The crystal structure of L-2-aminobutyric acid, an L-alanine analogue with an ethyl rather than a methyl side chain, has proved elusive owing to problems growing diffraction quality crystals. Good diffraction data have now been obtained for two polymorphs, in space groups P21 and I2, revealing surprisingly complex, yet fully ordered crystalline arrangements with Z′ = 4. The closely related structures are divided into hydrophilic and hydrophobic layers, the latter being the thinnest ever found for an amino acid (other than α-glycine). The hydrophobic layers furthermore contain conspicuous pseudo-centers-of-symmetry, leading to overall centrosymmetric intensity statistics. Uniquely, the four molecules in the asymmetric unit can be divided into two pairs that each forms an independent hydrogen-bond network.
Supporting information
CCDC references: 775213; 775214
For both structures, data collection: APEX2 (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
(
S)-2-aminobutyric acid (I)
top
Crystal data top
C4H9NO2 | F(000) = 448 |
Mr = 103.12 | Dx = 1.296 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 2696 reflections |
a = 9.614 (6) Å | θ = 2.5–27.8° |
b = 5.227 (3) Å | µ = 0.10 mm−1 |
c = 21.385 (13) Å | T = 110 K |
β = 100.326 (7)° | Elongated plate, colourless |
V = 1057.1 (11) Å3 | 1.10 × 0.34 × 0.10 mm |
Z = 8 | |
Data collection top
Bruker Apex II CCD diffractometer | 2700 independent reflections |
Radiation source: fine-focus sealed tube | 2468 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.042 |
Detector resolution: 8.3 pixels mm-1 | θmax = 28.6°, θmin = 2.2° |
Sets of exposures each taken over 0.5° ω rotation scans | h = −12→12 |
Absorption correction: multi-scan SADABS (Bruker, 2007) | k = −7→6 |
Tmin = 0.749, Tmax = 0.990 | l = −28→26 |
6460 measured reflections | |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.058 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.165 | H-atom parameters constrained |
S = 1.12 | w = 1/[σ2(Fo2) + (0.085P)2 + 0.488P] where P = (Fo2 + 2Fc2)/3 |
2700 reflections | (Δ/σ)max < 0.001 |
261 parameters | Δρmax = 0.37 e Å−3 |
1 restraint | Δρmin = −0.26 e Å−3 |
0 constraints | |
Special details top
Experimental. Soft crystal, easily bent. |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1A | 0.1618 (2) | 0.7249 (5) | 0.05862 (11) | 0.0189 (5) | |
O2A | 0.2490 (3) | 0.3333 (5) | 0.08128 (13) | 0.0269 (6) | |
N1A | 0.4156 (3) | 0.9310 (5) | 0.05725 (12) | 0.0165 (6) | |
H1A | 0.3903 | 0.9014 | 0.0148 | 0.025* | |
H2A | 0.5047 | 0.9968 | 0.0655 | 0.025* | |
H3A | 0.3543 | 1.0444 | 0.0698 | 0.025* | |
C1A | 0.2622 (3) | 0.5696 (7) | 0.07523 (15) | 0.0162 (6) | |
C2A | 0.4119 (3) | 0.6861 (7) | 0.09261 (16) | 0.0185 (7) | |
H21A | 0.4815 | 0.5645 | 0.0794 | 0.022* | |
C3A | 0.4532 (4) | 0.7370 (9) | 0.16363 (16) | 0.0291 (8) | |
H31A | 0.3766 | 0.8344 | 0.1781 | 0.035* | |
H32A | 0.5395 | 0.8443 | 0.1713 | 0.035* | |
C4A | 0.4810 (4) | 0.4918 (11) | 0.20304 (18) | 0.0413 (11) | |
H41A | 0.5037 | 0.5357 | 0.2483 | 0.062* | |
H42A | 0.5607 | 0.3993 | 0.1908 | 0.062* | |
H43A | 0.3965 | 0.3833 | 0.1953 | 0.062* | |
O1B | 0.6611 (2) | 0.2229 (5) | 0.06230 (11) | 0.0197 (5) | |
O2B | 0.7617 (3) | −0.1383 (5) | 0.10293 (13) | 0.0266 (6) | |
