Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107022469/av3090sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270107022469/av3090Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270107022469/av3090IIsup3.hkl |
CCDC references: 661804; 661805
Compound (I) was crystallized from an aqueous solution containing 4-aminobenzoic acid and (2R,3R)-tartaric acid in the stochiometric ratio of 1:1 at room temperature by the technique of slow evaporation. Compound (II) was crystallized from a saturated aqueous solution of 4-aminobenzoic acid.
All H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93 (aromatic CH) and 0.98 (–CH) Å, O—H = 0.82 Å and N—H = 0.89 Å, and with Uiso(H) = 1.2–1.5Ueq(parent). In compound (I), in addition to the 2721 unique reflections, 109 Friedel pairs were measured. However, owing to the absence of atoms with significant anomalous dispersion effects, these data were merged.
For both 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: SHELXTL/PC (Bruker, 2000); program(s) used to refine structure: SHELXTL/PC; molecular graphics: ORTEP-3 (Farrugia, 1997), Mercury (Version 1.4.1; Macrae et al., 2006 ) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXTL/PC.
C7H8NO2+·C4H5O6− | F(000) = 600 |
Mr = 287.22 | Dx = 1.557 Mg m−3 Dm = 1.54 (2) Mg m−3 Dm measured by flotation using a liquid mixture of xylene and carbon tetrachloride |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 25 reflections |
a = 6.021 (4) Å | θ = 10.3–13.8° |
b = 28.789 (11) Å | µ = 0.14 mm−1 |
c = 7.426 (5) Å | T = 293 K |
β = 107.89 (4)° | Needle, light pink |
V = 1225.0 (12) Å3 | 0.22 × 0.15 × 0.13 mm |
Z = 4 |
Nonius MACH-3 sealed-tube diffractometer | 2127 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.091 |
Graphite monochromator | θmax = 27.0°, θmin = 2.8° |
ω/2θ scans | h = 0→7 |
Absorption correction: ψ scan (North et al., 1968) | k = −1→36 |
Tmin = 0.930, Tmax = 0.981 | l = −9→9 |
3083 measured reflections | 3 standard reflections every 60 min |
2721 independent reflections | intensity decay: none |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.039 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.106 | w = 1/[σ2(Fo2) + (0.0312P)2 + 0.9248P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
