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ISSN: 2056-9890

Crystal structures of bis­­[(9S,13S,14S)-3-meth­­oxy-17-methyl­morphinanium] tetra­chlorido­cobaltate and tetra­chlorido­cuprate

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aChemistry Department, SUNY Buffalo State, 1300 Elmwood Ave, Buffalo, NY 14222, USA
*Correspondence e-mail: nazareay@buffalostate.edu

Edited by J. Simpson, University of Otago, New Zealand (Received 7 December 2016; accepted 14 December 2016; online 1 January 2017)

(9S,13S,14S)-3-Meth­oxy-17-methyl­morphinan (dextromethorphan) forms two isostructural salts with (a) tetra­chlorido­cobaltate, namely bis­[(9S,13S,14S)-3-meth­oxy-17-methyl­morphinanium] tetra­chlorido­cobaltate, (C18H26NO)2[CoCl4], and (b) tetra­chlorido­cuprate, namely bis­[(9S,13S,14S)-3-meth­oxy-17-methyl­morphinanium] tetra­chlorido­cuprate, (C18H26NO)2[CuCl4]. The distorted tetra­hedral anions are located on twofold rotational axes. The dextromethorphan cation can be described as being composed of two ring systems, a tetra­hydro­naphthalene system A+B and a deca­hydro­isoquinolinium subunit C+D, that are nearly perpendicular to one another: the angle between mean planes of the A+B and C+D moieties is 78.8 (1)° for (a) and 79.0 (1)° for (b). Two symmetry-related cations of protonated dextromethorphan are connected to the tetra­chlorido­cobaltate (or tetra­chlorido­cuprate) anions via strong N—H⋯Cl hydrogen bonds, forming neutral ion associates. These associates are packed in the (001) plane with no strong attractive bonding between them. Both compounds are attractive crystalline forms for unambiguous identification of the dextromethorphan and, presumably, of its optical isomer, levomethorphan.

1. Chemical context

Seemingly innocuous and common over-the-counter drugs have a wide range of uses to treat illness and relieve pain, but they can also lead to long-term abuse and fatalities. Dextromethorphan (systematic name (9S,13S,14S)-3-meth­oxy-17-methyl­morphinan) is a member of the Morphinan class of naturally occurring and semi-synthetic psychoactive drugs, chemically similar to morphine, codeine and oxycodone, and differing from these only by a few functional groups. It is commonly found in many cold and cough medicines. In high concentrations, dextromethorphan has effects similar to phencyclidine and ketamine, a dissociative anesthetic, which is known to induce visual hallucinations and a heightened sense of perceptual awareness (Bruera & Portenoy, 2010[Bruera, E. D. & Portenoy, R. K. (2010). Editors. Cancer Pain. Cambridge University Press.]). The similarity to well-known substances of abuse that are highly controlled makes dextromethorphan an attractive target for recreational ingestion and purification from over-the-counter products.

Cobalt(II) compounds have been employed in color tests for alkaloid detection: e.g., the Scott reagent (Cole, 2003[Cole, M. D. (2003). In The analysis of controlled substances. Hoboken: Wiley & Sons.]). However, color reactions are usually not very specific and may lead to numerous false positives. To complicate the issue, levomethorphan, an optical isomer of dextromethorphan, is a strong opiate drug and is restricted like morphine in the US and many other countries. Therefore, usual NMR and MS identification may be insufficient for clear identification of dextromethorphan and levomethorphan.

We suggest that easy-to-grow crystals of alkaloid metal complexes may provide a suitable analytical approach for unambiguous identification. As a part of this study, we report the crystal structures of two such compounds here.

[Scheme 1]

2. Structural commentary

The protonated dextromethorphan cations are nearly identical (Figs. 1[link]–3[link][link]). In both cases, protonation as well as inter­action with the tetra­chlorido­cobaltate or tetra­chlorido­cuprate anions does not affect the geometry of the methorphan ring system (Fig. 4[link]), leaving the shape of the organic mol­ecule intact. The derived mol­ecular dimensions within both structures are unexceptional and consistent with those known for similar mol­ecules (Gylbert & Carlström, 1977[Gylbert, L. & Carlström, D. (1977). Acta Cryst. B33, 2833-2837.]).

[Figure 1]
Figure 1
The numbering scheme of the dextromethorphan tetra­chlorido­cobaltate complex (a) with displacement ellipsoids drawn at the 50% probability level.
[Figure 2]
Figure 2
The numbering scheme of the dextromethorphan tetra­chlorido­cuprate complex (b) with displacement ellipsoids drawn at the 50% probability level.
[Figure 3]
Figure 3
Overlay of the dextromethorphan tetra­chlorido­cobaltate (green) and tetra­chlorido­cuprate (red) complexes.
[Figure 4]
Figure 4
Overlay of the protonated dextromethorphan cation (a) and the dextromethorphan mol­ecule (refcode XAPTAK01).

There are four six-membered rings in a dextromethorphan mol­ecule. The aromatic ring A is practically planar with deviations less than 0.01 Å in all cases. The cyclo­hexene ring B can be described as a half-chair shifted towards an envelope conformation: atoms C10, C11, C12 and C13 are adjacent to the aromatic ring and therefore almost planar while C9 and C14 deviate from this plane in opposite directions: C9 − 0.191 (6) Å (a) and −0.173 (8) Å (b); C14 + 0.553 (5) Å (a) and +0.562 (8) Å (b). This half-chair conformation is known (Ibberson et al., 2008[Ibberson, R. M., Telling, M. T. F. & Parsons, S. (2008). Cryst. Growth Des. 8, 512-518.]) for the unsubstituted cyclo­hexene mol­ecule in the solid state.

