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

Journal logoIUCrDATA
ISSN: 2414-3146

4-(Di­methyl­amino)­benzohydrazide

CROSSMARK_Color_square_no_text.svg

aDepartment of Chemistry, University of Missouri, Columbia, MO 65211, USA, and bDepartment of Biochemistry, University of Missouri, Columbia, MO 65211, USA
*Correspondence e-mail: MossineV@missouri.edu

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 21 September 2020; accepted 28 September 2020; online 9 October 2020)

The title compound, C9H13N3O, crystallizes in the monoclinic space group C2/c and all non-hydrogen atoms are within 0.1 Å of the mol­ecular mean plane. In the crystal, the hydrogen-bonding pattern results in [001] chains built up from fused R22(6) and R22(10) rings; the former consists of N—H⋯N bonds and the latter N—H⋯O bonds. Electrostatic and dispersion forces are major contributors to the lattice energy, which was estimated by DFT calculations to be −215.7 kJ mol−1.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

For decades, there has been an inter­est in aroyl hydrazides because of their numerous applications, for instance, as synthetic precursors to a large number of potential anti­microbial (Popiołek, 2017[Popiołek, Ł. (2017). Med. Chem. Res. 26, 287-301.]) or anti­cancer (Kumar & Narasimhan, 2013[Kumar, P. & Narasimhan, B. (2013). Mini Rev. Med. Chem. 13, 971-987.]) drugs, in addition to their own anti-tubercular activities (Sah & Peoples, 1954[Sah, P. P. T. & Peoples, S. A. (1954). J. Am. Pharm. Assoc. 43, 513-524.]). In our search for inhibitors of bacterial virulence factors (Mossine et al., 2016[Mossine, V. V., Waters, J. K., Chance, D. L. & Mawhinney, T. P. (2016). Toxicol. Sci. 154, 403-415.], 2020[Mossine, V. V., Kelley, S. P. & Mawhinney, T. P. (2020). Acta Cryst. E76, 557-561.]), we turned our attention to the title compound, which can be viewed as a structural analogue of isoniazid (Andrade et al., 2008[Andrade, C. H., Salum, L. de B., Castilho, M. S., Pasqualoto, K. F. M., Ferreira, E. I. & Andricopulo, A. D. (2008). Mol. Divers. 12, 47-59.]) and a potential precursor for pharmacologically active, iron-binding hydrazide-hydrazones. We now report its crystal structure.

The title compound crystallizes in the monoclinic space group C2/c, with eight mol­ecules per unit cell. The asymmetric unit contains one mol­ecule of the hydrazide (I), as shown in Fig. 1[link]. All bond lengths and angles are within their expected ranges. The mol­ecule is essentially flat, with the greatest deviation from the average mol­ecular plane, among the non-hydrogen atoms, found for atom N1 at 0.074 (1) Å. The aromatic ring plane is at 1.08 (4)° to the mol­ecular plane. The spatial arrangement of the hydrazido group, as defined by the torsion angle H2—N2—N3—H3B = 119.3 (15)°, corresponds to the lowest energy conformation that has been calculated for acyl hydrazides (Centore et al., 2010[Centore, R., Carella, A., Tuzi, A., Capobianco, A. & Peluso, A. (2010). CrystEngComm, 12, 1186-1193.]).

[Figure 1]
Figure 1
Atomic numbering and displacement ellipsoids at the 50% probability level for (I).