2721 reflections | Δρmax = 0.29 e Å−3 |
371 parameters | Δρmin = −0.29 e Å−3 |
1 restraint | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 10 (10) |
C7H8NO2+·C4H5O6− | V = 1225.0 (12) Å3 |
Mr = 287.22 | Z = 4 |
Monoclinic, P21 | Mo Kα radiation |
a = 6.021 (4) Å | µ = 0.14 mm−1 |
b = 28.789 (11) Å | T = 293 K |
c = 7.426 (5) Å | 0.22 × 0.15 × 0.13 mm |
β = 107.89 (4)° |
Nonius MACH-3 sealed-tube diffractometer | 2127 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.091 |
Tmin = 0.930, Tmax = 0.981 | 3 standard reflections every 60 min |
3083 measured reflections | intensity decay: none |
2721 independent reflections |
R[F2 > 2σ(F2)] = 0.039 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.106 | Δρmax = 0.29 e Å−3 |
S = 1.08 | Δρmin = −0.29 e Å−3 |
2721 reflections | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
371 parameters | Absolute structure parameter: 10 (10) |
1 restraint |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C11 | 0.8226 (8) | 0.67323 (16) | 0.0080 (6) | 0.0378 (10) | |
C111 | 0.8437 (10) | 0.72498 (19) | 0.0118 (7) | 0.0508 (13) | |
O1A | 0.6800 (8) | 0.75065 (14) | −0.0388 (7) | 0.0692 (12) | |
O1B | 1.0618 (8) | 0.73936 (15) | 0.0753 (9) | 0.0893 (16) | |
H1B | 1.0648 | 0.7678 | 0.0747 | 0.134* | |
C12 | 1.0157 (8) | 0.64471 (17) | 0.0696 (7) | 0.0460 (12) | |
H12 | 1.1640 | 0.6577 | 0.1142 | 0.055* | |
C13 | 0.9896 (8) | 0.59720 (16) | 0.0654 (7) | 0.0410 (11) | |
H13 | 1.1195 | 0.5780 | 0.1085 | 0.049* | |
C14 | 0.7689 (7) | 0.57829 (15) | −0.0034 (5) | 0.0288 (9) | |
N14 | 0.7443 (5) | 0.52768 (12) | −0.0075 (4) | 0.0277 (7) | |
H14A | 0.5936 | 0.5202 | −0.0447 | 0.042* | |
H14B | 0.8124 | 0.5163 | 0.1077 | 0.042* | |
H14C | 0.8121 | 0.5158 | −0.0881 | 0.042* | |
C15 | 0.5741 (8) | 0.60591 (18) | −0.0649 (7) | 0.0435 (11) | |
H15 | 0.4261 | 0.5928 | −0.1095 | 0.052* | |
C16 | 0.6028 (8) | 0.65377 (18) | −0.0589 (7) | 0.0463 (12) | |
H16 | 0.4727 | 0.6729 | −0.1004 | 0.056* | |
C21 | 0.8070 (10) | 0.67979 (17) | 0.5080 (7) | 0.0469 (13) | |
C211 | 0.8226 (17) | 0.6277 (2) | 0.5179 (10) | 0.080 (2) | |
O2A | 1.0033 (14) | 0.60777 (19) | 0.5926 (9) | 0.117 (2) | |
O2B | 0.6155 (13) | 0.60719 (17) | 0.4365 (10) | 0.110 (2) | |
H2B | 0.6352 | 0.5793 | 0.4260 | 0.165* | |