The cyclo­hexane C and piperidine B rings both have chair conformations. These two rings are nearly coplanar, with the angles between their mean planes being 7.8 (1)° (a) and 8.2 (2)° (b). As a result, the dextromethorphan cation can be described as two ring systems A+B and C+D, being nearly perpendicular to each other: the angle between the mean planes of the A+B and C+D moieties is 78.8 (1)° for (a) and 79.0 (1)° for (b).

The tetra­chlorido­cobaltate and tetra­chlorido­cuprate anions both have a distorted tetra­hedral geometry. In the cobalt complex, the Cl1—Co1—Cl2 angle is flattened to 116.59 (3)°, while in the copper analogue the Cl2—Cu1—Cl1 angle is 129.04 (4)°. The larger deviation from tetra­hedral geometry in the copper(II) compound is possibly due to the Jahn–Teller effect, as packing effects should be similar in both compounds.

3. Supra­molecular features

The tetra­chlorido­cobaltate and tetra­chlorido­cuprate anions are located on twofold rotational axes. Two identical protonated dextromethorphan cations are connected to tetra­chlorido­cobaltate (or tetra­chlorido­cuprate) anions via strong N—H⋯Cl hydrogen bonds (Tables 1[link] and 2[link]), thus forming neutral ion associates (Fig. 5[link]). These associates are packed into layers in the (001) plane (Fig. 6[link]) with no strong attractive bonding between them. Methyl groups adjacent to the protonated nitro­gen atoms separate the tetra­chlorido­metalate anions, thus reducing electrostatic repulsion between them. Close packing and electrostatic inter­action with anion results in several short C—H⋯Cl contacts (Tables 1[link] and 2[link]).

Table 1
Hydrogen-bond geometry (Å, °) for (a)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯Cl1 0.93 (4) 2.26 (4) 3.145 (2) 158 (4)
C10—H10B⋯Cl2i 0.97 (3) 2.71 (2) 3.609 (3) 153 (1)
C17—H17B⋯Cl2ii 0.98 (3) 2.75 (3) 3.615 (4) 148 (1)
Symmetry codes: (i) [x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]; (ii) [x-{\script{1\over 2}}, y-{\script{1\over 2}}, z].

Table 2
Hydrogen-bond geometry (Å, °) for (b)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯Cl1 0.81 (6) 2.46 (6) 3.207 (4) 154 (5)
C10—H10A⋯Cl2i 0.99 2.83 3.754 (5) 156
C17—H17B⋯Cl2ii 0.98 2.68 3.590 (5) 156
Symmetry codes: (i) [x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]; (ii) [x-{\script{1\over 2}}, y-{\script{1\over 2}}, z].
[Figure 5]
Figure 5
Two dextromethorphan cations forming an ion associate with the tetra­chlorido­cobaltate dianion. Hydrogen bonds are drawn as dashed lines.
[Figure 6]
Figure 6
Packing diagram of the ion associates in structure (a), viewed along [010].

The layers assemble in the 3D crystal (Fig. 6[link]) via weak inter­molecular forces: the only specific inter-layer contact is C15—H15B⋯O1 with C⋯O distances too long to be considered a strong hydrogen bond [3.473 (4) (a) and 3.507 (6) Å (b)].

4. Database survey

There are three reported dextromethorphan structures deposited in the Cambridge Structural Database (CSD Version 5.37; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]). Of these structures, two report structures of the neutral mol­ecule (refcodes XAPTAK and XAPTAK01), one of which (Swamy et al., 2005[Swamy, G. Y. S. K., Ravikumar, K. & Bhujanga Rao, A. K. S. (2005). Acta Cryst. E61, o2071-o2073.]) refers to a room-temperature measurement and the other (Scheins et al., 2007[Scheins, S., Messerschmidt, M., Morgenroth, W., Paulmann, C. & Luger, P. (2007). J. Phys. Chem. A, 111, 5499-5508.]) a high-quality charge-density investigation performed at 20 K.

A protonated form is also known in a form of the bromide salt (refcode DEXORP), in which one solvate water mol­ecule is connected to a protonated nitro­gen atom via a hydrogen bond (Gylbert & Carlström, 1977[Gylbert, L. & Carlström, D. (1977). Acta Cryst. B33, 2833-2837.]).

5. Synthesis and crystallization

Dextromethorphan was isolated during the analysis of a proprietary cough syrup using a standard Pharmacopoeia procedure (WHO, 2016[WHO (2016). The International Pharmacopoeia, 6th ed. (electronic resource) https://apps.who.int/phint/2016/index.html#p/home]). GC–MS assay of the hexane solution shows dextromethorphan to be a main component, with a small admixture of menthol.

Dextromethorphan was positively identified using NMR and FTIR spectra. Slow evaporation of a hexane solution at 274 K yields crystals which were also identified as dextromethorphan (refcode XAPTAK; Swamy et al., 2005[Swamy, G. Y. S. K., Ravikumar, K. & Bhujanga Rao, A. K. S. (2005). Acta Cryst. E61, o2071-o2073.]). Around 20 mg of the solid residue was treated with two drops of concentrated HCl and an excess of cobalt(II) chloride or copper(II) chloride. Overnight standing in a refrigerator yielded crystals of the title compounds. The colors of the resulting solids were characteristic with the tetra­chlorido­cobaltate(II) salt being blue and the tetra­chlorido­cuprate(II) salt yellow. The bright colors of the crystals make them easy to separate from possible crystalline impurities. We expect that levomethorphan would yield similar crystals with the opposite chirality.

Crystals suitable for X-ray investigation (Fig. 7[link]) were cut from larger blocks before mounting on Mitigen loops.

[Figure 7]
Figure 7
Crystals of the dextromethorphan tetra­chlorido­cobaltate (blue,left corner) and tetra­chlorido­cuprate (yellow) salts. The diagonal image sizes are ∼ 0.6 and 3 mm, respectively.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. In (a), the hydrogen atom H1 of the protonated amine was refined in an isotropic approximation; idealized methyl groups refined as rotating groups with stretchable bonds and Uiso = 1.5Uiso(C); all other hydrogen atoms were refined with riding coordinates and stretchable bonds with Uiso = 1.2Uiso(C). In (b), the hydrogen atom were treated in an similar fashion.

