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ISSN: 2056-9890

2-Amino-6-(quinoline-2-carboxamido)­pyridinium nitrate

aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
*Correspondence e-mail: vanderbergpcw@ufs.ac.za

(Received 31 July 2012; accepted 22 August 2012; online 31 August 2012)

In the title salt, C15H13N4O+·NO3, an extensive network of N—H⋯N, N—H⋯O and C—H⋯O hydrogen-bond inter­actions are observed throughout the structure. Further stabilization is obtained by ππ stacking inter­actions between inversion-related quinoline systems and inversion-related pyridine rings, with respective centroid–centroid distances of 3.5866 (6) and 3.3980 (6) Å.

Related literature

For related radiopharmaceutical structures, see: Al-Dajani et al. (2010[Al-Dajani, M. T. M., Mohamed, N., Wahab, H. A., Yeap, C. S. & Fun, H.-K. (2010). Acta Cryst. E66, o2150.]); Jain et al. (2004[Jain, S. L., Bhattacharyya, P., Milton, H. L., Slawin, A. M. Z., Crayston, J. A. & Woollins, J. D. (2004). Dalton Trans. pp. 862-871.]); Van der Berg et al. (2011[Van der Berg, P. C. W., Visser, H. G. & Roodt, A. (2011). Acta Cryst. E67, o3130.]).

[Scheme 1]

Experimental

Crystal data
  • C15H13N4O+·NO3

  • Mr = 327.30

  • Monoclinic, P 21 /c

  • a = 8.183 (2) Å

  • b = 11.768 (3) Å

  • c = 14.979 (4) Å

  • β = 98.37 (1)°

  • V = 1427.1 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 100 K

  • 0.49 × 0.41 × 0.31 mm

Data collection
  • Bruker X8 APEXII KappaCCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.990, Tmax = 0.994

  • 26710 measured reflections

  • 3555 independent reflections

  • 3180 reflections with I > 2σ(I)

  • Rint = 0.023

Refinement
  • R[F2 > 2σ(F2)] = 0.035

  • wR(F2) = 0.1

  • S = 1.04

  • 3555 reflections

  • 233 parameters

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

  • Δρmax = 0.42 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯O3 0.892 (18) 2.019 (19) 2.8721 (14) 159.7 (16)
N1—H1B⋯O4i 0.836 (19) 2.204 (19) 3.0202 (14) 165.1 (16)
N2—H2A⋯O1 0.848 (19) 1.984 (18) 2.6458 (12) 134.1 (16)
N2—H2A⋯O3 0.848 (19) 2.496 (18) 3.2058 (12) 141.7 (15)
N3—H3A⋯O3ii 0.857 (17) 2.153 (17) 2.9652 (12) 158.2 (15)
N3—H3A⋯N4 0.857 (17) 2.288 (16) 2.6879 (15) 108.7 (13)
C4—H4⋯O3ii 0.93 2.44 3.1947 (14) 138
C11—H11⋯O4iii 0.93 2.53 3.3460 (14) 147
C12—H12⋯O2iv 0.93 2.5 3.2901 (14) 142
C14—H14⋯O2ii 0.93 2.55 3.1840 (14) 126
Symmetry codes: (i) [-x+1, y+{\script{1\over 2}}, -z+{\script{5\over 2}}]; (ii) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (iii) [-x+2, y-{\script{1\over 2}}, -z+{\script{5\over 2}}]; (iv) -x+2, -y, -z+2.

Data collection: APEX2 (Bruker, 2011[Bruker (2011). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2008[Bruker (2008). SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; 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: DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

The title compound was synthesized as a ligand for potential use in medical and radiopharmaceutical applications. The asymmetric unit in the title compound contains a C15H13N4O cation and a NO3- counter ion. A range of N—H···N, N—H···O and C—H···O hydrogen interactions are observed throughout the structure. Further stabilization of the crystal structure is obtained by π-π stacking interactions between inversion-related quinolines and inversion-related pyridines with respective centroid-to-centroid distances of 3.5866 (6) Å and 3.3980 (6) Å (see Fig. 2). For similar structures that form part of our radiopharmaceutical research see: Al-Dajani et al. (2010); Jain et al. (2004) and Van der Berg et al. (2011).

