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The crystal structures of the title tryptophan-containing dipeptides, C
14H
17N
3O
3·H
2O, (I), C
13H
15N
3O
3·2H
2O, (II), and C
13H
15N
3O
3·H
2O, (III), respectively, contain at least one water molecule of solvation. As a result, the crystal packing of these compounds is composed of regions of water-mediated hydrogen bonding and tryptophan ring-to-ring stacking separated by the length of the molecule. The tryptophan rings stack in a continuous layer that, when viewed edge-on from the outermost part of the tryptophan ring, exhibits a herring-bone motif. However, owing to the lack of direct overlap of adjacent rings, no degree of
contact or long-range delocalization of ring systems is possible here. The overall molecular conformations of (I) and (III) contain a folding of one peptide over the other, such that a minimum in molecular volume occurs without any intramolecular hydrogen bonding. In these two dipeptides, extensive hydrogen bonding is observed to and from the single water molecule of solvation. In the crystal structure of (II), however, an extended molecule conformation complements a more extensive hydrogen-bonding scheme involving two water molecules of solvation per dipeptide.
Supporting information
CCDC references: 152671; 152672; 152673
Crystallization of the dipeptides occurred upon solvent evaporation: 50 mg of dipeptide, 1 ml me thanol and 1 ml water were combined in a 1-dram vial, placed with a loose-fitting cap on the shelf. The dipeptides were obtained from BAChem, the methanol was reagent grade (Fisher), and the water was distilled and deionized. Large colourless rods of (I) formed overnight after evaporation of either aqueous or 1:1 water–methanol solutions. The crystals of (II) also formed overnight from aqueous or 1:1 water–methanol solutions producing large colourless plates. The crystals of (III) formed only after very slow evaporation from the 1:1 water–methanol solution and produced only very thin irregularly shaped plates. Attempts to crystallize (I), (II) or (III) from non-aqueous solutions were not successful.
All H atoms were observed on difference Fourier maps. The positional and isotropic displacement parameters (Uiso) of the H atoms were refined, with C—H, N—H and O—H bond lengths in the ranges 0.92–1.02, 0.84–0.97 and 0.88–0.95 Å, respectively, for (I); 0.95–1.04, 0.89—0.93 and 0.87–0.94 Å, respectively, for (II); 0.91–1.01, 0.85–0.97 and 0.95–0.97 Å, respectively, for (III); except for H2WB of (II), which had x, y, and z fixed to the values observed on the map (O—H of 1.07 Å), and Uiso fixed to 0.35 Å2. For the refinement of (III), the bond distances of the H atoms were restrained to the refined values from (I) with estimated standard deviations of 0.04 Å. Extinction corrections were significant in all of the structure determinations, and the following reflections were omitted from the refinement of (III): 1 1 0, 2 2 0, 1 2 0. No other reflections were omitted in the refinements. For each of the structures here, the stereochemistry of each peptide was known (natural, l- or S-conformation). The absolute structure determinations were not necessary, although (III) showed an ambiguous Flack parameter of 0.6 (7). For (III), the calculated ranges of indicies h, k and l are ±19, ±19 and ±6, respectively, for θ < 70°. Some reflections with ABS(h) > ABS(k) were not measured, since their -khl equivalents were collected. The presence of many weak reflections, the asymmetrical shape of the sample (very thin and long plate) and the likelihood of anisotropic extinction (e.g., the isotropic value in SHELXL97 was high) led to an Rint value (0.106) that is slightly poorer than usually acceptable (<0.100).
For all compounds, data collection: CAD-4 EXPRESS (Enraf Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).
Crystal data top
C14H17N3O3·H2O | Dx = 1.363 Mg m−3 |
Mr = 293.32 | Cu Kα radiation, λ = 1.54180 Å |
Orthorhombic, P212121 | Cell parameters from 25 reflections |
a = 4.9475 (5) Å | θ = 26.1–28.8° |
b = 8.2059 (12) Å | µ = 0.84 mm−1 |
c = 35.213 (5) Å | T = 295 K |
V = 1429.6 (3) Å3 | Rod, colourless |
Z = 4 | 0.35 × 0.17 × 0.15 mm |
F(000) = 624 | |
Data collection top
Nonius CAD-4 diffractometer | 2538 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.012 |
Graphite monochromator | θmax = 70.0°, θmin = 2.5° |
ω–θ scans | h = 0→6 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→10 |
Tmin = 0.768, Tmax = 0.881 | l = −42→42 |
3190 measured reflections | 3 standard reflections every 60 min |
2688 independent reflections | intensity decay: 1% |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | All H-atom parameters refined |
R[F2 > 2σ(F2)] = 0.026 | w = 1/[σ2(Fo2) + (0.025P)2 + 0.315P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.063 | (Δ/σ)max < 0.001' |
S = 1.00 | Δρmax = 0.14 e Å−3 |
2688 reflections | Δρmin = −0.10 e Å−3 |
267 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0259 (7) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 1067 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.02 (18) |
Crystal data top
C14H17N3O3·H2O | V = 1429.6 (3) Å3 |
Mr = 293.32 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 4.9475 (5) Å | µ = 0.84 mm−1 |
b = 8.2059 (12) Å | T = 295 K |
c = 35.213 (5) Å | 0.35 × 0.17 × 0.15 mm |
Data collection top
Nonius CAD-4 diffractometer | 2538 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.012 |
Tmin = 0.768, Tmax = 0.881 | 3 standard reflections every 60 min |
3190 measured reflections | intensity decay: 1% |
2688 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.026 | All H-atom parameters refined |
wR(F2) = 0.063 | Δρmax = 0.14 e Å−3 |
S = 1.00 | Δρmin = −0.10 e Å−3 |
