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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 69| Part 2| February 2013| Pages o227-o228

N-(5-Amino-1H-1,2,4-triazol-3-yl)pyridine-2-carboxamide

aDepartament de Química Inorgànica, Universitat de València, Vicent Andrés Estellés s/n, 46100 Burjassot, València, Spain, bDepartament de Química Orgànica, Universitat de València, Vicent Andrés Estellés s/n, 46100 Burjassot, València, Spain, and cDeptament de Química Inorgánica, Universitat de Santiago de Compostela, Campus vida, Santiago de Compostela, Galicia, 15782, Spain
*Correspondence e-mail: alfonso.castineiras@usc.es

(Received 18 December 2012; accepted 2 January 2013; online 12 January 2013)

The title compound, C8H8N6O, was obtained by the reaction of 3,5-diamino-1,2,4-triazole with ethyl 2-picolinate in a glass oven. The dihedral angles formed between the plane of the amide group and the pyridine and triazole rings are 11.8 (3) and 5.8 (3)°, respectively. In the crystal, an extensive system of classical N—H⋯N and N—H⋯O hydrogen bonds generate an infinite three-dimensional network.

Related literature

For background to triazole derivatives, see: Aromí et al. (2011[Aromí, G., Barrios, L., Roubeuau, O. & Gámez, P. (2011). Coord. Chem. Rev. 255, 485-546.]); Olguín et al. (2012[Olguín, J., Kalisz, J. M., Clé, R. & Brooker, S. (2012). Inorg. Chem. 51, 5058-5069.]). For related triazole structures, see: Allouch et al. (2008[Allouch, F., Zouari, F., Chabchoub, F. & Salem, M. (2008). Acta Cryst. E64, o684.]); Ouakkaf et al. (2011[Ouakkaf, A., Berrah, F., Bouacida, S. & Roisnel, T. (2011). Acta Cryst. E67, o1171-o1172.]). For structures of metal complexes with related triazoles, see: Ferrer et al. (2004[Ferrer, S., Ballesteros, R., Sambartolomé, A., González, M., Alzuet, M. G., Borrás, J. & Liu, M. (2004). J. Inorg. Biochem. 98, 1436-1446.], 2012[Ferrer, S., Lloret, F., Pardo, E., Clemente-Juan, J. M., Liu-González, M. & García-Granda, S. (2012). Inorg. Chem. 51, 985-1001.]). For the synthesis of triazoles, see: Chernyshev et al. (2005[Chernyshev, V. M., Rakitov, V. A., Taranushich, V. A. & Blinov, V. V. (2005). Chem. Heterocycl. Compd, 41, 1139-1146.]). For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C8H8N6O

  • Mr = 204.20

  • Tetragonal, P 41 21 2

  • a = 9.5480 (5) Å

  • c = 21.9570 (9) Å

  • V = 2001.69 (17) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 293 K

  • 0.15 × 0.09 × 0.05 mm

Data collection
  • Nonius KappaCCD diffractometer

  • 4484 measured reflections

  • 1407 independent reflections

  • 915 reflections with I > 2σ(I)

  • Rint = 0.048

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.107

  • S = 1.07

  • 1407 reflections

  • 137 parameters

  • H-atom parameters constrained

  • Δρmax = 0.12 e Å−3

  • Δρmin = −0.13 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N21—H21⋯N23i 0.86 2.02 2.788 (3) 149
N21—H21⋯O17i 0.86 2.41 3.061 (3) 133
N18—H18⋯N20ii 0.86 2.45 3.253 (3) 155
N22—H22A⋯O17i 0.86 2.08 2.860 (3) 150
N22—H22B⋯N20iii 0.86 2.26 3.068 (3) 157
Symmetry codes: (i) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 4}}]; (ii) [-y, -x, -z+{\script{1\over 2}}]; (iii) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 4}}].