Table 3
Experimental details

  (a) (b)
Crystal data
Chemical formula (C18H26NO)2[CoCl4] (C18H26NO)[CuCl4]
Mr 745.52 750.13
Crystal system, space group Monoclinic, C2 Monoclinic, C2
Temperature (K) 173 173
a, b, c (Å) 13.8447 (6), 9.2316 (4), 14.7018 (6) 13.8066 (16), 9.2934 (12), 14.651 (3)
β (°) 99.605 (2) 99.318 (6)
V3) 1852.68 (14) 1855.1 (5)
Z 2 2
Radiation type Mo Kα Mo Kα
μ (mm−1) 0.79 0.91
Crystal size (mm) 0.48 × 0.26 × 0.14 0.45 × 0.3 × 0.15
 
Data collection
Diffractometer Bruker PHOTON-100 CMOS Bruker PHOTON-100 CMOS
Absorption correction Multi-scan (SADABS, Bruker, 2015[Bruker (2015). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Multi-scan (SADABS, Bruker, 2015[Bruker (2015). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.761, 0.979 0.714, 0.933
No. of measured, independent and observed [I > 2σ(I)] reflections 43153, 4803, 4183 31097, 4243, 3521
Rint 0.061 0.047
(sin θ/λ)max−1) 0.677 0.649
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.083, 1.04 0.039, 0.100, 1.08
No. of reflections 4803 4243
No. of parameters 224 209
No. of restraints 1 1
H-atom treatment H atoms treated by a mixture of independent and constrained refinement H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.50, −0.26 0.51, −0.33
Absolute structure Flack x determined using 1711 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.]) Flack x determined using 1463 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.])
Absolute structure parameter 0.000 (7) −0.005 (6)
Computer programs: APEX2 and SAINT (Bruker, 2013[Bruker (2013). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. A71, 3-8.]), SHELXS97 and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) 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

For both compounds, data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013). Program(s) used to solve structure: SHELXT (Sheldrick, 2015) for a; SHELXS97 (Sheldrick, 2008) for b. For both compounds, program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