C22 | 0.5945 (10) | 0.70212 (19) | 0.4390 (8) | 0.0549 (14) | |
H22 | 0.4576 | 0.6848 | 0.4003 | 0.066* | |
C23 | 0.5843 (8) | 0.75003 (17) | 0.4271 (7) | 0.0424 (11) | |
H23 | 0.4417 | 0.7652 | 0.3799 | 0.051* | |
C24 | 0.7882 (7) | 0.77484 (14) | 0.4862 (5) | 0.0284 (8) | |
N24 | 0.7733 (6) | 0.82591 (13) | 0.4695 (5) | 0.0318 (8) | |
H24A | 0.9151 | 0.8381 | 0.5174 | 0.048* | |
H24B | 0.6804 | 0.8366 | 0.5328 | 0.048* | |
H24C | 0.7155 | 0.8338 | 0.3481 | 0.048* | |
C25 | 1.0025 (8) | 0.75375 (18) | 0.5561 (7) | 0.0431 (11) | |
H25 | 1.1393 | 0.7711 | 0.5948 | 0.052* | |
C26 | 1.0073 (10) | 0.70549 (19) | 0.5668 (7) | 0.0533 (14) | |
H26 | 1.1498 | 0.6904 | 0.6149 | 0.064* | |
C1C | 0.4047 (6) | 0.87001 (14) | −0.2336 (5) | 0.0248 (8) | |
O2C | 0.2639 (5) | 0.89617 (12) | −0.3507 (4) | 0.0420 (8) | |
O1C | 0.5479 (5) | 0.84367 (11) | −0.2691 (4) | 0.0385 (7) | |
C2C | 0.4042 (6) | 0.87210 (15) | −0.0270 (5) | 0.0273 (8) | |
H2C | 0.4698 | 0.9022 | 0.0249 | 0.033* | |
O3C | 0.5475 (5) | 0.83688 (12) | 0.0836 (4) | 0.0389 (8) | |
H3C | 0.5871 | 0.8187 | 0.0140 | 0.058* | |
C3C | 0.1568 (6) | 0.86891 (15) | −0.0099 (5) | 0.0265 (8) | |
H3C1 | 0.0695 | 0.8972 | −0.0605 | 0.032* | |
O4C | 0.0436 (5) | 0.82991 (12) | −0.1144 (4) | 0.0415 (8) | |
H4C | −0.0956 | 0.8306 | −0.1235 | 0.062* | |
C4C | 0.1727 (6) | 0.86315 (15) | 0.1977 (5) | 0.0259 (8) | |
O5C | 0.1045 (6) | 0.82926 (12) | 0.2593 (4) | 0.0437 (8) | |
O6C | 0.2692 (6) | 0.89898 (11) | 0.2996 (4) | 0.0401 (7) | |
H6C | 0.2711 | 0.8950 | 0.4094 | 0.060* | |
C1D | 0.1114 (7) | 0.49961 (15) | 0.7123 (5) | 0.0287 (8) | |
O1D | −0.0936 (5) | 0.49943 (12) | 0.7115 (4) | 0.0403 (8) | |
O2D | 0.2886 (5) | 0.49398 (12) | 0.8581 (4) | 0.0407 (8) | |
C2D | 0.1614 (6) | 0.50738 (14) | 0.5273 (5) | 0.0263 (8) | |
H2D | 0.2464 | 0.5367 | 0.5350 | 0.032* | |
O3D | −0.0512 (5) | 0.51052 (12) | 0.3776 (4) | 0.0358 (7) | |
H3D | −0.1609 | 0.5058 | 0.4188 | 0.054* | |
C4D | 0.3464 (6) | 0.48222 (15) | 0.2962 (5) | 0.0260 (8) | |
O5D | 0.4770 (5) | 0.51416 (12) | 0.2901 (4) | 0.0373 (7) | |
O6D | 0.2221 (5) | 0.45940 (11) | 0.1483 (4) | 0.0357 (7) | |
H6D | 0.2486 | 0.4694 | 0.0536 | 0.054* | |
C3D | 0.3065 (6) | 0.46861 (14) | 0.4818 (5) | 0.0243 (8) | |
H3D1 | 0.4580 | 0.4680 | 0.5806 | 0.029* | |
