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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

[2-Acet­­oxy-3-(naphthalen-1-yl­­oxy)prop­yl](propan-2-yl)aza­nium chloride monohydrate

aDepartment of Chemical and Pharmaceutical Engineering, Southeast University ChengXian College, Nanjing 210088, People's Republic of China
*Correspondence e-mail: liuyuanyuan1985419@163.com

(Received 16 February 2013; accepted 26 February 2013; online 9 March 2013)

The title compound, C18H24NO3+·Cl·H2O, was synthesized by the reaction of propranolol hydro­chloride with acetyl chloride in chloro­form followed by slow evaporation in air. In the cation, the dihedral angle between the planes of the naphthalene ring system and the acetate group is 71.1 (2)°. An intra­molecular N—H⋯O hydrogen bond results in the formation of a non-planar pseudo-ring, with the ether O and the H atom displaced by −1.328 (2) and 0.65 Å, respectively, from the plane of the other ring atoms. The cation and anion are linked by an N—H⋯Cl hydrogen bond. The water molecule is linked to a methyl H atom by C—H⋯O hydrogen bond.

Related literature

The applications of the title compound, see: Barbosa et al. (2010[Barbosa, O., Ariza, C., Ortiz, C. & Torres, R. (2010). New Biotechnol. 27, 844-850.]). For the synthetic procedure, see: Irwin & Belaid (1987[Irwin, W. J. & Belaid, K. A. (1987). Drug Dev. Ind. Pharm. 13, 2017-2031.]). For bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C18H24NO3+·Cl·H2O

  • Mr = 355.85

  • Monoclinic, P 21 /c

  • a = 15.559 (3) Å

  • b = 8.2120 (16) Å

  • c = 14.665 (3) Å

  • β = 93.23 (3)°

  • V = 1870.8 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.23 mm−1

  • T = 293 K

  • 0.30 × 0.20 × 0.10 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.936, Tmax = 0.978

  • 3424 measured reflections

  • 3424 independent reflections

  • 1948 reflections with I > 2σ(I)

  • 3 standard reflections every 200 reflections intensity decay: 1%

Refinement
  • R[F2 > 2σ(F2)] = 0.070

  • wR(F2) = 0.200

  • S = 0.99

  • 3424 reflections

  • 219 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.60 e Å−3

  • Δρmin = −0.28 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N—H0A⋯Cl 0.90 2.37 3.194 (3) 152
N—H0A⋯O2 0.90 2.59 2.948 (3) 105
C15—H15B⋯O1Wi 0.96 2.53 3.469 (9) 166
Symmetry code: (i) -x+1, -y+1, -z+1.

Data collection: CAD-4 Software (Enraf–Nonius, 1985[Enraf-Nonius (1985). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Propranolol hydrochloride is an important beta-adrenergic blocking agent, and used in the treatment of hypertension and cardiovascular disorders. Molecular modifications of propranolol are varied with examples in the amino-substituent, side-chain variants and nuclear changes including all mono ring-hydroxylated products (Irwin et al., 1987). Here, the title compound, (I), an important propranolol derivative, was synthesized by the reaction of propranolol hydrochloride with acetyl chloride in chloroform, and we report the crystal structure of (I).

In the molecule of (I), (Fig.1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. The dihedral angle of naphthalene ring system and acetate group is 71.11 °. The amino hydrogen is linked to chloride and oxygen atoms by the intramolecular N—H···Cl and N—H···O hydrogen bonds, respectively, which seem to be very effective in the stabilization of the crystal structure. The intramolecular N—H···O hydrogen bond results in the formation of one non-planar pseudo ring (O2/C12/C13/N/H0A), with O2 and H0A atoms displaced by -1.328 Å and 0.65 Å, respectively, from the plane of the other ring atoms.

Related literature top

The title compound is an important propranolol derivative. For background to its applications, see: Barbosa et al. (2010). For the synthetic procedure, see: Irwin & Belaid (1987). For bond-length data, see: Allen et al. (1987).