Related literature top

For related radiopharmaceutical structures, see: Al-Dajani et al. (2010); Jain et al. (2004); Van der Berg et al. (2011).

Experimental top

Under oxygen atmosphere: Quinaldic acid (0.8013 g, 4.627 mmol) was added as a solid in one portion to a suspension of 2,6-diaminopyridine (0.5000 g, 4.582 mmol) in pyridine (10 ml) and the mixture was stirred at 40 °C for 40 min. Triphenylphosphite (10 ml) was added dropwise over 10 minutes, after which the temperature was increased to 90–100 °C and stirred for a further 24 h. On cooling the precipitate was filtered, washed with H2O (50 ml) and then MeOH (50 ml). The product was dissolved in diluted HNO3 and left to stand at room temperature. Yellow crystals were obtained after five days.

Refinement top

The N-bound hydrogen atoms were located in a difference Fourier map and refined freely. The remaining H atoms were placed in geometrically idealized positions at C—H = 0.93 Å, respectively and constrained to ride on their parent atoms, with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
Fig. 1. Representation of the title compound, showing displacement ellipsoids (50% probability).

Fig. 2. Packing and illustration of π-π stacking in the crystal.
2-Amino-6-(quinoline-2-carboxamido)pyridinium nitrate top
Crystal data top
C15H13N4O+·NO3F(000) = 680
Mr = 327.30Dx = 1.523 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 9936 reflections
a = 8.183 (2) Åθ = 2.2–28.3°
b = 11.768 (3) ŵ = 0.12 mm1
c = 14.979 (4) ÅT = 100 K
β = 98.37 (1)°Cuboid, yellow
V = 1427.1 (6) Å30.49 × 0.41 × 0.31 mm
Z = 4
Data collection top
Bruker X8 APEXII KappaCCD
diffractometer
3555 independent reflections
Radiation source: sealed tube3180 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
ϕ and ω scansθmax = 28.4°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 1010
Tmin = 0.990, Tmax = 0.994k = 1515
26710 measured reflectionsl = 1919
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.1H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.0537P)2 + 0.6672P]
where P = (Fo2 + 2Fc2)/3
3555 reflections(Δ/σ)max = 0.001
233 parametersΔρmax = 0.42 e Å3
0 restraintsΔρmin = 0.25 e Å3
Crystal data top
C15H13N4O+·NO3V = 1427.1 (6) Å3
Mr = 327.30Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.183 (2) ŵ = 0.12 mm1
b = 11.768 (3) ÅT = 100 K
c = 14.979 (4) Å0.49 × 0.41 × 0.31 mm
β = 98.37 (1)°
Data collection top
Bruker X8 APEXII KappaCCD
diffractometer
3555 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
3180 reflections with I > 2σ(I)
Tmin = 0.990, Tmax = 0.994Rint = 0.023
26710 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0350 restraints
wR(F2) = 0.1H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.42 e Å3
3555 reflectionsΔρmin = 0.25 e Å3
233 parameters
Special details top

Experimental. The intensity data were collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of 30 s/frame. A total of 1759 frames were collected with a frame width of 0.5° covering up to θ = 28.28° with 100.00% completeness accomplished.