(a) Bis[(9S,13S,14S)-3-methoxy-17-methylmorphinanium] tetrachloridocobaltate top
Crystal data top
(C18H26NO)2[CoCl4]F(000) = 786
Mr = 745.52Dx = 1.336 Mg m3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
a = 13.8447 (6) ÅCell parameters from 9174 reflections
b = 9.2316 (4) Åθ = 2.9–28.3°
c = 14.7018 (6) ŵ = 0.79 mm1
β = 99.605 (2)°T = 173 K
V = 1852.68 (14) Å3Plate, blue
Z = 20.48 × 0.26 × 0.14 mm
Data collection top
Bruker PHOTON-100 CMOS
diffractometer
4183 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.061
φ and ω scansθmax = 28.8°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS, Bruker, 2015)
h = 1818
Tmin = 0.761, Tmax = 0.979k = 1212
43153 measured reflectionsl = 1919
4803 independent reflections
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.034 w = 1/[σ2(Fo2) + (0.0494P)2 + 0.4319P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.083(Δ/σ)max < 0.001
S = 1.04Δρmax = 0.50 e Å3
4803 reflectionsΔρmin = 0.26 e Å3
224 parametersAbsolute structure: Flack x determined using 1711 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
1 restraintAbsolute structure parameter: 0.000 (7)
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
O10.16362 (18)0.6052 (3)0.55317 (15)0.0489 (6)
N10.25197 (17)0.4294 (2)0.12297 (15)0.0277 (5)
C30.1767 (2)0.6210 (3)0.4633 (2)0.0363 (7)
C40.2614 (2)0.5804 (3)0.43052 (18)0.0302 (5)
H40.316 (2)0.5398 (15)0.4727 (15)0.036*
C120.26809 (18)0.5975 (3)0.33709 (17)0.0257 (5)
C110.1890 (2)0.6534 (3)0.27670 (18)0.0295 (6)
C10.1055 (2)0.6958 (4)0.3114 (2)0.0429 (7)
H1A0.055 (2)0.7347 (18)0.2728 (17)0.051*
C20.0990 (2)0.6796 (5)0.4031 (2)0.0467 (8)
H20.037 (3)0.7107 (14)0.4268 (10)0.056*
C180.2367 (3)0.5315 (4)0.6139 (2)0.0544 (10)
H18A0.2440 (18)0.436 (3)0.5914 (14)0.082*
H18B0.2184 (13)0.526 (3)0.6733 (18)0.082*
H18C0.2970 (18)0.582 (2)0.6180 (18)0.082*
C100.1886 (2)0.6676 (3)0.17396 (18)0.0320 (6)
H10A0.1270 (16)0.6305 (10)0.1415 (9)0.038*
H10B0.1917 (2)0.770 (3)0.1590 (4)0.038*
C90.2708 (2)0.5904 (3)0.13877 (18)0.0277 (5)
H90.2785 (4)0.6312 (16)0.084 (2)0.033*
C140.3669 (2)0.6068 (3)0.20608 (18)0.0291 (5)
H140.4161 (19)0.554 (2)0.1814 (9)0.035*
C80.3998 (3)0.7643 (4)0.2153 (2)0.0424 (7)
H8A0.3525 (15)0.8185 (17)0.2353 (6)0.051*
H8B0.4083 (3)0.7987 (12)0.1591 (17)0.051*
C70.4956 (3)0.7790 (5)0.2833 (2)0.0519 (9)
H7A0.5481 (18)0.7293 (17)0.2587 (9)0.062*
H7B0.5132 (7)0.881 (3)0.2911 (3)0.062*
C60.4853 (2)0.7140 (5)0.3763 (2)0.0458 (8)
H6A0.4353 (13)0.7693 (15)0.4036 (8)0.055*
H6B0.5490 (17)0.7216 (5)0.4192 (12)0.055*
C50.4548 (2)0.5556 (4)0.36542 (19)0.0374 (7)
H5A0.4490 (2)0.5175 (12)0.4233 (17)0.045*
H5B0.5036 (14)0.5032 (16)0.3426 (6)0.045*
C130.35654 (19)0.5369 (3)0.29939 (17)0.0267 (5)
C150.33688 (19)0.3737 (4)0.28147 (16)0.0297 (5)
H15A0.3903 (14)0.3325 (11)0.2615 (5)0.036*
H15B0.3292 (3)0.3292 (12)0.3359 (14)0.036*
C160.2462 (2)0.3475 (3)0.20999 (18)0.0302 (6)
H16A0.2401 (3)0.248 (3)0.1968 (4)0.036*
H16B0.1903 (15)0.3772 (8)0.2337 (7)0.036*
C170.1662 (2)0.3993 (4)0.0495 (2)0.0412 (7)
H17A0.1063 (15)0.427 (3)0.0712 (9)0.062*
H17B0.1640 (12)0.296 (3)0.0350 (13)0.062*
H17C0.1725 (10)0.455 (3)0.0055 (16)0.062*
Co10.50000.37707 (5)0.00000.02972 (14)
Cl10.41931 (5)0.22074 (7)0.08249 (4)0.03266 (16)
Cl20.61476 (7)0.52069 (9)0.08226 (7)0.0570 (3)
H10.306 (3)0.389 (5)0.102 (2)0.045 (9)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0563 (15)0.0602 (15)0.0369 (11)0.0015 (13)0.0271 (10)0.0068 (11)
N10.0275 (11)0.0271 (11)0.0289 (11)0.0014 (9)0.0057 (9)0.0015 (8)
C30.0418 (16)0.0377 (16)0.0331 (14)0.0024 (13)0.0173 (12)0.0085 (12)
C40.0307 (13)0.0330 (14)0.0279 (12)0.0019 (12)0.0083 (10)0.0013 (11)
C120.0254 (12)0.0264 (12)0.0267 (11)0.0021 (11)0.0079 (9)0.0019 (10)
C110.0274 (13)0.0308 (14)0.0306 (13)0.0074 (11)0.0054 (10)0.0041 (10)
C10.0319 (15)0.0512 (19)0.0450 (16)0.0152 (14)0.0048 (13)0.0101 (15)
C20.0362 (16)0.060 (2)0.0474 (17)0.0076 (15)0.0187 (14)0.0163 (16)
C180.083 (3)0.049 (2)0.0373 (17)0.000 (2)0.0278 (18)0.0019 (15)
C100.0346 (14)0.0312 (13)0.0286 (12)0.0069 (12)0.0009 (11)0.0000 (10)
C90.0344 (14)0.0254 (12)0.0236 (11)0.0031 (11)0.0054 (10)0.0037 (10)
C140.0279 (13)0.0341 (14)0.0271 (12)0.0018 (11)0.0097 (10)0.0007 (11)
C80.0501 (19)0.0430 (18)0.0353 (15)0.0152 (15)0.0104 (13)0.0005 (13)
C70.0452 (19)0.062 (2)0.0488 (19)0.0242 (17)0.0089 (15)0.0114 (17)
C60.0308 (15)0.065 (2)0.0392 (15)0.0089 (16)0.0003 (12)0.0110 (16)
