Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100000548/qa0200sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100000548/qa0200Isup2.hkl |
CCDC reference: 142943
Crystals of the title compound were prepared by vapour diffusion of 2-propanol into 30 µl of an aqueous solution of the dipeptide. At low initial solute concentration (0.16–0.32 mg in 30 µl of water), bundles of exceedingly thin needles were formed which were too small for collection of X-ray data (<0.01 mm), but permitted determination of the unit cell. A second polymorph in the shape of ultrathin plates appeared (together with the needles) when higher concentrations were used. The plates are soft and easily bent, and can not be cut without inflicting substantial damage. They furthermore decay within a few s when exposed to air. The specimen used for data collection was obtained from a test tube containing 0.64 mg of the peptide, and was transferred to a drop of oil before being attached to the glass rod.
Thin plates were also obtained with 1-propanol as precipitating agent, but no unit cell was found for any of the crystals tested. 2-Butanol, on the other hand, gave very thin needles, while methanol and ethanol failed to give precipitates in the diffusion experiments.
The data collection nominally covered over a hemisphere of reciprocal space by a combination of three sets of exposures with the detector set at 2θ = 29° and a 4.95 cm crystal-to-detector distance.
Displacement ellipsoids for the solvent molecule are quite large, and for molecules C, E and F the disorder has been resolved into a major and a minor position, with occupancies 0.68 (2):0.32 (2), 0.896 (13):0.104 (13) and 0.806 (7):0.194 (7), respectively. For C and E, the disorder arises from a rotation around the O1—C2 bond, while for F, O1 and C2 are also shifted to alternative positions.
Heavy atoms were refined anisotropically, except for the O and C atoms of the least populated positions of the disordered 2-propanol molecules C, E and F, which were refined isotropically (C) or assigned Uiso values equivalent to Ueq for the corresponding atom in the most populated position. A mild SHELXTL (Sheldrick, 1997) SAME constraint (s1 = 0.006 and s2 = 0.009) was used for the geometry of the two peptide molecules, and similar commands (s1 = 0.008 and s2 = 0.012) for the geometry of all 2-propanol molecules. H atoms were placed geometrically and refined with a riding model which included free rotation for amino groups and methyl groups with occupancy greater than 0.5. Hydroxylic H atoms were constrained to have tetrahedral geometry and rotated so as to minimize the distance to the closest acceptor, but with deviations from perfect staggered positions not exceeding 30°. Uiso values were constrained to be 1.2Ueq of the carrier atom, or 1.5Ueq for methyl, hydroxyl and amino groups.
Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXTL (Sheldrick, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 1997).
C8H16N2O3S·2C3H8O | F(000) = 744 |
Mr = 340.48 | Dx = 1.118 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.9277 (2) Å | Cell parameters from 4393 reflections |
b = 16.4556 (3) Å | θ = 2–25° |
c = 12.4895 (2) Å | µ = 0.18 mm−1 |
β = 97.594 (1)° | T = 150 K |
V = 2022.47 (6) Å3 | Plate, colourless |
Z = 4 | 0.80 × 0.48 × 0.01 mm |
Siemens SMART CCD diffractometer | 6911 independent reflections |
Radiation source: fine-focus sealed tube | 4437 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.093 |
Detector resolution: 8.3 pixels mm-1 | θmax = 25.0°, θmin = 2.1° |
Sets of exposures each taken over 0.3° ω rotation scans | h = −11→11 |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | k = −19→19 |
Tmin = 0.865, Tmax = 0.998 | l = −14→14 |