2688 reflections | Absolute structure: Flack (1983), 1067 Friedel pairs |
267 parameters | Absolute structure parameter: −0.02 (18) |
0 restraints | |
Special details top
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. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 3.2656(0.0019) x + 2.5895(0.0029) y − 24.0053(0.0117) z = 3.8154(0.0017) * −0.0090 (0.0013) N3 * 0.0457 (0.0011) C6 * −0.0133 (0.0012) C7 * −0.0113 (0.0013) C8 * −0.0303 (0.0014) C9 * −0.0115 (0.0015) C10 * 0.0213 (0.0016) C11 * 0.0266 (0.0015) C12 * −0.0005 (0.0014) C13 * −0.0178 (0.0014) C14 − 0.0165 (0.0244) H3N −0.5252 (0.0169) H6A −0.2842 (0.0156) H6B −0.0345 (0.0199) H9 0.0603 (0.0238) H10 0.0882 (0.0230) H11 0.0106 (0.0243) H12 − 0.0556 (0.0192) H14 Rms deviation of fitted atoms = 0.0224 3.2656(0.0019) x + 2.5895(0.0029) y − 24.0053(0.0117) z = 7.0810(0.0034) A ngle to previous plane (with approximate e.s.d.) = 0.00 (0.07) * −0.0090 (0.0013) N3 1_655 * 0.0457 (0.0011) C6 1_655 * −0.0133 (0.0012) C7 1_655 * −0.0113 (0.0013) C8 1_655 * −0.0303 (0.0014) C9 1_655 * −0.0115 (0.0015) C10 1_655 * 0.0213 (0.0016) C11 1_655 * 0.0266 (0.0015) C12 1_655 * −0.0005 (0.0014) C13 1_655 * −0.0178 (0.0014) C14 1_655 − 3.2551 (0.0243) H12 Rms deviation of fitted atoms = 0.0224 |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.46933 (19) | −0.08683 (12) | −0.17340 (3) | 0.0391 (3) | |
O2 | 0.5989 (3) | −0.38871 (12) | −0.22298 (3) | 0.0450 (3) | |
O3 | 0.4148 (2) | −0.55802 (12) | −0.18147 (3) | 0.0436 (3) | |
N1 | 0.7162 (3) | 0.16433 (14) | −0.21145 (3) | 0.0317 (3) | |
N2 | 0.8676 (2) | −0.22006 (13) | −0.16684 (3) | 0.0273 (2) | |
N3 | 1.1100 (3) | −0.3232 (2) | −0.04242 (4) | 0.0611 (4) | |
C1 | 0.8795 (3) | 0.06174 (15) | −0.18529 (4) | 0.0289 (3) | |
C2 | 0.7178 (3) | −0.08945 (15) | −0.17477 (4) | 0.0279 (3) | |
C3 | 0.9554 (4) | 0.16083 (19) | −0.15034 (4) | 0.0397 (4) | |
C4 | 0.7538 (3) | −0.37928 (15) | −0.15802 (4) | 0.0285 (3) | |
C5 | 0.5713 (3) | −0.44347 (15) | −0.19035 (4) | 0.0301 (3) | |
C6 | 0.6120 (3) | −0.38588 (18) | −0.11921 (4) | 0.0363 (3) | |
C7 | 0.7871 (3) | −0.33073 (19) | −0.08698 (4) | 0.0381 (3) | |
C8 | 0.7888 (3) | −0.1720 (2) | −0.06972 (4) | 0.0396 (3) | |
C9 | 0.6351 (4) | −0.0313 (2) | −0.07466 (5) | 0.0482 (4) | |
C10 | 0.6911 (5) | 0.1046 (3) | −0.05317 (5) | 0.0615 (5) | |
C11 | 0.8996 (5) | 0.1029 (3) | −0.02634 (5) | 0.0677 (6) | |
C12 | 1.0527 (5) | −0.0330 (3) | −0.02040 (5) | 0.0666 (6) | |
C13 | 0.9951 (3) | −0.1716 (2) | −0.04206 (4) | 0.0492 (4) | |
C14 | 0.9844 (4) | −0.4183 (3) | −0.06940 (4) | 0.0508 (4) | |
H1NA | 0.834 (4) | 0.242 (2) | −0.2241 (5) | 0.056 (5)* | |
H1NB | 0.632 (4) | 0.104 (2) | −0.2299 (5) | 0.050 (5)* | |
H1NC | 0.586 (4) | 0.228 (2) | −0.1976 (5) | 0.052 (5)* | |
H2N | 1.036 (4) | −0.2143 (19) | −0.1701 (5) | 0.041 (5)* | |
H3N | 1.239 (5) | −0.352 (3) | −0.0277 (7) | 0.088 (8)* | |
H1 | 1.040 (3) | 0.0265 (17) | −0.1986 (4) | 0.029 (4)* | |
H3A | 1.072 (4) | 0.260 (2) | −0.1571 (5) | 0.050 (5)* | |
H3B | 0.792 (4) | 0.201 (2) | −0.1363 (5) | 0.055 (5)* | |
H3C | 1.044 (4) | 0.095 (2) | −0.1324 (5) | 0.049 (5)* | |
H4 | 0.903 (3) | −0.4547 (18) | −0.1582 (4) | 0.031 (4)* | |
H6A | 0.558 (4) | −0.5017 (19) | −0.1152 (4) | 0.041 (4)* | |
H6B | 0.451 (3) | −0.3183 (18) | −0.1201 (4) | 0.037 (4)* | |
H9 | 0.499 (4) | −0.029 (2) | −0.0928 (6) | 0.061 (6)* | |
H10 | 0.592 (5) | 0.211 (3) | −0.0582 (6) | 0.082 (7)* | |
H11 | 0.938 (5) | 0.208 (3) | −0.0127 (6) | 0.077 (7)* | |
H12 | 1.186 (5) | −0.040 (3) | −0.0024 (7) | 0.087 (8)* | |
H14 | 1.034 (4) | −0.532 (2) | −0.0733 (5) | 0.058 (6)* | |
O1W | 0.1118 (2) | −0.64928 (13) | −0.24289 (3) | 0.0403 (3) | |
H1WA | 0.203 (5) | −0.724 (3) | −0.2554 (6) | 0.069 (7)* | |
H1WB | 0.213 (5) | −0.606 (3) | −0.2222 (7) | 0.078 (7)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0231 (5) | 0.0355 (5) | 0.0587 (6) | 0.0008 (4) | 0.0004 (4) | 0.0048 (5) |
O2 | 0.0576 (7) | 0.0439 (6) | 0.0334 (5) | −0.0135 (6) | −0.0102 (5) | 0.0034 (4) |
O3 | 0.0476 (6) | 0.0401 (5) | 0.0431 (5) | −0.0153 (5) | 0.0004 (5) | −0.0042 (4) |
N1 | 0.0346 (6) | 0.0281 (5) | 0.0325 (6) | 0.0002 (5) | −0.0029 (5) | 0.0008 (5) |
N2 | 0.0227 (6) | 0.0258 (5) | 0.0334 (6) | −0.0005 (4) | −0.0017 (5) | 0.0002 (4) |
N3 | 0.0454 (8) | 0.0982 (13) | 0.0398 (7) | 0.0030 (10) | −0.0121 (7) | 0.0054 (8) |
C1 | 0.0274 (6) | 0.0251 (6) | 0.0342 (6) | −0.0002 (6) | −0.0018 (6) | 0.0006 (5) |
C2 | 0.0272 (6) | 0.0272 (6) | 0.0293 (6) | −0.0007 (5) | −0.0010 (5) | −0.0028 (5) |
C3 | 0.0464 (9) | 0.0347 (7) | 0.0379 (7) | −0.0081 (7) | −0.0095 (7) | −0.0006 (6) |
C4 | 0.0297 (7) | 0.0246 (6) | 0.0313 (6) | 0.0012 (5) | −0.0013 (5) | 0.0005 (5) |
C5 | 0.0320 (7) | 0.0231 (6) | 0.0352 (7) | 0.0020 (6) | −0.0014 (5) | −0.0031 (5) |
C6 | 0.0368 (7) | 0.0397 (8) | 0.0324 (7) | −0.0069 (7) | 0.0010 (6) | 0.0017 (6) |
C7 | 0.0369 (8) | 0.0495 (8) | 0.0278 (6) | −0.0036 (7) | 0.0016 (6) | 0.0045 (6) |
C8 | 0.0354 (8) | 0.0574 (9) | 0.0261 (6) | −0.0094 (7) | 0.0046 (5) | −0.0007 (6) |
C9 | 0.0498 (10) | 0.0571 (10) | 0.0378 (8) | −0.0043 (8) | 0.0040 (8) | −0.0049 (7) |
C10 | 0.0693 (13) | 0.0633 (12) | 0.0519 (10) | −0.0097 (11) | 0.0158 (9) | −0.0130 (9) |
C11 | 0.0696 (13) | 0.0822 (14) | 0.0513 (10) | −0.0306 (13) | 0.0149 (10) | −0.0241 (10) |
C12 | 0.0515 (12) | 0.1110 (18) | 0.0372 (9) | −0.0309 (13) | 0.0023 (8) | −0.0172 (10) |
C13 | 0.0375 (8) | 0.0783 (12) | 0.0319 (7) | −0.0124 (9) | 0.0014 (6) | −0.0016 (8) |
C14 | 0.0492 (9) | 0.0667 (12) | 0.0365 (8) | 0.0047 (9) | −0.0022 (7) | 0.0079 (8) |
O1W | 0.0436 (6) | 0.0401 (6) | 0.0371 (5) | −0.0013 (5) | −0.0005 (5) | 0.0002 (4) |
Geometric parameters (Å, º) top
O1—C2 | 1.2307 (16) | C4—C5 | 1.5458 (18) |