The conventional hydrogen bonding in the extended structure of (I) is limited to two inter­molecular heteroatom contacts (Table 1[link]) involving the hydrazido groups only and is shown in Fig. 2[link]. The hydrogen-bonding pattern includes infinite chains that propagate in the [001] direction and consist of fused R22(10) and R22(6) rings (Fig. 2[link]a). The R22(10) motif is formed by pairs of mol­ecules linked by the N3—H3B⋯O1 hydrogen bonds related by twofold rotation symmetry, while the R22(6) motif is formed by centrosymmetric dimers of (I) linked by the N2—H2⋯N3 hydrogen bonds. In addition, one short inter­molecular contact, C6—H6⋯O1, which satisfies the distance and directionality conditions [C6⋯O1iii = 3.4111 (13) Å, C6—H6⋯O1iii = 172°; symmetry code: (iii) x, 1 − y, ½ + z], and which is shown in Fig. 3[link] as a dotted line, may also contribute to the stability of the mol­ecular packing in the crystal. The inter­molecular non-polar inter­actions are dominated by hydrogen–hydrogen contacts between the methyl groups; the shortest of these contacts, H8C⋯H9B, is about 0.1 Å less than the sum of the VdW radii. These inter­actions form a pattern of infinite chains, propagating in the [001] direction, in parallel to the hydrogen-bonded chains (Fig. 2[link]b and 2c). The crystal structure lacks any strong ππ stacking inter­actions. However, a short N3—H3ACg1 [H3ACg1iv = 2.614 (15) Å; symmetry code: (iv) x, y − 1, z] contact is present.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2⋯N3i 0.89 (2) 2.11 (2) 2.9203 (13) 151 (1)
N3—H3B⋯O1ii 0.92 (2) 2.09 (1) 2.9516 (11) 157 (1)
Symmetry codes: (i) [-x, -y, -z+1]; (ii) [-x, y, -z+{\script{1\over 2}}].
[Figure 2]
Figure 2
Mol­ecular packing and hydrogen bonding in (I). (a) Hydrogen-bonding motifs; (b) and (c) mol­ecular packing views down [001] and [100], respectively. Hydrogen bonds are shown as cyan dotted lines.
[Figure 3]
Figure 3
Inter­action energies in crystal structure of (I). (a) A view of inter­actions between a central mol­ecule, shown as its Hirshfeld surface, and 13 mol­ecules that share the inter­action surfaces with the central mol­ecule. Red areas on the Hirshfeld surface encode the closest inter­molecular contacts, which are hydrogen bonds involving the hydrazido groups, a short C—H⋯O type contact is shown as a dotted line; (b) Calculated energies (electrostatic, polarization, dispersion, repulsion, and total) of pairwise inter­actions between the central mol­ecule and those indicated by respective colours.

To account for all inter­actions involved in the build-up of the crystal structure of (I) we have performed DFT calculations, at the B3LYP/6–31 G(d,p) theory level (Mackenzie et al., 2017[Mackenzie, C. F., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). IUCrJ, 4, 575-587.]; Thomas et al., 2018[Thomas, S. P., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2018). J. Chem. Theory Comput. 14, 1614-1623.]), of the electrostatic, dispersion, polarization, and repulsion energies. According to these calculations, the inter­actions between hydrogen-bonded pairs of mol­ecules contribute about 50% to the lattice energy, with the dispersion energy providing most of the attractive forces between non-hydrogen-bonded mol­ecules of (I) (i.e. Eele = −9.2 kJ mol−1, Edis = −44.2 kJ mol−1 for symmetry code = x, y, z). To estimate the lattice energy, all total energies of unique pairwise inter­actions between mol­ecules were summed up, thus yielding El (l = lattice) = −216 kJ mol−1 for the crystal of (I). The calculated contributions to the overall lattice energy (kJ mol−1) are as follows: Eele = −165.3; Epol = −46.0; Edis = −173.9; Erep = 234.1. The spatial distribution of the energetically most significant inter­actions is illustrated in Fig. 4[link], showing the inter­actions energy frameworks as cylinders penetrating the mol­ecular packing of (I). As expected, the most extensive inter­molecular inter­actions occur in the hydrogen-bonded chain direction parallel to [001].

[Figure 4]
Figure 4
Energy frameworks for separate (a) electrostatic and (b) dispersion contributions to the (c) total pairwise inter­action energies in (I). The cylinders link mol­ecular centroids, and the cylinder thickness is proportional to the magnitude of the energies (see Fig. 3[link]). For clarity, the cylinders corresponding to energies <5 kJ mol−1 are not shown. The directionality of the crystallographic axes is the same for all three diagrams.

Synthesis and crystallization

A sample of commercial 4-di­methyl­amino­benzhydrazide was recrystallized from hot 95% ethanol solution, affording colorless needles.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link].