14839 measured reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.078 | w = 1/[σ2(Fo2) + (0.040P)2 + 1.5P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.202 | (Δ/σ)max = 0.014 |
S = 1.01 | Δρmax = 0.53 e Å−3 |
6911 reflections | Δρmin = −0.30 e Å−3 |
448 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
198 restraints | Extinction coefficient: 0.0070 (16) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 3230 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.01 (16) |
C8H16N2O3S·2C3H8O | V = 2022.47 (6) Å3 |
Mr = 340.48 | Z = 4 |
Monoclinic, P21 | Mo Kα radiation |
a = 9.9277 (2) Å | µ = 0.18 mm−1 |
b = 16.4556 (3) Å | T = 150 K |
c = 12.4895 (2) Å | 0.80 × 0.48 × 0.01 mm |
β = 97.594 (1)° |
Siemens SMART CCD diffractometer | 6911 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | 4437 reflections with I > 2σ(I) |
Tmin = 0.865, Tmax = 0.998 | Rint = 0.093 |
14839 measured reflections |
R[F2 > 2σ(F2)] = 0.078 | H-atom parameters constrained |
wR(F2) = 0.202 | Δρmax = 0.53 e Å−3 |
S = 1.01 | Δρmin = −0.30 e Å−3 |
6911 reflections | Absolute structure: Flack (1983), 3230 Friedel pairs |
448 parameters | Absolute structure parameter: −0.01 (16) |
198 restraints |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
S1A | 0.2282 (2) | 0.17232 (14) | 0.84163 (16) | 0.0915 (6) | |
O1A | −0.0601 (3) | 0.1049 (2) | 0.4775 (4) | 0.0619 (11) | |
O2A | 0.2888 (3) | −0.0977 (2) | 0.5129 (4) | 0.0611 (11) | |
O3A | 0.1201 (3) | −0.18671 (18) | 0.5102 (4) | 0.0618 (11) | |
N1A | 0.1041 (4) | 0.2411 (2) | 0.4313 (3) | 0.0439 (10) | |
H1A | 0.1704 | 0.2791 | 0.4301 | 0.066* | |
H2A | 0.0297 | 0.2645 | 0.4540 | 0.066* | |
H3A | 0.0813 | 0.2204 | 0.3638 | 0.066* | |
N2A | 0.1305 (3) | 0.02973 (19) | 0.4767 (3) | 0.0426 (10) | |
H4A | 0.2193 | 0.0313 | 0.4783 | 0.051* | |
C1A | 0.1548 (4) | 0.1741 (2) | 0.5073 (4) | 0.0432 (12) | |
H11A | 0.2500 | 0.1600 | 0.4965 | 0.052* | |
C2A | 0.1533 (5) | 0.2042 (3) | 0.6219 (4) | 0.0480 (12) | |
H21A | 0.0582 | 0.2105 | 0.6363 | 0.058* | |
H22A | 0.1980 | 0.2580 | 0.6305 | 0.058* | |
C3A | 0.2290 (7) | 0.1430 (3) | 0.7041 (5) | 0.0744 (18) | |
H31A | 0.3243 | 0.1379 | 0.6897 | 0.089* | |
H32A | 0.1857 | 0.0890 | 0.6927 | 0.089* | |
C4A | 0.3376 (8) | 0.2583 (5) | 0.8515 (6) | 0.097 (2) | |
H41A | 0.3473 | 0.2797 | 0.9253 | 0.145* | |
H42A | 0.2990 | 0.3003 | 0.8010 | 0.145* | |
H43A | 0.4270 | 0.2422 | 0.8335 | 0.145* | |
C5A | 0.0644 (4) | 0.0993 (2) | 0.4851 (4) | 0.0420 (12) | |
C6A | 0.0628 (4) | −0.0490 (2) | 0.4651 (4) | 0.0474 (13) | |
H61A | −0.0095 | −0.0504 | 0.5136 | 0.057* | |
C7A | −0.0025 (6) | −0.0630 (3) | 0.3503 (5) | 0.0719 (18) | |
H71A | −0.0611 | −0.0167 | 0.3264 | 0.108* | |
H72A | −0.0572 | −0.1127 | 0.3469 | 0.108* | |
H73A | 0.0683 | −0.0686 | 0.3030 | 0.108* | |
C8A | 0.1668 (4) | −0.1154 (2) | 0.5006 (4) | 0.0490 (13) | |
S1B | 0.2703 (2) | 0.66958 (15) | 0.16478 (17) | 0.0916 (6) | |
O1B | 0.5559 (3) | 0.6103 (2) | 0.5374 (3) | 0.0586 (11) | |
O2B | 0.2226 (3) | 0.4381 (2) | 0.4017 (3) | 0.0586 (10) | |
O3B | 0.3336 (3) | 0.33245 (18) | 0.4827 (3) | 0.0549 (10) | |
N1B | 0.4242 (4) | 0.7599 (2) | 0.5637 (3) | 0.0458 (11) | |
H1B | 0.3760 | 0.8066 | 0.5499 | 0.069* | |
H2B | 0.5095 | 0.7667 | 0.5459 | 0.069* | |
H3B | 0.4294 | 0.7476 | 0.6352 | 0.069* | |
N2B | 0.3525 (3) | 0.54732 (19) | 0.5299 (4) | 0.0470 (11) | |
H4B | 0.2641 | 0.5542 | 0.5260 | 0.056* | |
C1B | 0.3547 (4) | 0.6919 (2) | 0.4980 (4) | 0.0440 (13) | |
H11B | 0.2590 | 0.6867 | 0.5140 | 0.053* | |
C2B | 0.3545 (5) | 0.7129 (3) | 0.3797 (4) | 0.0520 (13) | |
H21B | 0.4487 | 0.7114 | 0.3619 | 0.062* | |
H22B | 0.3190 | 0.7687 | 0.3660 | 0.062* | |
C3B | 0.2648 (6) | 0.6517 (3) | 0.3058 (5) | 0.0714 (17) | |