N1B | 0.9102 (3) | 0.4579 (6) | 0.06143 (12) | 0.0150 (5) | |
H1B | 0.8819 | 0.4100 | 0.0202 | 0.023* | |
H2B | 0.9993 | 0.5231 | 0.0667 | 0.023* | |
H3B | 0.8502 | 0.5791 | 0.0717 | 0.023* | |
C1B | 0.7664 (3) | 0.0909 (7) | 0.08684 (14) | 0.0164 (6) | |
C2B | 0.9089 (3) | 0.2305 (7) | 0.10364 (16) | 0.0206 (7) | |
H21B | 0.9874 | 0.1115 | 0.0983 | 0.025* | |
C3B | 0.9265 (4) | 0.3171 (8) | 0.17455 (16) | 0.0277 (8) | |
H31B | 0.8420 | 0.4167 | 0.1801 | 0.033* | |
H32B | 0.9304 | 0.1630 | 0.2017 | 0.033* | |
C4B | 1.0564 (4) | 0.4770 (10) | 0.19724 (17) | 0.0330 (9) | |
H41B | 1.0695 | 0.4971 | 0.2435 | 0.050* | |
H42B | 1.0447 | 0.6458 | 0.1770 | 0.050* | |
H43B | 1.1394 | 0.3921 | 0.1860 | 0.050* | |
O1C | 0.1142 (2) | 0.1140 (5) | 0.43818 (10) | 0.0187 (5) | |
O2C | 0.1771 (2) | 0.4896 (5) | 0.40269 (13) | 0.0262 (6) | |
N1C | 0.3644 (3) | −0.1063 (6) | 0.44032 (12) | 0.0165 (5) | |
H1C | 0.4488 | −0.1724 | 0.4347 | 0.025* | |
H2C | 0.2934 | −0.2140 | 0.4231 | 0.025* | |
H3C | 0.3643 | −0.0877 | 0.4826 | 0.025* | |
C1C | 0.2007 (3) | 0.2611 (7) | 0.41789 (15) | 0.0176 (6) | |
C2C | 0.3426 (3) | 0.1488 (6) | 0.40840 (15) | 0.0174 (6) | |
H21C | 0.4195 | 0.2660 | 0.4290 | 0.021* | |
C3C | 0.3509 (4) | 0.1284 (8) | 0.33786 (16) | 0.0264 (8) | |
H31C | 0.3459 | 0.3027 | 0.3195 | 0.032* | |
H32C | 0.4439 | 0.0551 | 0.3338 | 0.032* | |
C4C | 0.2358 (4) | −0.0335 (10) | 0.29949 (16) | 0.0349 (9) | |
H41C | 0.2479 | −0.0364 | 0.2550 | 0.052* | |
H42C | 0.1432 | 0.0393 | 0.3023 | 0.052* | |
H43C | 0.2418 | −0.2083 | 0.3163 | 0.052* | |
O1D | 0.6104 (2) | 0.6060 (5) | 0.43697 (10) | 0.0189 (5) | |
O2D | 0.6838 (2) | 1.0001 (5) | 0.41945 (13) | 0.0272 (6) | |
N1D | 0.8699 (3) | 0.4063 (5) | 0.44150 (12) | 0.0161 (6) | |
H1D | 0.9521 | 0.3410 | 0.4327 | 0.024* | |
H2D | 0.7987 | 0.2920 | 0.4296 | 0.024* | |
H3D | 0.8797 | 0.4370 | 0.4840 | 0.024* | |
C1D | 0.6999 (3) | 0.7623 (7) | 0.42291 (15) | 0.0168 (6) | |
C2D | 0.8361 (3) | 0.6502 (6) | 0.40584 (15) | 0.0161 (6) | |
H21D | 0.9153 | 0.7740 | 0.4187 | 0.019* | |
C3D | 0.8199 (3) | 0.5966 (7) | 0.33422 (15) | 0.0223 (7) | |
H31D | 0.9062 | 0.5093 | 0.3259 | 0.027* | |
H32D | 0.7391 | 0.4791 | 0.3213 | 0.027* | |
C4D | 0.7962 (4) | 0.8363 (9) | 0.29379 (17) | 0.0303 (8) | |
H41D | 0.7890 | 0.7903 | 0.2489 | 0.045* | |
H42D | 0.8759 | 0.9538 | 0.3062 | 0.045* | |
H43D | 0.7086 | 0.9197 | 0.3002 | 0.045* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1A | 0.0137 (9) | 0.0180 (12) | 0.0248 (12) | −0.0022 (9) | 0.0029 (8) | 0.0034 (10) |
O2A | 0.0188 (11) | 0.0160 (13) | 0.0468 (15) | −0.0007 (10) | 0.0087 (10) | 0.0047 (12) |
N1A | 0.0134 (11) | 0.0143 (15) | 0.0220 (13) | −0.0010 (10) | 0.0040 (9) | 0.0002 (10) |
C1A | 0.0145 (13) | 0.0158 (16) | 0.0185 (14) | −0.0019 (12) | 0.0035 (10) | 0.0007 (12) |
C2A | 0.0124 (13) | 0.0163 (17) | 0.0274 (16) | 0.0005 (12) | 0.0051 (11) | 0.0024 (12) |
C3A | 0.0209 (15) | 0.040 (2) | 0.0262 (18) | −0.0064 (16) | 0.0030 (12) | 0.0036 (17) |
C4A | 0.0315 (19) | 0.060 (3) | 0.0280 (19) | −0.010 (2) | −0.0059 (14) | 0.016 (2) |
O1B | 0.0133 (9) | 0.0218 (13) | 0.0242 (11) | −0.0031 (10) | 0.0039 (8) | 0.0027 (10) |
O2B | 0.0217 (12) | 0.0130 (12) | 0.0470 (15) | −0.0015 (10) | 0.0114 (10) | 0.0025 (12) |