C50.0239 (13)0.057 (2)0.0296 (13)0.0048 (13)0.0008 (11)0.0016 (13)
C130.0215 (12)0.0371 (15)0.0220 (11)0.0024 (11)0.0053 (9)0.0004 (10)
C150.0332 (13)0.0313 (13)0.0259 (11)0.0103 (13)0.0089 (10)0.0048 (12)
C160.0345 (14)0.0242 (14)0.0335 (13)0.0016 (11)0.0108 (11)0.0024 (10)
C170.0424 (16)0.0376 (18)0.0391 (15)0.0017 (14)0.0062 (12)0.0043 (13)
Co10.0263 (3)0.0280 (3)0.0351 (3)0.0000.0058 (2)0.000
Cl10.0312 (3)0.0354 (3)0.0342 (3)0.0025 (3)0.0137 (3)0.0038 (3)
Cl20.0577 (5)0.0342 (4)0.0711 (6)0.0164 (4)0.0130 (4)0.0022 (4)
Geometric parameters (Å, º) top
O1—C31.372 (3)C14—C131.544 (4)
O1—C181.408 (5)C8—H8A0.91 (3)
N1—C91.520 (3)C8—H8B0.91 (3)
N1—C161.500 (3)C8—C71.527 (5)
N1—C171.491 (3)C7—H7A0.98 (3)
N1—H10.93 (4)C7—H7B0.98 (3)
C3—C41.391 (4)C7—C61.521 (5)
C3—C21.384 (5)C6—H6A1.00 (3)
C4—H40.97 (3)C6—H6B1.00 (3)
C4—C121.401 (3)C6—C51.523 (6)
C12—C111.389 (4)C5—H5A0.94 (3)
C12—C131.532 (3)C5—H5B0.94 (3)
C11—C11.396 (4)C5—C131.543 (4)
C11—C101.515 (4)C13—C151.546 (4)
C1—H1A0.90 (4)C15—H15A0.92 (2)
C1—C21.375 (5)C15—H15B0.92 (2)
C2—H21.02 (4)C15—C161.516 (4)
C18—H18A0.95 (3)C16—H16A0.94 (2)
C18—H18B0.95 (3)C16—H16B0.94 (2)
C18—H18C0.95 (3)C17—H17A0.97 (2)
C10—H10A0.97 (2)C17—H17B0.97 (2)
C10—H10B0.97 (2)C17—H17C0.97 (2)
C10—C91.506 (4)Co1—Cl1i2.2920 (7)
C9—H90.91 (3)Co1—Cl12.2921 (7)
C9—C141.527 (4)Co1—Cl2i2.2592 (8)
C14—H140.96 (4)Co1—Cl22.2591 (8)
C14—C81.523 (4)
C3—O1—C18117.8 (3)H8A—C8—H8B108.0
C9—N1—H1109 (3)C7—C8—H8A109.5
C16—N1—C9113.3 (2)C7—C8—H8B109.5
C16—N1—H1104 (2)C8—C7—H7A109.5
C17—N1—C9112.9 (2)C8—C7—H7B109.5
C17—N1—C16112.0 (2)H7A—C7—H7B108.1
C17—N1—H1106 (2)C6—C7—C8110.6 (3)
O1—C3—C4124.0 (3)C6—C7—H7A109.5
O1—C3—C2116.3 (3)C6—C7—H7B109.5
C2—C3—C4119.7 (3)C7—C6—H6A109.6
C3—C4—H4119.8C7—C6—H6B109.6
C3—C4—C12120.4 (3)C7—C6—C5110.5 (3)
C12—C4—H4119.8H6A—C6—H6B108.1
C4—C12—C13120.1 (2)C5—C6—H6A109.6
C11—C12—C4119.6 (2)C5—C6—H6B109.6
C11—C12—C13119.8 (2)C6—C5—H5A109.2
C12—C11—C1118.9 (3)C6—C5—H5B109.2
C12—C11—C10122.7 (2)C6—C5—C13111.9 (3)
C1—C11—C10118.3 (3)H5A—C5—H5B107.9
C11—C1—H1A119.3C13—C5—H5A109.2
C2—C1—C11121.4 (3)C13—C5—H5B109.2
C2—C1—H1A119.3C12—C13—C14111.5 (2)
C3—C2—H2120.1C12—C13—C5113.9 (2)
C1—C2—C3119.9 (3)C12—C13—C15106.8 (2)
C1—C2—H2120.1C14—C13—C15107.2 (2)
O1—C18—H18A109.5C5—C13—C14108.0 (2)
O1—C18—H18B109.5C5—C13—C15109.1 (2)
O1—C18—H18C109.5C13—C15—H15A109.2
H18A—C18—H18B109.5C13—C15—H15B109.2
H18A—C18—H18C109.5H15A—C15—H15B107.9
H18B—C18—H18C109.5C16—C15—C13112.1 (2)
C11—C10—H10A108.5C16—C15—H15A109.2
C11—C10—H10B108.5C16—C15—H15B109.2
H10A—C10—H10B107.5N1—C16—C15110.8 (2)
C9—C10—C11115.1 (2)N1—C16—H16A109.5
C9—C10—H10A108.5N1—C16—H16B109.5
C9—C10—H10B108.5C15—C16—H16A109.5
N1—C9—H9108.3C15—C16—H16B109.5
N1—C9—C14107.7 (2)H16A—C16—H16B108.1
C10—C9—N1113.3 (2)N1—C17—H17A109.5
C10—C9—H9108.3N1—C17—H17B109.5
C10—C9—C14110.9 (2)N1—C17—H17C109.5
C14—C9—H9108.3H17A—C17—H17B109.5
C9—C14—H14107.5H17A—C17—H17C109.5
C9—C14—C13109.5 (2)H17B—C17—H17C109.5
C8—C14—C9111.5 (2)Cl1i—Co1—Cl1101.95 (4)
C8—C14—H14107.5Cl2i—Co1—Cl1106.94 (3)
C8—C14—C13113.0 (2)Cl2—Co1—Cl1i106.94 (3)
C13—C14—H14107.5Cl2—Co1—Cl1116.59 (3)
C14—C8—H8A109.5Cl2i—Co1—Cl1i116.59 (3)
C14—C8—H8B109.5Cl2—Co1—Cl2i108.13 (5)
C14—C8—C7110.9 (3)
O1—C3—C4—C12178.7 (3)C10—C9—C14—C1361.9 (3)
O1—C3—C2—C1178.5 (3)C9—N1—C16—C1554.1 (3)
N1—C9—C14—C8171.6 (2)C9—C14—C8—C7179.6 (2)
N1—C9—C14—C1362.6 (3)C9—C14—C13—C1254.0 (3)
C3—C4—C12—C111.0 (4)C9—C14—C13—C5180.0 (2)
C3—C4—C12—C13173.0 (3)C9—C14—C13—C1562.5 (3)
C4—C3—C2—C10.7 (5)C14—C8—C7—C655.7 (4)
C4—C12—C11—C12.2 (4)C14—C13—C15—C1657.8 (3)
C4—C12—C11—C10176.6 (3)C8—C14—C13—C1271.0 (3)
C4—C12—C13—C14162.0 (2)C8—C14—C13—C555.0 (3)
C4—C12—C13—C539.4 (4)C8—C14—C13—C15172.5 (2)
C4—C12—C13—C1581.2 (3)C8—C7—C6—C557.4 (4)
C12—C11—C1—C21.9 (5)C7—C6—C5—C1359.0 (4)
C12—C11—C10—C911.7 (4)C6—C5—C13—C1268.1 (3)
C12—C13—C15—C1661.8 (3)C6—C5—C13—C1456.4 (3)
C11—C12—C13—C1426.0 (4)C6—C5—C13—C15172.6 (2)
C11—C12—C13—C5148.6 (3)C5—C13—C15—C16174.6 (2)
C11—C12—C13—C1590.8 (3)C13—C12—C11—C1174.2 (3)
C11—C1—C2—C30.4 (6)C13—C12—C11—C104.6 (4)
C11—C10—C9—N181.1 (3)C13—C14—C8—C755.7 (3)
C11—C10—C9—C1440.1 (3)C13—C15—C16—N153.7 (3)
C1—C11—C10—C9167.1 (3)C16—N1—C9—C1064.7 (3)
C2—C3—C4—C120.4 (5)C16—N1—C9—C1458.4 (3)
C18—O1—C3—C46.0 (5)C17—N1—C9—C1063.9 (3)
C18—O1—C3—C2173.2 (3)C17—N1—C9—C14173.0 (2)
C10—C11—C1—C2176.9 (3)C17—N1—C16—C15176.9 (2)