H31B | 0.1696 | 0.6560 | 0.3207 | 0.086* | |
H32B | 0.2965 | 0.5957 | 0.3239 | 0.086* | |
C4B | 0.1806 (9) | 0.7636 (5) | 0.1482 (7) | 0.118 (3) | |
H41B | 0.1719 | 0.7803 | 0.0722 | 0.177* | |
H42B | 0.2306 | 0.8053 | 0.1932 | 0.177* | |
H43B | 0.0899 | 0.7569 | 0.1699 | 0.177* | |
C5B | 0.4308 (4) | 0.6124 (2) | 0.5257 (4) | 0.0437 (13) | |
C6B | 0.4068 (4) | 0.4650 (2) | 0.5406 (4) | 0.0481 (14) | |
H61B | 0.4965 | 0.4652 | 0.5124 | 0.058* | |
C7B | 0.4315 (6) | 0.4376 (3) | 0.6569 (5) | 0.0687 (17) | |
H71B | 0.5002 | 0.4725 | 0.6973 | 0.103* | |
H72B | 0.4636 | 0.3812 | 0.6601 | 0.103* | |
H73B | 0.3466 | 0.4411 | 0.6887 | 0.103* | |
C8B | 0.3124 (4) | 0.4089 (2) | 0.4687 (4) | 0.0448 (12) | |
O1C | 0.4489 (5) | 0.7337 (3) | 0.7847 (4) | 0.0997 (17) | 0.677 (18) |
H1C | 0.4850 | 0.7703 | 0.8272 | 0.150* | |
C1C | 0.2379 (11) | 0.6617 (11) | 0.7601 (11) | 0.135 (6) | 0.677 (18) |
H11C | 0.2754 | 0.6147 | 0.7259 | 0.203* | 0.677 (18) |
H12C | 0.2070 | 0.7023 | 0.7048 | 0.203* | 0.677 (18) |
H13C | 0.1610 | 0.6443 | 0.7962 | 0.203* | 0.677 (18) |
C2C | 0.3459 (9) | 0.6983 (7) | 0.8417 (9) | 0.090 (7) | 0.677 (18) |
H21C | 0.3056 | 0.7407 | 0.8853 | 0.108* | 0.677 (18) |
C3C | 0.4142 (15) | 0.6342 (8) | 0.9137 (11) | 0.123 (6) | 0.677 (18) |
H31C | 0.4580 | 0.5950 | 0.8704 | 0.185* | 0.677 (18) |
H32C | 0.3467 | 0.6063 | 0.9510 | 0.185* | 0.677 (18) |
H33C | 0.4830 | 0.6593 | 0.9671 | 0.185* | 0.677 (18) |
O12C | 0.4489 (5) | 0.7337 (3) | 0.7847 (4) | 0.0997 (17) | 0.323 (18) |
C12C | 0.2162 (14) | 0.7400 (19) | 0.807 (3) | 0.156 (16)* | 0.323 (18) |
H14C | 0.2148 | 0.7991 | 0.8159 | 0.234* | 0.323 (18) |
H15C | 0.1451 | 0.7153 | 0.8435 | 0.234* | 0.323 (18) |
H16C | 0.1998 | 0.7268 | 0.7295 | 0.234* | 0.323 (18) |
C22C | 0.3523 (15) | 0.7074 (12) | 0.8542 (14) | 0.108 (19)* | 0.323 (18) |
H22C | 0.3780 | 0.7290 | 0.9289 | 0.130* | 0.323 (18) |
C32C | 0.352 (3) | 0.6171 (12) | 0.855 (3) | 0.131 (13)* | 0.323 (18) |
H34C | 0.4441 | 0.5971 | 0.8778 | 0.196* | 0.323 (18) |
H35C | 0.3191 | 0.5968 | 0.7827 | 0.196* | 0.323 (18) |
H36C | 0.2916 | 0.5978 | 0.9060 | 0.196* | 0.323 (18) |
O1D | 0.5978 (4) | −0.1430 (2) | 0.8885 (3) | 0.0759 (12) | |
H1D | 0.6699 | −0.1342 | 0.8604 | 0.114* | |
C1D | 0.4878 (8) | −0.0328 (5) | 0.7862 (6) | 0.115 (3) | |
H11D | 0.5651 | −0.0176 | 0.7491 | 0.172* | |
H12D | 0.4297 | 0.0148 | 0.7915 | 0.172* | |
H13D | 0.4353 | −0.0757 | 0.7453 | 0.172* | |
C2D | 0.5387 (7) | −0.0632 (4) | 0.8970 (6) | 0.093 (2) | |
H21D | 0.6106 | −0.0253 | 0.9313 | 0.111* | |
C3D | 0.4306 (8) | −0.0697 (6) | 0.9676 (7) | 0.123 (3) | |
H31D | 0.4719 | −0.0784 | 1.0424 | 0.184* | |
H32D | 0.3712 | −0.1157 | 0.9441 | 0.184* | |
H33D | 0.3771 | −0.0195 | 0.9629 | 0.184* | |
O1E | 0.1652 (4) | 0.3782 (2) | 0.2026 (3) | 0.0696 (11) | 0.896 (13) |
H1E | 0.1821 | 0.3987 | 0.2654 | 0.104* | |
C1E | −0.0471 (9) | 0.4478 (8) | 0.1984 (10) | 0.144 (5) | 0.896 (13) |
H11E | −0.0260 | 0.4860 | 0.2584 | 0.216* | 0.896 (13) |
H12E | −0.0750 | 0.3956 | 0.2263 | 0.216* | 0.896 (13) |
H13E | −0.1212 | 0.4697 | 0.1468 | 0.216* | 0.896 (13) |
C2E | 0.0755 (8) | 0.4357 (5) | 0.1434 (6) | 0.098 (3) | 0.896 (13) |
H21E | 0.1239 | 0.4888 | 0.1409 | 0.117* | 0.896 (13) |
C3E | 0.0437 (11) | 0.4037 (6) | 0.0316 (6) | 0.122 (4) | 0.896 (13) |
H31E | 0.1134 | 0.4219 | −0.0118 | 0.182* | 0.896 (13) |
H32E | −0.0453 | 0.4239 | −0.0006 | 0.182* | 0.896 (13) |
H33E | 0.0422 | 0.3442 | 0.0336 | 0.182* | 0.896 (13) |
O12E | 0.1652 (4) | 0.3782 (2) | 0.2026 (3) | 0.0696 (11) | 0.104 (13) |
C12E | −0.003 (7) | 0.482 (4) | 0.209 (9) | 0.140* | 0.104 (13) |
H14E | 0.0663 | 0.5228 | 0.2324 | 0.210* | 0.104 (13) |
H15E | −0.0300 | 0.4543 | 0.2724 | 0.210* | 0.104 (13) |
H16E | −0.0820 | 0.5077 | 0.1681 | 0.210* | 0.104 (13) |