Data collection: COLLECT (Nonius, 1998[Nonius (1998). COLLECT. Nonius BV, Delft. The Netherlands.]); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzimology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Cortes Jr & R. M. Sweet, pp 307-326. New York: Academic Press.]); data reduction: DENZO and SCALEPACK; 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: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and DIAMOND (Brandenburg & Putz, 2006[Brandenburg, K. & Putz, H. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

A significantly large variety of 1,2,4-triazole-based compounds have been prepared to serve as ligands with the aim of obtaining discrete polynuclear metal complexes or polymeric coordination networks, owing to the ability of the 1,2,4-triazole ring to bridge metal ions through different coordination ways (Aromí et al., 2011; Olguín et al., 2012). Usually the 1,2,4-triazole-based family of ligands are classified in three categories (Aromí et al., 2011): (a) those containing an unique coordinative ring, (b) those possessing two or more coordinative rings linked by a spacer, and (c) the mixed ligands, which present two or more functional groups. Most of the 3,5-disubstituted derivatives can be included in the last category (Allouch et al., 2008; Ouakkaf et al., 2011).

Our group has been reporting on the synthesis and structure of some 3,5-disubstituted triazole-based ligands, i.e. 5-amino-3-pyridin-2-yl-1,2,4-triazole (Ferrer et al., 2004) and 3-acetylamino-5-amino-1,2,4-triazole (Ferrer et al., 2012). In those cases, single crystals of the ligands suitable for X-ray analysis were not obtained. Instead, crystal structures of some of their CuII complexes could be determined, thus confirming the structure of the triazole, either in neutral or in anionic form. In this work we describe a novel compound of this series, namely: 5-amino-3-picolinamido-1H-1,2,4-triazole or 5-amino-3-(pyridin-2-yl-acetamido)-1H-1,2,4-triazole (abbreviated as H2V to account for the presence of two acidic H atoms), for which it has been possible to solve the crystal structure.

The obtained H2V species is an attractive ligand since it presents 5 to 7 donor atoms (depending on the degree of deprotonation) but also the possibility of forming different chelating rings when coordinated to metals. Besides, in metal complexes the pyridyl ring often rotates around the single C–C bond leading to different binding conformations (Ouakkaf et al., 2011). This enlarges its capability to produce novel metal-organic structures.

As shown in Figure 1, the NH hydrogen is trans to the C=O group, as is observed for all N monosustituted amides. Molecular dimensions, such as the C=O bond length of 1.227 (3) Å and the central C–N–C amide angle of 127.40 (17)°, may be considered normal.

In the crystal packing, the triazole ligands are linked by pairs of weak N—H···N hydrogen bonds involving the H18 and N20 atoms, thus generating a characteristic R22(8) ring motif (Bernstein et al., 1995) (Fig. 2). Moreover, the molecules are also linked by N—H···N and N—H···O hydrogen bonds, forming fused non-centrosymmetric rings R22(7), R21(6) and R12(6) and giving rise to one-dimensional tapes parallel to the [010] and [100] directions (Fig. 3). These tapes joined by the R22(8) motif of N-H···N hydrogen bonds form a three dimensional framework (Fig.4).

Related literature top

For background to triazole derivatives, see: Aromí et al. (2011); Olguín et al. (2012). For related triazole structures, see: Allouch et al. (2008); Ouakkaf et al. (2011). For structures of metal complexes with related triazoles, see: Ferrer et al. (2004, 2012). For the synthesis of triazoles, see: Chernyshev et al. (2005). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

An evaporating flask containing 3,5-diamino-1,2,4-triazole (41.4 mmol, 4.10 g) and ethyl 2-picolinate (6.3 ml, 7 g, 46.3 mmol) was connected to a glass oven and the reaction temperature was slowly raised to 210 °C. The mixture was stirred (rotated) for 4 h. At this point, a vacuum pump was connected during 60 minutes to remove the excess of ethyl 2-picolinate. Afterwards, the reaction was cooled down to room temperature and the mixture solidified. The crude product was washed with ethanol and acetone and then recrystallized from methanol to give analytically pure crystals.

