Literature DB >> 28529783

Crystal structure of (S)-sec-butyl-ammonium l-tartrate monohydrate.

Ernlie A Publicover1, Jennifer Kolwich1, Darcie L Stack1, Alyssa J Doué1, Kai E O Ylijoki1.   

Abstract

The title hydrated mol-ecular salt, C4H12N+·C4H5O6-·H2O, was prepared by deprotonation of enanti-opure l-tartaric acid with racemic sec-butyl-amine in water. Only one enanti-omer was observed crystallographically, resulting from the combination of (S)-sec-butyl-amine with l-tartaric acid. The sec-butyl-ammonium moiety is disordered over two conformations related by rotation around the CH-CH2 bond; the refined occupancy ratio is 0.68 (1):0.32 (1). In the crystal, mol-ecules are linked through a network of O-H⋯O and N-H⋯O hydrogen-bonding inter-actions, between the ammonium H atoms, the tartrate hy-droxy H atoms, and the inter-stitial water, forming a three-dimensional supra-molecular structure.

Entities:  

Keywords:  chiral resolution; crystal structure; hydrogen bonding; l-tartaric acid; monohydrate; sec-butyl­amine

Year:  2017        PMID: 28529783      PMCID: PMC5418791          DOI: 10.1107/S2056989017005448

Source DB:  PubMed          Journal:  Acta Crystallogr E Crystallogr Commun


Chemical context

Given that the two enanti­omers of chiral compounds can display significantly different reactivity in the presence of other chiral compounds (e.g., enzymatic reactions), the separation of racemic mixtures is an important process in chemical synthesis. Since enanti­omers have identical physical properties, they cannot be separated by standard physical means such as distillation, crystallization, or chromatography. One common method to overcome this issue is to convert the racemic compound into a mixture of diastereomers through reaction with an enanti­opure component (Fogassy et al., 2006 ▸). This method has been used for the resolution of amine enanti­omers by protonation with chiral tartaric acid to produce diastereomeric salts. Examples include resolution of α-phenyl­ethyl­amine (Ault 1965 ▸; Kokila et al., 2002 ▸), N-methyl­amphetamines (Kmecz et al., 2004 ▸), 2-(benzyl­amino)-4-oxo-4-phenyl­butano­ate (Berkeš et al., 2003 ▸), 3-amino­butanol (Yatcherla et al., 2015 ▸), aminona­phthols (Periasamy et al., 2009 ▸), and serotonin and dopamine antagonists (Campiani et al., 2002 ▸).

Structural commentary

The mol­ecular structure of the title hydrated mol­ecular salt is shown in Fig. 1 ▸. The salt crystallized as a single enanti­omer, consisting of an (S)-sec-butyl ammonium cation, the l-tartrate anion, and one mol­ecule of water in the asymmetric unit. The Flack parameter [–2.7 (8)] was not of use in determining the absolute configuration of the sec-butyl­amine in the crystal. The absolute configuration of the (S)-sec-butyl ammonium cation is therefore based on the known absolute configuration of the l-tartaric acid used during compound preparation. The final structure is disordered, with the sec-butyl ammonium moiety taking on two different rotamers about the C2–C3 axis [refined occupancy ratio is 0.68 (1):0.32 (1)]. The major component takes on a conformation where the C4 methyl group and N9 ammonium are in a gauche relationship (Fig. 1 ▸ a), while the minor component places the C4A methyl group anti­periplanar to the N9A ammonium (Fig. 1 ▸ b). The C—C bond lengths in the amine and tartrate units average 1.523 (11) Å [1.516 (22) Å for the minor component of the disorder] and 1.532 (5) Å, respectively. The C—N bonds of the two components of the disorder average 1.498 (17) Å. The tartrate C—OH bonds average 1.411 (4) Å, while the C—O bonds of the carboxyl moieties average 1.257 (4) Å for the one involved in hydrogen bonding with the amine, and 1.258 (4) Å for the other. An intra­molecular hydrogen bond [2.00 (3) Å] occurs with O12 acting as a hydrogen-bond donor to O11.
Figure 1

The mol­ecular structure of the title hydrated mol­ecular salt, showing (a) the major and (b) the minor components of the disordered sec-butyl­ammonium moiety. Displacement ellipsoids are drawn at the 50% probability level. Red lines indicate the hydrogen bonds present within the asymmetric unit (see Table 1 ▸).