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
C50.44014 (13)0.29849 (9)1.00107 (7)0.0136 (2)
C40.36313 (14)0.35271 (9)0.92503 (7)0.0165 (2)
H40.36740.3230.86790.02*
C30.27835 (14)0.45365 (10)0.93606 (8)0.0190 (2)
H30.22430.49090.88540.023*
C20.27319 (14)0.49912 (10)1.02018 (8)0.0191 (2)
H20.21650.56651.02630.023*
C10.35435 (13)0.44278 (9)1.09694 (8)0.0161 (2)
C60.61016 (12)0.13855 (9)1.06647 (7)0.0130 (2)
C70.70961 (12)0.03990 (9)1.04078 (7)0.0128 (2)
C80.80954 (13)0.01866 (9)1.11085 (7)0.0148 (2)
H80.8120.00281.17080.018*
C90.90254 (13)0.10779 (9)1.08810 (7)0.0156 (2)
H90.97090.14751.13250.019*
C100.89350 (13)0.13878 (9)0.99620 (7)0.0143 (2)
C110.98613 (14)0.23014 (10)0.96740 (8)0.0182 (2)
H111.05480.27271.00980.022*
C120.97515 (14)0.25610 (10)0.87763 (8)0.0208 (2)
H121.03710.31570.85930.025*
C130.86987 (14)0.19264 (10)0.81263 (8)0.0196 (2)
H130.86330.21110.75180.024*
C140.77756 (14)0.10438 (9)0.83805 (7)0.0165 (2)
H140.70780.0640.79470.02*
C150.78850 (13)0.07462 (9)0.93054 (7)0.0133 (2)
N10.36061 (13)0.48153 (9)1.18100 (7)0.0199 (2)
N20.43161 (11)0.34266 (8)1.08430 (6)0.01391 (19)
N30.53164 (11)0.20051 (8)0.99536 (6)0.01377 (19)
N40.69803 (11)0.01543 (7)0.95409 (6)0.01317 (18)
N50.68666 (12)0.29972 (8)1.29263 (6)0.01620 (19)
O10.60217 (10)0.16082 (7)1.14574 (5)0.01639 (17)
O20.75498 (11)0.36208 (7)1.24246 (6)0.0224 (2)
O30.53418 (10)0.31398 (7)1.29794 (5)0.01974 (18)
O40.76463 (11)0.22297 (7)1.33845 (6)0.0228 (2)
H1B0.326 (2)0.5477 (16)1.1861 (12)0.033 (4)*
H1A0.423 (2)0.4444 (15)1.2254 (12)0.031 (4)*
H2A0.481 (2)0.3072 (15)1.1296 (12)0.032 (4)*
H3A0.5452 (19)0.1790 (14)0.9423 (11)0.026 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C50.0144 (4)0.0117 (5)0.0151 (5)0.0008 (4)0.0036 (4)0.0006 (4)
C40.0196 (5)0.0159 (5)0.0139 (5)0.0001 (4)0.0027 (4)0.0000 (4)
C30.0215 (5)0.0168 (5)0.0182 (5)0.0031 (4)0.0017 (4)0.0045 (4)
C20.0230 (5)0.0134 (5)0.0212 (6)0.0051 (4)0.0045 (4)0.0017 (4)
C10.0182 (5)0.0131 (5)0.0178 (5)0.0006 (4)0.0060 (4)0.0002 (4)
C60.0127 (4)0.0112 (5)0.0152 (5)0.0015 (4)0.0018 (4)0.0011 (4)
C70.0125 (5)0.0111 (4)0.0151 (5)0.0010 (3)0.0027 (4)0.0007 (4)
C80.0152 (5)0.0165 (5)0.0129 (5)0.0006 (4)0.0025 (4)0.0002 (4)
C90.0141 (5)0.0165 (5)0.0158 (5)0.0010 (4)0.0006 (4)0.0031 (4)
C100.0125 (5)0.0130 (5)0.0177 (5)0.0005 (4)0.0034 (4)0.0004 (4)
C110.0164 (5)0.0160 (5)0.0219 (6)0.0037 (4)0.0018 (4)0.0007 (4)
C120.0198 (5)0.0165 (5)0.0268 (6)0.0041 (4)0.0062 (4)0.0045 (4)
C130.0223 (5)0.0198 (5)0.0173 (5)0.0010 (4)0.0049 (4)0.0043 (4)
C140.0191 (5)0.0153 (5)0.0150 (5)0.0006 (4)0.0018 (4)0.0003 (4)
C150.0130 (4)0.0115 (5)0.0156 (5)0.0008 (3)0.0035 (4)0.0001 (4)
N10.0288 (5)0.0151 (5)0.0166 (5)0.0058 (4)0.0059 (4)0.0011 (4)
N20.0171 (4)0.0119 (4)0.0129 (4)0.0021 (3)0.0027 (3)0.0005 (3)