N1B | 0.0122 (10) | 0.0121 (13) | 0.0209 (13) | −0.0026 (10) | 0.0034 (8) | 0.0001 (10) |
C1B | 0.0179 (14) | 0.0147 (16) | 0.0177 (14) | −0.0016 (13) | 0.0062 (10) | −0.0024 (13) |
C2B | 0.0125 (13) | 0.0176 (17) | 0.0305 (17) | −0.0013 (12) | 0.0009 (11) | 0.0073 (14) |
C3B | 0.0239 (16) | 0.031 (2) | 0.0277 (18) | −0.0062 (15) | 0.0028 (12) | 0.0050 (15) |
C4B | 0.0252 (17) | 0.044 (2) | 0.0295 (18) | −0.0087 (18) | 0.0028 (13) | −0.0009 (18) |
O1C | 0.0149 (10) | 0.0183 (12) | 0.0238 (11) | 0.0038 (9) | 0.0060 (8) | 0.0029 (10) |
O2C | 0.0178 (11) | 0.0156 (13) | 0.0451 (15) | 0.0027 (10) | 0.0050 (9) | 0.0034 (12) |
N1C | 0.0129 (11) | 0.0148 (14) | 0.0224 (13) | 0.0019 (10) | 0.0048 (9) | 0.0006 (11) |
C1C | 0.0161 (13) | 0.0157 (17) | 0.0203 (15) | 0.0005 (13) | 0.0014 (10) | −0.0018 (13) |
C2C | 0.0149 (13) | 0.0115 (15) | 0.0258 (16) | 0.0021 (12) | 0.0037 (11) | 0.0018 (12) |
C3C | 0.0230 (15) | 0.029 (2) | 0.0286 (18) | 0.0039 (15) | 0.0091 (12) | 0.0038 (16) |
C4C | 0.045 (2) | 0.038 (2) | 0.0219 (18) | 0.000 (2) | 0.0056 (14) | 0.0015 (17) |
O1D | 0.0143 (10) | 0.0153 (12) | 0.0277 (12) | 0.0011 (9) | 0.0057 (8) | 0.0013 (10) |
O2D | 0.0156 (11) | 0.0154 (13) | 0.0516 (16) | 0.0040 (10) | 0.0083 (10) | 0.0028 (12) |
N1D | 0.0113 (11) | 0.0150 (14) | 0.0223 (13) | 0.0025 (10) | 0.0039 (9) | −0.0006 (10) |
C1D | 0.0137 (13) | 0.0152 (16) | 0.0214 (15) | 0.0015 (12) | 0.0029 (10) | −0.0011 (13) |
C2D | 0.0127 (13) | 0.0133 (15) | 0.0229 (16) | 0.0009 (11) | 0.0045 (10) | 0.0019 (12) |
C3D | 0.0203 (15) | 0.0232 (18) | 0.0237 (16) | 0.0008 (14) | 0.0045 (11) | −0.0013 (14) |
C4D | 0.0333 (19) | 0.031 (2) | 0.0276 (18) | −0.0018 (16) | 0.0071 (14) | 0.0037 (16) |
Geometric parameters (Å, º) top
O1A—C1A | 1.262 (4) | O1C—C1C | 1.265 (4) |
O2A—C1A | 1.251 (4) | O2C—C1C | 1.248 (5) |
N1A—C2A | 1.490 (4) | N1C—C2C | 1.495 (4) |
N1A—H1A | 0.9100 | N1C—H1C | 0.9100 |
N1A—H2A | 0.9100 | N1C—H2C | 0.9100 |
N1A—H3A | 0.9100 | N1C—H3C | 0.9100 |
C1A—C2A | 1.545 (4) | C1C—C2C | 1.532 (4) |
C2A—C3A | 1.523 (5) | C2C—C3C | 1.529 (5) |
C2A—H21A | 1.0000 | C2C—H21C | 1.0000 |
C3A—C4A | 1.531 (5) | C3C—C4C | 1.513 (5) |
C3A—H31A | 0.9900 | C3C—H31C | 0.9900 |
C3A—H32A | 0.9900 | C3C—H32C | 0.9900 |
C4A—H41A | 0.9800 | C4C—H41C | 0.9800 |
C4A—H42A | 0.9800 | C4C—H42C | 0.9800 |
C4A—H43A | 0.9800 | C4C—H43C | 0.9800 |
O1B—C1B | 1.259 (4) | O1D—C1D | 1.261 (4) |
O2B—C1B | 1.249 (4) | O2D—C1D | 1.253 (4) |
N1B—C2B | 1.494 (4) | N1D—C2D | 1.491 (4) |
N1B—H1B | 0.9100 | N1D—H1D | 0.9100 |
N1B—H2B | 0.9100 | N1D—H2D | 0.9100 |
N1B—H3B | 0.9100 | N1D—H3D | 0.9100 |
C1B—C2B | 1.537 (4) | C1D—C2D | 1.536 (4) |
C2B—C3B | 1.562 (5) | C2D—C3D | 1.537 (4) |
C2B—H21B | 1.0000 | C2D—H21D | 1.0000 |
C3B—C4B | 1.509 (5) | C3D—C4D | 1.516 (5) |
C3B—H31B | 0.9900 | C3D—H31D | 0.9900 |
C3B—H32B | 0.9900 | C3D—H32D | 0.9900 |
C4B—H41B | 0.9800 | C4D—H41D | 0.9800 |
C4B—H42B | 0.9800 | C4D—H42D | 0.9800 |
C4B—H43B | 0.9800 | C4D—H43D | 0.9800 |
| | | |
C2A—N1A—H1A | 109.5 | C2C—N1C—H1C | 109.5 |
C2A—N1A—H2A | 109.5 | C2C—N1C—H2C | 109.5 |
H1A—N1A—H2A | 109.5 | H1C—N1C—H2C | 109.5 |
C2A—N1A—H3A | 109.5 | C2C—N1C—H3C | 109.5 |
H1A—N1A—H3A | 109.5 | H1C—N1C—H3C | 109.5 |
H2A—N1A—H3A | 109.5 | H2C—N1C—H3C | 109.5 |