C22E | 0.055 (4) | 0.420 (3) | 0.139 (4) | 0.096* | 0.104 (13) |
H22E | 0.0903 | 0.4488 | 0.0774 | 0.115* | 0.104 (13) |
C32E | −0.048 (5) | 0.359 (5) | 0.096 (7) | 0.120* | 0.104 (13) |
H34E | −0.0067 | 0.3204 | 0.0501 | 0.180* | 0.104 (13) |
H35E | −0.1246 | 0.3863 | 0.0533 | 0.180* | 0.104 (13) |
H36E | −0.0797 | 0.3299 | 0.1562 | 0.180* | 0.104 (13) |
O1F | 0.1040 (7) | 0.2156 (3) | 0.2105 (5) | 0.090 (2) | 0.806 (7) |
H1F | 0.0939 | 0.2593 | 0.1742 | 0.136* | 0.806 (7) |
C1F | 0.0579 (10) | 0.1151 (7) | 0.0724 (9) | 0.119 (4) | 0.806 (7) |
H11F | −0.0019 | 0.1537 | 0.0294 | 0.178* | 0.806 (7) |
H12F | 0.0049 | 0.0833 | 0.1183 | 0.178* | 0.806 (7) |
H13F | 0.0992 | 0.0785 | 0.0240 | 0.178* | 0.806 (7) |
C2F | 0.1679 (7) | 0.1609 (5) | 0.1421 (6) | 0.077 (3) | 0.806 (7) |
H21F | 0.2253 | 0.1919 | 0.0962 | 0.116* | 0.806 (7) |
C3F | 0.2533 (13) | 0.1028 (7) | 0.2137 (10) | 0.146 (5) | 0.806 (7) |
H31F | 0.3318 | 0.1317 | 0.2518 | 0.219* | 0.806 (7) |
H32F | 0.2850 | 0.0592 | 0.1699 | 0.219* | 0.806 (7) |
H33F | 0.1992 | 0.0796 | 0.2664 | 0.219* | 0.806 (7) |
O12F | 0.228 (3) | 0.1562 (15) | 0.2713 (19) | 0.092* | 0.194 (7) |
H2F | 0.3021 | 0.1328 | 0.2963 | 0.138* | 0.194 (7) |
C12F | 0.259 (5) | 0.055 (2) | 0.140 (3) | 0.120* | 0.194 (7) |
H34F | 0.3538 | 0.0481 | 0.1724 | 0.180* | 0.194 (7) |
H35F | 0.2513 | 0.0436 | 0.0623 | 0.180* | 0.194 (7) |
H36F | 0.2010 | 0.0175 | 0.1739 | 0.180* | 0.194 (7) |
C22F | 0.215 (3) | 0.1408 (16) | 0.1567 (19) | 0.080* | 0.194 (7) |
H22F | 0.2736 | 0.1794 | 0.1217 | 0.120* | 0.194 (7) |
C32F | 0.070 (5) | 0.154 (3) | 0.113 (4) | 0.150* | 0.194 (7) |
H37F | 0.0445 | 0.2101 | 0.1250 | 0.225* | 0.194 (7) |
H38F | 0.0127 | 0.1170 | 0.1489 | 0.225* | 0.194 (7) |
H39F | 0.0570 | 0.1424 | 0.0349 | 0.225* | 0.194 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1A | 0.1140 (15) | 0.1014 (13) | 0.0610 (12) | −0.0102 (11) | 0.0188 (11) | 0.0088 (10) |
O1A | 0.0345 (18) | 0.0431 (16) | 0.109 (4) | −0.0002 (14) | 0.011 (2) | −0.002 (2) |
O2A | 0.0407 (19) | 0.0439 (17) | 0.099 (3) | −0.0004 (14) | 0.011 (2) | 0.0034 (19) |
O3A | 0.047 (2) | 0.0397 (17) | 0.102 (3) | −0.0004 (14) | 0.022 (2) | 0.0054 (19) |
N1A | 0.041 (2) | 0.0417 (19) | 0.050 (3) | −0.0014 (16) | 0.009 (2) | −0.0027 (18) |
N2A | 0.0286 (18) | 0.0379 (19) | 0.062 (3) | 0.0023 (15) | 0.0075 (19) | 0.0002 (19) |
C1A | 0.030 (2) | 0.039 (2) | 0.061 (4) | 0.0011 (18) | 0.009 (2) | 0.003 (2) |
C2A | 0.051 (3) | 0.046 (2) | 0.045 (4) | 0.001 (2) | 0.003 (3) | 0.001 (2) |
C3A | 0.088 (4) | 0.060 (3) | 0.077 (5) | −0.004 (3) | 0.018 (4) | 0.000 (3) |
C4A | 0.116 (6) | 0.108 (5) | 0.064 (6) | −0.010 (5) | 0.005 (5) | −0.011 (4) |
C5A | 0.030 (2) | 0.040 (2) | 0.056 (4) | 0.0013 (18) | 0.006 (2) | −0.002 (2) |
C6A | 0.036 (2) | 0.038 (2) | 0.069 (4) | −0.0021 (18) | 0.010 (3) | 0.002 (2) |
C7A | 0.063 (3) | 0.056 (3) | 0.091 (5) | −0.007 (3) | −0.012 (3) | 0.005 (3) |
C8A | 0.039 (3) | 0.043 (2) | 0.068 (4) | −0.0029 (19) | 0.015 (3) | 0.002 (2) |
S1B | 0.1044 (14) | 0.1030 (13) | 0.0684 (13) | 0.0003 (11) | 0.0158 (11) | −0.0068 (11) |
O1B | 0.0354 (18) | 0.0421 (16) | 0.098 (3) | 0.0005 (14) | 0.0091 (19) | 0.0030 (19) |
O2B | 0.050 (2) | 0.0557 (19) | 0.068 (3) | 0.0024 (16) | −0.001 (2) | −0.0111 (18) |
O3B | 0.0479 (19) | 0.0415 (18) | 0.077 (3) | −0.0033 (14) | 0.0141 (19) | −0.0047 (17) |
N1B | 0.042 (2) | 0.0383 (19) | 0.057 (3) | −0.0043 (15) | 0.008 (2) | −0.0017 (19) |
N2B | 0.0316 (19) | 0.0384 (19) | 0.070 (3) | −0.0002 (15) | 0.004 (2) | −0.0010 (19) |
C1B | 0.029 (2) | 0.042 (2) | 0.061 (4) | −0.0045 (17) | 0.005 (2) | −0.006 (2) |
C2B | 0.046 (3) | 0.050 (3) | 0.057 (4) | −0.001 (2) | 0.000 (3) | 0.001 (3) |
C3B | 0.081 (4) | 0.065 (3) | 0.070 (5) | −0.004 (3) | 0.019 (4) | −0.006 (3) |