Table 2
Experimental details

Crystal data
Chemical formula C9H13N3O
Mr 179.22
Crystal system, space group Monoclinic, C2/c
Temperature (K) 100
a, b, c (Å) 24.7018 (6), 6.3093 (1), 13.2103 (3)
β (°) 118.0496 (8)
V3) 1817.01 (7)
Z 8
Radiation type Cu Kα
μ (mm−1) 0.72
Crystal size (mm) 0.25 × 0.24 × 0.23
 
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (AXScale; Bruker, 2016[Bruker (2016). APEX3, SAINT and AXScale. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.684, 0.754
No. of measured, independent and observed [I > 2σ(I)] reflections 15813, 1786, 1770
Rint 0.019
(sin θ/λ)max−1) 0.618
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.098, 1.07
No. of reflections 1786
No. of parameters 130
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.22, −0.22
Computer programs: APEX3 and SAINT (Bruker, 2016[Bruker (2016). APEX3, SAINT and AXScale. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXS (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), 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.]), CrystalExplorer17.5 (Mackenzie et al., 2017[Mackenzie, C. F., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). IUCrJ, 4, 575-587.]), Mercury (Macrae et al., 2020[Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226-235.]), and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Structural data


Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: APEX3 and SAINT (Bruker, 2016); data reduction: APEX3 and SAINT (Bruker, 2016); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009), CrystalExplorer17.5 (Mackenzie et al., 2017) and Mercury (Macrae et al., 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

4-(Dimethylamino)benzohydrazide top
Crystal data top
C9H13N3OF(000) = 768
Mr = 179.22Dx = 1.310 Mg m3
Monoclinic, C2/cCu Kα radiation, λ = 1.54178 Å
a = 24.7018 (6) ÅCell parameters from 9928 reflections
b = 6.3093 (1) Åθ = 4.1–72.3°
c = 13.2103 (3) ŵ = 0.72 mm1
β = 118.0496 (8)°T = 100 K
V = 1817.01 (7) Å3Irregular, colourless
Z = 80.25 × 0.24 × 0.23 mm
Data collection top
Bruker APEXII CCD
diffractometer
1786 independent reflections
Radiation source: Incoatec IMuS microfocus Cu tube1770 reflections with I > 2σ(I)
Multi-layer optics monochromatorRint = 0.019
φ and ω scansθmax = 72.4°, θmin = 4.1°
Absorption correction: multi-scan
(AXScale; Bruker, 2016)
h = 2926
Tmin = 0.684, Tmax = 0.754k = 77
15813 measured reflectionsl = 1616
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.098 w = 1/[σ2(Fo2) + (0.0541P)2 + 1.3587P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
1786 reflectionsΔρmax = 0.22 e Å3
130 parametersΔρmin = 0.22 e Å3
0 restraintsExtinction correction: SHELXL2017/1 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0036 (3)
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.