C10—C9—C14—C863.9 (3)
Symmetry code: (i) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cl10.93 (4)2.26 (4)3.145 (2)158 (4)
C10—H10B···Cl2ii0.97 (3)2.71 (2)3.609 (3)153 (1)
C17—H17B···Cl2iii0.98 (3)2.75 (3)3.615 (4)148 (1)
Symmetry codes: (ii) x1/2, y+1/2, z; (iii) x1/2, y1/2, z.
(b) Bis[(9S,13S,14S)-3-methoxy-17-methylmorphinanium] tetrachloridocuprate top
Crystal data top
(C18H26NO)[CuCl4]F(000) = 790
Mr = 750.13Dx = 1.343 Mg m3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
a = 13.8066 (16) ÅCell parameters from 1064 reflections
b = 9.2934 (12) Åθ = 3.1–24.8°
c = 14.651 (3) ŵ = 0.91 mm1
β = 99.318 (6)°T = 173 K
V = 1855.1 (5) Å3Plate, yellow
Z = 20.45 × 0.3 × 0.15 mm
Data collection top
Bruker PHOTON-100 CMOS
diffractometer
3521 reflections with I > 2σ(I)
Radiation source: sealedtubeRint = 0.047
φ and ω scansθmax = 27.5°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS, Bruker, 2015)
h = 1717
Tmin = 0.714, Tmax = 0.933k = 1212
31097 measured reflectionsl = 1919
4243 independent reflections
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.039 w = 1/[σ2(Fo2) + (0.0512P)2 + 1.3109P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.100(Δ/σ)max < 0.001
S = 1.08Δρmax = 0.51 e Å3
4243 reflectionsΔρmin = 0.33 e Å3
209 parametersAbsolute structure: Flack x determined using 1463 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
1 restraintAbsolute structure parameter: 0.005 (6)
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
O10.1671 (3)0.6033 (4)0.5575 (2)0.0560 (9)
N10.2499 (3)0.4329 (4)0.1218 (2)0.0329 (8)
H10.296 (4)0.402 (6)0.100 (4)0.049*
C10.1031 (3)0.6887 (6)0.3155 (4)0.0497 (12)
H1A0.04770.72610.27560.060*
C20.0989 (4)0.6737 (7)0.4073 (4)0.0535 (13)
H20.04130.70180.43040.064*
C30.1774 (3)0.6181 (5)0.4669 (3)0.0400 (10)
C40.2621 (3)0.5790 (5)0.4319 (3)0.0340 (9)
H40.31670.54040.47230.041*
C50.4546 (3)0.5603 (6)0.3624 (3)0.0456 (12)
H5A0.44990.51910.42390.055*
H5B0.50640.50720.33690.055*
C60.4833 (4)0.7196 (7)0.3735 (3)0.0562 (14)
H6A0.43330.77250.40160.067*
H6B0.54710.72880.41500.067*
C70.4911 (4)0.7841 (7)0.2798 (4)0.0639 (16)
H7A0.54380.73470.25350.077*
H7B0.50850.88720.28730.077*
C80.3941 (4)0.7686 (6)0.2138 (3)0.0506 (13)
H8A0.34260.82460.23760.061*
H8B0.40140.80780.15240.061*
C90.2665 (3)0.5938 (4)0.1385 (3)0.0325 (9)
H90.27290.64020.07810.039*
C100.1834 (3)0.6653 (5)0.1759 (3)0.0374 (9)
H10A0.18340.76900.16040.045*
H10B0.12080.62420.14410.045*
C110.1865 (3)0.6506 (4)0.2785 (3)0.0335 (9)
C120.2669 (3)0.5965 (4)0.3383 (3)0.0287 (8)
C130.3559 (3)0.5401 (5)0.2980 (3)0.0313 (9)
C140.3634 (3)0.6116 (5)0.2038 (3)0.0340 (9)
H140.41490.55900.17630.041*
C150.3388 (3)0.3775 (5)0.2790 (3)0.0364 (9)
H15A0.39660.33650.25620.044*
H15B0.33220.32830.33760.044*
C160.2482 (3)0.3492 (5)0.2089 (3)0.0349 (9)
H16A0.24400.24510.19430.042*
H16B0.18930.37610.23560.042*
C170.1634 (4)0.4004 (5)0.0501 (3)0.0492 (12)
H17A0.10310.42610.07360.074*
H17B0.16250.29750.03550.074*
H17C0.16760.45620.00580.074*
C180.2410 (5)0.5329 (7)0.6180 (4)0.0624 (16)
H18A0.25010.43560.59500.094*
H18B0.22220.52700.67960.094*
H18C0.30260.58680.62180.094*
Cu10.50000.36997 (7)0.00000.0369 (2)
Cl10.41472 (7)0.21415 (11)0.07511 (7)0.0354 (2)
Cl20.62112 (11)0.51975 (14)0.05807 (10)0.0632 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.068 (2)0.066 (2)0.043 (2)0.0020 (19)0.0321 (18)0.0075 (17)
N10.0336 (19)0.0322 (17)0.0332 (19)0.0029 (15)0.0062 (15)0.0022 (15)
C10.036 (2)0.059 (3)0.053 (3)0.017 (2)0.005 (2)0.014 (2)
C20.036 (2)0.067 (3)0.061 (3)0.010 (2)0.020 (2)0.016 (3)
C30.047 (3)0.040 (2)0.038 (2)0.003 (2)0.020 (2)0.0082 (19)
C40.036 (2)0.035 (2)0.033 (2)0.0031 (17)0.0112 (17)0.0017 (17)
C50.027 (2)0.073 (4)0.036 (2)0.004 (2)0.0010 (17)0.002 (2)
C60.036 (2)0.087 (4)0.044 (3)0.013 (3)0.000 (2)0.011 (3)
C70.052 (3)0.075 (4)0.064 (4)0.034 (3)0.011 (3)0.012 (3)
C80.059 (3)0.055 (3)0.038 (3)0.023 (2)0.008 (2)0.001 (2)
C90.039 (2)0.031 (2)0.027 (2)0.0030 (17)0.0024 (16)0.0040 (16)
C100.039 (2)0.034 (2)0.036 (2)0.0091 (18)0.0027 (18)0.0012 (18)
C110.027 (2)0.032 (2)0.042 (2)0.0062 (16)0.0047 (17)0.0049 (18)
C120.0298 (19)0.0282 (19)0.030 (2)0.0030 (16)0.0097 (16)0.0006 (16)
C130.0249 (19)0.043 (2)0.027 (2)0.0045 (17)0.0049 (15)0.0007 (18)
C140.033 (2)0.041 (2)0.029 (2)0.0017 (18)0.0101 (17)0.0025 (18)
C150.041 (2)0.036 (2)0.034 (2)0.015 (2)0.0109 (16)0.004 (2)