O4D | 0.1992 (5) | 0.42501 (10) | 0.4784 (4) | 0.0321 (6) | |
H4D | 0.0613 | 0.4268 | 0.4153 | 0.048* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C11 | 0.049 (3) | 0.032 (2) | 0.030 (2) | −0.003 (2) | 0.0094 (19) | 0.0020 (18) |
C111 | 0.066 (3) | 0.037 (3) | 0.045 (3) | −0.002 (3) | 0.010 (2) | 0.000 (2) |
O1A | 0.076 (3) | 0.035 (2) | 0.085 (3) | 0.008 (2) | 0.009 (2) | 0.002 (2) |
O1B | 0.073 (3) | 0.036 (2) | 0.136 (5) | −0.014 (2) | −0.002 (3) | −0.005 (3) |
C12 | 0.033 (2) | 0.038 (3) | 0.060 (3) | −0.008 (2) | 0.005 (2) | −0.005 (2) |
C13 | 0.033 (2) | 0.029 (2) | 0.057 (3) | 0.0022 (18) | 0.007 (2) | 0.001 (2) |
C14 | 0.029 (2) | 0.032 (2) | 0.0262 (19) | −0.0008 (17) | 0.0094 (16) | 0.0003 (17) |
N14 | 0.0288 (16) | 0.0290 (19) | 0.0263 (16) | −0.0020 (14) | 0.0099 (13) | −0.0007 (14) |
C15 | 0.030 (2) | 0.043 (3) | 0.053 (3) | 0.004 (2) | 0.006 (2) | 0.002 (2) |
C16 | 0.039 (3) | 0.040 (3) | 0.054 (3) | 0.010 (2) | 0.006 (2) | 0.002 (2) |
C21 | 0.080 (4) | 0.027 (2) | 0.039 (3) | 0.008 (2) | 0.025 (3) | 0.000 (2) |
C211 | 0.154 (8) | 0.035 (3) | 0.068 (4) | 0.015 (4) | 0.061 (5) | 0.000 (3) |
O2A | 0.193 (6) | 0.052 (3) | 0.115 (5) | 0.061 (4) | 0.060 (5) | 0.022 (3) |
O2B | 0.189 (6) | 0.033 (3) | 0.121 (5) | −0.025 (3) | 0.067 (5) | −0.014 (3) |
C22 | 0.063 (3) | 0.039 (3) | 0.059 (3) | −0.012 (3) | 0.014 (3) | −0.008 (3) |
C23 | 0.036 (2) | 0.035 (3) | 0.050 (3) | 0.006 (2) | 0.004 (2) | 0.002 (2) |
C24 | 0.037 (2) | 0.026 (2) | 0.0245 (19) | 0.0064 (17) | 0.0130 (16) | 0.0017 (16) |
N24 | 0.0393 (18) | 0.031 (2) | 0.0250 (16) | 0.0055 (15) | 0.0104 (14) | 0.0011 (14) |
C25 | 0.036 (2) | 0.043 (3) | 0.048 (3) | 0.008 (2) | 0.011 (2) | 0.006 (2) |
C26 | 0.061 (3) | 0.047 (3) | 0.050 (3) | 0.029 (3) | 0.016 (3) | 0.011 (2) |
C1C | 0.0288 (19) | 0.027 (2) | 0.0198 (17) | −0.0007 (16) | 0.0096 (15) | −0.0008 (16) |
O2C | 0.0476 (18) | 0.055 (2) | 0.0239 (14) | 0.0222 (16) | 0.0116 (13) | 0.0101 (14) |
O1C | 0.0459 (17) | 0.046 (2) | 0.0281 (15) | 0.0163 (15) | 0.0176 (13) | 0.0044 (13) |
C2C | 0.0279 (18) | 0.034 (2) | 0.0192 (18) | 0.0027 (16) | 0.0060 (15) | 0.0017 (16) |
O3C | 0.0416 (17) | 0.050 (2) | 0.0236 (14) | 0.0220 (15) | 0.0082 (12) | 0.0063 (13) |
C3C | 0.0233 (18) | 0.035 (2) | 0.0202 (18) | 0.0010 (16) | 0.0050 (14) | −0.0005 (16) |