O2—C5 | 1.2412 (16) | C4—H4 | 0.963 (16) |
O3—C5 | 1.2573 (17) | C6—C7 | 1.498 (2) |
N1—C1 | 1.4867 (17) | C6—H6A | 0.996 (16) |
N1—H1NA | 0.97 (2) | C6—H6B | 0.973 (17) |
N1—H1NB | 0.92 (2) | C7—C14 | 1.361 (2) |
N1—H1NC | 0.963 (19) | C7—C8 | 1.437 (2) |
N2—C2 | 1.3324 (17) | C8—C9 | 1.394 (2) |
N2—C4 | 1.4562 (17) | C8—C13 | 1.411 (2) |
N2—H2N | 0.842 (19) | C9—C10 | 1.376 (3) |
N3—C13 | 1.368 (3) | C9—H9 | 0.93 (2) |
N3—C14 | 1.378 (2) | C10—C11 | 1.399 (3) |
N3—H3N | 0.86 (3) | C10—H10 | 1.02 (2) |
C1—C2 | 1.5219 (18) | C11—C12 | 1.364 (3) |
C1—C3 | 1.5222 (19) | C11—H11 | 1.00 (2) |
C1—H1 | 0.967 (15) | C12—C13 | 1.399 (3) |
C3—H3A | 1.025 (19) | C12—H12 | 0.92 (3) |
C3—H3B | 1.00 (2) | C14—H14 | 0.972 (19) |
C3—H3C | 0.940 (19) | O1W—H1WA | 0.88 (2) |
C4—C6 | 1.5369 (18) | O1W—H1WB | 0.95 (2) |
| | | |
C1—N1—H1NA | 109.2 (11) | O2—C5—C4 | 119.61 (12) |
C1—N1—H1NB | 112.3 (11) | O3—C5—C4 | 115.55 (11) |
H1NA—N1—H1NB | 107.7 (16) | C7—C6—C4 | 113.52 (12) |
C1—N1—H1NC | 110.9 (10) | C7—C6—H6A | 109.5 (9) |
H1NA—N1—H1NC | 106.2 (15) | C4—C6—H6A | 106.3 (9) |
H1NB—N1—H1NC | 110.3 (16) | C7—C6—H6B | 109.2 (9) |
C2—N2—C4 | 123.47 (11) | C4—C6—H6B | 108.9 (9) |
C2—N2—H2N | 118.5 (11) | H6A—C6—H6B | 109.3 (14) |
C4—N2—H2N | 117.5 (11) | C14—C7—C8 | 106.36 (14) |
C13—N3—C14 | 109.51 (15) | C14—C7—C6 | 126.88 (15) |
C13—N3—H3N | 124.1 (17) | C8—C7—C6 | 126.70 (14) |
C14—N3—H3N | 126.4 (17) | C9—C8—C13 | 118.62 (16) |
N1—C1—C2 | 109.07 (11) | C9—C8—C7 | 134.01 (14) |
N1—C1—C3 | 109.43 (11) | C13—C8—C7 | 107.36 (15) |
C2—C1—C3 | 111.61 (11) | C10—C9—C8 | 119.52 (18) |
N1—C1—H1 | 108.3 (8) | C10—C9—H9 | 120.6 (12) |
C2—C1—H1 | 107.8 (9) | C8—C9—H9 | 119.8 (12) |
C3—C1—H1 | 110.5 (9) | C9—C10—C11 | 120.8 (2) |
O1—C2—N2 | 124.15 (13) | C9—C10—H10 | 120.1 (13) |
O1—C2—C1 | 121.35 (12) | C11—C10—H10 | 118.9 (14) |
N2—C2—C1 | 114.49 (11) | C12—C11—C10 | 121.40 (18) |
C1—C3—H3A | 112.1 (10) | C12—C11—H11 | 121.5 (14) |
C1—C3—H3B | 112.1 (11) | C10—C11—H11 | 117.0 (14) |
H3A—C3—H3B | 107.8 (14) | C11—C12—C13 | 117.89 (19) |
C1—C3—H3C | 110.5 (10) | C11—C12—H12 | 123.8 (16) |
H3A—C3—H3C | 110.4 (15) | C13—C12—H12 | 118.3 (16) |
H3B—C3—H3C | 103.7 (15) | N3—C13—C12 | 131.28 (17) |
N2—C4—C6 | 113.44 (11) | N3—C13—C8 | 106.99 (15) |
N2—C4—C5 | 111.99 (11) | C12—C13—C8 | 121.73 (19) |
C6—C4—C5 | 112.10 (11) | C7—C14—N3 | 109.78 (17) |
N2—C4—H4 | 106.2 (9) | C7—C14—H14 | 128.3 (12) |
C6—C4—H4 | 109.4 (9) | N3—C14—H14 | 121.8 (12) |
C5—C4—H4 | 103.0 (9) | H1WA—O1W—H1WB | 112.0 (19) |
O2—C5—O3 | 124.67 (13) | | |
| | | |
H1NA—N1—C1—C2 | −163 (1) | C14—C7—C8—C13 | 0.60 (17) |
N1—C1—C2—N2 | 151.0 (1) | C6—C7—C8—C13 | −176.69 (13) |
C1—C2—N2—C4 | −176.8 (1) | C13—C8—C9—C10 | 1.3 (2) |
C2—N2—C4—C5 | 57.9 (2) | C7—C8—C9—C10 | −179.53 (16) |
N2—C4—C5—O2 | 21.5 (2) | C8—C9—C10—C11 | −0.2 (3) |
C4—N2—C2—O1 | 4.3 (2) | C9—C10—C11—C12 | −0.4 (3) |
N1—C1—C2—O1 | −30.04 (18) | C10—C11—C12—C13 | 0.1 (3) |
C3—C1—C2—O1 | 90.99 (17) | C14—N3—C13—C12 | −179.10 (17) |
C3—C1—C2—N2 | −88.00 (15) | C14—N3—C13—C8 | 0.30 (18) |
C2—N2—C4—C6 | −70.25 (16) | C11—C12—C13—N3 | −179.66 (18) |
C6—C4—C5—O2 | 150.35 (13) | C11—C12—C13—C8 | 1.0 (3) |
N2—C4—C5—O3 | −163.09 (12) | C9—C8—C13—N3 | 178.84 (14) |
C6—C4—C5—O3 | −34.26 (16) | C7—C8—C13—N3 | −0.56 (17) |
N2—C4—C6—C7 | −54.24 (17) | C9—C8—C13—C12 | −1.7 (2) |
C5—C4—C6—C7 | 177.70 (12) | C7—C8—C13—C12 | 178.91 (15) |
C4—C6—C7—C14 | −78.70 (19) | C8—C7—C14—N3 | −0.43 (18) |
C4—C6—C7—C8 | 98.05 (17) | C6—C7—C14—N3 | 176.86 (14) |
C14—C7—C8—C9 | −178.66 (17) | C13—N3—C14—C7 | 0.1 (2) |
C6—C7—C8—C9 | 4.0 (3) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1NA···O1Wi | 0.97 (2) | 1.77 (2) | 2.720 (2) | 166 (1) |
O1W—H1WB···O3 | 0.95 (2) | 1.79 (2) | 2.737 (2) | 171 (1) |
O1W—H1WA···O2ii | 0.88 (2) | 1.83 (2) | 2.712 (2) | 175 (1) |
N1—H1NB···O2iii | 0.92 (2) | 2.02 (2) | 2.820 (2) | 146 (1) |
N1—H1NC···O3iv | 0.96 (2) | 2.03 (2) | 2.920 (2) | 153 (1) |
N2—H2N···O1v | 0.84 (2) | 2.39 (2) | 3.180 (2) | 157 (1) |
Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, y−1/2, −z−1/2; (iii) −x+1, y+1/2, −z−1/2; (iv) x, y+1, z; (v) x+1, y, z. |
Crystal data top
C13H15N3O3·2H2O | F(000) = 316 |
Mr = 297.31 | Dx = 1.391 Mg m−3 |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54180 Å |
a = 5.8404 (6) Å | Cell parameters from 25 reflections |
b = 8.2429 (8) Å | θ = 35.4–42.8° |
c = 14.8299 (10) Å | µ = 0.91 mm−1 |
β = 96.178 (8)° | T = 295 K |
V = 709.79 (11) Å3 | Plate, colourless |
Z = 2 | 0.60 × 0.32 × 0.02 mm |
Data collection top
Nonius CAD-4 diffractometer | 1404 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.015 |
Graphite monochromator | θmax = 69.9°, θmin = 3.0° |
ω–θ scans | h = 0→7 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→10 |
Tmin = 0.811, Tmax = 0.982 | l = −18→17 |
1583 measured reflections | 3 standard reflections every 3600 min |
1440 independent reflections | intensity decay: 1% |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms: see text |
R[F2 > 2σ(F2)] = 0.034 | w = 1/[σ2(Fo2) + (0.033P)2 + 0.295P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.080 | (Δ/σ)max = 0.001 |
S = 1.00 | Δρmax = 0.17 e Å−3 |
1440 reflections | Δρmin = −0.17 e Å−3 |
263 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.0227 (17) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), no Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.0 (3) |
Crystal data top
C13H15N3O3·2H2O | V = 709.79 (11) Å3 |
Mr = 297.31 | Z = 2 |
Monoclinic, P21 | Cu Kα radiation |
a = 5.8404 (6) Å | µ = 0.91 mm−1 |
b = 8.2429 (8) Å | T = 295 K |
c = 14.8299 (10) Å | 0.60 × 0.32 × 0.02 mm |
β = 96.178 (8)° | |
Data collection top
Nonius CAD-4 diffractometer | 1404 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.015 |