C4B | 0.143 (7) | 0.118 (6) | 0.085 (7) | 0.021 (6) | −0.017 (6) | 0.023 (5) |
C5B | 0.033 (2) | 0.033 (2) | 0.065 (4) | 0.0003 (18) | 0.007 (2) | 0.001 (2) |
C6B | 0.034 (2) | 0.035 (2) | 0.073 (4) | 0.0008 (18) | 0.000 (3) | −0.004 (2) |
C7B | 0.080 (4) | 0.058 (3) | 0.065 (5) | 0.009 (3) | −0.002 (3) | −0.002 (3) |
C8B | 0.032 (2) | 0.049 (2) | 0.055 (4) | 0.0028 (19) | 0.010 (2) | −0.005 (2) |
O1C | 0.140 (4) | 0.104 (4) | 0.060 (3) | −0.049 (3) | 0.031 (3) | −0.010 (3) |
C1C | 0.107 (8) | 0.175 (11) | 0.129 (10) | −0.031 (7) | 0.038 (7) | 0.003 (8) |
C2C | 0.117 (11) | 0.090 (9) | 0.073 (9) | −0.014 (5) | 0.049 (7) | −0.021 (6) |
C3C | 0.148 (9) | 0.139 (9) | 0.086 (8) | −0.004 (7) | 0.026 (7) | 0.016 (7) |
O12C | 0.140 (4) | 0.104 (4) | 0.060 (3) | −0.049 (3) | 0.031 (3) | −0.010 (3) |
O1D | 0.094 (3) | 0.076 (2) | 0.057 (3) | 0.000 (2) | 0.006 (2) | 0.003 (2) |
C1D | 0.116 (7) | 0.114 (7) | 0.110 (8) | 0.033 (5) | −0.004 (6) | 0.019 (6) |
C2D | 0.102 (5) | 0.080 (4) | 0.092 (6) | 0.010 (4) | −0.002 (5) | −0.017 (4) |
C3D | 0.135 (7) | 0.140 (8) | 0.101 (8) | 0.007 (6) | 0.044 (6) | −0.011 (6) |
O1E | 0.073 (2) | 0.065 (2) | 0.065 (3) | 0.0094 (19) | −0.014 (2) | −0.009 (2) |
C1E | 0.116 (7) | 0.161 (8) | 0.151 (8) | 0.049 (6) | −0.001 (6) | 0.001 (7) |
C2E | 0.098 (6) | 0.096 (6) | 0.085 (7) | 0.029 (5) | −0.036 (5) | −0.013 (5) |
C3E | 0.136 (7) | 0.125 (7) | 0.085 (7) | 0.025 (6) | −0.053 (5) | −0.016 (5) |
O12E | 0.073 (2) | 0.065 (2) | 0.065 (3) | 0.0094 (19) | −0.014 (2) | −0.009 (2) |
O1F | 0.150 (6) | 0.067 (3) | 0.061 (4) | −0.012 (3) | 0.040 (4) | −0.015 (3) |
C1F | 0.108 (6) | 0.141 (7) | 0.106 (7) | −0.016 (6) | 0.008 (6) | −0.026 (6) |
C2F | 0.086 (7) | 0.086 (6) | 0.064 (6) | −0.007 (5) | 0.023 (5) | −0.007 (5) |
C3F | 0.161 (8) | 0.160 (8) | 0.119 (8) | 0.048 (7) | 0.028 (7) | 0.010 (7) |
S1A—C4A | 1.778 (7) | C3C—H31C | 0.9800 |
S1A—C3A | 1.785 (6) | C3C—H32C | 0.9800 |
O1A—C5A | 1.230 (4) | C3C—H33C | 0.9800 |
O2A—C8A | 1.236 (4) | C12C—C22C | 1.501 (9) |
O3A—C8A | 1.274 (4) | C12C—H14C | 0.9800 |
N1A—C1A | 1.497 (5) | C12C—H15C | 0.9800 |
N1A—H1A | 0.9100 | C12C—H16C | 0.9800 |
N1A—H2A | 0.9100 | C22C—C32C | 1.487 (9) |
N1A—H3A | 0.9100 | C22C—H22C | 1.0000 |
N2A—C5A | 1.331 (4) | C32C—H34C | 0.9800 |
N2A—C6A | 1.458 (5) | C32C—H35C | 0.9800 |
N2A—H4A | 0.8800 | C32C—H36C | 0.9800 |
C1A—C2A | 1.516 (6) | O1D—C2D | 1.449 (6) |
C1A—C5A | 1.527 (5) | O1D—H1D | 0.8504 |
C1A—H11A | 1.0000 | C1D—C2D | 1.495 (7) |
C2A—C3A | 1.559 (6) | C1D—H11D | 0.9800 |
C2A—H21A | 0.9900 | C1D—H12D | 0.9800 |
C2A—H22A | 0.9900 | C1D—H13D | 0.9800 |
C3A—H31A | 0.9900 | C2D—C3D | 1.480 (8) |
C3A—H32A | 0.9900 | C2D—H21D | 1.0000 |
C4A—H41A | 0.9800 | C3D—H31D | 0.9800 |
C4A—H42A | 0.9800 | C3D—H32D | 0.9800 |
C4A—H43A | 0.9800 | C3D—H33D | 0.9800 |
C6A—C7A | 1.511 (7) | O1E—C2E | 1.436 (6) |
C6A—C8A | 1.527 (5) | O1E—H1E | 0.8502 |
C6A—H61A | 1.0000 | C1E—C2E | 1.488 (8) |
C7A—H71A | 0.9800 | C1E—H11E | 0.9800 |
C7A—H72A | 0.9800 | C1E—H12E | 0.9800 |
C7A—H73A | 0.9800 | C1E—H13E | 0.9800 |
S1B—C4B | 1.784 (7) | C2E—C3E | 1.486 (8) |
S1B—C3B | 1.794 (6) | C2E—H21E | 1.0000 |
O1B—C5B | 1.232 (4) | C3E—H31E | 0.9800 |
O2B—C8B | 1.237 (5) | C3E—H32E | 0.9800 |
O3B—C8B | 1.284 (4) | C3E—H33E | 0.9800 |
N1B—C1B | 1.500 (5) | C12E—C22E | 1.498 (9) |
N1B—H1B | 0.9100 | C12E—H14E | 0.9800 |
N1B—H2B | 0.9100 | C12E—H15E | 0.9800 |
N1B—H3B | 0.9100 | C12E—H16E | 0.9800 |
N2B—C5B | 1.329 (4) | C22E—C32E | 1.486 (9) |
N2B—C6B | 1.457 (4) | C22E—H22E | 1.0000 |
N2B—H4B | 0.8800 | C32E—H34E | 0.9800 |
C1B—C2B | 1.517 (6) | C32E—H35E | 0.9800 |
C1B—C5B | 1.527 (5) | C32E—H36E | 0.9800 |
C1B—H11B | 1.0000 | O1F—C2F | 1.445 (6) |
C2B—C3B | 1.562 (6) | O1F—H1F | 0.8491 |