O4C | 0.0368 (16) | 0.053 (2) | 0.0310 (15) | −0.0126 (15) | 0.0054 (13) | −0.0137 (15) |
C4C | 0.0219 (17) | 0.032 (2) | 0.0243 (18) | 0.0023 (15) | 0.0072 (14) | 0.0012 (16) |
O5C | 0.0540 (19) | 0.046 (2) | 0.0343 (16) | −0.0158 (16) | 0.0181 (14) | 0.0005 (15) |
O6C | 0.0602 (19) | 0.0387 (19) | 0.0249 (14) | −0.0137 (15) | 0.0182 (14) | −0.0078 (13) |
C1D | 0.0321 (19) | 0.035 (2) | 0.0202 (17) | −0.0063 (17) | 0.0106 (15) | −0.0022 (16) |
O1D | 0.0309 (15) | 0.063 (2) | 0.0306 (15) | −0.0045 (15) | 0.0143 (12) | −0.0056 (15) |
O2D | 0.0332 (15) | 0.065 (2) | 0.0214 (14) | −0.0122 (14) | 0.0054 (12) | 0.0017 (14) |
C2D | 0.0274 (18) | 0.031 (2) | 0.0214 (17) | −0.0021 (16) | 0.0084 (14) | 0.0001 (16) |
O3D | 0.0274 (13) | 0.055 (2) | 0.0240 (13) | 0.0107 (14) | 0.0060 (11) | 0.0080 (14) |
C4D | 0.0183 (16) | 0.036 (2) | 0.0242 (18) | 0.0034 (16) | 0.0066 (14) | −0.0001 (16) |
O5D | 0.0311 (14) | 0.050 (2) | 0.0318 (14) | −0.0135 (14) | 0.0108 (12) | 0.0000 (14) |
O6D | 0.0426 (16) | 0.0421 (19) | 0.0231 (13) | −0.0134 (14) | 0.0108 (13) | −0.0040 (13) |
C3D | 0.0215 (17) | 0.028 (2) | 0.0208 (16) | 0.0019 (15) | 0.0027 (14) | 0.0023 (15) |
O4D | 0.0324 (14) | 0.0290 (16) | 0.0326 (15) | −0.0009 (12) | 0.0067 (12) | 0.0045 (12) |
C11—C16 | 1.381 (7) | N24—H24C | 0.8900 |
C11—C12 | 1.381 (7) | C25—C26 | 1.391 (7) |
C11—C111 | 1.495 (7) | C25—H25 | 0.9300 |
C111—O1A | 1.196 (7) | C26—H26 | 0.9300 |
C111—O1B | 1.318 (7) | C1C—O1C | 1.236 (5) |
O1B—H1B | 0.8200 | C1C—O2C | 1.261 (5) |
C12—C13 | 1.376 (7) | C1C—C2C | 1.536 (5) |
C12—H12 | 0.9300 | C2C—O3C | 1.418 (5) |
C13—C14 | 1.381 (6) | C2C—C3C | 1.537 (5) |
C13—H13 | 0.9300 | C2C—H2C | 0.9800 |
C14—C15 | 1.374 (6) | O3C—H3C | 0.8200 |
C14—N14 | 1.464 (6) | C3C—O4C | 1.415 (5) |
N14—H14A | 0.8900 | C3C—C4C | 1.524 (5) |
N14—H14B | 0.8900 | C3C—H3C1 | 0.9800 |
N14—H14C | 0.8900 | O4C—H4C | 0.8200 |
C15—C16 | 1.388 (7) | C4C—O5C | 1.202 (5) |
C15—H15 | 0.9300 | C4C—O6C | 1.306 (5) |
C16—H16 | 0.9300 | O6C—H6C | 0.8200 |
C21—C26 | 1.367 (8) | C1D—O1D | 1.232 (5) |
C21—C22 | 1.382 (8) | C1D—O2D | 1.276 (5) |
C21—C211 | 1.502 (8) | C1D—C2D | 1.511 (5) |
C211—O2A | 1.205 (10) | C2D—O3D | 1.418 (4) |
C211—O2B | 1.344 (10) | C2D—C3D | 1.518 (5) |