Tmin = 0.811, Tmax = 0.982 | 3 standard reflections every 3600 min |
1583 measured reflections | intensity decay: 1% |
1440 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.034 | H atoms: see text |
wR(F2) = 0.080 | Δρmax = 0.17 e Å−3 |
S = 1.00 | Δρmin = −0.17 e Å−3 |
1440 reflections | Absolute structure: Flack (1983), no Friedel pairs |
263 parameters | Absolute structure parameter: 0.0 (3) |
1 restraint | |
Special details top
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. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) −3.0006(0.0047) x + 6.9611(0.0043) y − 1.4095(0.0099) z = 1.0443(0.0013) * −0.0083 (0.0029) N3 * 0.0079 (0.0021) C5 * −0.0044 (0.0026) C6 * −0.0023 (0.0024) C7 * −0.0039 (0.0027) C8 * −0.0036 (0.0028) C9 * 0.0025 (0.0028) C10 * 0.0086 (0.0029) C11 * 0.0012 (0.0029) C12 * 0.0024 (0.0031) C13 − 0.0962 (0.0689) H3N 0.0019 (0.0358) H5B −0.0406 (0.0318) H8 − 0.0695 (0.0434) H9 0.0553 (0.0357) H10 − 0.0520 (0.0407) H11 0.0174 (0.0505) H13 Rms deviation of fitted atoms = 0.0052 3.0006(0.0047) x − 6.9611(0.0043) y + 1.4095(0.0099) z = 1.9563(0.0040) A ngle to previous plane (with approximate e.s.d.) = 0.00 (0.12) * 0.0083 (0.0029) N3 1_655 * −0.0079 (0.0021) C5 1_655 * 0.0044 (0.0026) C6 1_655 * 0.0023 (0.0024) C7 1_655 * 0.0039 (0.0027) C8 1_655 * 0.0036 (0.0028) C9 1_655 * −0.0025 (0.0028) C10 1_655 * −0.0086 (0.0029) C11 1_655 * −0.0012 (0.0029) C12 1_655 * −0.0024 (0.0031) C13 1_655 − 2.9600 (0.0320) H8 Rms deviation of fitted atoms = 0.0052 |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | −0.0226 (3) | −0.2538 (3) | 0.36209 (14) | 0.0520 (6) | |
O2 | 0.0773 (3) | 0.1764 (3) | 0.38823 (13) | 0.0550 (6) | |
O3 | 0.3526 (3) | 0.1228 (3) | 0.30149 (13) | 0.0464 (5) | |
N1 | −0.3879 (4) | −0.3496 (3) | 0.44959 (16) | 0.0429 (6) | |
N2 | −0.2160 (3) | −0.0433 (3) | 0.29312 (14) | 0.0347 (5) | |
N3 | −0.5126 (5) | −0.0712 (4) | 0.0048 (2) | 0.0592 (8) | |
C1 | −0.4259 (5) | −0.2261 (4) | 0.3785 (2) | 0.0437 (7) | |
C2 | −0.2004 (4) | −0.1748 (3) | 0.34440 (16) | 0.0352 (6) | |
C3 | −0.0202 (4) | 0.0227 (3) | 0.25173 (16) | 0.0319 (5) | |
C4 | 0.1498 (4) | 0.1133 (3) | 0.32004 (15) | 0.0338 (5) | |
C5 | −0.1070 (5) | 0.1405 (4) | 0.17519 (17) | 0.0402 (6) | |
C6 | −0.2446 (4) | 0.0631 (4) | 0.09479 (17) | 0.0384 (6) | |
C7 | −0.1874 (4) | 0.0696 (3) | 0.00347 (17) | 0.0363 (6) | |
C8 | −0.0060 (5) | 0.1392 (4) | −0.03820 (19) | 0.0455 (6) | |
C9 | −0.0042 (6) | 0.1212 (5) | −0.1306 (2) | 0.0562 (8) | |
C10 | −0.1759 (6) | 0.0374 (5) | −0.1832 (2) | 0.0568 (8) | |
C11 | −0.3573 (6) | −0.0321 (5) | −0.1450 (2) | 0.0543 (8) | |
C12 | −0.3596 (4) | −0.0153 (4) | −0.05183 (19) | 0.0428 (6) | |
C13 | −0.4445 (5) | −0.0227 (5) | 0.0917 (2) | 0.0556 (8) | |
H1NA | −0.524 (8) | −0.363 (6) | 0.470 (3) | 0.087 (13)* | |
H1NB | −0.286 (6) | −0.324 (5) | 0.500 (3) | 0.065 (11)* | |
H1NC | −0.335 (7) | −0.440 (6) | 0.420 (3) | 0.087 (14)* | |
H2N | −0.350 (6) | 0.013 (5) | 0.284 (2) | 0.055 (9)* | |
H3N | −0.636 (10) | −0.139 (9) | −0.004 (4) | 0.15 (2)* | |
H1A | −0.511 (7) | −0.135 (5) | 0.399 (3) | 0.070 (11)* | |
H1B | −0.539 (6) | −0.268 (5) | 0.324 (2) | 0.057 (9)* | |
H3 | 0.062 (4) | −0.071 (4) | 0.2285 (17) | 0.028 (6)* | |
H5A | −0.195 (6) | 0.228 (5) | 0.203 (2) | 0.061 (10)* | |
H5B | 0.032 (6) | 0.195 (5) | 0.153 (2) | 0.058 (10)* | |
H8 | 0.117 (5) | 0.195 (4) | 0.002 (2) | 0.044 (8)* | |
H9 | 0.124 (6) | 0.161 (6) | −0.162 (2) | 0.071 (11)* | |
H10 | −0.178 (5) | 0.031 (5) | −0.249 (2) | 0.053 (9)* | |
H11 | −0.472 (7) | −0.097 (5) | −0.179 (2) | 0.071 (12)* | |
H13 | −0.538 (7) | −0.051 (7) | 0.141 (3) | 0.083 (13)* | |
O1W | 0.6617 (5) | 0.3387 (4) | 0.3906 (3) | 0.0977 (13) | |
H1WA | 0.543 (8) | 0.277 (7) | 0.361 (3) | 0.092 (14)* | |
H1WB | 0.788 (12) | 0.315 (11) | 0.367 (4) | 0.16 (3)* | |
O2W | 0.1908 (4) | −0.4914 (4) | 0.4744 (2) | 0.0837 (9) | |
H2WA | 0.126 (11) | −0.446 (10) | 0.419 (4) | 0.16 (3)* | |
H2WB | 0.0960 | −0.4338 | 0.5232 | 0.350* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0398 (10) | 0.0575 (13) | 0.0609 (12) | 0.0160 (10) | 0.0161 (8) | 0.0205 (11) |
O2 | 0.0340 (9) | 0.0864 (17) | 0.0450 (10) | −0.0016 (10) | 0.0062 (8) | −0.0202 (11) |
O3 | 0.0234 (8) | 0.0554 (12) | 0.0609 (11) | −0.0007 (9) | 0.0072 (7) | −0.0066 (11) |
N1 | 0.0378 (12) | 0.0494 (15) | 0.0426 (12) | −0.0033 (11) | 0.0089 (10) | 0.0050 (12) |
N2 | 0.0246 (10) | 0.0398 (12) | 0.0404 (11) | 0.0019 (9) | 0.0062 (8) | 0.0041 (10) |
N3 | 0.0438 (12) | 0.083 (2) | 0.0485 (13) | −0.0217 (15) | −0.0050 (10) | 0.0017 (14) |
C1 | 0.0320 (13) | 0.0516 (18) | 0.0479 (15) | −0.0024 (13) | 0.0068 (11) | 0.0103 (14) |
C2 | 0.0323 (12) | 0.0389 (14) | 0.0346 (11) | 0.0021 (11) | 0.0050 (9) | 0.0019 (11) |
C3 | 0.0255 (10) | 0.0358 (13) | 0.0350 (12) | 0.0006 (10) | 0.0066 (9) | 0.0018 (10) |
C4 | 0.0259 (10) | 0.0396 (14) | 0.0359 (11) | 0.0039 (11) | 0.0031 (9) | 0.0028 (11) |
C5 | 0.0406 (13) | 0.0424 (15) | 0.0363 (12) | −0.0049 (13) | −0.0018 (10) | 0.0043 (13) |
C6 | 0.0333 (11) | 0.0430 (14) | 0.0375 (12) | −0.0034 (11) | −0.0024 (10) | 0.0043 (12) |
C7 | 0.0348 (12) | 0.0332 (13) | 0.0395 (13) | 0.0035 (11) | −0.0029 (10) | 0.0049 (11) |
C8 | 0.0453 (14) | 0.0427 (15) | 0.0483 (14) | −0.0047 (13) | 0.0040 (11) | 0.0089 (13) |
C9 | 0.0606 (17) | 0.057 (2) | 0.0533 (16) | 0.0027 (17) | 0.0166 (14) | 0.0121 (16) |
C10 | 0.071 (2) | 0.058 (2) | 0.0415 (16) | 0.0099 (17) | 0.0063 (14) | 0.0025 (15) |
C11 | 0.0580 (18) | 0.057 (2) | 0.0449 (15) | 0.0022 (16) | −0.0081 (14) | −0.0041 (15) |
C12 | 0.0370 (13) | 0.0439 (16) | 0.0454 (14) | −0.0010 (12) | −0.0048 (11) | 0.0026 (13) |
C13 | 0.0407 (14) | 0.080 (2) | 0.0456 (15) | −0.0153 (16) | 0.0010 (12) | 0.0052 (17) |
