Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803001107/wn6133sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536803001107/wn6133Isup2.hkl |
CCDC reference: 204706
Colourless plate-shaped single crystals of (I) were grown from a saturated aqueous solution containing β-alanine and trichloroacetic acid in a 1:1 stoichiometric ratio. The density was determined by the flotation method using a liquid mixture of xylene and bromoform.
All the H atoms were positioned geometrically and were allowed to ride on their respective parent atoms with SHELXL97 (Sheldrick, 1997) defaults for bond lengths and thermal parameters. The residual density peaks in the final difference Fourier map (1.745 and −1.394 e Å−3) indicate ripples around the Cl atoms and have no structural significance.
Data collection: SMART-NT (Bruker, 1999); cell refinement: SMART-NT; data reduction: SAINT-NT (Bruker, 1999); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.
Fig. 1. The molecular structure of (I), showing the atom-numbering scheme and 50% probability displacement ellipsoids. | |
Fig. 2. Packing of the molecules of (I), viewed down the a axis. |
C3H8NO2+·C2Cl3O2− | F(000) = 512 |
Mr = 252.47 | Dx = 1.702 Mg m−3 Dm = 1.69 Mg m−3 Dm measured by floatation in a mixture of xylene and bromoform |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 1024 reflections |
a = 6.8049 (14) Å | θ = 3–28° |
b = 21.100 (4) Å | µ = 0.91 mm−1 |
c = 6.8968 (14) Å | T = 105 K |
β = 95.75 (3)° | Plate, colourless |
V = 985.3 (3) Å3 | 0.4 × 0.3 × 0.3 mm |
Z = 4 |
Bruker SMART diffractometer | 2442 independent reflections |
Radiation source: fine-focus sealed tube | 2350 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
Detector resolution: 8 pixels mm-1 | θmax = 28.3°, θmin = 3.1° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (SADABS; Bruker, 1998) | k = −28→28 |
Tmin = 0.694, Tmax = 0.761 | l = −9→9 |
12338 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.046 | H-atom parameters constrained |
wR(F2) = 0.104 | w = 1/[σ2(Fo2) + (0.031P)2 + 2.3578P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
2442 reflections | Δρmax = 1.75 e Å−3 |
119 parameters | Δρmin = −1.39 e Å−3 |
0 restraints | Extinction correction: SHELXL97 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0067 (14) |
C3H8NO2+·C2Cl3O2− | V = 985.3 (3) Å3 |
Mr = 252.47 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.8049 (14) Å | µ = 0.91 mm−1 |
b = 21.100 (4) Å | T = 105 K |
c = 6.8968 (14) Å | 0.4 × 0.3 × 0.3 mm |
β = 95.75 (3)° |
Bruker SMART diffractometer | 2442 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1998) | 2350 reflections with I > 2σ(I) |