Experimental top

The title compound, (I) was prepared by the literature method (Irwin et al., 1987). Crystals suitable for X-ray analysis were obtained by dissolving (I) (0.5 g) in methanol (20 ml) and evaporating the solvent slowly at room temperature for about 10 d.

Refinement top

H atoms were positioned geometrically, with N—H = 0.90 Å (for NH), C—H = 0.93, 0.96, 0.97 and 0.98 Å for aromatic, methyl, methylene and methine H, respectively, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.2 for aromatic H, and x = 1.5 for other H.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software (Enraf–Nonius, 1985); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are shown by dashed lines.
[Figure 2] Fig. 2. A packing diagram of (I). Hydrogen bonds are shown by dashed lines.
[2-Acetoxy-3-(naphthalen-1-yloxy)propyl](propan-2-yl)azanium chloride monohydrate top
Crystal data top
C18H24NO3+·Cl·H2OF(000) = 760
Mr = 355.85Dx = 1.263 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 15.559 (3) Åθ = 9–13°
b = 8.2120 (16) ŵ = 0.23 mm1
c = 14.665 (3) ÅT = 293 K
β = 93.23 (3)°Block, yellow
V = 1870.8 (6) Å30.30 × 0.20 × 0.10 mm
Z = 4
Data collection top
Enraf–Nonius CAD-4
diffractometer
1948 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 25.4°, θmin = 1.3°
ω/2θ scansh = 1818
Absorption correction: ψ scan
(North et al., 1968)
k = 09
Tmin = 0.936, Tmax = 0.978l = 017
3424 measured reflections3 standard reflections every 200 reflections
3424 independent reflections intensity decay: 1%
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)] = 0.070Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.200H-atom parameters constrained
S = 0.99 w = 1/[σ2(Fo2) + (0.1097P)2]
where P = (Fo2 + 2Fc2)/3
3424 reflections(Δ/σ)max = 0.001
219 parametersΔρmax = 0.60 e Å3
1 restraintΔρmin = 0.28 e Å3
Crystal data top
C18H24NO3+·Cl·H2OV = 1870.8 (6) Å3
Mr = 355.85Z = 4
Monoclinic, P21/cMo Kα radiation
a = 15.559 (3) ŵ = 0.23 mm1
b = 8.2120 (16) ÅT = 293 K
c = 14.665 (3) Å0.30 × 0.20 × 0.10 mm
β = 93.23 (3)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
1948 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.000
Tmin = 0.936, Tmax = 0.9783 standard reflections every 200 reflections
3424 measured reflections intensity decay: 1%
3424 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0701 restraint
wR(F2) = 0.200H-atom parameters constrained
S = 0.99Δρmax = 0.60 e Å3
3424 reflectionsΔρmin = 0.28 e Å3
219 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
N0.40172 (17)0.4306 (4)0.60092 (17)0.0541 (7)
H0A0.38550.50680.55930.065*
H0B0.45410.39430.58740.065*