Refinement top

All H atoms were positioned geometrically and were treated as riding on their parent atoms, with C—H distances of 0.93 Å and N—H distances of 0.86 Å with Uiso(H) = 1.2Ueq(C/N). In the absence of significant anomalous dispersion, Friedel pairs were merged.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title molecule with atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radii.
[Figure 2] Fig. 2. Scheme with details of the crossing of two chains of molecules (along the cb plane). Hydrogen bonds are shown as dashed lines. Symmetry code: (ii) -y, -x, -z + 1/2
[Figure 3] Fig. 3. Tapes of title molecules via N—H···N and N—H···O interactions seen along the [100] direction. Hydrogen bonds are shown as orange dashed lines.
[Figure 4] Fig. 4. A view of the unit-cell content of the title compound in projection down the b axis. Hydrogen bonds are shown as dashed lines.
N-(5-Amino-1H-1,2,4-triazol-3-yl)pyridine-2-carboxamide top
Crystal data top
C8H8N6ODx = 1.355 Mg m3
Mr = 204.20Melting point: 494(1) K
Tetragonal, P41212Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 4abw 2nwCell parameters from 2353 reflections
a = 9.5480 (5) Åθ = 1.0–27.5°
c = 21.9570 (9) ŵ = 0.10 mm1
V = 2001.69 (17) Å3T = 293 K
Z = 8Prism, colourless
F(000) = 8480.15 × 0.09 × 0.05 mm
Data collection top
Nonius KappaCCD
diffractometer
915 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.048
Graphite monochromatorθmax = 27.5°, θmin = 2.3°
Detector resolution: 9 pixels mm-1h = 1212
ω and phi scansk = 88
4484 measured reflectionsl = 2827
1407 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.107 w = 1/[σ2(Fo2) + (0.0557P)2 + 0.0085P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
1407 reflectionsΔρmax = 0.12 e Å3
137 parametersΔρmin = 0.13 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.013 (2)
Crystal data top
C8H8N6OZ = 8
Mr = 204.20Mo Kα radiation
Tetragonal, P41212µ = 0.10 mm1
a = 9.5480 (5) ÅT = 293 K
c = 21.9570 (9) Å0.15 × 0.09 × 0.05 mm
V = 2001.69 (17) Å3
Data collection top
Nonius KappaCCD
diffractometer
915 reflections with I > 2σ(I)
4484 measured reflectionsRint = 0.048
1407 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.107H-atom parameters constrained
S = 1.07Δρmax = 0.12 e Å3
1407 reflectionsΔρmin = 0.13 e Å3
137 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
O170.1793 (2)0.33529 (18)0.25244 (8)0.0726 (6)
N110.0462 (3)0.1210 (3)0.36912 (9)0.0708 (7)
N180.1596 (2)0.09855 (19)0.25946 (8)0.0513 (5)
H180.13990.03180.28430.062*
N200.2076 (2)0.0746 (2)0.18712 (8)0.0495 (5)
N210.2450 (2)0.0695 (2)0.12653 (8)0.0503 (5)
H210.25930.14120.10360.060*
N220.2887 (3)0.1049 (2)0.05253 (9)0.0797 (9)
H22A0.30460.04380.02460.096*
H22B0.29390.19280.04420.096*
N230.2279 (2)0.14920 (19)0.15549 (8)0.0543 (6)
C120.0006 (4)0.1273 (4)0.42633 (13)0.0885 (11)
H120.03870.04670.44340.106*
C130.0043 (4)0.2465 (4)0.46156 (14)0.0871 (10)
H130.02880.24600.50140.104*
C140.0583 (5)0.3637 (4)0.43690 (15)0.1011 (12)
H140.06270.44580.45960.121*
C150.1072 (4)0.3613 (3)0.37768 (13)0.0877 (11)
H150.14510.44120.35990.105*
C160.0983 (3)0.2377 (3)0.34567 (11)0.0585 (7)
C170.1488 (3)0.2302 (3)0.28160 (11)0.0541 (6)