N30.0175 (4)0.0120 (4)0.0122 (4)0.0018 (3)0.0033 (3)0.0009 (3)
N40.0142 (4)0.0111 (4)0.0144 (4)0.0003 (3)0.0026 (3)0.0008 (3)
N50.0221 (5)0.0142 (4)0.0121 (4)0.0034 (3)0.0016 (3)0.0018 (3)
O10.0202 (4)0.0155 (4)0.0133 (4)0.0019 (3)0.0020 (3)0.0023 (3)
O20.0317 (5)0.0184 (4)0.0195 (4)0.0055 (3)0.0111 (3)0.0005 (3)
O30.0196 (4)0.0234 (4)0.0163 (4)0.0020 (3)0.0031 (3)0.0002 (3)
O40.0269 (4)0.0182 (4)0.0206 (4)0.0006 (3)0.0052 (3)0.0025 (3)
Geometric parameters (Å, º) top
C5—N21.3618 (14)C9—H90.93
C5—C41.3758 (15)C10—C111.4183 (15)
C5—N31.3842 (13)C10—C151.4246 (15)
C4—C31.3974 (15)C11—C121.3690 (17)
C4—H40.93C11—H110.93
C3—C21.3753 (16)C12—C131.4156 (17)
C3—H30.93C12—H120.93
C2—C11.4073 (16)C13—C141.3704 (15)
C2—H20.93C13—H130.93
C1—N11.3332 (15)C14—C151.4191 (15)
C1—N21.3633 (14)C14—H140.93
C6—O11.2270 (13)C15—N41.3680 (13)
C6—N31.3711 (14)N1—H1B0.836 (19)
C6—C71.4997 (14)N1—H1A0.892 (18)
C7—N41.3200 (13)N2—H2A0.848 (19)
C7—C81.4125 (14)N3—H3A0.857 (17)
C8—C91.3679 (15)N5—O21.2402 (12)
C8—H80.93N5—O41.2516 (13)
C9—C101.4155 (15)N5—O31.2729 (13)
N2—C5—C4120.18 (10)C11—C10—C15119.15 (10)
N2—C5—N3118.34 (9)C12—C11—C10120.42 (10)
C4—C5—N3121.46 (10)C12—C11—H11119.8
C5—C4—C3118.15 (10)C10—C11—H11119.8
C5—C4—H4120.9C11—C12—C13120.28 (10)
C3—C4—H4120.9C11—C12—H12119.9
C2—C3—C4121.40 (10)C13—C12—H12119.9
C2—C3—H3119.3C14—C13—C12120.90 (10)
C4—C3—H3119.3C14—C13—H13119.5
C3—C2—C1119.44 (10)C12—C13—H13119.5
C3—C2—H2120.3C13—C14—C15119.95 (10)
C1—C2—H2120.3C13—C14—H14120
N1—C1—N2118.16 (10)C15—C14—H14120
N1—C1—C2124.00 (10)N4—C15—C14118.90 (10)
N2—C1—C2117.84 (10)N4—C15—C10121.82 (10)
O1—C6—N3123.59 (10)C14—C15—C10119.28 (10)
O1—C6—C7121.40 (9)C1—N1—H1B116.0 (12)
N3—C6—C7115.01 (9)C1—N1—H1A118.4 (11)
N4—C7—C8125.13 (10)H1B—N1—H1A123.6 (16)
N4—C7—C6117.22 (9)C5—N2—C1122.93 (10)
C8—C7—C6117.65 (9)C5—N2—H2A117.6 (12)
C9—C8—C7118.16 (10)C1—N2—H2A119.4 (12)
C9—C8—H8120.9C6—N3—C5126.27 (9)
C7—C8—H8120.9C6—N3—H3A117.0 (11)
C8—C9—C10119.18 (10)C5—N3—H3A116.6 (11)
C8—C9—H9120.4C7—N4—C15117.29 (9)
C10—C9—H9120.4O2—N5—O4121.37 (10)
C9—C10—C11122.44 (10)O2—N5—O3119.49 (9)
C9—C10—C15118.40 (9)O4—N5—O3119.14 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O30.892 (18)2.019 (19)2.8721 (14)159.7 (16)
N1—H1B···O4i0.836 (19)2.204 (19)3.0202 (14)165.1 (16)
N2—H2A···O10.848 (19)1.984 (18)2.6458 (12)134.1 (16)
N2—H2A···O30.848 (19)2.496 (18)3.2058 (12)141.7 (15)
N3—H3A···O3ii0.857 (17)2.153 (17)2.9652 (12)158.2 (15)
N3—H3A···N40.857 (17)2.288 (16)2.6879 (15)108.7 (13)
C4—H4···O3ii0.932.443.1947 (14)138
C11—H11···O4iii0.932.533.3460 (14)147
C12—H12···O2iv0.932.53.2901 (14)142
C14—H14···O2ii0.932.553.1840 (14)126
Symmetry codes: (i) x+1, y+1/2, z+5/2; (ii) x, y+1/2, z1/2; (iii) x+2, y1/2, z+5/2; (iv) x+2, y, z+2.