Tmin = 0.694, Tmax = 0.761 | Rint = 0.018 |
12338 measured reflections |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.104 | H-atom parameters constrained |
S = 1.05 | Δρmax = 1.75 e Å−3 |
2442 reflections | Δρmin = −1.39 e Å−3 |
119 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.15023 (8) | 0.16912 (3) | 0.29334 (9) | 0.02548 (15) | |
Cl2 | 0.48640 (12) | 0.19390 (3) | 0.56369 (12) | 0.0474 (2) | |
Cl3 | 0.50623 (14) | 0.21729 (3) | 0.15200 (16) | 0.0590 (3) | |
O1 | 0.2626 (2) | 0.04083 (8) | 0.6603 (3) | 0.0228 (3) | |
H1 | 0.3001 | 0.0044 | 0.6445 | 0.034* | |
O2 | 0.0002 (3) | −0.00889 (8) | 0.7582 (3) | 0.0297 (4) | |
O3 | 0.6033 (2) | 0.07340 (8) | 0.4162 (2) | 0.0236 (3) | |
O4 | 0.4179 (2) | 0.07398 (8) | 0.1273 (2) | 0.0218 (3) | |
N1 | −0.3247 (3) | 0.06472 (9) | 0.8289 (3) | 0.0183 (4) | |
H1A | −0.4147 | 0.0665 | 0.9140 | 0.027* | |
H1B | −0.2829 | 0.0250 | 0.8197 | 0.027* | |
H1C | −0.3783 | 0.0778 | 0.7128 | 0.027* | |
C1 | −0.1540 (3) | 0.10643 (10) | 0.8966 (3) | 0.0190 (4) | |
H1D | −0.0978 | 0.0926 | 1.0244 | 0.023* | |
H1E | −0.2005 | 0.1496 | 0.9086 | 0.023* | |
C2 | 0.0051 (3) | 0.10514 (10) | 0.7568 (3) | 0.0204 (4) | |
H2A | −0.0497 | 0.1216 | 0.6315 | 0.024* | |
H2B | 0.1121 | 0.1330 | 0.8061 | 0.024* | |
C3 | 0.0876 (3) | 0.03971 (10) | 0.7278 (3) | 0.0180 (4) | |
C4 | 0.4108 (3) | 0.16624 (10) | 0.3246 (3) | 0.0219 (4) | |
C5 | 0.4842 (3) | 0.09696 (10) | 0.2860 (3) | 0.0177 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0223 (3) | 0.0249 (3) | 0.0288 (3) | 0.0054 (2) | 0.0004 (2) | −0.0014 (2) |
Cl2 | 0.0459 (4) | 0.0352 (4) | 0.0552 (4) | 0.0152 (3) | −0.0237 (3) | −0.0292 (3) |
Cl3 | 0.0700 (6) | 0.0211 (3) | 0.0958 (7) | 0.0015 (3) | 0.0566 (5) | 0.0146 (4) |
O1 | 0.0152 (7) | 0.0206 (7) | 0.0332 (9) | 0.0007 (6) | 0.0059 (6) | −0.0056 (6) |
O2 | 0.0298 (9) | 0.0155 (8) | 0.0465 (11) | 0.0005 (6) | 0.0175 (8) | 0.0012 (7) |
O3 | 0.0240 (8) | 0.0240 (8) | 0.0229 (8) | 0.0067 (6) | 0.0033 (6) | −0.0041 (6) |
O4 | 0.0252 (8) | 0.0204 (7) | 0.0204 (7) | −0.0020 (6) | 0.0060 (6) | −0.0029 (6) |
N1 | 0.0156 (8) | 0.0193 (8) | 0.0204 (8) | −0.0018 (6) | 0.0039 (6) | −0.0016 (7) |
C1 | 0.0160 (9) | 0.0182 (9) | 0.0224 (10) | −0.0005 (7) | 0.0008 (8) | −0.0039 (8) |
C2 | 0.0155 (9) | 0.0153 (9) | 0.0309 (11) | 0.0004 (7) | 0.0054 (8) | 0.0007 (8) |
C3 | 0.0156 (9) | 0.0179 (9) | 0.0203 (10) | 0.0009 (7) | 0.0010 (7) | −0.0001 (8) |
C4 | 0.0218 (10) | 0.0158 (10) | 0.0285 (11) | −0.0022 (8) | 0.0038 (8) | −0.0026 (8) |
C5 | 0.0168 (9) | 0.0151 (9) | 0.0222 (10) | −0.0013 (7) | 0.0076 (7) | −0.0013 (7) |
Cl1—C4 | 1.765 (2) | N1—H1B | 0.8900 |