C2B—H21B | 0.9900 | C1F—C2F | 1.505 (8) |
C2B—H22B | 0.9900 | C1F—H11F | 0.9800 |
C3B—H31B | 0.9900 | C1F—H12F | 0.9800 |
C3B—H32B | 0.9900 | C1F—H13F | 0.9800 |
C4B—H41B | 0.9800 | C2F—C3F | 1.493 (8) |
C4B—H42B | 0.9800 | C2F—H21F | 1.0000 |
C4B—H43B | 0.9800 | C3F—H31F | 0.9800 |
C6B—C7B | 1.510 (7) | C3F—H32F | 0.9800 |
C6B—C8B | 1.521 (5) | C3F—H33F | 0.9800 |
C6B—H61B | 1.0000 | C3F—H2F | 1.1882 |
C7B—H71B | 0.9800 | O12F—C22F | 1.442 (8) |
C7B—H72B | 0.9800 | O12F—H2F | 0.8497 |
C7B—H73B | 0.9800 | C12F—C22F | 1.500 (9) |
O1C—C2C | 1.443 (6) | C12F—H34F | 0.9800 |
O1C—H1C | 0.8511 | C12F—H35F | 0.9800 |
C1C—C2C | 1.504 (9) | C12F—H36F | 0.9800 |
C1C—H11C | 0.9800 | C22F—C32F | 1.487 (9) |
C1C—H12C | 0.9800 | C22F—H22F | 1.0000 |
C1C—H13C | 0.9800 | C32F—H37F | 0.9800 |
C2C—C3C | 1.490 (9) | C32F—H38F | 0.9800 |
C2C—H21C | 1.0000 | C32F—H39F | 0.9800 |
C4A—S1A—C3A | 101.6 (3) | H71B—C7B—H73B | 109.5 |
C1A—N1A—H1A | 109.5 | H72B—C7B—H73B | 109.5 |
C1A—N1A—H2A | 109.5 | O2B—C8B—O3B | 124.2 (4) |
H1A—N1A—H2A | 109.5 | O2B—C8B—C6B | 119.8 (4) |
C1A—N1A—H3A | 109.5 | O3B—C8B—C6B | 116.0 (4) |
H1A—N1A—H3A | 109.5 | C2C—O1C—H1C | 104.2 |
H2A—N1A—H3A | 109.5 | O1C—C2C—C3C | 106.7 (7) |
C5A—N2A—C6A | 123.2 (3) | O1C—C2C—C1C | 108.4 (7) |
C5A—N2A—H4A | 118.4 | C3C—C2C—C1C | 110.7 (8) |
C6A—N2A—H4A | 118.4 | O1C—C2C—H21C | 110.3 |
N1A—C1A—C2A | 108.2 (3) | C3C—C2C—H21C | 110.3 |
N1A—C1A—C5A | 109.7 (3) | C1C—C2C—H21C | 110.3 |
C2A—C1A—C5A | 110.8 (4) | C22C—C12C—H14C | 109.5 |
N1A—C1A—H11A | 109.3 | C22C—C12C—H15C | 109.5 |
C2A—C1A—H11A | 109.3 | H14C—C12C—H15C | 109.5 |
C5A—C1A—H11A | 109.3 | C22C—C12C—H16C | 109.5 |
C1A—C2A—C3A | 110.3 (4) | H14C—C12C—H16C | 109.5 |
C1A—C2A—H21A | 109.6 | H15C—C12C—H16C | 109.5 |
C3A—C2A—H21A | 109.6 | C32C—C22C—C12C | 110.8 (9) |
C1A—C2A—H22A | 109.6 | C32C—C22C—H22C | 110.3 |
C3A—C2A—H22A | 109.6 | C12C—C22C—H22C | 110.4 |
H21A—C2A—H22A | 108.1 | C22C—C32C—H34C | 109.5 |
C2A—C3A—S1A | 113.4 (4) | C22C—C32C—H35C | 109.5 |
C2A—C3A—H31A | 108.9 | H34C—C32C—H35C | 109.5 |
S1A—C3A—H31A | 108.9 | C22C—C32C—H36C | 109.5 |
C2A—C3A—H32A | 108.9 | H34C—C32C—H36C | 109.5 |
S1A—C3A—H32A | 108.9 | H35C—C32C—H36C | 109.5 |
H31A—C3A—H32A | 107.7 | C2D—O1D—H1D | 104.3 |
S1A—C4A—H41A | 109.5 | C2D—C1D—H11D | 109.5 |
S1A—C4A—H42A | 109.5 | C2D—C1D—H12D | 109.5 |
H41A—C4A—H42A | 109.5 | H11D—C1D—H12D | 109.5 |
S1A—C4A—H43A | 109.5 | C2D—C1D—H13D | 109.5 |
H41A—C4A—H43A | 109.5 | H11D—C1D—H13D | 109.5 |
H42A—C4A—H43A | 109.5 | H12D—C1D—H13D | 109.5 |
O1A—C5A—N2A | 124.0 (3) | O1D—C2D—C3D | 108.1 (6) |
O1A—C5A—C1A | 120.9 (3) | O1D—C2D—C1D | 109.0 (5) |
N2A—C5A—C1A | 115.1 (3) | C3D—C2D—C1D | 113.1 (6) |
N2A—C6A—C7A | 111.4 (4) | O1D—C2D—H21D | 108.9 |
N2A—C6A—C8A | 108.8 (3) | C3D—C2D—H21D | 108.9 |
C7A—C6A—C8A | 110.8 (4) | C1D—C2D—H21D | 108.9 |
N2A—C6A—H61A | 108.6 | C2D—C3D—H31D | 109.5 |
C7A—C6A—H61A | 108.6 | C2D—C3D—H32D | 109.5 |
C8A—C6A—H61A | 108.6 | H31D—C3D—H32D | 109.5 |
C6A—C7A—H71A | 109.5 | C2D—C3D—H33D | 109.5 |
C6A—C7A—H72A | 109.5 | H31D—C3D—H33D | 109.5 |
H71A—C7A—H72A | 109.5 | H32D—C3D—H33D | 109.5 |
C6A—C7A—H73A | 109.5 | C2E—O1E—H1E | 104.3 |
H71A—C7A—H73A | 109.5 | O1E—C2E—C3E | 106.8 (5) |
H72A—C7A—H73A | 109.5 | O1E—C2E—C1E | 109.9 (6) |
O2A—C8A—O3A | 124.6 (4) | C3E—C2E—C1E | 113.3 (7) |
O2A—C8A—C6A | 118.8 (3) | O1E—C2E—H21E | 108.9 |
O3A—C8A—C6A | 116.5 (3) | C3E—C2E—H21E | 108.9 |
C4B—S1B—C3B | 100.2 (3) | C1E—C2E—H21E | 108.9 |
C1B—N1B—H1B | 109.5 | C22E—C12E—H14E | 109.5 |
C1B—N1B—H2B | 109.5 | C22E—C12E—H15E | 109.5 |
H1B—N1B—H2B | 109.5 | H14E—C12E—H15E | 109.5 |
C1B—N1B—H3B | 109.5 | C22E—C12E—H16E | 109.5 |
H1B—N1B—H3B | 109.5 | H14E—C12E—H16E | 109.5 |
H2B—N1B—H3B | 109.5 | H15E—C12E—H16E | 109.5 |