Refinement. The hydrazide H2, H3A, and H3B atoms were located in difference-Fourier maps while all other hydrogen atoms were initially placed in calculated positions with their coordinates constrained to ride on their carrier atoms [C—H(aromatic) = 0.95?Å, C—H(methyl) = 0.98?Å]. The constraint Uiso(H) = 1.2Ueq(carrier) or 1.5Ueq(methyl carrier) was applied in all cases.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.07812 (3)0.16597 (12)0.32634 (6)0.0191 (2)
N20.03227 (4)0.11655 (14)0.43722 (7)0.0155 (2)
H20.0261 (6)0.151 (2)0.4964 (12)0.023*
N30.00327 (4)0.07477 (14)0.38183 (7)0.0155 (2)
H3A0.0319 (7)0.162 (2)0.3826 (12)0.023*
H3B0.0235 (6)0.037 (2)0.3076 (13)0.023*
N10.18614 (4)0.97723 (15)0.64989 (8)0.0218 (3)
C50.08706 (4)0.50333 (16)0.56022 (8)0.0147 (2)
H50.0608860.4282000.5821340.018*
C60.11601 (4)0.68522 (16)0.61942 (8)0.0155 (2)
H60.1092060.7332940.6806480.019*
C10.15565 (4)0.80037 (16)0.58975 (8)0.0156 (2)
C20.16280 (5)0.72556 (17)0.49598 (9)0.0174 (3)
H2A0.1882580.8012080.4725280.021*
C40.09528 (4)0.42708 (16)0.46894 (8)0.0144 (2)
C30.13326 (5)0.54379 (17)0.43786 (9)0.0166 (2)
H30.1389250.4969510.3751320.020*
C70.06791 (4)0.22760 (16)0.40464 (8)0.0141 (2)
C80.17404 (5)1.06515 (18)0.73873 (9)0.0210 (3)
H8A0.1316561.1165550.7043560.032*
H8B0.2022371.1830840.7763850.032*
H8C0.1800520.9551970.7954690.032*
C90.22406 (5)1.09916 (18)0.61407 (10)0.0222 (3)
H9A0.2583981.0115480.6209940.033*
H9B0.2399601.2247110.6629610.033*
H9C0.1994031.1434610.5340790.033*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0220 (4)0.0209 (4)0.0193 (4)0.0049 (3)0.0137 (3)0.0052 (3)
N20.0196 (4)0.0142 (4)0.0150 (4)0.0038 (3)0.0101 (4)0.0026 (3)
N30.0172 (4)0.0139 (4)0.0148 (4)0.0023 (3)0.0071 (4)0.0015 (3)
N10.0232 (5)0.0217 (5)0.0240 (5)0.0086 (4)0.0140 (4)0.0071 (4)
C50.0137 (5)0.0157 (5)0.0156 (5)0.0009 (4)0.0077 (4)0.0024 (4)
C60.0157 (5)0.0171 (5)0.0143 (5)0.0016 (4)0.0075 (4)0.0006 (4)
C10.0130 (5)0.0153 (5)0.0160 (5)0.0007 (4)0.0049 (4)0.0007 (4)
C20.0167 (5)0.0182 (5)0.0194 (5)0.0023 (4)0.0103 (4)0.0012 (4)
C40.0135 (5)0.0143 (5)0.0145 (5)0.0010 (4)0.0058 (4)0.0012 (4)
C30.0176 (5)0.0188 (5)0.0165 (5)0.0006 (4)0.0105 (4)0.0001 (4)
C70.0125 (5)0.0159 (5)0.0133 (5)0.0018 (4)0.0055 (4)0.0016 (4)
C80.0214 (5)0.0185 (5)0.0225 (5)0.0020 (4)0.0098 (4)0.0054 (4)
C90.0197 (5)0.0199 (6)0.0270 (6)0.0059 (4)0.0109 (5)0.0024 (4)
Geometric parameters (Å, º) top
O1—C71.2371 (12)N2—H20.891 (15)
N2—N31.4187 (12)N3—H3A0.892 (17)
N2—C71.3444 (13)N3—H3B0.920 (15)
N1—C11.3715 (14)C2—H2A0.95
N1—C81.4506 (14)C3—H30.95
N1—C91.4526 (14)C5—H50.95
C5—C61.3835 (14)C6—H60.95
C5—C41.3989 (14)C8—H8A0.98
C6—C11.4146 (14)C8—H8B0.98
C1—C21.4120 (14)C8—H8C0.98
C2—C31.3821 (15)C9—H9A0.98
C4—C31.3976 (14)C9—H9B0.98
C4—C71.4909 (14)C9—H9C0.98
C7—N2—N3121.75 (8)H3A—N3—H3B109.9 (13)
C1—N1—C8120.93 (9)C1—C2—H2A120
C1—N1—C9120.31 (9)C3—C2—H2A120
C8—N1—C9118.09 (9)C2—C3—H3119
C6—C5—C4121.76 (9)C4—C3—H3119
C5—C6—C1120.70 (9)C4—C5—H5119
N1—C1—C6121.36 (9)C6—C5—H5119
N1—C1—C2121.27 (9)C1—C6—H6120
C2—C1—C6117.37 (9)C5—C6—H6120
C3—C2—C1120.90 (9)N1—C8—H8A109
C5—C4—C7124.79 (9)N1—C8—H8B109
C3—C4—C5117.50 (9)N1—C8—H8C109
C3—C4—C7117.69 (9)H8A—C8—H8B109
C2—C3—C4121.73 (9)H8A—C8—H8C109
O1—C7—N2121.71 (10)H8B—C8—H8C109
O1—C7—C4121.71 (9)N1—C9—H9A109
N2—C7—C4116.58 (9)N1—C9—H9B109
N3—N2—H2114.0 (9)N1—C9—H9C109
C7—N2—H2124.2 (9)H9A—C9—H9B109
N2—N3—H3A108.3 (10)H9A—C9—H9C109
N2—N3—H3B105.4 (8)H9B—C9—H9C109
C8—N1—C1—C2173.90 (10)C1—N1—C9—H9A64
C8—N1—C1—C66.35 (15)C1—N1—C9—H9B176
C9—N1—C1—C23.50 (16)C1—N1—C9—H9C56
C9—N1—C1—C6176.75 (10)C8—N1—C9—H9A125
N3—N2—C7—O11.50 (15)C8—N1—C9—H9B5
N3—N2—C7—C4179.43 (9)C8—N1—C9—H9C115
N1—C1—C2—C3178.16 (11)C7—N2—N3—H3A54.0 (10)
C6—C1—C2—C31.60 (16)C7—N2—N3—H3B63.6 (11)
N1—C1—C6—C5177.96 (10)H2—N2—N3—H3A123.2 (14)
C2—C1—C6—C51.79 (15)H2—N2—N3—H3B119.3 (15)
C1—C2—C3—C40.07 (18)H2—N2—C7—O1175.4 (11)
C2—C3—C4—C51.28 (16)H2—N2—C7—C43.7 (11)
C2—C3—C4—C7177.07 (10)N1—C1—C2—H2A2
C3—C4—C5—C61.08 (15)C6—C1—C2—H2A178
C7—C4—C5—C6177.14 (10)N1—C1—C6—H62
C3—C4—C7—O10.02 (15)C2—C1—C6—H6178
C3—C4—C7—N2179.06 (10)C1—C2—C3—H3180
C5—C4—C7—O1178.23 (10)H2A—C2—C3—C4180
C5—C4—C7—N20.84 (15)H2A—C2—C3—H30
C4—C5—C6—C10.47 (16)H3—C3—C4—C5179
C1—N1—C8—H8A65H3—C3—C4—C73
C1—N1—C8—H8B175C3—C4—C5—H5179
C1—N1—C8—H8C55C7—C4—C5—H53
C9—N1—C8—H8A106C4—C5—C6—H6180
C9—N1—C8—H8B14H5—C5—C6—C1180
C9—N1—C8—H8C134H5—C5—C6—H60
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···N3i0.89 (2)2.11 (2)2.9203 (13)151 (1)
N3—H3B···O1ii0.92 (2)2.09 (1)2.9516 (11)157 (1)
Symmetry codes: (i) x, y, z+1; (ii) x, y, z+1/2.
 