Supra­molecular features

The supra­molecular structure of the crystal consists of a network of inter­molecular O—H⋯O and N—H⋯O hydrogen bonds (Table 1 ▸, Fig. 2 ▸). Within the asymmetric unit, the N9—H9A atom of the sec-butyl ammonium cation acts as a hydrogen-bond donor to O11 of the tartrate anion [1.89 (2) Å], and the tartrate O13 donates a hydrogen bond to O16 of water [1.83 (3) Å]. The water in turn acts as a hydrogen-bond donor to O10 [2.01 (3) Å] and O15 [1.93 (4) Å] of two adjacent symmetry-related mol­ecules. Three additional hydrogen bonds are formed from N9, with N9—H9B donating to O12 of an adjacent mol­ecule [1.97 (3) Å], and N9—H9C donating to both O13 [2.16 (4) Å] and O15 [2.20 (4) Å] of a second adjacent mol­ecule. Finally, O14 donates a hydrogen bond to O10 of an additional symmetry-related mol­ecule [1.58 (5) Å]. A view of the crystal packing reveals the amine, tartrate, and water mol­ecules form columns when viewed down the c axis (Fig. 2 ▸).
Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A D—HH⋯A DA D—H⋯A
O12—H12⋯O110.90 (3)2.00 (3)2.602 (2)123 (3)
O13—H13⋯O160.85 (3)1.83 (3)2.662 (2)167 (3)
O14—H14⋯O10i 0.93 (4)1.58 (5)2.499 (2)171 (5)
O16—H16A⋯O15ii 0.87 (4)1.93 (4)2.791 (2)169 (4)
O16—H16B⋯O10iii 0.83 (4)2.01 (3)2.822 (2)167 (3)
N9—H9A⋯O110.93 (2)1.89 (2)2.803 (9)167 (4)
N9—H9B⋯O12ii 0.91 (2)1.97 (3)2.869 (11)169 (4)
N9—H9C⋯O13iv 0.92 (2)2.16 (4)2.922 (13)140 (5)
N9—H9C⋯O15iv 0.92 (2)2.20 (4)3.001 (12)145 (5)
N9A—H9AA⋯O110.91 (3)1.87 (4)2.76 (2)164 (8)
N9A—H9AB⋯O13iv 0.90 (3)1.96 (6)2.79 (3)151 (9)
N9A—H9AB⋯O15iv 0.90 (3)2.21 (8)2.83 (3)126 (6)
N9A—H9AC⋯O12ii 0.91 (3)1.99 (5)2.81 (3)150 (7)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .

Figure 2

A view of the crystal packing of the title hydrated mol­ecular salt, viewed along the c axis (major component of the disorder only). Red dashed lines indicate the inter­molecular hydrogen-bonding network (see Table 1 ▸). Displacement ellipsoids are drawn at the 50% probability level.

Database survey

The Cambridge Structural Database (CSD, Version 5.37; Groom et al., 2016 ▸) does not contain any other examples of simple secondary alkyl ammonium tartrate compounds. Two primary alkyl ammonium compounds have been reported: methyl­ammonium l-tartrate (XOJMOA; Callear et al., 2008a ▸) and n-butyl ammonium tartrate monohydrate (XOJDIL; Callear et al., 2008b ▸). Multiple stereoisomers of the phenyl­ethyl­ammonium tartrate salt have also been reported, viz. BUSHED (Mei et al., 2010 ▸), JADTUD (Molins et al., 1989 ▸), QAMYIN (Turkington et al., 2005 ▸), along with the related napthylethyl ammonium tartrate (QAPTEG; Gül & Nelson, 1999 ▸).

Synthesis and crystallization

The title compound was prepared via a modification to a previously published procedure (Helmkamp & Johnson, 1983 ▸). Racemic sec-butyl­amine (23.7 g, 17.2 ml, 324.0 mmol) was added to 40 ml of water and stirred to ensure homogeneity. While stirring, l-tartaric acid (50.0 g, 333.1 mmol) was slowly added. The solution was covered and allowed to stand at ambient temperature. After 24 h, crystal formation was evident. The crystallization process was allowed to continue undisturbed for one week, at which point a crystal for diffraction analysis was selected directly from the reaction mixture without further purification or isolation. The crystals can be isolated by vacuum filtration to yield a white crystalline solid (33.5 g, 42%).

Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 2 ▸. The H atoms on the N and O atoms were located in a difference-Fourier map and freely refined. The alkyl H atoms were included at geometrically idealized positions (C—H = 0.98–1.00 Å) and treated as riding with U iso(H) = 1.5U eq(C-meth­yl) and 1.2U eq(C) for other H atoms. The sec-butyl ammonium moiety displays a twofold disorder arising from two different rotamers being present that is best described as a 0.68 (1):0.32 (1) ratio of the two possible conformations. In the final cycles of refinement SAME restraints were applied to the two components of the disordered sec-butyl ammonium moiety and DFIX restraints were applied to the N—H bonds [N—H = 0.91 (2) Å] and the ammonium H⋯H distances [H⋯H = 1.50 (2) Å], to improve the refinement and geometry.
Table 2

Experimental details

Crystal data
Chemical formulaC4H12N+·C4H5O6 ·H2O
M r 241.24
Crystal system, space groupOrthorhombic, P21212
Temperature (K)125
a, b, c (Å)11.0921 (10), 14.8876 (14), 7.2070 (7)
V3)1190.13 (19)
Z 4
Radiation typeMo Kα
μ (mm−1)0.12
Crystal size (mm)0.21 × 0.09 × 0.04
 
Data collection
DiffractometerBruker APEXII CCD
Absorption correctionMulti-scan (SADABS; Bruker, 2008)
T min, T max 0.567, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections9652, 2925, 2613
R int 0.067
(sin θ/λ)max−1)0.680
 
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S 0.040, 0.104, 1.03
No. of reflections2925
No. of parameters236
No. of restraints20
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.30, −0.27

Computer programs: APEX2 and SAINT (Bruker, 2008 ▸), SHELXT (Sheldrick, 2015a ▸), SHELXL (Sheldrick, 2015b ▸), DIAMOND (Crystal Impact, 2014 ▸) and OLEX2 (Dolomanov et al., 2009 ▸).