C5B—N2B—C6B | 122.8 (3) | C32E—C22E—C12E | 111.7 (10) |
C5B—N2B—H4B | 118.6 | C32E—C22E—H22E | 109.5 |
C6B—N2B—H4B | 118.6 | C12E—C22E—H22E | 109.5 |
N1B—C1B—C2B | 107.8 (3) | C22E—C32E—H34E | 109.5 |
N1B—C1B—C5B | 109.6 (3) | C22E—C32E—H35E | 109.5 |
C2B—C1B—C5B | 110.6 (4) | H34E—C32E—H35E | 109.5 |
N1B—C1B—H11B | 109.6 | C22E—C32E—H36E | 109.4 |
C2B—C1B—H11B | 109.6 | H34E—C32E—H36E | 109.5 |
C5B—C1B—H11B | 109.6 | H35E—C32E—H36E | 109.5 |
C1B—C2B—C3B | 110.9 (4) | C2F—O1F—H1F | 104.1 |
C1B—C2B—H21B | 109.5 | O1F—C2F—C3F | 107.7 (6) |
C3B—C2B—H21B | 109.5 | O1F—C2F—C1F | 108.2 (6) |
C1B—C2B—H22B | 109.5 | C3F—C2F—C1F | 109.7 (7) |
C3B—C2B—H22B | 109.5 | O1F—C2F—H21F | 110.4 |
H21B—C2B—H22B | 108.1 | C3F—C2F—H21F | 110.4 |
C2B—C3B—S1B | 112.7 (4) | C1F—C2F—H21F | 110.4 |
C2B—C3B—H31B | 109.1 | C2F—C3F—H2F | 112.9 |
S1B—C3B—H31B | 109.1 | H31F—C3F—H2F | 33.9 |
C2B—C3B—H32B | 109.1 | H32F—C3F—H2F | 131.7 |
S1B—C3B—H32B | 109.1 | H33F—C3F—H2F | 77.0 |
H31B—C3B—H32B | 107.8 | C22F—O12F—H2F | 104.3 |
S1B—C4B—H41B | 109.5 | C22F—C12F—H34F | 109.5 |
S1B—C4B—H42B | 109.5 | C22F—C12F—H35F | 109.5 |
H41B—C4B—H42B | 109.5 | H34F—C12F—H35F | 109.5 |
S1B—C4B—H43B | 109.5 | C22F—C12F—H36F | 109.5 |
H41B—C4B—H43B | 109.5 | H34F—C12F—H36F | 109.5 |
H42B—C4B—H43B | 109.5 | H35F—C12F—H36F | 109.5 |
O1B—C5B—N2B | 123.9 (3) | O12F—C22F—C32F | 107.4 (9) |
O1B—C5B—C1B | 120.8 (3) | O12F—C22F—C12F | 108.3 (9) |
N2B—C5B—C1B | 115.2 (3) | C32F—C22F—C12F | 111.6 (10) |
N2B—C6B—C7B | 112.2 (4) | O12F—C22F—H22F | 109.8 |
N2B—C6B—C8B | 108.6 (3) | C32F—C22F—H22F | 109.8 |
C7B—C6B—C8B | 113.3 (4) | C12F—C22F—H22F | 109.8 |
N2B—C6B—H61B | 107.5 | C22F—C32F—H37F | 109.5 |
C7B—C6B—H61B | 107.5 | C22F—C32F—H38F | 109.5 |
C8B—C6B—H61B | 107.5 | H37F—C32F—H38F | 109.5 |
C6B—C7B—H71B | 109.5 | C22F—C32F—H39F | 109.5 |
C6B—C7B—H72B | 109.5 | H37F—C32F—H39F | 109.5 |
H71B—C7B—H72B | 109.5 | H38F—C32F—H39F | 109.5 |
C6B—C7B—H73B | 109.5 | ||
N1A—C1A—C2A—C3A | −169.9 (4) | N1B—C1B—C2B—C3B | −171.4 (4) |
C5A—C1A—C2A—C3A | 69.7 (5) | C5B—C1B—C2B—C3B | 68.7 (5) |
C1A—C2A—C3A—S1A | −178.4 (4) | C1B—C2B—C3B—S1B | −176.0 (4) |
C4A—S1A—C3A—C2A | −69.8 (5) | C4B—S1B—C3B—C2B | −69.3 (5) |
C6A—N2A—C5A—O1A | −4.5 (8) | C6B—N2B—C5B—O1B | −4.9 (9) |
C6A—N2A—C5A—C1A | 174.5 (4) | C6B—N2B—C5B—C1B | 171.5 (4) |
N1A—C1A—C5A—O1A | −49.2 (6) | N1B—C1B—C5B—O1B | −42.1 (6) |
C2A—C1A—C5A—O1A | 70.3 (6) | C2B—C1B—C5B—O1B | 76.6 (6) |
N1A—C1A—C5A—N2A | 131.8 (4) | N1B—C1B—C5B—N2B | 141.3 (4) |
C2A—C1A—C5A—N2A | −108.7 (5) | C2B—C1B—C5B—N2B | −99.9 (5) |
C5A—N2A—C6A—C7A | 79.1 (6) | C5B—N2B—C6B—C7B | 93.9 (6) |
C5A—N2A—C6A—C8A | −158.5 (5) | C5B—N2B—C6B—C8B | −140.1 (5) |
N2A—C6A—C8A—O2A | −13.2 (7) | N2B—C6B—C8B—O2B | 11.5 (6) |
C7A—C6A—C8A—O2A | 109.5 (5) | C7B—C6B—C8B—O2B | 136.9 (5) |
N2A—C6A—C8A—O3A | 170.1 (5) | N2B—C6B—C8B—O3B | −168.7 (4) |
C7A—C6A—C8A—O3A | −67.1 (6) | C7B—C6B—C8B—O3B | −43.4 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A···O3B | 0.91 | 1.88 | 2.734 (5) | 155 |
N1A—H2A···O3Ai | 0.91 | 1.80 | 2.706 (5) | 176 |
N1A—H3A···O1F | 0.91 | 1.96 | 2.790 (7) | 151 |
N2A—H4A···O1Bii | 0.88 | 2.61 | 3.410 (5) | 151 |
C1A—H11B···O1Bii | 1.00 | 2.18 | 3.176 (5) | 171 |
N1B—H1B···O2Aiii | 0.91 | 1.83 | 2.735 (5) | 175 |
N1B—H2B···O3Biv | 0.91 | 1.97 | 2.813 (5) | 153 |
N1B—H3B···O1C | 0.91 | 1.87 | 2.772 (6) | 174 |
N2B—H4B···O1Ai | 0.88 | 2.19 | 3.044 (5) | 165 |
C1B—H11A···O1Ai | 1.00 | 2.40 | 3.307 (5) | 150 |
O1C—H1C···O1Diii | 0.85 | 1.91 | 2.734 (6) | 163 |
O1D—H1D···O1Eii | 0.85 | 1.92 | 2.768 (6) | 176 |
O1E—H1E···O2B | 0.85 | 1.82 | 2.666 (5) | 177 |
O1F—H1F···O1E | 0.85 | 2.09 | 2.748 (7) | 133 |
Symmetry codes: (i) −x, y+1/2, −z+1; (ii) −x+1, y−1/2, −z+1; (iii) x, y+1, z; (iv) −x+1, y+1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C8H16N2O3S·2C3H8O |