O2A—C1A—O1A | 125.2 (3) | O2C—C1C—O1C | 124.8 (3) |
O2A—C1A—C2A | 118.2 (3) | O2C—C1C—C2C | 117.2 (3) |
O1A—C1A—C2A | 116.5 (3) | O1C—C1C—C2C | 117.9 (3) |
N1A—C2A—C3A | 109.3 (3) | N1C—C2C—C3C | 111.1 (3) |
N1A—C2A—C1A | 108.8 (2) | N1C—C2C—C1C | 109.7 (2) |
C3A—C2A—C1A | 112.0 (3) | C3C—C2C—C1C | 111.3 (3) |
N1A—C2A—H21A | 108.9 | N1C—C2C—H21C | 108.2 |
C3A—C2A—H21A | 108.9 | C3C—C2C—H21C | 108.2 |
C1A—C2A—H21A | 108.9 | C1C—C2C—H21C | 108.2 |
C2A—C3A—C4A | 113.1 (3) | C4C—C3C—C2C | 114.3 (3) |
C2A—C3A—H31A | 109.0 | C4C—C3C—H31C | 108.7 |
C4A—C3A—H31A | 109.0 | C2C—C3C—H31C | 108.7 |
C2A—C3A—H32A | 109.0 | C4C—C3C—H32C | 108.7 |
C4A—C3A—H32A | 109.0 | C2C—C3C—H32C | 108.7 |
H31A—C3A—H32A | 107.8 | H31C—C3C—H32C | 107.6 |
C3A—C4A—H41A | 109.5 | C3C—C4C—H41C | 109.5 |
C3A—C4A—H42A | 109.5 | C3C—C4C—H42C | 109.5 |
H41A—C4A—H42A | 109.5 | H41C—C4C—H42C | 109.5 |
C3A—C4A—H43A | 109.5 | C3C—C4C—H43C | 109.5 |
H41A—C4A—H43A | 109.5 | H41C—C4C—H43C | 109.5 |
H42A—C4A—H43A | 109.5 | H42C—C4C—H43C | 109.5 |
C2B—N1B—H1B | 109.5 | C2D—N1D—H1D | 109.5 |
C2B—N1B—H2B | 109.5 | C2D—N1D—H2D | 109.5 |
H1B—N1B—H2B | 109.5 | H1D—N1D—H2D | 109.5 |
C2B—N1B—H3B | 109.5 | C2D—N1D—H3D | 109.5 |
H1B—N1B—H3B | 109.5 | H1D—N1D—H3D | 109.5 |
H2B—N1B—H3B | 109.5 | H2D—N1D—H3D | 109.5 |
O2B—C1B—O1B | 125.1 (3) | O2D—C1D—O1D | 125.0 (3) |
O2B—C1B—C2B | 117.7 (3) | O2D—C1D—C2D | 117.8 (3) |
O1B—C1B—C2B | 117.0 (3) | O1D—C1D—C2D | 117.1 (3) |
N1B—C2B—C1B | 109.9 (2) | N1D—C2D—C1D | 108.8 (2) |
N1B—C2B—C3B | 110.2 (3) | N1D—C2D—C3D | 109.1 (3) |
C1B—C2B—C3B | 107.6 (3) | C1D—C2D—C3D | 111.6 (2) |
N1B—C2B—H21B | 109.7 | N1D—C2D—H21D | 109.1 |
C1B—C2B—H21B | 109.7 | C1D—C2D—H21D | 109.1 |
C3B—C2B—H21B | 109.7 | C3D—C2D—H21D | 109.1 |
C4B—C3B—C2B | 114.4 (3) | C4D—C3D—C2D | 113.3 (3) |
C4B—C3B—H31B | 108.7 | C4D—C3D—H31D | 108.9 |
C2B—C3B—H31B | 108.7 | C2D—C3D—H31D | 108.9 |
C4B—C3B—H32B | 108.7 | C4D—C3D—H32D | 108.9 |
C2B—C3B—H32B | 108.7 | C2D—C3D—H32D | 108.9 |
H31B—C3B—H32B | 107.6 | H31D—C3D—H32D | 107.7 |
C3B—C4B—H41B | 109.5 | C3D—C4D—H41D | 109.5 |
C3B—C4B—H42B | 109.5 | C3D—C4D—H42D | 109.5 |
H41B—C4B—H42B | 109.5 | H41D—C4D—H42D | 109.5 |
C3B—C4B—H43B | 109.5 | C3D—C4D—H43D | 109.5 |
H41B—C4B—H43B | 109.5 | H41D—C4D—H43D | 109.5 |
H42B—C4B—H43B | 109.5 | H42D—C4D—H43D | 109.5 |
| | | |
N1A—C2A—C1A—O1A | −27.4 (4) | O2B—C1B—C2B—N1B | 158.7 (3) |
N1A—C2A—C3A—C4A | −168.6 (3) | O2B—C1B—C2B—C3B | −81.4 (4) |
N1B—C2B—C1B—O1B | −26.7 (4) | O1B—C1B—C2B—C3B | 93.2 (3) |
N1B—C2B—C3B—C4B | −55.5 (4) | C1B—C2B—C3B—C4B | −175.2 (3) |
N1C—C2C—C1C—O1C | −13.5 (4) | O2C—C1C—C2C—N1C | 169.1 (3) |
N1C—C2C—C3C—C4C | 64.2 (4) | O2C—C1C—C2C—C3C | −67.5 (4) |
N1D—C2D—C1D—O1D | −30.4 (4) | O1C—C1C—C2C—C3C | 109.9 (3) |
N1D—C2D—C3D—C4D | −175.6 (3) | C1C—C2C—C3C—C4C | −58.4 (4) |
O2A—C1A—C2A—N1A | 155.7 (3) | O2D—C1D—C2D—N1D | 152.3 (3) |
O2A—C1A—C2A—C3A | −83.4 (4) | O2D—C1D—C2D—C3D | −87.3 (4) |
O1A—C1A—C2A—C3A | 93.5 (4) | O1D—C1D—C2D—C3D | 90.0 (4) |
C1A—C2A—C3A—C4A | 70.8 (4) | C1D—C2D—C3D—C4D | 64.1 (4) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A···O1Bi | 0.91 | 1.88 | 2.754 (4) | 160 |
N1A—H2A···O1Bii | 0.91 | 1.92 | 2.796 (4) | 160 |
N1A—H3A···O2Aii | 0.91 | 1.86 | 2.747 (4) | 165 |
N1B—H1B···O1Aiii | 0.91 | 1.92 | 2.814 (4) | 165 |