O1W | 0.0459 (15) | 0.079 (2) | 0.165 (3) | 0.0081 (14) | −0.0053 (18) | −0.061 (2) |
O2W | 0.0462 (13) | 0.084 (2) | 0.120 (2) | −0.0063 (13) | 0.0053 (14) | 0.0323 (19) |
Geometric parameters (Å, º) top
O1—C2 | 1.230 (3) | C5—H5A | 1.00 (4) |
O2—C4 | 1.251 (3) | C5—H5B | 1.01 (4) |
O3—C4 | 1.247 (3) | C6—C13 | 1.362 (4) |
N1—C1 | 1.465 (4) | C6—C7 | 1.430 (4) |
N1—H1NA | 0.89 (5) | C7—C8 | 1.405 (4) |
N1—H1NB | 0.93 (4) | C7—C12 | 1.413 (4) |
N1—H1NC | 0.93 (5) | C8—C9 | 1.379 (4) |
N2—C2 | 1.322 (4) | C8—H8 | 1.00 (3) |
N2—C3 | 1.460 (3) | C9—C10 | 1.387 (5) |
N2—H2N | 0.90 (4) | C9—H9 | 0.98 (4) |
N3—C13 | 1.366 (4) | C10—C11 | 1.379 (5) |
N3—C12 | 1.370 (4) | C10—H10 | 0.97 (3) |
N3—H3N | 0.91 (6) | C11—C12 | 1.390 (4) |
C1—C2 | 1.521 (3) | C11—H11 | 0.95 (4) |
C1—H1A | 0.97 (4) | C13—H13 | 0.99 (4) |
C1—H1B | 1.05 (3) | O1W—H1WA | 0.93 (5) |
C3—C4 | 1.534 (3) | O1W—H1WB | 0.87 (7) |
C3—C5 | 1.538 (3) | O2W—H2WA | 0.94 (7) |
C3—H3 | 0.99 (3) | O2W—H2WB | 1.068 (3) |
C5—C6 | 1.506 (3) | | |
| | | |
C1—N1—H1NA | 105 (3) | C6—C5—H5A | 112.4 (19) |
C1—N1—H1NB | 117 (3) | C3—C5—H5A | 107 (2) |
H1NA—N1—H1NB | 106 (3) | C6—C5—H5B | 108.0 (18) |
C1—N1—H1NC | 105 (3) | C3—C5—H5B | 107.9 (18) |
H1NA—N1—H1NC | 114 (4) | H5A—C5—H5B | 106 (3) |
H1NB—N1—H1NC | 110 (4) | C13—C6—C7 | 105.9 (2) |
C2—N2—C3 | 122.6 (2) | C13—C6—C5 | 129.0 (3) |
C2—N2—H2N | 121 (2) | C7—C6—C5 | 125.1 (2) |
C3—N2—H2N | 117 (2) | C8—C7—C12 | 118.1 (2) |
C13—N3—C12 | 109.7 (3) | C8—C7—C6 | 134.1 (2) |
C13—N3—H3N | 117 (4) | C12—C7—C6 | 107.9 (2) |
C12—N3—H3N | 133 (4) | C9—C8—C7 | 118.7 (3) |
N1—C1—C2 | 111.3 (2) | C9—C8—H8 | 124.5 (17) |
N1—C1—H1A | 111 (2) | C7—C8—H8 | 116.7 (17) |
C2—C1—H1A | 113 (2) | C8—C9—C10 | 122.0 (3) |
N1—C1—H1B | 111 (2) | C8—C9—H9 | 122 (2) |
C2—C1—H1B | 109.5 (18) | C10—C9—H9 | 116 (2) |
H1A—C1—H1B | 101 (3) | C11—C10—C9 | 121.1 (3) |
O1—C2—N2 | 124.2 (2) | C11—C10—H10 | 117 (2) |
O1—C2—C1 | 121.6 (2) | C9—C10—H10 | 122 (2) |
N2—C2—C1 | 114.2 (2) | C10—C11—C12 | 117.2 (3) |
N2—C3—C4 | 112.60 (19) | C10—C11—H11 | 123 (2) |
N2—C3—C5 | 109.54 (19) | C12—C11—H11 | 120 (2) |
C4—C3—C5 | 108.6 (2) | N3—C12—C11 | 130.8 (3) |
N2—C3—H3 | 106.6 (16) | N3—C12—C7 | 106.3 (2) |
C4—C3—H3 | 108.0 (15) | C11—C12—C7 | 122.9 (3) |
C5—C3—H3 | 111.6 (15) | C6—C13—N3 | 110.2 (3) |
O3—C4—O2 | 124.4 (2) | C6—C13—H13 | 129 (3) |
O3—C4—C3 | 116.6 (2) | N3—C13—H13 | 120 (3) |
O2—C4—C3 | 119.04 (19) | H1WA—O1W—H1WB | 108 (6) |
C6—C5—C3 | 115.0 (2) | H2WA—O2W—H2WB | 103 (4) |
| | | |
H1NA—N1—C1—C2 | 173 (2) | C5—C6—C7—C12 | −179.2 (3) |
N1—C1—C2—N2 | −167.8 (3) | C12—C7—C8—C9 | −0.1 (4) |
C1—C2—N2—C3 | −178.2 (2) | C6—C7—C8—C9 | 179.9 (3) |
C2—N2—C3—C4 | −76.1 (3) | C7—C8—C9—C10 | 0.2 (5) |
N2—C3—C4—O2 | −26.9 (3) | C8—C9—C10—C11 | 0.0 (5) |
C3—N2—C2—O1 | −0.1 (4) | C9—C10—C11—C12 | −0.3 (5) |
N1—C1—C2—O1 | 14.0 (4) | C13—N3—C12—C11 | −179.3 (4) |
C2—N2—C3—C5 | 163.0 (2) | C13—N3—C12—C7 | 0.9 (4) |
N2—C3—C4—O3 | 155.2 (2) | C10—C11—C12—N3 | −179.3 (4) |
C5—C3—C4—O3 | −83.3 (3) | C10—C11—C12—C7 | 0.5 (5) |
C5—C3—C4—O2 | 94.6 (3) | C8—C7—C12—N3 | 179.5 (3) |
N2—C3—C5—C6 | −66.4 (3) | C6—C7—C12—N3 | −0.4 (3) |
C4—C3—C5—C6 | 170.3 (2) | C8—C7—C12—C11 | −0.3 (4) |
C3—C5—C6—C13 | 59.7 (4) | C6—C7—C12—C11 | 179.8 (3) |
C3—C5—C6—C7 | −121.5 (3) | C7—C6—C13—N3 | 0.8 (4) |
C13—C6—C7—C8 | 179.8 (3) | C5—C6—C13—N3 | 179.8 (3) |
C5—C6—C7—C8 | 0.8 (5) | C12—N3—C13—C6 | −1.1 (4) |
C13—C6—C7—C12 | −0.2 (3) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O3 | 0.93 (5) | 1.85 (4) | 2.767 (3) | 169 (3) |
N1—H1NC···O1Wi | 0.93 (5) | 1.88 (6) | 2.740 (4) | 153 (4) |
N1—H1NB···O2ii | 0.93 (4) | 1.95 (4) | 2.860 (3) | 166 (3) |
O2W—H2WA···O1 | 0.94 (7) | 1.95 (6) | 2.778 (4) | 145 (4) |
O2W—H2WB···O2ii | 1.07 | 1.97 | 3.034 (5) | 179 |
N1—H1NA···O2Wiii | 0.89 (5) | 1.98 (6) | 2.784 (4) | 150 (4) |
N2—H2N···O3iii | 0.90 (4) | 2.00 (4) | 2.884 (3) | 164 (3) |
O1W—H1WB···O2iv | 0.87 (7) | 2.04 (6) | 2.775 (4) | 142 (4) |
Symmetry codes: (i) x−1, y−1, z; (ii) −x, y−1/2, −z+1; (iii) x−1, y, z; (iv) x+1, y, z. |
Crystal data top
C13H15N3O3·H2O | Dx = 1.373 Mg m−3 |
Mr = 279.30 | Cu Kα radiation, λ = 1.54180 Å |
Tetragonal, P41 | Cell parameters from 25 reflections |
Hall symbol: P 41 | θ = 24.3–24.9° |
a = 16.128 (2) Å | µ = 0.86 mm−1 |
c = 5.195 (1) Å | T = 295 K |
V = 1351.3 (4) Å3 | Thin elongated plates, colourless |
Z = 4 | 0.44 × 0.12 × 0.02 mm |
F(000) = 592 | |
Data collection top
Nonius CAD-4 diffractometer | 871 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.107 |
Graphite monochromator | θmax = 70.0°, θmin = 2.7° |
ω–θ scans | h = −13→13 |
Absorption correction: ψ scan (North et al., 1968) | k = −10→19 |
Tmin = 0.719, Tmax = 0.996 | l = 0→6 |
3174 measured reflections | 3 standard reflections every 3600 min |
1438 independent reflections | intensity decay: 1% |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms: see text |
R[F2 > 2σ(F2)] = 0.061 | w = 1/[σ2(Fo2) + (0.04P)2 + 1.0P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.147 | (Δ/σ)max < 0.001 |
S = 1.01 | Δρmax = 0.30 e Å−3 |
1434 reflections | Δρmin = −0.23 e Å−3 |
250 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
27 restraints | Extinction coefficient: 0.0101 (13) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), no Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.6 (7) |
Crystal data top
C13H15N3O3·H2O | Z = 4 |
Mr = 279.30 | Cu Kα radiation |
Tetragonal, P41 | µ = 0.86 mm−1 |
a = 16.128 (2) Å | T = 295 K |
c = 5.195 (1) Å | 0.44 × 0.12 × 0.02 mm |
V = 1351.3 (4) Å3 | |
Data collection top
Nonius CAD-4 diffractometer | 871 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.107 |
Tmin = 0.719, Tmax = 0.996 | 3 standard reflections every 3600 min |
3174 measured reflections | intensity decay: 1% |