Funding information

Funding for this research was provided by: National Institute of Food and Agriculture (award No. Hatch 1023929); University of Missouri, Agriculture Experiment Station Chemical Laboratories .

References

First citationAndrade, C. H., Salum, L. de B., Castilho, M. S., Pasqualoto, K. F. M., Ferreira, E. I. & Andricopulo, A. D. (2008). Mol. Divers. 12, 47–59.  Web of Science CrossRef PubMed CAS Google Scholar
First citationBruker (2016). APEX3, SAINT and AXScale. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCentore, R., Carella, A., Tuzi, A., Capobianco, A. & Peluso, A. (2010). CrystEngComm, 12, 1186–1193.  Web of Science CSD CrossRef CAS Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationKumar, P. & Narasimhan, B. (2013). Mini Rev. Med. Chem. 13, 971–987.  Web of Science CrossRef CAS PubMed Google Scholar
First citationMackenzie, C. F., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). IUCrJ, 4, 575–587.  Web of Science CrossRef CAS PubMed IUCr Journals Google Scholar
First citationMacrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226–235.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationMossine, V. V., Kelley, S. P. & Mawhinney, T. P. (2020). Acta Cryst. E76, 557–561.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationMossine, V. V., Waters, J. K., Chance, D. L. & Mawhinney, T. P. (2016). Toxicol. Sci. 154, 403–415.  Web of Science CrossRef CAS PubMed Google Scholar
First citationPopiołek, Ł. (2017). Med. Chem. Res. 26, 287–301.  Web of Science PubMed Google Scholar
First citationSah, P. P. T. & Peoples, S. A. (1954). J. Am. Pharm. Assoc. 43, 513–524.  CrossRef CAS Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationThomas, S. P., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2018). J. Chem. Theory Comput. 14, 1614–1623.  Web of Science CrossRef CAS PubMed Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals 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 logoIUCrDATA
ISSN: 2414-3146
Follow IUCr Journals
Sign up for e-alerts
Follow IUCr on Twitter
Follow us on facebook
Sign up for RSS feeds