O10.20414 (15)0.0867 (3)0.54378 (16)0.0606 (7)
C10.0783 (2)0.0245 (5)0.5948 (2)0.0591 (10)
O20.27260 (14)0.3625 (3)0.45087 (15)0.0553 (6)
C20.0499 (2)0.1326 (6)0.6206 (2)0.0669 (11)
H2A0.08420.22310.61100.080*
O30.3081 (2)0.2709 (4)0.31387 (19)0.0930 (10)
C30.0272 (3)0.1522 (7)0.6592 (3)0.0810 (13)
H3A0.04500.25550.67580.097*
C40.0788 (3)0.0189 (9)0.6735 (3)0.0974 (17)
H4A0.13140.03430.69930.117*
C50.0547 (3)0.1334 (8)0.6510 (3)0.0886 (15)
H5A0.09080.22060.66190.106*
C60.0248 (3)0.1623 (6)0.6110 (3)0.0714 (12)
C70.0532 (3)0.3184 (6)0.5867 (3)0.0811 (13)
H7A0.01940.40910.59720.097*
C80.1295 (3)0.3368 (6)0.5482 (3)0.0821 (13)
H8A0.14730.44060.53220.099*
C90.1817 (3)0.2049 (5)0.5320 (3)0.0652 (10)
H9A0.23380.22110.50520.078*
C100.1576 (2)0.0522 (5)0.5546 (2)0.0538 (9)
C110.2810 (2)0.0738 (5)0.4924 (3)0.0592 (9)
H11A0.26570.04390.42960.071*
H11B0.31920.00880.51910.071*
C120.3240 (2)0.2361 (4)0.4961 (2)0.0537 (9)
H12A0.37910.22800.46720.064*
C130.3402 (2)0.2938 (5)0.5934 (2)0.0582 (9)
H13A0.28610.32760.61720.070*
H13B0.36260.20390.63050.070*
C140.4085 (2)0.5085 (5)0.6944 (2)0.0603 (10)
H14A0.41130.42110.74000.072*
C150.4901 (3)0.6048 (6)0.7055 (3)0.1012 (17)
H15A0.49670.64630.76660.152*
H15B0.48790.69390.66300.152*
H15C0.53810.53590.69380.152*
C160.3301 (3)0.6086 (6)0.7096 (3)0.0930 (15)
H16A0.33480.65480.76980.140*
H16B0.27980.54090.70350.140*
H16C0.32550.69450.66520.140*
C170.2726 (2)0.3674 (5)0.3586 (2)0.0626 (10)
C180.2213 (3)0.5119 (6)0.3213 (3)0.0890 (14)
H18A0.22180.51280.25590.134*
H18B0.24650.61080.34530.134*
H18C0.16300.50370.33910.134*
Cl0.41641 (6)0.70545 (13)0.44852 (7)0.0688 (4)
O1W0.5140 (4)0.0297 (9)0.4132 (5)0.252 (3)
H1WB0.53280.06740.41720.302*
H1WA0.55740.09220.41130.302*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N0.0495 (16)0.0682 (19)0.0441 (15)0.0011 (15)0.0008 (12)0.0002 (14)
O10.0526 (14)0.0639 (16)0.0663 (16)0.0022 (13)0.0111 (12)0.0077 (13)
C10.050 (2)0.085 (3)0.0401 (18)0.002 (2)0.0130 (16)0.0034 (18)
O20.0534 (14)0.0682 (16)0.0438 (13)0.0015 (12)0.0022 (10)0.0029 (11)
C20.054 (2)0.090 (3)0.056 (2)0.002 (2)0.0078 (17)0.008 (2)
O30.110 (3)0.121 (3)0.0496 (16)0.022 (2)0.0121 (16)0.0121 (17)
C30.056 (3)0.122 (4)0.064 (3)0.021 (3)0.004 (2)0.008 (3)
C40.058 (3)0.165 (6)0.069 (3)0.010 (4)0.007 (2)0.010 (3)
C50.056 (3)0.138 (5)0.071 (3)0.019 (3)0.004 (2)0.019 (3)
C60.053 (2)0.106 (4)0.054 (2)0.012 (2)0.0072 (17)0.018 (2)
C70.086 (3)0.082 (3)0.074 (3)0.021 (3)0.010 (2)0.018 (2)
C80.089 (3)0.074 (3)0.082 (3)0.001 (3)0.008 (3)0.008 (2)
C90.061 (2)0.072 (3)0.061 (2)0.003 (2)0.0072 (18)0.001 (2)
C100.0479 (19)0.066 (3)0.0473 (19)0.0038 (19)0.0015 (15)0.0021 (17)