N1B—H2B···O1Aiv | 0.91 | 1.92 | 2.803 (3) | 164 |
N1B—H3B···O2Bii | 0.91 | 1.89 | 2.781 (4) | 168 |
N1C—H1C···O1Dv | 0.91 | 1.93 | 2.815 (4) | 163 |
N1C—H2C···O2Cv | 0.91 | 1.91 | 2.799 (4) | 163 |
N1C—H3C···O1Dvi | 0.91 | 1.97 | 2.819 (4) | 154 |
N1D—H1D···O1Civ | 0.91 | 1.95 | 2.813 (3) | 159 |
N1D—H2D···O2Dv | 0.91 | 1.87 | 2.762 (4) | 165 |
N1D—H3D···O1Cvii | 0.91 | 1.90 | 2.771 (4) | 161 |
Symmetry codes: (i) −x+1, y+1/2, −z; (ii) x, y+1, z; (iii) −x+1, y−1/2, −z; (iv) x+1, y, z; (v) x, y−1, z; (vi) −x+1, y−1/2, −z+1; (vii) −x+1, y+1/2, −z+1. |
(
S)-2-aminobutyric acid (II)
top
Crystal data top
C4H9NO2 | F(000) = 896 |
Mr = 103.12 | Dx = 1.291 Mg m−3 |
Monoclinic, I2 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: I 2y | Cell parameters from 3867 reflections |
a = 9.646 (2) Å | θ = 1.9–25.0° |
b = 5.2145 (12) Å | µ = 0.10 mm−1 |
c = 42.885 (10) Å | T = 110 K |
β = 100.295 (3)° | Block, colourless |
V = 2122.5 (8) Å3 | 0.40 × 0.32 × 0.18 mm |
Z = 16 | |
Data collection top
Bruker Apex II CCD diffractometer | 2083 independent reflections |
Radiation source: fine-focus sealed tube | 1852 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
Detector resolution: 8.3 pixels mm-1 | θmax = 25.0°, θmin = 1.9° |
Sets of exposures each taken over 0.5° ω rotation scans | h = −11→11 |
Absorption correction: multi-scan SADABS (Bruker, 2007) | k = −6→6 |
Tmin = 0.791, Tmax = 0.982 | l = −50→50 |
7238 measured reflections | |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0531P)2 + 3.6316P] where P = (Fo2 + 2Fc2)/3 |
2083 reflections | (Δ/σ)max < 0.001 |
261 parameters | Δρmax = 0.26 e Å−3 |
1 restraint | Δρmin = −0.25 e Å−3 |
0 constraints | |
Special details top
Experimental. Broad reflections |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1A | −0.0869 (2) | 0.7794 (5) | 0.03248 (6) | 0.0173 (6) | |
O2A | 0.0039 (3) | 0.3905 (5) | 0.04313 (7) | 0.0235 (7) | |
N1A | 0.1646 (3) | 0.9851 (6) | 0.02779 (6) | 0.0147 (7) | |
H1A | 0.1327 | 0.9516 | 0.0069 | 0.022* | |
H2A | 0.2539 | 1.0481 | 0.0303 | 0.022* | |
H3A | 0.1075 | 1.1029 | 0.0347 | 0.022* | |
C1A | 0.0151 (4) | 0.6258 (8) | 0.03974 (8) | 0.0157 (8) | |
C2A | 0.1642 (3) | 0.7444 (7) | 0.04644 (8) | 0.0160 (8) | |
H21A | 0.2329 | 0.6204 | 0.0400 | 0.019* | |
C3A | 0.2086 (4) | 0.8080 (9) | 0.08173 (8) | 0.0256 (9) | |
H32A | 0.2977 | 0.9066 | 0.0847 | 0.031* | |
H31A | 0.1359 | 0.9192 | 0.0883 | 0.031* | |
C4A | 0.2295 (4) | 0.5748 (11) | 0.10308 (10) | 0.0372 (12) | |
H41A | 0.2625 | 0.6292 | 0.1250 | 0.056* | |
H42A | 0.2996 | 0.4610 | 0.0964 | 0.056* | |
H43A | 0.1399 | 0.4831 | 0.1016 | 0.056* | |
O1B | 0.4092 (2) | 0.2807 (5) | 0.02806 (5) | 0.0171 (6) | |
O2B | 0.5037 (3) | −0.0834 (5) | 0.04897 (7) | 0.0253 (7) | |
N1B | 0.6605 (3) | 0.5128 (7) | 0.03150 (6) | 0.0141 (6) | |
H1B | 0.6329 | 0.4693 | 0.0108 | 0.021* | |
H2B | 0.7505 | 0.5731 | 0.0346 | 0.021* | |
H3B | 0.6024 | 0.6367 | 0.0368 | 0.021* | |
C1B | 0.5113 (3) | 0.1463 (8) | 0.04154 (8) | 0.0146 (8) | |
C2B | 0.6537 (3) | 0.2824 (8) | 0.05180 (8) | 0.0155 (8) | |
H21B | 0.7318 | 0.1621 | 0.0493 | 0.019* | |
C3B | 0.6679 (4) | 0.3597 (8) | 0.08685 (8) | 0.0211 (9) | |
H31B | 0.5844 | 0.4625 | 0.0895 | 0.025* | |
H32B | 0.6677 | 0.2024 | 0.0998 | 0.025* | |