C160.039 (2)0.028 (2)0.039 (2)0.0003 (17)0.0110 (17)0.0042 (18)
C170.052 (3)0.041 (3)0.049 (3)0.002 (2)0.008 (2)0.008 (2)
C180.099 (5)0.054 (3)0.041 (3)0.002 (3)0.033 (3)0.006 (3)
Cu10.0381 (4)0.0337 (4)0.0402 (4)0.0000.0105 (3)0.000
Cl10.0329 (5)0.0376 (5)0.0381 (5)0.0018 (4)0.0126 (4)0.0028 (4)
Cl20.0780 (10)0.0484 (7)0.0639 (8)0.0284 (7)0.0131 (7)0.0041 (6)
Geometric parameters (Å, º) top
O1—C31.366 (5)C9—H91.0000
O1—C181.401 (7)C9—C101.504 (6)
N1—H10.81 (5)C9—C141.523 (6)
N1—C91.526 (5)C10—H10A0.9900
N1—C161.499 (5)C10—H10B0.9900
N1—C171.487 (6)C10—C111.503 (6)
C1—H1A0.9500C11—C121.392 (6)
C1—C21.363 (7)C12—C131.539 (5)
C1—C111.395 (6)C13—C141.551 (6)
C2—H20.9500C13—C151.548 (7)
C2—C31.377 (7)C14—H141.0000
C3—C41.398 (6)C15—H15A0.9900
C4—H40.9500C15—H15B0.9900
C4—C121.394 (6)C15—C161.507 (6)
C5—H5A0.9900C16—H16A0.9900
C5—H5B0.9900C16—H16B0.9900
C5—C61.535 (9)C17—H17A0.9800
C5—C131.538 (6)C17—H17B0.9800
C6—H6A0.9900C17—H17C0.9800
C6—H6B0.9900C18—H18A0.9800
C6—C71.517 (8)C18—H18B0.9800
C7—H7A0.9900C18—H18C0.9800
C7—H7B0.9900Cu1—Cl1i2.2615 (11)
C7—C81.526 (7)Cu1—Cl12.2614 (11)
C8—H8A0.9900Cu1—Cl22.2354 (13)
C8—H8B0.9900Cu1—Cl2i2.2354 (13)
C8—C141.519 (6)
C3—O1—C18118.8 (4)C11—C10—C9115.1 (3)
C9—N1—H1108 (4)C11—C10—H10A108.5
C16—N1—H1106 (4)C11—C10—H10B108.5
C16—N1—C9113.3 (3)C1—C11—C10118.2 (4)
C17—N1—H1104 (4)C12—C11—C1118.1 (4)
C17—N1—C9113.3 (3)C12—C11—C10123.6 (4)
C17—N1—C16112.0 (3)C4—C12—C13120.4 (3)
C2—C1—H1A119.1C11—C12—C4120.1 (4)
C2—C1—C11121.8 (4)C11—C12—C13119.1 (4)
C11—C1—H1A119.1C5—C13—C12114.0 (3)
C1—C2—H2119.7C5—C13—C14108.3 (3)
C1—C2—C3120.6 (4)C5—C13—C15108.9 (4)
C3—C2—H2119.7C12—C13—C14111.6 (3)
O1—C3—C2117.3 (4)C12—C13—C15107.0 (3)
O1—C3—C4123.7 (4)C15—C13—C14106.8 (3)
C2—C3—C4119.0 (4)C8—C14—C9111.6 (4)
C3—C4—H4119.8C8—C14—C13112.5 (4)
C12—C4—C3120.4 (4)C8—C14—H14107.7
C12—C4—H4119.8C9—C14—C13109.5 (3)
H5A—C5—H5B107.9C9—C14—H14107.7
C6—C5—H5A109.3C13—C14—H14107.7
C6—C5—H5B109.3C13—C15—H15A109.1
C6—C5—C13111.7 (4)C13—C15—H15B109.1
C13—C5—H5A109.3H15A—C15—H15B107.9
C13—C5—H5B109.3C16—C15—C13112.3 (3)
C5—C6—H6A109.7C16—C15—H15A109.1
C5—C6—H6B109.7C16—C15—H15B109.1
H6A—C6—H6B108.2N1—C16—C15111.4 (3)
C7—C6—C5109.9 (4)N1—C16—H16A109.4
C7—C6—H6A109.7N1—C16—H16B109.4
C7—C6—H6B109.7C15—C16—H16A109.4
C6—C7—H7A109.5C15—C16—H16B109.4
C6—C7—H7B109.5H16A—C16—H16B108.0
C6—C7—C8110.7 (4)N1—C17—H17A109.5
H7A—C7—H7B108.1N1—C17—H17B109.5
C8—C7—H7A109.5N1—C17—H17C109.5
C8—C7—H7B109.5H17A—C17—H17B109.5
C7—C8—H8A109.5H17A—C17—H17C109.5
C7—C8—H8B109.5H17B—C17—H17C109.5
H8A—C8—H8B108.1O1—C18—H18A109.5
C14—C8—C7110.8 (5)O1—C18—H18B109.5
C14—C8—H8A109.5O1—C18—H18C109.5
C14—C8—H8B109.5H18A—C18—H18B109.5
N1—C9—H9108.3H18A—C18—H18C109.5
C10—C9—N1112.8 (3)H18B—C18—H18C109.5
C10—C9—H9108.3Cl1—Cu1—Cl1i100.36 (6)
C10—C9—C14111.6 (3)Cl2—Cu1—Cl1i99.65 (5)
C14—C9—N1107.5 (3)Cl2i—Cu1—Cl199.65 (5)
C14—C9—H9108.3Cl2i—Cu1—Cl1i129.04 (4)
C9—C10—H10A108.5Cl2—Cu1—Cl1129.04 (4)
C9—C10—H10B108.5Cl2i—Cu1—Cl2102.97 (9)
H10A—C10—H10B107.5
O1—C3—C4—C12179.5 (4)C9—C10—C11—C1167.6 (4)
N1—C9—C10—C1182.2 (4)C9—C10—C11—C1210.2 (6)
N1—C9—C14—C8171.7 (3)C10—C9—C14—C864.1 (5)
N1—C9—C14—C1363.0 (4)C10—C9—C14—C1361.2 (5)
C1—C2—C3—O1178.6 (5)C10—C11—C12—C4176.6 (4)
C1—C2—C3—C40.9 (8)C10—C11—C12—C133.6 (6)
C1—C11—C12—C41.2 (6)C11—C1—C2—C30.8 (9)
C1—C11—C12—C13174.2 (4)C11—C12—C13—C5148.6 (4)
C2—C1—C11—C10177.7 (5)C11—C12—C13—C1425.5 (5)
C2—C1—C11—C120.2 (7)C11—C12—C13—C1591.0 (4)
C2—C3—C4—C120.1 (7)C12—C13—C14—C871.2 (5)
C3—C4—C12—C111.2 (6)C12—C13—C14—C953.6 (5)
C3—C4—C12—C13174.1 (4)C12—C13—C15—C1661.9 (4)
C4—C12—C13—C538.4 (6)C13—C5—C6—C759.2 (6)
C4—C12—C13—C14161.5 (4)C13—C15—C16—N153.3 (4)
C4—C12—C13—C1582.0 (4)C14—C9—C10—C1139.0 (5)
C5—C6—C7—C858.2 (6)C14—C13—C15—C1657.7 (4)
C5—C13—C14—C855.1 (5)C15—C13—C14—C8172.2 (4)
C5—C13—C14—C9179.8 (4)C15—C13—C14—C963.1 (4)
C5—C13—C15—C16174.4 (3)C16—N1—C9—C1065.5 (4)
C6—C5—C13—C1268.5 (5)C16—N1—C9—C1458.0 (4)
C6—C5—C13—C1456.3 (5)C17—N1—C9—C1063.5 (5)
C6—C5—C13—C15172.1 (4)C17—N1—C9—C14173.1 (3)
C6—C7—C8—C1457.0 (6)C17—N1—C16—C15177.1 (4)
C7—C8—C14—C9179.7 (4)C18—O1—C3—C2173.1 (5)
C7—C8—C14—C1356.1 (5)C18—O1—C3—C46.3 (7)
C9—N1—C16—C1553.3 (5)
Symmetry code: (i) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cl10.81 (6)2.46 (6)3.207 (4)154 (5)
C10—H10A···Cl2ii0.992.833.754 (5)156
C17—H17B···Cl2iii0.982.683.590 (5)156
Symmetry codes: (ii) x1/2, y+1/2, z; (iii) x1/2, y1/2, z.
 