1438 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.061 | H atoms: see text |
wR(F2) = 0.147 | Δρmax = 0.30 e Å−3 |
S = 1.01 | Δρmin = −0.23 e Å−3 |
1434 reflections | Absolute structure: Flack (1983), no Friedel pairs |
250 parameters | Absolute structure parameter: 0.6 (7) |
27 restraints | |
Special details top
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. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 7.5085(0.0228) x + 7.4397(0.0181) y − 3.9238(0.0042) z = 4.5624(0.0068) * −0.6122 (0.0039) N3 * 0.4562 (0.0054) C3 * 0.1230 (0.0053) C4 * 0.1356 (0.0055) C5 * 0.4457 (0.0059) C6 * 0.3293 (0.0056) C7 * −0.0586 (0.0056) C8 * −0.3613 (0.0057) C9 * −0.2349 (0.0050) C10 * −0.2229 (0.0051) C11 1.1316 (0.0464) H3A 0.4788 (0.0555) H3B 0.6194 (0.0542) H6 0.6518 (0.0763) H7 0.0084 (0.0643) H8 − 0.6113 (0.0715) H9 − 0.4804 (0.0644) H11 Rms deviation of fitted atoms = 0.3409 7.5085(0.0228) x + 7.4397(0.0181) y − 3.9238(0.0042) z = 0.6386(0.0106) A ngle to previous plane (with approximate e.s.d.) = 0.00 (0.21) * −0.6122 (0.0039) N3 1_556 * 0.4562 (0.0054) C3 1_556 * 0.1230 (0.0053) C4 1_556 * 0.1356 (0.0055) C5 1_556 * 0.4457 (0.0059) C6 1_556 * 0.3293 (0.0056) C7 1_556 * −0.0586 (0.0056) C8 1_556 * −0.3613 (0.0057) C9 1_556 * −0.2349 (0.0050) C10 1_556 * −0.2229 (0.0051) C11 1_556 Rms deviation of fitted atoms = 0.3409 |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.1942 (3) | 0.2068 (3) | 0.1682 (7) | 0.0550 (12) | |
O2 | 0.2508 (3) | 0.0199 (3) | 0.1125 (9) | 0.0586 (12) | |
O3 | 0.3419 (3) | 0.0621 (3) | 0.4073 (8) | 0.0552 (12) | |
N1 | 0.0632 (4) | 0.2361 (4) | −0.1287 (11) | 0.0523 (14) | |
N2 | 0.1340 (4) | 0.4892 (4) | 0.1427 (11) | 0.0573 (15) | |
N3 | 0.2758 (4) | 0.1674 (4) | −0.1616 (9) | 0.0509 (14) | |
C1 | 0.2076 (4) | 0.2019 (3) | −0.0678 (11) | 0.0452 (15) | |
C2 | 0.1455 (4) | 0.2368 (4) | −0.2544 (11) | 0.0436 (15) | |
C3 | 0.1664 (4) | 0.3249 (4) | −0.3446 (12) | 0.0454 (15) | |
C4 | 0.1698 (4) | 0.3887 (4) | −0.1322 (12) | 0.0437 (14) | |
C5 | 0.2388 (4) | 0.4055 (3) | 0.0285 (11) | 0.0389 (13) | |
C6 | 0.3186 (4) | 0.3756 (4) | 0.0454 (12) | 0.0498 (16) | |
C7 | 0.3718 (5) | 0.4052 (4) | 0.2331 (14) | 0.0589 (18) | |
C8 | 0.3459 (5) | 0.4677 (4) | 0.4008 (13) | 0.0559 (17) | |
C9 | 0.2671 (5) | 0.4994 (4) | 0.3874 (14) | 0.0563 (17) | |
C10 | 0.2143 (4) | 0.4693 (4) | 0.1969 (11) | 0.0442 (14) | |
C11 | 0.1082 (4) | 0.4402 (4) | −0.0644 (14) | 0.0518 (16) | |
C12 | 0.3381 (4) | 0.1353 (4) | 0.0114 (14) | 0.0513 (16) | |
C13 | 0.3060 (4) | 0.0668 (4) | 0.1831 (12) | 0.0469 (15) | |
H1NA | 0.025 (3) | 0.268 (3) | −0.217 (14) | 0.08 (2)* | |
H1NB | 0.071 (6) | 0.266 (4) | 0.032 (11) | 0.15 (4)* | |
H1NC | 0.040 (3) | 0.185 (3) | −0.088 (12) | 0.07 (2)* | |
H2N | 0.105 (3) | 0.533 (3) | 0.177 (13) | 0.040 (16)* | |
H3N | 0.283 (4) | 0.160 (4) | −0.321 (8) | 0.06 (2)* | |
H2 | 0.136 (4) | 0.195 (3) | −0.368 (11) | 0.055 (19)* | |
H3A | 0.222 (2) | 0.324 (3) | −0.412 (11) | 0.034 (14)* | |
H3B | 0.113 (2) | 0.338 (3) | −0.428 (11) | 0.040 (15)* | |
H6 | 0.337 (3) | 0.331 (3) | −0.048 (10) | 0.036 (15)* | |
H7 | 0.432 (3) | 0.392 (4) | 0.241 (17) | 0.07 (2)* | |
H8 | 0.390 (3) | 0.486 (4) | 0.502 (12) | 0.056 (19)* | |
H9 | 0.239 (4) | 0.543 (3) | 0.479 (14) | 0.07 (2)* | |
H11 | 0.050 (2) | 0.446 (4) | −0.099 (14) | 0.055 (17)* | |
H12A | 0.360 (3) | 0.185 (3) | 0.106 (13) | 0.057 (19)* | |
H12B | 0.387 (2) | 0.119 (3) | −0.088 (10) | 0.030 (13)* | |
O1W | 0.0890 (4) | 0.0528 (4) | −0.011 (2) | 0.119 (3) | |
H1WA | 0.087 (4) | 0.003 (3) | −0.116 (12) | 0.07 (2)* | |
H1WB | 0.141 (4) | 0.048 (5) | 0.075 (19) | 0.14 (5)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.074 (3) | 0.075 (3) | 0.015 (2) | 0.012 (2) | 0.003 (2) | −0.005 (2) |
O2 | 0.073 (3) | 0.061 (3) | 0.043 (3) | −0.014 (2) | −0.006 (2) | −0.001 (2) |
O3 | 0.070 (3) | 0.075 (3) | 0.021 (2) | −0.004 (2) | −0.003 (2) | 0.008 (2) |
N1 | 0.064 (4) | 0.065 (4) | 0.028 (3) | −0.005 (3) | −0.002 (3) | 0.007 (3) |
N2 | 0.069 (4) | 0.060 (3) | 0.043 (3) | 0.013 (3) | 0.007 (3) | −0.015 (3) |
N3 | 0.070 (4) | 0.065 (3) | 0.017 (2) | 0.005 (3) | 0.009 (3) | 0.002 (2) |
C1 | 0.071 (4) | 0.045 (3) | 0.020 (3) | −0.007 (3) | 0.004 (3) | 0.002 (3) |
C2 | 0.058 (4) | 0.054 (4) | 0.019 (3) | 0.003 (3) | −0.002 (3) | −0.005 (3) |
C3 | 0.056 (4) | 0.058 (4) | 0.022 (3) | −0.001 (3) | −0.006 (3) | −0.001 (3) |
C4 | 0.052 (3) | 0.051 (3) | 0.028 (3) | 0.005 (3) | 0.004 (3) | 0.009 (3) |
C5 | 0.053 (3) | 0.043 (3) | 0.021 (3) | 0.003 (3) | 0.005 (3) | 0.001 (2) |
C6 | 0.069 (4) | 0.052 (4) | 0.028 (3) | 0.008 (3) | 0.003 (3) | −0.003 (3) |
C7 | 0.067 (5) | 0.068 (4) | 0.042 (4) | −0.001 (4) | −0.005 (4) | 0.012 (3) |
C8 | 0.072 (5) | 0.067 (4) | 0.028 (3) | −0.019 (4) | −0.007 (4) | −0.002 (3) |
C9 | 0.080 (5) | 0.062 (4) | 0.027 (3) | −0.011 (4) | 0.002 (3) | −0.004 (3) |
C10 | 0.060 (4) | 0.048 (3) | 0.025 (3) | −0.006 (3) | 0.008 (3) | −0.003 (3) |
C11 | 0.055 (4) | 0.059 (4) | 0.042 (4) | −0.005 (3) | −0.002 (3) | 0.006 (3) |
C12 | 0.057 (4) | 0.057 (4) | 0.039 (3) | 0.005 (3) | 0.007 (3) | 0.007 (3) |
C13 | 0.051 (3) | 0.056 (4) | 0.034 (3) | 0.000 (3) | 0.011 (3) | 0.002 (3) |
O1W | 0.093 (5) | 0.115 (6) | 0.148 (8) | −0.016 (4) | −0.006 (5) | −0.027 (5) |
Geometric parameters (Å, º) top
O1—C1 | 1.247 (7) | C3—H3B | 0.98 (3) |
O2—C13 | 1.224 (7) | C4—C11 | 1.341 (9) |
O2—H1WB | 1.84 (6) | C4—C5 | 1.417 (8) |
O3—C13 | 1.303 (8) | C5—C6 | 1.377 (8) |
O3—H1NAi | 1.95 (4) | C5—C10 | 1.407 (8) |
O3—H2Nii | 2.14 (4) | C6—C7 | 1.384 (9) |
N1—C2 | 1.480 (8) | C6—H6 | 0.92 (3) |
N1—H1NA | 0.93 (4) | C7—C8 | 1.396 (10) |
N1—H1NB | 0.97 (4) | C7—H7 | 1.00 (4) |
N1—H1NC | 0.93 (4) | C8—C9 | 1.371 (10) |
N2—C10 | 1.364 (8) | C8—H8 | 0.93 (4) |