C4B | 0.7997 (4) | 0.5129 (10) | 0.09953 (8) | 0.0275 (9) | |
H41B | 0.8093 | 0.5310 | 0.1226 | 0.041* | |
H42B | 0.7927 | 0.6831 | 0.0897 | 0.041* | |
H43B | 0.8824 | 0.4234 | 0.0945 | 0.041* | |
O1C | −0.1360 (2) | 0.1523 (5) | 0.21886 (5) | 0.0157 (5) | |
O2C | −0.0733 (3) | 0.5268 (5) | 0.20093 (6) | 0.0232 (6) | |
N1C | 0.1143 (3) | −0.0685 (6) | 0.21989 (6) | 0.0151 (7) | |
H1C | 0.1128 | −0.0502 | 0.2409 | 0.023* | |
H3C | 0.1990 | −0.1337 | 0.2173 | 0.023* | |
H2C | 0.0443 | −0.1773 | 0.2111 | 0.023* | |
C1C | −0.0498 (4) | 0.2987 (8) | 0.20865 (8) | 0.0155 (8) | |
C2C | 0.0925 (4) | 0.1868 (7) | 0.20399 (8) | 0.0159 (8) | |
H21C | 0.1690 | 0.3048 | 0.2142 | 0.019* | |
C3C | 0.1008 (4) | 0.1653 (9) | 0.16876 (8) | 0.0218 (9) | |
H31C | 0.0963 | 0.3398 | 0.1596 | 0.026* | |
H32C | 0.1934 | 0.0911 | 0.1668 | 0.026* | |
C4C | −0.0146 (4) | 0.0026 (10) | 0.14943 (8) | 0.0279 (9) | |
H41C | −0.0048 | 0.0061 | 0.1271 | 0.042* | |
H42C | −0.1069 | 0.0715 | 0.1516 | 0.042* | |
H43C | −0.0064 | −0.1745 | 0.1572 | 0.042* | |
O1D | 0.3607 (2) | 0.6429 (5) | 0.21874 (5) | 0.0160 (6) | |
O2D | 0.4339 (3) | 1.0372 (5) | 0.21033 (6) | 0.0238 (6) | |
N1D | 0.6197 (3) | 0.4426 (6) | 0.22100 (6) | 0.0138 (7) | |
H1D | 0.6245 | 0.4710 | 0.2421 | 0.021* | |
H2D | 0.5512 | 0.3250 | 0.2142 | 0.021* | |
H3D | 0.7040 | 0.3824 | 0.2175 | 0.021* | |
C1D | 0.4505 (3) | 0.8002 (8) | 0.21183 (8) | 0.0139 (8) | |
C2D | 0.5857 (3) | 0.6874 (7) | 0.20336 (8) | 0.0141 (8) | |
H21D | 0.6647 | 0.8114 | 0.2098 | 0.017* | |
C3D | 0.5697 (4) | 0.6341 (8) | 0.16771 (8) | 0.0201 (8) | |
H31D | 0.6544 | 0.5416 | 0.1637 | 0.024* | |
H32D | 0.4873 | 0.5210 | 0.1611 | 0.024* | |
C4D | 0.5508 (4) | 0.8772 (9) | 0.14760 (9) | 0.0263 (10) | |
H41D | 0.5433 | 0.8316 | 0.1252 | 0.039* | |
H42D | 0.6321 | 0.9902 | 0.1539 | 0.039* | |
H43D | 0.4648 | 0.9659 | 0.1507 | 0.039* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1A | 0.0135 (11) | 0.0169 (14) | 0.0220 (12) | −0.0016 (12) | 0.0046 (9) | 0.0043 (12) |
O2A | 0.0205 (14) | 0.0143 (17) | 0.0377 (16) | −0.0023 (12) | 0.0105 (12) | 0.0035 (13) |
N1A | 0.0123 (13) | 0.0145 (17) | 0.0183 (14) | −0.0026 (13) | 0.0055 (11) | −0.0029 (14) |
C1A | 0.0146 (17) | 0.019 (2) | 0.0158 (18) | −0.0013 (17) | 0.0080 (14) | 0.0012 (17) |
C2A | 0.0141 (16) | 0.013 (2) | 0.0222 (18) | −0.0016 (16) | 0.0062 (14) | 0.0021 (16) |
C3A | 0.0186 (18) | 0.035 (3) | 0.0237 (19) | −0.005 (2) | 0.0044 (15) | 0.000 (2) |
C4A | 0.028 (2) | 0.052 (3) | 0.029 (2) | −0.008 (2) | −0.0027 (17) | 0.014 (2) |
O1B | 0.0136 (11) | 0.0170 (14) | 0.0209 (13) | −0.0019 (12) | 0.0037 (10) | 0.0020 (12) |
O2B | 0.0198 (13) | 0.0113 (15) | 0.0475 (17) | −0.0005 (12) | 0.0130 (12) | 0.0023 (14) |
N1B | 0.0106 (13) | 0.0127 (16) | 0.0197 (14) | −0.0022 (13) | 0.0046 (11) | 0.0002 (14) |
C1B | 0.0136 (17) | 0.013 (2) | 0.0192 (18) | 0.0010 (17) | 0.0093 (14) | −0.0016 (17) |
C2B | 0.0144 (16) | 0.0090 (19) | 0.0234 (18) | 0.0011 (16) | 0.0041 (14) | 0.0043 (17) |
C3B | 0.0224 (19) | 0.023 (2) | 0.0190 (18) | −0.0029 (17) | 0.0070 (15) | 0.0048 (16) |
C4B | 0.028 (2) | 0.036 (2) | 0.0186 (18) | −0.009 (2) | 0.0039 (15) | −0.003 (2) |
O1C | 0.0131 (11) | 0.0126 (13) | 0.0227 (12) | 0.0020 (11) | 0.0063 (9) | 0.0027 (12) |
