044 (13)0.0004 (11)
N20.0362 (15)0.0295 (13)0.0295 (15)0.0017 (11)0.0028 (12)0.0031 (11)
N30.0332 (14)0.0286 (13)0.0313 (15)0.0013 (11)0.0018 (12)0.0008 (11)
N40.0342 (14)0.0265 (13)0.0292 (14)0.0033 (11)0.0048 (12)0.0011 (10)
N50.0555 (19)0.0264 (14)0.0331 (16)0.0100 (13)0.0127 (14)0.0034 (12)
N60.064 (2)0.0359 (16)0.0331 (17)0.0112 (15)0.0151 (15)0.0028 (13)
C10.053 (2)0.0324 (17)0.037 (2)0.0067 (15)0.0083 (17)0.0076 (14)
C20.054 (2)0.0386 (18)0.0298 (18)0.0102 (16)0.0034 (16)0.0041 (14)
C30.0321 (17)0.0261 (15)0.0323 (18)0.0027 (12)0.0002 (14)0.0006 (12)
C40.0305 (16)0.0259 (14)0.0287 (16)0.0015 (12)0.0006 (13)0.0007 (12)
C50.0273 (15)0.0266 (15)0.0300 (17)0.0002 (12)0.0028 (13)0.0027 (12)
C60.0309 (16)0.0309 (16)0.0301 (17)0.0002 (13)0.0033 (14)0.0002 (12)
C70.0392 (18)0.0327 (16)0.0314 (18)0.0054 (14)0.0082 (15)0.0043 (13)
C80.0376 (18)0.0272 (15)0.0355 (19)0.0065 (13)0.0021 (15)0.0019 (13)
O10.0621 (18)0.0385 (14)0.0474 (16)0.0045 (13)0.0123 (14)0.0006 (12)
Geometric parameters (Å, º) top
S1—C11.720 (4)N6—H6A0.863 (10)
S1—C31.733 (3)N6—H6B0.860 (10)
N1—C21.370 (4)C1—H10.9300
N1—C31.305 (4)C1—C21.342 (5)
N2—N31.300 (3)C2—H20.9300
N2—C31.379 (4)C4—C51.445 (4)
N3—C41.360 (4)C4—C81.408 (4)
N4—C51.347 (4)C6—C71.423 (4)
N4—C61.336 (4)C7—H70.9300
N5—C51.326 (4)C7—C81.348 (4)
N5—H5A0.858 (10)C8—H80.9300
N5—H5B0.861 (10)O1—H1A0.841 (10)
N6—C61.333 (4)O1—H1B0.840 (10)
C1—S1—C388.47 (16)N1—C3—N2119.9 (3)
C3—N1—C2110.2 (3)N2—C3—S1125.2 (2)
N3—N2—C3113.9 (2)N3—C4—C5126.9 (3)
N2—N3—C4117.2 (2)N3—C4—C8116.5 (3)
C6—N4—C5119.0 (2)C8—C4—C5116.5 (3)
C5—N5—H5A120 (2)N4—C5—C4121.7 (3)
C5—N5—H5B119 (2)N5—C5—N4116.6 (3)
H5A—N5—H5B121 (3)N5—C5—C4121.7 (3)
C6—N6—H6A118 (3)N4—C6—C7123.0 (3)
C6—N6—H6B122 (3)N6—C6—N4117.6 (3)
H6A—N6—H6B120 (4)N6—C6—C7119.3 (3)
S1—C1—H1124.8C6—C7—H7121.0
C2—C1—S1110.4 (3)C8—C7—C6118.0 (3)
C2—C1—H1124.8C8—C7—H7121.0
N1—C2—H2122.0C4—C8—H8119.2
C1—C2—N1116.0 (3)C7—C8—C4121.6 (3)
C1—C2—H2122.0C7—C8—H8119.2
N1—C3—S1114.9 (2)H1A—O1—H1B104 (7)
S1—C1—C2—N10.1 (4)C2—N1—C3—N2178.4 (3)
N2—N3—C4—C52.5 (5)C3—S1—C1—C20.0 (3)
N2—N3—C4—C8178.2 (3)C3—N1—C2—C10.2 (5)
N3—N2—C3—S11.5 (4)C3—N2—N3—C4179.2 (3)
N3—N2—C3—N1180.0 (3)C5—N4—C6—N6179.6 (3)
N3—C4—C5—N4179.3 (3)C5—N4—C6—C70.7 (5)
N3—C4—C5—N50.5 (5)C5—C4—C8—C71.8 (5)
N3—C4—C8—C7178.8 (3)C6—N4—C5—N5179.9 (3)
N4—C6—C7—C80.3 (5)C6—N4—C5—C40.3 (4)
N6—C6—C7—C8179.3 (3)C6—C7—C8—C41.0 (5)
C1—S1—C3—N10.1 (3)C8—C4—C5—N41.4 (4)
C1—S1—C3—N2178.5 (3)C8—C4—C5—N5178.8 (3)
C2—N1—C3—S10.2 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···S1i0.933.023.665 (3)128
N5—H5A···N20.86 (1)2.03 (3)2.645 (4)128 (3)
N5—H5A···O10.86 (1)2.59 (2)3.314 (4)143 (3)
N5—H5B···N4ii0.86 (1)2.14 (1)2.998 (4)172 (3)
N6—H6A···O1ii0.86 (1)2.27 (2)3.048 (4)151 (4)
N6—H6B···O1iii0.86 (1)2.13 (1)2.988 (4)177 (4)
O1—H1A···N10.84 (1)2.13 (3)2.923 (4)158 (6)
O1—H1B···N2iv0.84 (1)2.31 (2)3.143 (4)170 (9)
Symmetry codes: (i) x+1/2, y+3/2, z1/2; (ii) x+1, y+1, z+1; (iii) x1, y, z+1; (iv) x+1, y, z.
 

Funding information

RC and BB thank the Faculty of Science, Naresuan University for financial support. AS thanks the Development and Promotion of Science and Technology Talents Project (DPST) for a scholarship. The authors thank the Faculty of Science and Technology, Thammasat University, for funds to purchase the X-ray diffractometer.

References

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