C110.051 (2)0.063 (2)0.063 (2)0.0006 (18)0.0019 (17)0.0068 (18)
C120.0424 (18)0.066 (2)0.053 (2)0.0026 (17)0.0037 (15)0.0012 (17)
C130.059 (2)0.067 (2)0.049 (2)0.008 (2)0.0005 (16)0.0014 (18)
C140.064 (2)0.076 (3)0.0399 (18)0.002 (2)0.0031 (16)0.0029 (18)
C150.100 (4)0.113 (4)0.090 (3)0.035 (3)0.004 (3)0.036 (3)
C160.090 (3)0.108 (4)0.079 (3)0.028 (3)0.009 (2)0.027 (3)
C170.058 (2)0.081 (3)0.049 (2)0.016 (2)0.0001 (17)0.001 (2)
C180.093 (3)0.099 (3)0.073 (3)0.012 (3)0.021 (2)0.016 (3)
Cl0.0648 (6)0.0687 (7)0.0732 (7)0.0056 (5)0.0059 (5)0.0091 (5)
O1W0.240 (7)0.227 (7)0.286 (8)0.022 (6)0.014 (7)0.026 (6)
Geometric parameters (Å, º) top
N—C131.476 (4)C9—C101.355 (5)
N—C141.511 (4)C9—H9A0.9300
N—H0A0.9000C11—C121.491 (5)
N—H0B0.9000C11—H11A0.9700
O1—C101.365 (4)C11—H11B0.9700
O1—C111.452 (4)C12—C131.511 (5)
C1—C101.416 (5)C12—H12A0.9800
C1—C21.422 (5)C13—H13A0.9700
C1—C61.432 (5)C13—H13B0.9700
O2—C171.353 (4)C14—C151.498 (5)
O2—C121.448 (4)C14—C161.498 (5)
C2—C31.364 (5)C14—H14A0.9800
C2—H2A0.9300C15—H15A0.9600
O3—C171.186 (5)C15—H15B0.9600
C3—C41.380 (7)C15—H15C0.9600
C3—H3A0.9300C16—H16A0.9600
C4—C51.352 (7)C16—H16B0.9600
C4—H4A0.9300C16—H16C0.9600
C5—C61.419 (6)C17—C181.515 (6)
C5—H5A0.9300C18—H18A0.9600
C6—C71.409 (6)C18—H18B0.9600
C7—C81.351 (6)C18—H18C0.9600
C7—H7A0.9300O1W—H1WB0.8500
C8—C91.382 (6)O1W—H1WA0.8500
C8—H8A0.9300
C13—N—C14113.7 (3)C12—C11—H11B110.3
C13—N—H0A108.8H11A—C11—H11B108.5
C14—N—H0A108.8O2—C12—C11112.9 (3)
C13—N—H0B108.8O2—C12—C13105.5 (3)
C14—N—H0B108.8C11—C12—C13111.4 (3)
H0A—N—H0B107.7O2—C12—H12A109.0
C10—O1—C11117.2 (3)C11—C12—H12A109.0
C10—C1—C2123.2 (4)C13—C12—H12A109.0
C10—C1—C6118.1 (4)N—C13—C12112.5 (3)
C2—C1—C6118.7 (4)N—C13—H13A109.1
C17—O2—C12116.6 (3)C12—C13—H13A109.1
C3—C2—C1120.7 (4)N—C13—H13B109.1
C3—C2—H2A119.6C12—C13—H13B109.1
C1—C2—H2A119.6H13A—C13—H13B107.8
C2—C3—C4120.2 (5)C15—C14—C16112.7 (4)
C2—C3—H3A119.9C15—C14—N109.7 (3)
C4—C3—H3A119.9C16—C14—N110.6 (3)
C5—C4—C3121.6 (5)C15—C14—H14A107.9
C5—C4—H4A119.2C16—C14—H14A107.9
C3—C4—H4A119.2N—C14—H14A107.9
C4—C5—C6121.0 (5)C14—C15—H15A109.5
C4—C5—H5A119.5C14—C15—H15B109.5
C6—C5—H5A119.5H15A—C15—H15B109.5
C7—C6—C5123.4 (5)C14—C15—H15C109.5
C7—C6—C1118.9 (4)H15A—C15—H15C109.5
C5—C6—C1117.7 (5)H15B—C15—H15C109.5
C8—C7—C6120.2 (4)C14—C16—H16A109.5
C8—C7—H7A119.9C14—C16—H16B109.5
C6—C7—H7A119.9H16A—C16—H16B109.5
C7—C8—C9121.5 (5)C14—C16—H16C109.5
C7—C8—H8A119.3H16A—C16—H16C109.5
C9—C8—H8A119.3H16B—C16—H16C109.5
C10—C9—C8120.7 (4)O3—C17—O2124.0 (4)
C10—C9—H9A119.7O3—C17—C18125.2 (4)
C8—C9—H9A119.7O2—C17—C18110.8 (4)
C9—C10—O1126.1 (3)C17—C18—H18A109.5