Crystal structure: contains datablock(s) I, Global. DOI: 10.1107/S2056989017005448/su5364sup1.cif Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989017005448/su5364Isup2.hkl Click here for additional data file. Supporting information file. DOI: 10.1107/S2056989017005448/su5364Isup3.cml CCDC reference: 1543331 Additional supporting information: crystallographic information; 3D view; checkCIF report
C4H12N+·C4H5O6·H2ODx = 1.346 Mg m3
Mr = 241.24Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P21212Cell parameters from 5745 reflections
a = 11.0921 (10) Åθ = 2.3–28.6°
b = 14.8876 (14) ŵ = 0.12 mm1
c = 7.2070 (7) ÅT = 125 K
V = 1190.13 (19) Å3Needle, clear light colourless
Z = 40.21 × 0.09 × 0.04 mm
F(000) = 520
Bruker APEXII CCD diffractometer2613 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.067
φ and ω scansθmax = 28.9°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2008)h = −14→14
Tmin = 0.567, Tmax = 0.746k = −19→20
9652 measured reflectionsl = −9→9
2925 independent reflections
Refinement on F2Primary atom site location: dual
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: mixed
wR(F2) = 0.104H atoms treated by a mixture of independent and constrained refinement
S = 1.03w = 1/[σ2(Fo2) + (0.0447P)2 + 0.1359P] where P = (Fo2 + 2Fc2)/3
2925 reflections(Δ/σ)max < 0.001
236 parametersΔρmax = 0.30 e Å3
20 restraintsΔρmin = −0.27 e Å3
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.
xyzUiso*/UeqOcc. (<1)
O100.78822 (15)0.45123 (9)0.6188 (2)0.0219 (3)
O110.72627 (15)0.30780 (10)0.6134 (2)0.0250 (4)
O120.72284 (14)0.29621 (10)0.2532 (2)0.0225 (3)
H120.702 (3)0.264 (2)0.353 (4)0.047 (9)*
O130.97215 (14)0.34543 (11)0.3063 (2)0.0232 (4)
H131.001 (3)0.358 (2)0.412 (4)0.041 (9)*
O140.78763 (14)0.44450 (10)−0.0347 (2)0.0212 (3)
H140.792 (4)0.442 (3)−0.163 (6)0.092 (15)*
O150.96848 (16)0.37910 (14)−0.0496 (3)0.0382 (5)
C50.75823 (18)0.37845 (14)0.5374 (3)0.0177 (4)
C60.75836 (18)0.38090 (14)0.3251 (3)0.0181 (4)
H60.6988770.4271170.2832100.022*
C70.88300 (18)0.40657 (13)0.2505 (3)0.0184 (4)
H70.9045880.4675670.2981690.022*
C80.88361 (19)0.40887 (13)0.0376 (3)0.0189 (4)
O161.09484 (15)0.38045 (11)0.6154 (2)0.0239 (4)
H16A1.048 (3)0.383 (3)0.713 (6)0.057 (11)*
H16B1.139 (3)0.425 (2)0.614 (5)0.049 (10)*
C10.4453 (5)0.3844 (4)0.7178 (9)0.0343 (12)0.683 (8)
H1A0.4096480.3280620.6737320.052*0.683 (8)
H1B0.5139090.4004090.6387530.052*0.683 (8)
H1C0.3847590.4322490.7127190.052*0.683 (8)
C20.4888 (4)0.3725 (4)0.9196 (8)0.0251 (11)0.683 (8)
H20.5321250.4283490.9579900.030*0.683 (8)
C30.3852 (3)0.3571 (3)1.0525 (6)0.0325 (11)0.683 (8)
H3A0.3237960.4042271.0315520.039*0.683 (8)
H3B0.3475760.2984781.0232350.039*0.683 (8)
C40.4201 (4)0.3577 (3)1.2555 (6)0.0386 (12)0.683 (8)
H4A0.4696750.3048461.2828530.058*0.683 (8)
H4B0.3470900.3562921.3320280.058*0.683 (8)
H4C0.4660330.4123061.2829610.058*0.683 (8)
N90.5762 (8)0.2958 (8)0.9253 (15)0.0176 (14)0.683 (8)
H9C0.544 (7)0.240 (3)0.909 (7)0.07 (2)*0.683 (8)
H9A0.634 (3)0.305 (3)0.834 (5)0.015 (11)*0.683 (8)
H9B0.615 (4)0.300 (3)1.037 (4)0.030 (12)*0.683 (8)
C1A0.4346 (13)0.3806 (9)0.8007 (19)0.040 (3)0.317 (8)
H1AA0.3879490.3310550.7473480.060*0.317 (8)
H1AB0.4945910.4012060.7103390.060*0.317 (8)
H1AC0.3802460.4303370.8316450.060*0.317 (8)
C2A0.4980 (13)0.3487 (9)0.9750 (18)0.034 (3)0.317 (8)
H2A0.5442710.4009261.0254130.041*0.317 (8)
C3A0.4163 (8)0.3153 (6)1.1293 (12)0.033 (2)0.317 (8)
H3AA0.3652090.2664241.0795280.039*0.317 (8)
H3AB0.4672130.2892961.2285550.039*0.317 (8)
C4A0.3352 (11)0.3859 (7)1.2147 (17)0.058 (4)0.317 (8)
H4AA0.2818800.4106071.1189910.088*0.317 (8)
H4AB0.3846000.4341911.2671140.088*0.317 (8)
H4AC0.2865380.3585571.3131440.088*0.317 (8)
N9A0.588 (2)0.2777 (18)0.925 (4)0.022 (4)0.317 (8)
H9AA0.645 (7)0.290 (8)0.837 (10)0.027*0.317 (8)
H9AB0.535 (8)0.236 (6)0.885 (12)0.027*0.317 (8)
H9AC0.623 (7)0.263 (6)1.034 (7)0.027*0.317 (8)
U11U22U33U12U13U23
O100.0275 (8)0.0241 (7)0.0140 (7)0.0008 (6)0.0003 (6)−0.0008 (6)
O110.0334 (9)0.0258 (7)0.0157 (7)−0.0013 (7)0.0032 (7)0.0015 (6)