C190.1992 (2)0.0590 (2)0.20093 (10)0.0463 (6)
C220.2557 (3)0.0633 (2)0.10904 (10)0.0503 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O170.1132 (17)0.0408 (10)0.0639 (11)0.0008 (10)0.0054 (11)0.0032 (9)
N110.0937 (19)0.0633 (16)0.0552 (13)0.0053 (13)0.0148 (12)0.0079 (11)
N180.0701 (14)0.0370 (11)0.0468 (11)0.0015 (10)0.0061 (10)0.0016 (9)
N200.0677 (14)0.0356 (11)0.0453 (10)0.0003 (9)0.0062 (9)0.0003 (9)
N210.0723 (14)0.0345 (11)0.0442 (10)0.0013 (10)0.0061 (9)0.0020 (8)
N220.147 (3)0.0395 (13)0.0522 (13)0.0045 (14)0.0264 (15)0.0046 (10)
N230.0790 (15)0.0351 (10)0.0487 (11)0.0009 (10)0.0068 (11)0.0014 (9)
C120.115 (3)0.085 (2)0.0647 (18)0.010 (2)0.0275 (18)0.0075 (17)
C130.104 (3)0.093 (3)0.0643 (18)0.014 (2)0.0149 (17)0.0163 (19)
C140.148 (4)0.080 (3)0.076 (2)0.018 (3)0.009 (2)0.033 (2)
C150.136 (3)0.0541 (19)0.073 (2)0.0064 (19)0.0134 (19)0.0150 (16)
C160.0715 (18)0.0512 (17)0.0528 (14)0.0080 (13)0.0001 (12)0.0059 (13)
C170.0664 (16)0.0402 (14)0.0558 (14)0.0025 (12)0.0052 (12)0.0005 (12)
C190.0576 (15)0.0364 (13)0.0448 (13)0.0009 (11)0.0011 (11)0.0022 (10)
C220.0686 (17)0.0355 (13)0.0468 (13)0.0007 (12)0.0043 (12)0.0005 (11)
Geometric parameters (Å, º) top
O17—C171.225 (3)N22—H22B0.8600
N11—C161.324 (3)N23—C221.335 (3)
N11—C121.335 (3)N23—C191.347 (3)
N18—C171.352 (3)C12—C131.377 (4)
N18—C191.392 (3)C12—H120.9300
N18—H180.8600C13—C141.346 (5)
N20—C191.314 (3)C13—H130.9300
N20—N211.378 (2)C14—C151.382 (4)
N21—C221.329 (3)C14—H140.9300
N21—H210.8600C15—C161.376 (4)
N22—C221.340 (3)C15—H150.9300
N22—H22A0.8600C16—C171.489 (3)
C16—N11—C12117.0 (2)C13—C14—C15119.6 (3)
C17—N18—C19127.3 (2)C13—C14—H14120.2
C17—N18—H18116.4C15—C14—H14120.2
C19—N18—H18116.3C16—C15—C14118.3 (3)
C19—N20—N21101.78 (18)C16—C15—H15120.9
C22—N21—N20109.41 (18)C14—C15—H15120.9
C22—N21—H21125.3N11—C16—C15123.1 (2)
N20—N21—H21125.3N11—C16—C17116.7 (2)
C22—N22—H22A120.0C15—C16—C17120.2 (3)
C22—N22—H22B120.0O17—C17—N18123.7 (2)
H22A—N22—H22B120.0O17—C17—C16122.1 (2)
C22—N23—C19102.32 (19)N18—C17—C16114.1 (2)
N11—C12—C13123.7 (3)N20—C19—N23116.0 (2)
N11—C12—H12118.1N20—C19—N18119.6 (2)
C13—C12—H12118.1N23—C19—N18124.4 (2)
C14—C13—C12118.3 (3)N21—C22—N23110.5 (2)
C14—C13—H13120.8N21—C22—N22124.6 (2)
C12—C13—H13120.8N23—C22—N22124.9 (2)
C19—N20—N21—C220.1 (3)N11—C16—C17—N1812.1 (4)
C16—N11—C12—C130.8 (6)C15—C16—C17—N18167.8 (3)
N11—C12—C13—C140.6 (6)N21—N20—C19—N230.2 (3)
C12—C13—C14—C150.2 (6)N21—N20—C19—N18178.5 (2)
C13—C14—C15—C160.2 (5)C22—N23—C19—N200.5 (3)
C12—N11—C16—C150.8 (5)C22—N23—C19—N18178.2 (2)
C12—N11—C16—C17179.3 (3)C17—N18—C19—N20178.4 (2)
C14—C15—C16—N110.5 (5)C17—N18—C19—N233.0 (4)
C14—C15—C16—C17179.6 (3)N20—N21—C22—N230.4 (3)
C19—N18—C17—O173.3 (4)N20—N21—C22—N22179.1 (3)
C19—N18—C17—C16177.7 (2)C19—N23—C22—N210.5 (3)
N11—C16—C17—O17168.9 (3)C19—N23—C22—N22179.0 (3)
C15—C16—C17—O1711.3 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N21—H21···N23i0.862.022.788 (3)149
N21—H21···O17i0.862.413.061 (3)133
N18—H18···N20ii0.862.453.253 (3)155
N22—H22A···O17i0.862.082.860 (3)150
N22—H22B···N20iii0.862.263.068 (3)157
Symmetry codes: (i) x+1/2, y1/2, z+1/4; (ii) y, x, z+1/2; (iii) x+1/2, y+1/2, z+1/4.