O2B—H2B | 0.8200 | C2D—H2D | 0.9800 |
C22—C23 | 1.382 (7) | O3D—H3D | 0.8200 |
C22—H22 | 0.9300 | C4D—O5D | 1.219 (5) |
C23—C24 | 1.371 (6) | C4D—O6D | 1.301 (5) |
C23—H23 | 0.9300 | C4D—C3D | 1.521 (5) |
C24—C25 | 1.375 (6) | O6D—H6D | 0.8200 |
C24—N24 | 1.476 (5) | C3D—O4D | 1.408 (5) |
N24—H24A | 0.8900 | C3D—H3D1 | 0.9800 |
N24—H24B | 0.8900 | O4D—H4D | 0.8200 |
C16—C11—C12 | 119.6 (4) | H24B—N24—H24C | 109.5 |
C16—C11—C111 | 118.5 (5) | C24—C25—C26 | 117.6 (5) |
C12—C11—C111 | 121.9 (4) | C24—C25—H25 | 121.2 |
O1A—C111—O1B | 123.5 (6) | C26—C25—H25 | 121.2 |
O1A—C111—C11 | 123.6 (5) | C21—C26—C25 | 121.4 (5) |
O1B—C111—C11 | 112.9 (5) | C21—C26—H26 | 119.3 |
C111—O1B—H1B | 109.5 | C25—C26—H26 | 119.3 |
C13—C12—C11 | 120.3 (4) | O1C—C1C—O2C | 125.8 (3) |
C13—C12—H12 | 119.8 | O1C—C1C—C2C | 116.9 (3) |
C11—C12—H12 | 119.8 | O2C—C1C—C2C | 117.3 (3) |
C12—C13—C14 | 119.4 (4) | O3C—C2C—C1C | 111.3 (3) |
C12—C13—H13 | 120.3 | O3C—C2C—C3C | 110.0 (3) |
C14—C13—H13 | 120.3 | C1C—C2C—C3C | 112.3 (3) |
C15—C14—C13 | 121.4 (4) | O3C—C2C—H2C | 107.7 |
C15—C14—N14 | 119.9 (4) | C1C—C2C—H2C | 107.7 |
C13—C14—N14 | 118.7 (4) | C3C—C2C—H2C | 107.7 |
C14—N14—H14A | 109.5 | C2C—O3C—H3C | 109.5 |
C14—N14—H14B | 109.5 | O4C—C3C—C4C | 109.8 (3) |
H14A—N14—H14B | 109.5 | O4C—C3C—C2C | 108.5 (3) |
C14—N14—H14C | 109.5 | C4C—C3C—C2C | 109.2 (3) |
H14A—N14—H14C | 109.5 | O4C—C3C—H3C1 | 109.8 |
H14B—N14—H14C | 109.5 | C4C—C3C—H3C1 | 109.8 |
C14—C15—C16 | 118.6 (4) | C2C—C3C—H3C1 | 109.8 |
C14—C15—H15 | 120.7 | C3C—O4C—H4C | 109.5 |
C16—C15—H15 | 120.7 | O5C—C4C—O6C | 124.3 (4) |
C11—C16—C15 | 120.7 (4) | O5C—C4C—C3C | 123.4 (4) |
C11—C16—H16 | 119.7 | O6C—C4C—C3C | 112.3 (3) |
C15—C16—H16 | 119.7 | C4C—O6C—H6C | 109.5 |
C26—C21—C22 | 119.5 (5) | O1D—C1D—O2D | 125.4 (4) |
C26—C21—C211 | 119.3 (6) | O1D—C1D—C2D | 118.4 (3) |
C22—C21—C211 | 121.3 (6) | O2D—C1D—C2D | 116.2 (3) |
O2A—C211—O2B | 125.3 (7) | O3D—C2D—C1D | 109.8 (3) |
O2A—C211—C21 | 122.2 (8) | O3D—C2D—C3D | 108.4 (3) |
O2B—C211—C21 | 112.5 (7) | C1D—C2D—C3D | 112.5 (3) |
C211—O2B—H2B | 109.5 | O3D—C2D—H2D | 108.7 |
C21—C22—C23 | 120.4 (5) | C1D—C2D—H2D | 108.7 |
C21—C22—H22 | 119.8 | C3D—C2D—H2D | 108.7 |
C23—C22—H22 | 119.8 | C2D—O3D—H3D | 109.5 |
C24—C23—C22 | 118.8 (5) | O5D—C4D—O6D | 124.0 (4) |