N2—C11 | 1.399 (9) | C9—C10 | 1.394 (9) |
N2—H2N | 0.86 (3) | C9—H9 | 0.96 (4) |
N3—C1 | 1.326 (8) | C11—H11 | 0.95 (4) |
N3—C12 | 1.444 (8) | C12—C13 | 1.512 (9) |
N3—H3N | 0.85 (4) | C12—H12A | 1.01 (4) |
C1—C2 | 1.503 (9) | C12—H12B | 0.97 (3) |
C2—C3 | 1.533 (8) | O1W—H1WAiii | 1.75 (4) |
C2—H2 | 0.91 (4) | O1W—H1NC | 2.30 (5) |
C3—C4 | 1.510 (8) | O1W—H1WA | 0.97 (4) |
C3—H3A | 0.97 (3) | O1W—H1WB | 0.95 (4) |
| | | |
C13—O2—H1WB | 125 (2) | C6—C5—C4 | 134.8 (6) |
C13—O3—H1NAi | 94 (2) | C10—C5—C4 | 106.5 (5) |
C13—O3—H2Nii | 116.4 (18) | C5—C6—C7 | 120.3 (7) |
H1NAi—O3—H2Nii | 143 (2) | C5—C6—H6 | 123 (3) |
C2—N1—H1NA | 112 (5) | C7—C6—H6 | 116 (3) |
C2—N1—H1NB | 105 (6) | C6—C7—C8 | 120.2 (7) |
H1NA—N1—H1NB | 104 (5) | C6—C7—H7 | 124 (5) |
C2—N1—H1NC | 117 (4) | C8—C7—H7 | 115 (5) |
H1NA—N1—H1NC | 110 (4) | C9—C8—C7 | 121.0 (7) |
H1NB—N1—H1NC | 107 (5) | C9—C8—H8 | 128 (4) |
C10—N2—C11 | 107.9 (5) | C7—C8—H8 | 111 (4) |
C10—N2—H2N | 131 (4) | C8—C9—C10 | 118.2 (7) |
C11—N2—H2N | 118 (4) | C8—C9—H9 | 133 (4) |
C1—N3—C12 | 120.0 (5) | C10—C9—H9 | 108 (4) |
C1—N3—H3N | 122 (5) | N2—C10—C9 | 130.2 (6) |
C12—N3—H3N | 118 (5) | N2—C10—C5 | 108.1 (5) |
O1—C1—N3 | 122.1 (6) | C9—C10—C5 | 121.6 (6) |
O1—C1—C2 | 119.6 (6) | C4—C11—N2 | 109.3 (6) |
N3—C1—C2 | 118.2 (5) | C4—C11—H11 | 137 (4) |
N1—C2—C1 | 108.1 (5) | N2—C11—H11 | 112 (4) |
N1—C2—C3 | 109.8 (5) | N3—C12—C13 | 112.9 (6) |
C1—C2—C3 | 113.5 (5) | N3—C12—H12A | 105 (4) |
N1—C2—H2 | 98 (4) | C13—C12—H12A | 114 (4) |
C1—C2—H2 | 105 (4) | N3—C12—H12B | 109 (3) |
C3—C2—H2 | 122 (4) | C13—C12—H12B | 113 (3) |
C4—C3—C2 | 114.6 (5) | H12A—C12—H12B | 101 (4) |
C4—C3—H3A | 104 (3) | O2—C13—O3 | 123.7 (6) |
C2—C3—H3A | 107 (3) | O2—C13—C12 | 121.6 (6) |
C4—C3—H3B | 102 (3) | O3—C13—C12 | 114.7 (6) |
C2—C3—H3B | 98 (3) | H1WAiii—O1W—H1NC | 60 (3) |
H3A—C3—H3B | 131 (5) | H1WAiii—O1W—H1WA | 118 (5) |
C11—C4—C5 | 108.0 (6) | H1NC—O1W—H1WA | 131 (5) |
C11—C4—C3 | 125.9 (6) | H1WAiii—O1W—H1WB | 124 (7) |
C5—C4—C3 | 126.1 (5) | H1NC—O1W—H1WB | 117 (5) |
C6—C5—C10 | 118.6 (6) | H1WA—O1W—H1WB | 104 (5) |
| | | |
H1NA—N1—C2—C1 | 167 (3) | C6—C7—C8—C9 | 1.6 (10) |
N1—C2—C1—N3 | 154.7 (6) | C7—C8—C9—C10 | −1.8 (10) |
C2—C1—N3—C12 | 178.1 (6) | C11—N2—C10—C9 | −178.8 (6) |
C1—N3—C12—C13 | 60.7 (8) | C11—N2—C10—C5 | −1.7 (7) |
N3—C12—C13—O2 | 30.5 (9) | C8—C9—C10—N2 | 179.4 (7) |
C12—N3—C1—O1 | −1.1 (10) | C8—C9—C10—C5 | 2.7 (9) |
O1—C1—C2—N1 | −26.1 (8) | C6—C5—C10—N2 | 179.2 (6) |
O1—C1—C2—C3 | 95.9 (7) | C4—C5—C10—N2 | 0.8 (7) |
N3—C1—C2—C3 | −83.3 (7) | C6—C5—C10—C9 | −3.4 (9) |
N1—C2—C3—C4 | 60.1 (7) | C4—C5—C10—C9 | 178.1 (5) |
C1—C2—C3—C4 | −60.9 (7) | C5—C4—C11—N2 | −1.6 (7) |
C2—C3—C4—C11 | −96.7 (7) | C3—C4—C11—N2 | 179.1 (5) |
C2—C3—C4—C5 | 84.1 (8) | C10—N2—C11—C4 | 2.1 (7) |
C11—C4—C5—C6 | −177.6 (7) | H1WB—O2—C13—O3 | 109 (4) |
C3—C4—C5—C6 | 1.8 (11) | H1WB—O2—C13—C12 | −72 (4) |
C11—C4—C5—C10 | 0.5 (7) | H1NAi—O3—C13—O2 | −6 (2) |
C3—C4—C5—C10 | 179.9 (5) | H2Nii—O3—C13—O2 | 151.7 (16) |
C10—C5—C6—C7 | 3.1 (9) | H1NAi—O3—C13—C12 | 174.6 (19) |
C4—C5—C6—C7 | −178.9 (7) | H2Nii—O3—C13—C12 | −27.9 (17) |
C5—C6—C7—C8 | −2.2 (10) | N3—C12—C13—O3 | −149.9 (5) |
Symmetry codes: (i) y, −x, z+3/4; (ii) −y+1, x, z+1/4; (iii) −y, x, z+1/4. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O1Wiv | 0.97 (4) | 1.75 (4) | 2.695 (8) | 163 (3) |
O1W—H1WB···O2 | 0.95 (4) | 1.84 (5) | 2.738 (7) | 156 (3) |
N1—H1NA···O3v | 0.93 (4) | 1.95 (4) | 2.868 (6) | 170 (4) |
N2—H2N···O3vi | 0.86 (3) | 2.14 (4) | 2.961 (6) | 160 (3) |
N1—H1NB···O2iii | 0.97 (4) | 2.27 (4) | 2.892 (6) | 121 (3) |
N1—H1NC···O1W | 0.93 (4) | 2.30 (4) | 3.048 (7) | 137 (4) |
N1—H1NA···O2v | 0.93 (4) | 2.31 (4) | 2.973 (8) | 128 (4) |
Symmetry codes: (iii) −y, x, z+1/4; (iv) y, −x, z−1/4; (v) −y, x, z−3/4; (vi) y, −x+1, z−1/4. |
Experimental details
| (I) | (II) | (III) |
Crystal data |
Chemical formula | C14H17N3O3·H2O | C13H15N3O3·2H2O | C13H15N3O3·H2O |
Mr | 293.32 | 297.31 | 279.30 |
Crystal system, space group | Orthorhombic, P212121 | Monoclinic, P21 | Tetragonal, P41 |
Temperature (K) | 295 | 295 | 295 |
a, b, c (Å) | 4.9475 (5), 8.2059 (12), 35.213 (5) | 5.8404 (6), 8.2429 (8), 14.8299 (10) | 16.128 (2), 16.128 (2), 5.195 (1) |
α, β, γ (°) | 90, 90, 90 | 90, 96.178 (8), 90 | 90, 90, 90 |
V (Å3) | 1429.6 (3) | 709.79 (11) | 1351.3 (4) |
Z | 4 | 2 | 4 |
Radiation type | Cu Kα | Cu Kα | Cu Kα |
µ (mm−1) | 0.84 | 0.91 | 0.86 |
Crystal size (mm) | 0.35 × 0.17 × 0.15 | 0.60 × 0.32 × 0.02 | 0.44 × 0.12 × 0.02 |
|
Data collection |
Diffractometer | Nonius CAD-4 diffractometer | Nonius CAD-4 diffractometer | Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) | ψ scan (North et al., 1968) | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.768, 0.881 | 0.811, 0.982 | 0.719, 0.996 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3190, 2688, 2538 | 1583, 1440, 1404 | 3174, 1438, 871 |
Rint | 0.012 | 0.015 | 0.107 |
(sin θ/λ)max (Å−1) | 0.609 | 0.609 | 0.610 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.063, 1.00 | 0.034, 0.080, 1.00 | 0.061, 0.147, 1.01 |
No. of reflections | 2688 | 1440 | 1434 |
No. of parameters | 267 | 263 | 250 |
No. of restraints | 0 | 1 | 27 |
H-atom treatment | All H-atom parameters refined | H atoms: see text | H atoms: see text |
Δρmax, Δρmin (e Å−3) | 0.14, −0.10 | 0.17, −0.17 | 0.30, −0.23 |
Absolute structure | Flack (1983), 1067 Friedel pairs | Flack (1983), no Friedel pairs | Flack (1983), no Friedel pairs |
Absolute structure parameter | −0.02 (18) | 0.0 (3) | 0.6 (7) |
Selected torsion angles (º) for (I) topH1NA—N1—C1—C2 | −163 (1) | C2—N2—C4—C5 | 57.9 (2) |
N1—C1—C2—N2 | 151.0 (1) | N2—C4—C5—O2 | 21.5 (2) |
C1—C2—N2—C4 | −176.8 (1) | | |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1NA···O1Wi | 0.97 (2) | 1.77 (2) | 2.720 (2) | 166 (1) |