Mr | 340.48 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 150 |
a, b, c (Å) | 9.9277 (2), 16.4556 (3), 12.4895 (2) |
β (°) | 97.594 (1) |
V (Å3) | 2022.47 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.18 |
Crystal size (mm) | 0.80 × 0.48 × 0.01 |
Data collection | |
Diffractometer | Siemens SMART CCD diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.865, 0.998 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14839, 6911, 4437 |
Rint | 0.093 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.078, 0.202, 1.01 |
No. of reflections | 6911 |
No. of parameters | 448 |
No. of restraints | 198 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.53, −0.30 |
Absolute structure | Flack (1983), 3230 Friedel pairs |
Absolute structure parameter | −0.01 (16) |
Computer programs: SMART (Siemens, 1995), SAINT (Siemens, 1995), SIR92 (Altomare et al., 1994), SHELXTL (Sheldrick, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A···O3B | 0.91 | 1.88 | 2.734 (5) | 155 |
N1A—H2A···O3Ai | 0.91 | 1.80 | 2.706 (5) | 176 |
N1A—H3A···O1F | 0.91 | 1.96 | 2.790 (7) | 151 |
N2A—H4A···O1Bii | 0.88 | 2.61 | 3.410 (5) | 151 |
C1A—H11B···O1Bii | 1.00 | 2.18 | 3.176 (5) | 171 |
N1B—H1B···O2Aiii | 0.91 | 1.83 | 2.735 (5) | 175 |
N1B—H2B···O3Biv | 0.91 | 1.97 | 2.813 (5) | 153 |
N1B—H3B···O1C | 0.91 | 1.87 | 2.772 (6) | 174 |
N2B—H4B···O1Ai | 0.88 | 2.19 | 3.044 (5) | 165 |
C1B—H11A···O1Ai | 1.00 | 2.40 | 3.307 (5) | 150 |
O1C—H1C···O1Diii | 0.85 | 1.91 | 2.734 (6) | 163 |
O1D—H1D···O1Eii | 0.85 | 1.92 | 2.768 (6) | 176 |
O1E—H1E···O2B | 0.85 | 1.82 | 2.666 (5) | 177 |
O1F—H1F···O1E | 0.85 | 2.09 | 2.748 (7) | 133 |
Symmetry codes: (i) −x, y+1/2, −z+1; (ii) −x+1, y−1/2, −z+1; (iii) x, y+1, z; (iv) −x+1, y+1/2, −z+1. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Like several other dipeptides with two hydrophobic residues (Görbitz, 1999a,b, and references therein), the crystal structure of the title compound, (I), is divided into hydrophobic and hydrophilic layers, but the specific molecular arrangement is different from those observed previously. The two dipeptide molecules A and B in the asymmetric unit are stacked in an alternating sequence along the a axis with pseudo-translational symmetry. The geometries of the L-Met residues of A an B are almost identical, and both side chains are in the trans,trans,gauche- conformation for χ1, χ2 and χ3. The general pseudo-translational symmetry along the a axis includes the two 2-propanol solvent molecules C and F, but not D and E which have different orientations.
As expected, two of the three amino H atoms of each peptide molecule are engaged in hydrogen bonding in the hydrophilic layers, while 2-propanol molecules C and F, which are very similarly embedded in the hydrophobic layers, serve the important roles as acceptors for the remaining amino H atoms. The 2-propanol molecules C, D and F are donors in O—H···O—H interactions, but molecule E is unique in donating its hydroxylic H atom to a carboxylate group. The acceptor atom, O2B, is made available through a rotation of the carboxylate group compared with peptide molecule A, with N2—C6—C8—O2 = 11.5 (6)° compared to −13.2 (7)° for A. Unlike O2A, O2B can then no longer accept an amino H atom, which is instead accepted by O3B.
The unit cell for the thin needle-shaped crystals also obtained in the crystallization experiments has a = b = 14.2459 (12) Å, c = 9.7152 (11) Å, α = β = 90° and γ = 120°. An unambiguous determination of the space group was not possible, but we suspect that the structure is closely related to the hexagonal P61 structures of L-Val-L-Ala (Görbitz & Gundersen, 1996), L-Val-L-Val and L-Ala-L-Ile (Görbitz, 2000).