Experimental details

Crystal data
Chemical formulaC15H13N4O+·NO3
Mr327.30
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)8.183 (2), 11.768 (3), 14.979 (4)
β (°) 98.37 (1)
V3)1427.1 (6)
Z4
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.49 × 0.41 × 0.31
Data collection
DiffractometerBruker X8 APEXII KappaCCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.990, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
26710, 3555, 3180
Rint0.023
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.1, 1.03
No. of reflections3555
No. of parameters233
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.42, 0.25

Computer programs: APEX2 (Bruker, 2011), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O30.892 (18)2.019 (19)2.8721 (14)159.7 (16)
N1—H1B···O4i0.836 (19)2.204 (19)3.0202 (14)165.1 (16)
N2—H2A···O10.848 (19)1.984 (18)2.6458 (12)134.1 (16)
N2—H2A···O30.848 (19)2.496 (18)3.2058 (12)141.7 (15)
N3—H3A···O3ii0.857 (17)2.153 (17)2.9652 (12)158.2 (15)
N3—H3A···N40.857 (17)2.288 (16)2.6879 (15)108.7 (13)
C4—H4···O3ii0.932.443.1947 (14)137.8
C11—H11···O4iii0.932.533.3460 (14)147.3
C12—H12···O2iv0.932.53.2901 (14)142.4
C14—H14···O2ii0.932.553.1840 (14)125.8
Symmetry codes: (i) x+1, y+1/2, z+5/2; (ii) x, y+1/2, z1/2; (iii) x+2, y1/2, z+5/2; (iv) x+2, y, z+2.
 

Acknowledgements

The authors would like to thank the Department of Chemistry of the University of the Free State, the NRF, NTeMBI, THRIP and Sasol Ltd for funding.

References

First citationAl-Dajani, M. T. M., Mohamed, N., Wahab, H. A., Yeap, C. S. & Fun, H.-K. (2010). Acta Cryst. E66, o2150.  CrossRef IUCr Journals
First citationBrandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.
First citationBruker (2008). SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBruker (2011). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals
First citationJain, S. L., Bhattacharyya, P., Milton, H. L., Slawin, A. M. Z., Crayston, J. A. & Woollins, J. D. (2004). Dalton Trans. pp. 862–871.  Web of Science CSD CrossRef PubMed
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationVan der Berg, P. C. W., Visser, H. G. & Roodt, A. (2011). Acta Cryst. E67, o3130.  Web of Science CSD CrossRef IUCr Journals

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