Cl2—C4 | 1.776 (2) | N1—H1C | 0.8900 |
Cl3—C4 | 1.776 (2) | C1—C2 | 1.521 (3) |
O1—C3 | 1.321 (3) | C1—H1D | 0.9700 |
O1—H1 | 0.8200 | C1—H1E | 0.9700 |
O2—C3 | 1.214 (3) | C2—C3 | 1.511 (3) |
O3—C5 | 1.251 (3) | C2—H2A | 0.9700 |
O4—C5 | 1.240 (3) | C2—H2B | 0.9700 |
N1—C1 | 1.494 (3) | C4—C5 | 1.576 (3) |
N1—H1A | 0.8900 | ||
C3—O1—H1 | 109.5 | C3—C2—H2B | 108.9 |
C1—N1—H1A | 109.5 | C1—C2—H2B | 108.9 |
C1—N1—H1B | 109.5 | H2A—C2—H2B | 107.7 |
H1A—N1—H1B | 109.5 | O2—C3—O1 | 123.4 (2) |
C1—N1—H1C | 109.5 | O2—C3—C2 | 123.63 (19) |
H1A—N1—H1C | 109.5 | O1—C3—C2 | 112.95 (18) |
H1B—N1—H1C | 109.5 | C5—C4—Cl1 | 110.05 (15) |
N1—C1—C2 | 111.84 (17) | C5—C4—Cl2 | 113.23 (16) |
N1—C1—H1D | 109.2 | Cl1—C4—Cl2 | 107.24 (13) |
C2—C1—H1D | 109.2 | C5—C4—Cl3 | 107.79 (15) |
N1—C1—H1E | 109.2 | Cl1—C4—Cl3 | 109.11 (13) |
C2—C1—H1E | 109.2 | Cl2—C4—Cl3 | 109.36 (12) |
H1D—C1—H1E | 107.9 | O4—C5—O3 | 129.1 (2) |
C3—C2—C1 | 113.44 (18) | O4—C5—C4 | 114.73 (19) |
C3—C2—H2A | 108.9 | O3—C5—C4 | 116.15 (19) |
C1—C2—H2A | 108.9 | ||
N1—C1—C2—C3 | −58.9 (2) | Cl3—C4—C5—O4 | −65.6 (2) |
C1—C2—C3—O2 | 22.3 (3) | Cl1—C4—C5—O3 | −128.13 (18) |
C1—C2—C3—O1 | −159.62 (18) | Cl2—C4—C5—O3 | −8.1 (2) |
Cl1—C4—C5—O4 | 53.3 (2) | Cl3—C4—C5—O3 | 112.97 (19) |
Cl2—C4—C5—O4 | 173.27 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O3i | 0.82 | 1.83 | 2.649 (2) | 173 |
N1—H1A···O4ii | 0.89 | 1.96 | 2.840 (2) | 172 |
N1—H1B···O2 | 0.89 | 2.14 | 2.785 (3) | 129 |
N1—H1B···O4iii | 0.89 | 2.32 | 3.016 (2) | 135 |
N1—H1C···Cl2iv | 0.89 | 2.78 | 3.458 (2) | 134 |
N1—H1C···O3iv | 0.89 | 2.04 | 2.846 (3) | 150 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x−1, y, z+1; (iii) −x, −y, −z+1; (iv) x−1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C3H8NO2+·C2Cl3O2− |
Mr | 252.47 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 105 |
a, b, c (Å) | 6.8049 (14), 21.100 (4), 6.8968 (14) |
β (°) | 95.75 (3) |
V (Å3) | 985.3 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.91 |
Crystal size (mm) | 0.4 × 0.3 × 0.3 |
Data collection | |
Diffractometer | Bruker SMART diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1998) |
Tmin, Tmax | 0.694, 0.761 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12338, 2442, 2350 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.668 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.104, 1.05 |
No. of reflections | 2442 |
No. of parameters | 119 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.75, −1.39 |
Computer programs: SMART-NT (Bruker, 1999), SMART-NT, SAINT-NT (Bruker, 1999), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1999), SHELXL97.