Experimental details

Crystal data
Chemical formulaC8H8N6O
Mr204.20
Crystal system, space groupTetragonal, P41212
Temperature (K)293
a, c (Å)9.5480 (5), 21.9570 (9)
V3)2001.69 (17)
Z8
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.15 × 0.09 × 0.05
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
4484, 1407, 915
Rint0.048
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.107, 1.07
No. of reflections1407
No. of parameters137
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.12, 0.13

Computer programs: COLLECT (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and DIAMOND (Brandenburg & Putz, 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N21—H21···N23i0.862.022.788 (3)149
N21—H21···O17i0.862.413.061 (3)133
N18—H18···N20ii0.862.453.253 (3)155
N22—H22A···O17i0.862.082.860 (3)150
N22—H22B···N20iii0.862.263.068 (3)157
Symmetry codes: (i) x+1/2, y1/2, z+1/4; (ii) y, x, z+1/2; (iii) x+1/2, y+1/2, z+1/4.
 

Acknowledgements

This work was supported by the Ministerio de Educación y Ciencia (MEC, Spain) (project CTQ2007–63690/BQU) and by the Ministerio de Ciencia e Innovación and FEDER-EC (project MAT2010–15594). JHG acknowledges a PhD grant (project CTQ2007–63690/BQU, MEC, Spain). Technical support (X-ray measurements at S.C.S.I.E., University of Valencia) from M. Liu-González is gratefully acknowledged.

References

First citationAllouch, F., Zouari, F., Chabchoub, F. & Salem, M. (2008). Acta Cryst. E64, o684.  Web of Science CSD CrossRef IUCr Journals
First citationAromí, G., Barrios, L., Roubeuau, O. & Gámez, P. (2011). Coord. Chem. Rev. 255, 485–546.
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
First citationBrandenburg, K. & Putz, H. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.
First citationChernyshev, V. M., Rakitov, V. A., Taranushich, V. A. & Blinov, V. V. (2005). Chem. Heterocycl. Compd, 41, 1139–1146.  CrossRef CAS
First citationFerrer, S., Ballesteros, R., Sambartolomé, A., González, M., Alzuet, M. G., Borrás, J. & Liu, M. (2004). J. Inorg. Biochem. 98, 1436–1446.  Web of Science CSD CrossRef PubMed CAS
First citationFerrer, S., Lloret, F., Pardo, E., Clemente-Juan, J. M., Liu-González, M. & García-Granda, S. (2012). Inorg. Chem. 51, 985–1001.  Web of Science CSD CrossRef CAS PubMed
First citationNonius (1998). COLLECT. Nonius BV, Delft. The Netherlands.
First citationOlguín, J., Kalisz, J. M., Clé, R. & Brooker, S. (2012). Inorg. Chem. 51, 5058–5069.  Web of Science PubMed
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzimology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Cortes Jr & R. M. Sweet, pp 307–326. New York: Academic Press.
First citationOuakkaf, A., Berrah, F., Bouacida, S. & Roisnel, T. (2011). Acta Cryst. E67, o1171–o1172.  Web of Science CrossRef CAS IUCr Journals
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals

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Volume 69| Part 2| February 2013| Pages o227-o228
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