C9—C10—C1120.7 (4)C17—C18—H18B109.5
O1—C10—C1113.2 (3)H18A—C18—H18B109.5
O1—C11—C12107.3 (3)C17—C18—H18C109.5
O1—C11—H11A110.3H18A—C18—H18C109.5
C12—C11—H11A110.3H18B—C18—H18C109.5
O1—C11—H11B110.3H1WB—O1W—H1WA107.3
C10—C1—C2—C3179.9 (3)C11—O1—C10—C1172.2 (3)
C6—C1—C2—C30.6 (5)C2—C1—C10—C9179.6 (3)
C1—C2—C3—C40.1 (6)C6—C1—C10—C90.2 (5)
C2—C3—C4—C50.7 (7)C2—C1—C10—O10.4 (5)
C3—C4—C5—C60.4 (7)C6—C1—C10—O1178.9 (3)
C4—C5—C6—C7179.6 (4)C10—O1—C11—C12175.7 (3)
C4—C5—C6—C10.4 (6)C17—O2—C12—C1178.9 (4)
C10—C1—C6—C70.2 (5)C17—O2—C12—C13159.2 (3)
C2—C1—C6—C7179.1 (3)O1—C11—C12—O264.4 (4)
C10—C1—C6—C5179.8 (3)O1—C11—C12—C1354.0 (4)
C2—C1—C6—C50.9 (5)C14—N—C13—C12170.7 (3)
C5—C6—C7—C8179.5 (4)O2—C12—C13—N72.0 (3)
C1—C6—C7—C80.5 (6)C11—C12—C13—N165.1 (3)
C6—C7—C8—C90.3 (6)C13—N—C14—C15161.4 (4)
C7—C8—C9—C100.1 (6)C13—N—C14—C1673.6 (4)
C8—C9—C10—O1178.6 (3)C12—O2—C17—O34.0 (5)
C8—C9—C10—C10.4 (5)C12—O2—C17—C18176.2 (3)
C11—O1—C10—C98.8 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N—H0A···Cl0.902.373.194 (3)152
N—H0A···O20.902.592.948 (3)105
C15—H15B···O1Wi0.962.533.469 (9)166
Symmetry code: (i) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC18H24NO3+·Cl·H2O
Mr355.85
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)15.559 (3), 8.2120 (16), 14.665 (3)
β (°) 93.23 (3)
V3)1870.8 (6)
Z4
Radiation typeMo Kα
µ (mm1)0.23
Crystal size (mm)0.30 × 0.20 × 0.10
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.936, 0.978
No. of measured, independent and
observed [I > 2σ(I)] reflections
3424, 3424, 1948
Rint0.000
(sin θ/λ)max1)0.603
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.070, 0.200, 0.99
No. of reflections3424
No. of parameters219
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.60, 0.28

Computer programs: CAD-4 Software (Enraf–Nonius, 1985), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N—H0A···Cl0.902.373.194 (3)152
N—H0A···O20.902.592.948 (3)105
C15—H15B···O1Wi0.96002.53003.469 (9)166.00
Symmetry code: (i) x+1, y+1, z+1.
 

Acknowledgements

The authors thank the Center of Testing and Analysis, Nanjing University, for the data collection.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science
First citationBarbosa, O., Ariza, C., Ortiz, C. & Torres, R. (2010). New Biotechnol. 27, 844–850.  Web of Science CrossRef CAS
First citationEnraf–Nonius (1985). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
First citationIrwin, W. J. & Belaid, K. A. (1987). Drug Dev. Ind. Pharm. 13, 2017–2031.  CrossRef CAS Web of Science
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals

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