O120.0247 (8)0.0274 (7)0.0153 (7)−0.0058 (6)−0.0008 (6)−0.0013 (6)
O130.0196 (8)0.0349 (9)0.0150 (7)0.0060 (6)−0.0035 (6)−0.0035 (6)
O140.0217 (8)0.0293 (7)0.0127 (7)0.0025 (6)0.0002 (6)0.0004 (6)
O150.0310 (9)0.0638 (12)0.0197 (8)0.0206 (9)0.0083 (8)0.0092 (8)
C50.0153 (9)0.0247 (9)0.0132 (9)0.0035 (7)0.0017 (7)−0.0002 (8)
C60.0175 (10)0.0236 (9)0.0133 (9)0.0003 (8)−0.0001 (7)−0.0009 (7)
C70.0171 (10)0.0232 (9)0.0151 (10)0.0000 (8)−0.0009 (8)−0.0001 (8)
C80.0199 (10)0.0215 (9)0.0153 (9)−0.0010 (8)0.0015 (8)0.0008 (8)
O160.0232 (8)0.0309 (8)0.0178 (8)−0.0013 (7)0.0002 (7)−0.0037 (7)
C10.026 (2)0.037 (2)0.039 (3)0.0030 (17)−0.009 (2)0.004 (3)
C20.0195 (19)0.023 (3)0.033 (3)0.0017 (17)0.000 (2)0.000 (2)
C30.0249 (18)0.029 (2)0.044 (2)0.0039 (15)0.0006 (17)−0.0014 (18)
C40.031 (2)0.041 (2)0.044 (2)−0.0027 (17)0.0089 (18)−0.0054 (19)
N90.015 (3)0.021 (4)0.017 (2)−0.0038 (19)−0.0024 (18)−0.001 (2)
C1A0.050 (7)0.030 (5)0.040 (7)0.001 (4)−0.007 (8)0.002 (6)
C2A0.043 (6)0.033 (7)0.025 (6)0.005 (5)0.001 (5)0.010 (4)
C3A0.030 (4)0.038 (5)0.030 (5)0.007 (4)0.010 (4)0.000 (4)
C4A0.065 (8)0.048 (6)0.063 (7)0.027 (5)0.029 (6)0.015 (5)
N9A0.024 (6)0.021 (9)0.021 (5)0.010 (4)0.003 (4)−0.003 (5)
O10—C51.276 (3)C3—H3B0.9900
O11—C51.238 (3)C3—C41.513 (6)
O12—H120.90 (3)C4—H4A0.9800
O12—C61.419 (2)C4—H4B0.9800
O13—H130.85 (3)C4—H4C0.9800
O13—C71.403 (3)N9—H9C0.92 (2)
O14—H140.93 (4)N9—H9A0.93 (2)
O14—C81.299 (3)N9—H9B0.91 (2)
O15—C81.216 (3)C1A—H1AA0.9800
C5—C61.530 (3)C1A—H1AB0.9800
C6—H61.0000C1A—H1AC0.9800
C6—C71.532 (3)C1A—C2A1.517 (14)
C7—H71.0000C2A—H2A1.0000
C7—C81.535 (3)C2A—C3A1.518 (12)
O16—H16A0.87 (4)C2A—N9A1.497 (15)
O16—H16B0.83 (4)C3A—H3AA0.9900
C1—H1A0.9800C3A—H3AB0.9900
C1—H1B0.9800C3A—C4A1.514 (12)
C1—H1C0.9800C4A—H4AA0.9800
C1—C21.542 (7)C4A—H4AB0.9800
C2—H21.0000C4A—H4AC0.9800
C2—C31.513 (6)N9A—H9AA0.91 (3)
C2—N91.498 (8)N9A—H9AB0.90 (3)
C3—H3A0.9900N9A—H9AC0.91 (3)
C6—O12—H12105 (2)C3—C4—H4B109.5
C7—O13—H13112 (2)C3—C4—H4C109.5
C8—O14—H14110 (3)H4A—C4—H4B109.5
O10—C5—C6116.04 (18)H4A—C4—H4C109.5
O11—C5—O10126.33 (19)H4B—C4—H4C109.5
O11—C5—C6117.59 (18)C2—N9—H9C116 (5)
O12—C6—C5110.11 (17)C2—N9—H9A108 (3)
O12—C6—H6108.5C2—N9—H9B106 (3)
O12—C6—C7110.12 (16)H9C—N9—H9A108 (3)
C5—C6—H6108.5H9C—N9—H9B111 (4)
C5—C6—C7110.96 (17)H9A—N9—H9B107 (3)
C7—C6—H6108.5H1AA—C1A—H1AB109.5
O13—C7—C6111.94 (17)H1AA—C1A—H1AC109.5
O13—C7—H7108.8H1AB—C1A—H1AC109.5
O13—C7—C8107.33 (16)C2A—C1A—H1AA109.5
C6—C7—H7108.8C2A—C1A—H1AB109.5
C6—C7—C8111.13 (17)C2A—C1A—H1AC109.5
C8—C7—H7108.8C1A—C2A—H2A107.1
O14—C8—C7114.02 (18)C1A—C2A—C3A115.6 (11)
O15—C8—O14125.2 (2)C3A—C2A—H2A107.1
O15—C8—C7120.83 (19)N9A—C2A—C1A109.4 (13)
H16A—O16—H16B109 (3)N9A—C2A—H2A107.1
H1A—C1—H1B109.5N9A—C2A—C3A110.0 (12)
H1A—C1—H1C109.5C2A—C3A—H3AA108.5
H1B—C1—H1C109.5C2A—C3A—H3AB108.5
C2—C1—H1A109.5H3AA—C3A—H3AB107.5
C2—C1—H1B109.5C4A—C3A—C2A115.2 (8)
C2—C1—H1C109.5C4A—C3A—H3AA108.5
C1—C2—H2108.4C4A—C3A—H3AB108.5
C3—C2—C1112.1 (4)C3A—C4A—H4AA109.5
C3—C2—H2108.4C3A—C4A—H4AB109.5
N9—C2—C1108.4 (5)C3A—C4A—H4AC109.5
N9—C2—H2108.4H4AA—C4A—H4AB109.5
N9—C2—C3111.0 (5)H4AA—C4A—H4AC109.5
C2—C3—H3A108.6H4AB—C4A—H4AC109.5
C2—C3—H3B108.6C2A—N9A—H9AA119 (8)
H3A—C3—H3B107.6C2A—N9A—H9AB98 (8)
C4—C3—C2114.7 (4)C2A—N9A—H9AC104 (6)
C4—C3—H3A108.6H9AA—N9A—H9AB111 (4)
C4—C3—H3B108.6H9AA—N9A—H9AC111 (4)
C3—C4—H4A109.5H9AB—N9A—H9AC112 (4)
D—H···AD—HH···AD···AD—H···A
O12—H12···O110.90 (3)2.00 (3)2.602 (2)123 (3)
O13—H13···O160.85 (3)1.83 (3)2.662 (2)167 (3)
O14—H14···O10i0.93 (4)1.58 (5)2.499 (2)171 (5)
O16—H16A···O15ii0.87 (4)1.93 (4)2.791 (2)169 (4)
O16—H16B···O10iii0.83 (4)2.01 (3)2.822 (2)167 (3)
N9—H9A···O110.93 (2)1.89 (2)2.803 (9)167 (4)
N9—H9B···O12ii0.91 (2)1.97 (3)2.869 (11)169 (4)
N9—H9C···O13iv0.92 (2)2.16 (4)2.922 (13)140 (5)
N9—H9C···O15iv0.92 (2)2.20 (4)3.001 (12)145 (5)
N9A—H9AA···O110.91 (3)1.87 (4)2.76 (2)164 (8)
N9A—H9AB···O13iv0.90 (3)1.96 (6)2.79 (3)151 (9)
N9A—H9AB···O15iv0.90 (3)2.21 (8)2.83 (3)126 (6)
N9A—H9AC···O12ii0.91 (3)1.99 (5)2.81 (3)150 (7)
  6 in total