O2C | 0.0179 (12) | 0.0123 (14) | 0.0392 (15) | 0.0044 (12) | 0.0048 (11) | 0.0066 (15) |
N1C | 0.0144 (14) | 0.0132 (16) | 0.0188 (15) | 0.0017 (14) | 0.0055 (11) | −0.0003 (13) |
C1C | 0.0156 (16) | 0.015 (2) | 0.0160 (17) | −0.0003 (17) | 0.0019 (13) | −0.0028 (17) |
C2C | 0.0144 (16) | 0.0120 (19) | 0.0218 (18) | −0.0002 (16) | 0.0041 (14) | −0.0012 (16) |
C3C | 0.0191 (17) | 0.023 (2) | 0.026 (2) | 0.0007 (18) | 0.0097 (15) | 0.0028 (19) |
C4C | 0.039 (2) | 0.028 (2) | 0.0178 (18) | 0.000 (2) | 0.0076 (16) | 0.0014 (19) |
O1D | 0.0112 (11) | 0.0133 (14) | 0.0247 (13) | 0.0021 (11) | 0.0065 (9) | 0.0025 (12) |
O2D | 0.0205 (13) | 0.0103 (15) | 0.0419 (16) | 0.0024 (13) | 0.0092 (12) | 0.0020 (14) |
N1D | 0.0122 (14) | 0.0110 (16) | 0.0189 (14) | 0.0014 (13) | 0.0042 (11) | −0.0022 (13) |
C1D | 0.0148 (16) | 0.014 (2) | 0.0120 (16) | 0.0012 (17) | 0.0008 (13) | −0.0008 (16) |
C2D | 0.0146 (16) | 0.0070 (18) | 0.0208 (18) | 0.0021 (15) | 0.0038 (13) | 0.0011 (15) |
C3D | 0.0201 (18) | 0.021 (2) | 0.0208 (18) | 0.0019 (18) | 0.0079 (14) | −0.0001 (18) |
C4D | 0.031 (2) | 0.027 (2) | 0.0226 (19) | −0.0012 (19) | 0.0087 (16) | 0.0057 (18) |
Geometric parameters (Å, º) top
O1A—C1A | 1.264 (5) | O1C—C1C | 1.263 (4) |
O2A—C1A | 1.243 (5) | O2C—C1C | 1.245 (5) |
N1A—C2A | 1.489 (5) | N1C—C2C | 1.494 (5) |
N1A—H1A | 0.9100 | N1C—H1C | 0.9100 |
N1A—H2A | 0.9100 | N1C—H3C | 0.9100 |
N1A—H3A | 0.9100 | N1C—H2C | 0.9100 |
C1A—C2A | 1.544 (5) | C1C—C2C | 1.538 (5) |
C2A—C3A | 1.534 (5) | C2C—C3C | 1.531 (5) |
C2A—H21A | 1.0000 | C2C—H21C | 1.0000 |
C3A—C4A | 1.514 (6) | C3C—C4C | 1.522 (6) |
C3A—H32A | 0.9900 | C3C—H31C | 0.9900 |
C3A—H31A | 0.9900 | C3C—H32C | 0.9900 |
C4A—H41A | 0.9800 | C4C—H41C | 0.9800 |
C4A—H42A | 0.9800 | C4C—H42C | 0.9800 |
C4A—H43A | 0.9800 | C4C—H43C | 0.9800 |
O1B—C1B | 1.261 (4) | O1D—C1D | 1.266 (4) |
O2B—C1B | 1.245 (5) | O2D—C1D | 1.247 (5) |
N1B—C2B | 1.492 (5) | N1D—C2D | 1.490 (5) |
N1B—H1B | 0.9100 | N1D—H3D | 0.9100 |
N1B—H2B | 0.9100 | N1D—H2D | 0.9100 |
N1B—H3B | 0.9100 | N1D—H1D | 0.9100 |
C1B—C2B | 1.539 (5) | C1D—C2D | 1.532 (5) |
C2B—C3B | 1.538 (5) | C2D—C3D | 1.534 (5) |
C2B—H21B | 1.0000 | C2D—H21D | 1.0000 |
C3B—C4B | 1.518 (5) | C3D—C4D | 1.526 (6) |
C3B—H31B | 0.9900 | C3D—H31D | 0.9900 |
C3B—H32B | 0.9900 | C3D—H32D | 0.9900 |
C4B—H41B | 0.9800 | C4D—H41D | 0.9800 |
C4B—H42B | 0.9800 | C4D—H42D | 0.9800 |
C4B—H43B | 0.9800 | C4D—H43D | 0.9800 |
| | | |
C2A—N1A—H1A | 109.5 | C2C—N1C—H1C | 109.5 |
C2A—N1A—H2A | 109.5 | C2C—N1C—H3C | 109.5 |
H1A—N1A—H2A | 109.5 | H1C—N1C—H3C | 109.5 |
C2A—N1A—H3A | 109.5 | C2C—N1C—H2C | 109.5 |
H1A—N1A—H3A | 109.5 | H1C—N1C—H2C | 109.5 |
H2A—N1A—H3A | 109.5 | H3C—N1C—H2C | 109.5 |
O2A—C1A—O1A | 125.0 (4) | O2C—C1C—O1C | 124.7 (3) |
O2A—C1A—C2A | 118.1 (4) | O2C—C1C—C2C | 116.9 (3) |
O1A—C1A—C2A | 116.8 (4) | O1C—C1C—C2C | 118.3 (3) |
N1A—C2A—C3A | 108.7 (3) | N1C—C2C—C3C | 110.9 (3) |
N1A—C2A—C1A | 109.2 (3) | N1C—C2C—C1C | 109.6 (3) |
C3A—C2A—C1A | 110.9 (3) | C3C—C2C—C1C | 111.2 (3) |
N1A—C2A—H21A | 109.3 | N1C—C2C—H21C | 108.4 |
C3A—C2A—H21A | 109.3 | C3C—C2C—H21C | 108.4 |
C1A—C2A—H21A | 109.3 | C1C—C2C—H21C | 108.4 |
C4A—C3A—C2A | 114.0 (4) | C4C—C3C—C2C | 114.6 (3) |
C4A—C3A—H32A | 108.8 | C4C—C3C—H31C | 108.6 |