O1W—H1WB···O3 | 0.95 (2) | 1.79 (2) | 2.737 (2) | 171 (1) |
O1W—H1WA···O2ii | 0.88 (2) | 1.83 (2) | 2.712 (2) | 175 (1) |
N1—H1NB···O2iii | 0.92 (2) | 2.02 (2) | 2.820 (2) | 146 (1) |
N1—H1NC···O3iv | 0.96 (2) | 2.03 (2) | 2.920 (2) | 153 (1) |
N2—H2N···O1v | 0.84 (2) | 2.39 (2) | 3.180 (2) | 157 (1) |
Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, y−1/2, −z−1/2; (iii) −x+1, y+1/2, −z−1/2; (iv) x, y+1, z; (v) x+1, y, z. |
Selected torsion angles (º) for (II) topH1NA—N1—C1—C2 | 173 (2) | C2—N2—C3—C4 | −76.1 (3) |
N1—C1—C2—N2 | −167.8 (3) | N2—C3—C4—O2 | −26.9 (3) |
C1—C2—N2—C3 | −178.2 (2) | C3—N2—C2—O1 | −0.1 (4) |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O3 | 0.93 (5) | 1.85 (4) | 2.767 (3) | 169 (3) |
N1—H1NC···O1Wi | 0.93 (5) | 1.88 (6) | 2.740 (4) | 153 (4) |
N1—H1NB···O2ii | 0.93 (4) | 1.95 (4) | 2.860 (3) | 166 (3) |
O2W—H2WA···O1 | 0.94 (7) | 1.95 (6) | 2.778 (4) | 145 (4) |
O2W—H2WB···O2ii | 1.07 | 1.97 | 3.034 (5) | 179 |
N1—H1NA···O2Wiii | 0.89 (5) | 1.98 (6) | 2.784 (4) | 150 (4) |
N2—H2N···O3iii | 0.90 (4) | 2.00 (4) | 2.884 (3) | 164 (3) |
O1W—H1WB···O2iv | 0.87 (7) | 2.04 (6) | 2.775 (4) | 142 (4) |
Symmetry codes: (i) x−1, y−1, z; (ii) −x, y−1/2, −z+1; (iii) x−1, y, z; (iv) x+1, y, z. |
Selected torsion angles (º) for (III) topH1NA—N1—C2—C1 | 167 (3) | C1—N3—C12—C13 | 60.7 (8) |
N1—C2—C1—N3 | 154.7 (6) | N3—C12—C13—O2 | 30.5 (9) |
C2—C1—N3—C12 | 178.1 (6) | | |
Hydrogen-bond geometry (Å, º) for (III) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O1Wi | 0.97 (4) | 1.75 (4) | 2.695 (8) | 163 (3) |
O1W—H1WB···O2 | 0.95 (4) | 1.84 (5) | 2.738 (7) | 156 (3) |
N1—H1NA···O3ii | 0.93 (4) | 1.95 (4) | 2.868 (6) | 170 (4) |
N2—H2N···O3iii | 0.86 (3) | 2.14 (4) | 2.961 (6) | 160 (3) |
N1—H1NB···O2iv | 0.97 (4) | 2.27 (4) | 2.892 (6) | 121 (3) |
N1—H1NC···O1W | 0.93 (4) | 2.30 (4) | 3.048 (7) | 137 (4) |
N1—H1NA···O2ii | 0.93 (4) | 2.31 (4) | 2.973 (8) | 128 (4) |
Symmetry codes: (i) y, −x, z−1/4; (ii) −y, x, z−3/4; (iii) y, −x+1, z−1/4; (iv) −y, x, z+1/4. |
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We have determined the crystal structures of three dipeptides containing tryptophan, namely alaninyltryptophan hydrate [Ala-Trp, (I)], glycyltryptophan dihydrate [Gly-Trp, (II)] and tryptophylglycine hydrate [Trp-Gly, (III)]. It is expected that the sequence and certain features of the solid-state peptide geometry will play a key role in the binding affinity and conformation of the peptide. Another important factor is the presence of significant hydrogen bonding due to the presence of water molecules in the immediate vicinity of the dipeptide. Noteworthy di- (or higher) peptides containing Trp include Trp-Gly-Gly dihydrate (Subramanian et al., 1989), Gly-Trp dihydrate (Pasternak 1956) and Trp-Glu 7-methylguanosine-5'-phosphate trihydrate (Ishida et al., 1991). The second of these, Gly-Trp, (II), needed to be redetermined [e.g. dated 1956 with R(F) = 0.165 and included no H-atom coordinates].
The role of hydrogen bonding of the dipeptide appears to be a generally important one for crystallization of the dipeptide hydrates (Allen et al., 1983). In fact, the size and quality of the crystals formed after solvent evaporation generally follows the apparent strength and number of hydrogen bonds, namely (I) > (II) > (III). There are three short hydrogen-bond contacts in (I), and all are from the one water molecule of solvation to the dipeptide (e.g. no short water–water hydrogen-bond contacts).
The overall conformation of (I) is that of a hairpin that segregates the hydrogen-bond donors and acceptors on one side and the methyl and tryptophan groups on the other. The maximum atom–atom distance within the molecule is therefore short, at 9.0 Å. Analogous maxima for (II) and (III) are 11.6 and 8.6 Å, respectively. The hairpin or `u' shape of (I) is also observed in (III), which contrasts the fully extended conformation of (II). The hairpin motif is also found in Trp-Gly-Gly (Subramanian et al., 1989). These comformations are further described by the selected torsion angles about the respective dipeptide bonds (see Tables 1, 3 and 5). The unique hydrogen-bond contacts are comprised of the acceptor carboxylate, carbonyl and water O atoms and the donor protons from the water molecule and the primary and quaternary amines of the dipeptide bonds and the N termini. The two-dimensional networks of these sheets of hydrogen bonds extend throughout the crystallographic ab, ab and ac planes, respectively, for (I), (II) and (III). Connecting these layers of hydrogen-bond interactions, are layers of adjacent and parallel tryptophan rings. The tryptophan rings in these sheets, when viewed edge-on, compose a herring-bone motif rather than a direct ring-over-ring overlap. As a result, the interplanar separations are close (e.g. 3.3, 3.0 and 3.9 Å for (I), (II) and (III), respectively), but not overlapping. The non-overlapping herring-bone motif of tryptophan rings and adjacent sheets of hydrogen-bond interactions are obtained for (II) and (III) also. This situation may be expected, although the tryptophan rings have been known to overlap directly with similar ring systems, such as that in tryptophanylglutamic acid 7-methylguanosine-5'-phosphate trihydrate (Ishida et al., 1991). The unit-cell packing motif may thus be described as having alternating hydrogen-bond-containing (e.g. hydrophilic) regions and tryptophan ring (e.g. hydrophobic) regions. For (III), which has tetragonal symmetry, the hydrogen-bonding regions appear in both the ac and bc planes, the intersection of which contains rather large channels of hydrogen-bonding water molecules along the c axis.