Cl1—C4 | 1.765 (2) | O2—C3 | 1.214 (3) |
Cl2—C4 | 1.776 (2) | O3—C5 | 1.251 (3) |
Cl3—C4 | 1.776 (2) | O4—C5 | 1.240 (3) |
O1—C3 | 1.321 (3) | ||
O2—C3—O1 | 123.4 (2) | O4—C5—O3 | 129.1 (2) |
O2—C3—C2 | 123.63 (19) | O4—C5—C4 | 114.73 (19) |
O1—C3—C2 | 112.95 (18) | O3—C5—C4 | 116.15 (19) |
N1—C1—C2—C3 | −58.9 (2) | C1—C2—C3—O1 | −159.62 (18) |
C1—C2—C3—O2 | 22.3 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O3i | 0.82 | 1.83 | 2.649 (2) | 173 |
N1—H1A···O4ii | 0.89 | 1.96 | 2.840 (2) | 172 |
N1—H1B···O2 | 0.89 | 2.14 | 2.785 (3) | 129 |
N1—H1B···O4iii | 0.89 | 2.32 | 3.016 (2) | 135 |
N1—H1C···Cl2iv | 0.89 | 2.78 | 3.458 (2) | 134 |
N1—H1C···O3iv | 0.89 | 2.04 | 2.846 (3) | 150 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x−1, y, z+1; (iii) −x, −y, −z+1; (iv) x−1, y, z. |
Precise X-ray crystallographic investigations on amino acid–carboxylic acid complexes have provided a wealth of information regarding intermolecular interactions and biomolecular aggregation patterns that might well have occurred in prebiotic polymerization (Vijayan, 1988; Prasad & Vijayan, 1993). The crystal structures of β-alanine (Papavinasam et al., 1986), β-alaninium maleate (Rajagopal et al., 2001), bis(β-alanine) hydrogen nitrate (Sridhar et al., 2001), β-alaninium perchlorate (Pandiarajan et al., 2001), β-alaninium oxalate hemihydrate (Krishnakumar et al., 2002), DL-valinium trichloroacetate (Rajagopal et al., 2002) and DL-methioninium trichloroacetate (Rajagopal et al., 2003) have already been reported. A brief survey of the Cambridge Structural Database (Allen, 2002) revealed a scarcity of precise crystallographic data on amino acid–halogenoacetic acid complexes. We report here the crystal structure of a complex of β-alanine with trichloroacetic acid, namely β-alaninium trichloroacetate, (I). β-Alanine (3-aminopropionic acid) is the only naturally occurring β-amino acid and is a component of the naturally occurring peptides carnosine and anserine, and also of pantothenic acid. Trichloroacetic acid is an excellent medicine for people who have dynamic wrinkles.
Fig. 1 shows the molecular structure of (I) with the atom-numbering scheme. The β-alanine molecule in (I) exists in the cationic form, with a positively charged amino group and an uncharged carboxylic acid group. The trichloroacetic acid molecule exists as an anion. The asymmetric unit of (I) consists of one β-alanininium residue and a trichloroacetate anion. The backbone conformation angles ψ1 and ψ2 are 22.3 (3) and −159.62 (1)°, respectively, for the alaninium residue. These are significantly different from the values reported for β-alanine (25.3 and −177.8°), β-alaninium oxalate hemihydrate [8.3 (2) and −173.0 (2)°] and β-alaninium perchlorate [8.0 (4) and −171.5 (3)°], but are in good agreement with the values reported for β-alaninium maleate [24.6 (4) and −155.8 (2)°]. The straight-chain conformation angle χ1 is in the gauche II form [−58.9 (2)°], as was also observed in β-alaninium perchlorate [−65.0 (3)°]. The straight-chain conformation angles for β-alanine, β-alaninium maleate and β-alaninium oxalate hemihydrate are −154.8, −177.4 (2) and 77.0 (2)° respectively, indicating different conformations.
Fig. 2 shows the packing of molecules of (I), viewed down the a axis. In the crystal, the alanine and trichloroacetic acid molecules are alternately linked by O—H···O and N—H···O hydrogen bonds to form infinite one-dimensional chains along [110]. The glide-related chains are interlinked by N—H···O hydrogen bonds to form an infinite two-dimensional network parallel to (001), similar to that in DL-valinium trichloroacetate. The trichloroacetate ions do not have direct hydrogen-bonded interactions among themselves. The β-alaninium ions link trichloroacetate ions through bifurcated N—H···O hydrogen bonds. The O—H···O, N—H···O and N—H···Cl interactions that exist between the trichloroacetate anion and the alaninium residue play an important role in stabilizing the structure. A short contact between Cl1 and Cl2(x − 1/2, −y + 1/2, z − 1/2) of 3.428 (1) Å is also observed in the structure. Strikingly, the title compound, (I), β-alaninium maleate and β-alaninium perchlorate all crystallize in the same space group, but the crystal packings are distinctly different.