C2A—C3A—H32A | 108.8 | C2C—C3C—H31C | 108.6 |
C4A—C3A—H31A | 108.8 | C4C—C3C—H32C | 108.6 |
C2A—C3A—H31A | 108.8 | C2C—C3C—H32C | 108.6 |
H32A—C3A—H31A | 107.7 | H31C—C3C—H32C | 107.6 |
C3A—C4A—H41A | 109.5 | C3C—C4C—H41C | 109.5 |
C3A—C4A—H42A | 109.5 | C3C—C4C—H42C | 109.5 |
H41A—C4A—H42A | 109.5 | H41C—C4C—H42C | 109.5 |
C3A—C4A—H43A | 109.5 | C3C—C4C—H43C | 109.5 |
H41A—C4A—H43A | 109.5 | H41C—C4C—H43C | 109.5 |
H42A—C4A—H43A | 109.5 | H42C—C4C—H43C | 109.5 |
C2B—N1B—H1B | 109.5 | C2D—N1D—H3D | 109.5 |
C2B—N1B—H2B | 109.5 | C2D—N1D—H2D | 109.5 |
H1B—N1B—H2B | 109.5 | H3D—N1D—H2D | 109.5 |
C2B—N1B—H3B | 109.5 | C2D—N1D—H1D | 109.5 |
H1B—N1B—H3B | 109.5 | H3D—N1D—H1D | 109.5 |
H2B—N1B—H3B | 109.5 | H2D—N1D—H1D | 109.5 |
O2B—C1B—O1B | 125.1 (4) | O2D—C1D—O1D | 124.5 (3) |
O2B—C1B—C2B | 117.4 (3) | O2D—C1D—C2D | 118.4 (3) |
O1B—C1B—C2B | 117.3 (3) | O1D—C1D—C2D | 117.0 (3) |
N1B—C2B—C3B | 110.7 (3) | N1D—C2D—C1D | 109.1 (3) |
N1B—C2B—C1B | 109.5 (3) | N1D—C2D—C3D | 108.9 (3) |
C3B—C2B—C1B | 108.6 (3) | C1D—C2D—C3D | 111.6 (3) |
N1B—C2B—H21B | 109.3 | N1D—C2D—H21D | 109.0 |
C3B—C2B—H21B | 109.3 | C1D—C2D—H21D | 109.0 |
C1B—C2B—H21B | 109.3 | C3D—C2D—H21D | 109.0 |
C4B—C3B—C2B | 114.2 (3) | C4D—C3D—C2D | 113.2 (3) |
C4B—C3B—H31B | 108.7 | C4D—C3D—H31D | 108.9 |
C2B—C3B—H31B | 108.7 | C2D—C3D—H31D | 108.9 |
C4B—C3B—H32B | 108.7 | C4D—C3D—H32D | 108.9 |
C2B—C3B—H32B | 108.7 | C2D—C3D—H32D | 108.9 |
H31B—C3B—H32B | 107.6 | H31D—C3D—H32D | 107.8 |
C3B—C4B—H41B | 109.5 | C3D—C4D—H41D | 109.5 |
C3B—C4B—H42B | 109.5 | C3D—C4D—H42D | 109.5 |
H41B—C4B—H42B | 109.5 | H41D—C4D—H42D | 109.5 |
C3B—C4B—H43B | 109.5 | C3D—C4D—H43D | 109.5 |
H41B—C4B—H43B | 109.5 | H41D—C4D—H43D | 109.5 |
H42B—C4B—H43B | 109.5 | H42D—C4D—H43D | 109.5 |
| | | |
N1A—C2A—C1A—O1A | −28.9 (4) | O2B—C1B—C2B—N1B | 159.0 (3) |
N1A—C2A—C3A—C4A | −173.1 (3) | O2B—C1B—C2B—C3B | −80.0 (4) |
N1B—C2B—C1B—O1B | −25.5 (4) | O1B—C1B—C2B—C3B | 95.5 (4) |
N1B—C2B—C3B—C4B | −55.7 (4) | C1B—C2B—C3B—C4B | −176.0 (4) |
N1C—C2C—C1C—O1C | −13.0 (4) | O2C—C1C—C2C—N1C | 169.4 (3) |
N1C—C2C—C3C—C4C | 64.4 (4) | O2C—C1C—C2C—C3C | −67.6 (4) |
N1D—C2D—C1D—O1D | −30.6 (4) | O1C—C1C—C2C—C3C | 109.9 (4) |
N1D—C2D—C3D—C4D | −173.7 (3) | C1C—C2C—C3C—C4C | −57.8 (5) |
O2A—C1A—C2A—N1A | 154.1 (3) | O2D—C1D—C2D—N1D | 152.1 (3) |
O2A—C1A—C2A—C3A | −86.2 (4) | O2D—C1D—C2D—C3D | −87.5 (4) |
O1A—C1A—C2A—C3A | 90.9 (4) | O1D—C1D—C2D—C3D | 89.9 (4) |
C1A—C2A—C3A—C4A | 66.8 (4) | C1D—C2D—C3D—C4D | 65.8 (4) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A···O1Ai | 0.91 | 1.89 | 2.775 (4) | 162 |
N1A—H2A···O1Bii | 0.91 | 1.94 | 2.816 (4) | 160 |
N1A—H3A···O2Aii | 0.91 | 1.87 | 2.769 (4) | 168 |
N1B—H1B···O1Biii | 0.91 | 1.91 | 2.798 (4) | 163 |
N1B—H2B···O1Aiv | 0.91 | 1.92 | 2.799 (4) | 163 |
N1B—H3B···O2Bii | 0.91 | 1.87 | 2.773 (4) | 173 |
N1C—H1C···O1Dv | 0.91 | 1.98 | 2.824 (4) | 154 |
N1C—H2C···O2Cvi | 0.91 | 1.92 | 2.804 (4) | 164 |
N1C—H3C···O1Dvi | 0.91 | 1.94 | 2.821 (4) | 163 |
N1D—H1D···O1Cvii | 0.91 | 1.91 | 2.780 (4) | 160 |
N1D—H2D···O2Dvi | 0.91 | 1.87 | 2.756 (4) | 164 |
N1D—H3D···O1Civ | 0.91 | 1.95 | 2.817 (4) | 159 |
Symmetry codes: (i) −x, y, −z; (ii) x, y+1, z; (iii) −x+1, y, −z; (iv) x+1, y, z; (v) −x+1/2, y−1/2, −z+1/2; (vi) x, y−1, z; (vii) −x+1/2, y+1/2, −z+1/2. |