1.  Supramolecular structures of 1-phenylethylammonium tartrates.

Authors:  David E Turkington; Elizabeth J MacLean; Alan J Lough; George Ferguson; Christopher Glidewell
Journal:  Acta Crystallogr B       Date:  2005-01-19

2.  Optical resolution methods.

Authors:  Elemér Fogassy; Mihály Nógrádi; Dávid Kozma; Gabriella Egri; Emese Pálovics; Violetta Kiss
Journal:  Org Biomol Chem       Date:  2006-07-07       Impact factor: 3.876

3.  Pyrrolo[1,3]benzothiazepine-based atypical antipsychotic agents. Synthesis, structure-activity relationship, molecular modeling, and biological studies.

Authors:  Giuseppe Campiani; Stefania Butini; Sandra Gemma; Vito Nacci; Caterina Fattorusso; Bruno Catalanotti; Gianluca Giorgi; Alfredo Cagnotto; Mara Goegan; Tiziana Mennini; Patrizia Minetti; M Assunta Di Cesare; Domenico Mastroianni; Nazzareno Scafetta; Bruno Galletti; M Antonietta Stasi; Massimo Castorina; Licia Pacifici; Orlando Ghirardi; Ornella Tinti; Paolo Carminati
Journal:  J Med Chem       Date:  2002-01-17       Impact factor: 7.446

4.  SHELXT - integrated space-group and crystal-structure determination.

Authors:  George M Sheldrick
Journal:  Acta Crystallogr A Found Adv       Date:  2015-01-01       Impact factor: 2.290

5.  Crystal structure refinement with SHELXL.

Authors:  George M Sheldrick
Journal:  Acta Crystallogr C Struct Chem       Date:  2015-01-01       Impact factor: 1.172

6.  The Cambridge Structural Database.

Authors:  Colin R Groom; Ian J Bruno; Matthew P Lightfoot; Suzanna C Ward
Journal:  Acta Crystallogr B Struct Sci Cryst Eng Mater       Date:  2016-04-01
  6 in total

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