Acknowledgements

Financial support from the State University of New York for acquisition and maintenance of the X-ray diffractometer is gratefully acknowledged.

References

First citationBruera, E. D. & Portenoy, R. K. (2010). Editors. Cancer Pain. Cambridge University Press.  Google Scholar
First citationBruker (2013). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2015). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCole, M. D. (2003). In The analysis of controlled substances. Hoboken: Wiley & Sons.  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 citationGroom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationGylbert, L. & Carlström, D. (1977). Acta Cryst. B33, 2833–2837.  CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
First citationIbberson, R. M., Telling, M. T. F. & Parsons, S. (2008). Cryst. Growth Des. 8, 512–518.  CSD CrossRef CAS Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationScheins, S., Messerschmidt, M., Morgenroth, W., Paulmann, C. & Luger, P. (2007). J. Phys. Chem. A, 111, 5499–5508.  Web of Science CSD CrossRef PubMed CAS 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. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSwamy, G. Y. S. K., Ravikumar, K. & Bhujanga Rao, A. K. S. (2005). Acta Cryst. E61, o2071–o2073.  CSD CrossRef IUCr Journals Google Scholar
First citationWHO (2016). The International Pharmacopoeia, 6th ed. (electronic resource) https://apps.who.int/phint/2016/index.html#p/home  Google Scholar

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