C24—C23—H23 | 120.6 | O5D—C4D—C3D | 120.7 (3) |
C22—C23—H23 | 120.6 | O6D—C4D—C3D | 115.1 (3) |
C23—C24—C25 | 122.3 (4) | C4D—O6D—H6D | 109.5 |
C23—C24—N24 | 117.8 (4) | O4D—C3D—C2D | 111.5 (3) |
C25—C24—N24 | 119.8 (4) | O4D—C3D—C4D | 114.4 (3) |
C24—N24—H24A | 109.5 | C2D—C3D—C4D | 105.9 (3) |
C24—N24—H24B | 109.5 | O4D—C3D—H3D1 | 108.3 |
H24A—N24—H24B | 109.5 | C2D—C3D—H3D1 | 108.3 |
C24—N24—H24C | 109.5 | C4D—C3D—H3D1 | 108.3 |
H24A—N24—H24C | 109.5 | C3D—O4D—H4D | 109.5 |
C16—C11—C111—O1A | 0.5 (8) | C211—C21—C26—C25 | 178.4 (5) |
C12—C11—C111—O1A | −179.3 (5) | C24—C25—C26—C21 | 0.7 (8) |
C16—C11—C111—O1B | −178.9 (5) | O1C—C1C—C2C—O3C | −9.6 (5) |
C12—C11—C111—O1B | 1.3 (7) | O2C—C1C—C2C—O3C | 172.3 (3) |
C16—C11—C12—C13 | −0.3 (8) | O1C—C1C—C2C—C3C | −133.4 (4) |
C111—C11—C12—C13 | 179.5 (5) | O2C—C1C—C2C—C3C | 48.5 (5) |
C11—C12—C13—C14 | 0.9 (8) | O3C—C2C—C3C—O4C | −73.5 (4) |
C12—C13—C14—C15 | −1.1 (7) | C1C—C2C—C3C—O4C | 51.1 (4) |
C12—C13—C14—N14 | 179.8 (4) | O3C—C2C—C3C—C4C | 46.2 (4) |
C13—C14—C15—C16 | 0.8 (7) | C1C—C2C—C3C—C4C | 170.7 (3) |
N14—C14—C15—C16 | 179.9 (4) | O4C—C3C—C4C—O5C | 2.3 (5) |
C12—C11—C16—C15 | 0.0 (8) | C2C—C3C—C4C—O5C | −116.5 (4) |
C111—C11—C16—C15 | −179.8 (5) | O4C—C3C—C4C—O6C | −177.9 (3) |
C14—C15—C16—C11 | −0.2 (8) | C2C—C3C—C4C—O6C | 63.2 (4) |
C26—C21—C211—O2A | 7.3 (9) | O1D—C1D—C2D—O3D | −3.5 (5) |
C22—C21—C211—O2A | −173.4 (6) | O2D—C1D—C2D—O3D | 176.9 (4) |
C26—C21—C211—O2B | −173.1 (5) | O1D—C1D—C2D—C3D | −124.3 (4) |
C22—C21—C211—O2B | 6.2 (8) | O2D—C1D—C2D—C3D | 56.1 (5) |
C26—C21—C22—C23 | 0.8 (8) | O3D—C2D—C3D—O4D | −65.1 (4) |
C211—C21—C22—C23 | −178.5 (5) | C1D—C2D—C3D—O4D | 56.5 (4) |
C21—C22—C23—C24 | −0.5 (8) | O3D—C2D—C3D—C4D | 59.9 (4) |
C22—C23—C24—C25 | 0.3 (7) | C1D—C2D—C3D—C4D | −178.5 (3) |
C22—C23—C24—N24 | 179.1 (4) | O5D—C4D—C3D—O4D | −165.4 (3) |
C23—C24—C25—C26 | −0.4 (7) | O6D—C4D—C3D—O4D | 18.5 (5) |
N24—C24—C25—C26 | −179.2 (4) | O5D—C4D—C3D—C2D | 71.3 (4) |
C22—C21—C26—C25 | −0.9 (8) | O6D—C4D—C3D—C2D | −104.8 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1B···O5Ci | 0.82 | 2.20 | 2.901 (6) | 143 |
O1B—H1B···O4Ci | 0.82 | 2.25 | 2.949 (6) | 143 |
N14—H14A···O2Dii | 0.89 | 1.91 | 2.790 (5) | 170 |
N14—H14B···O3Di | 0.89 | 1.93 | 2.788 (4) | 163 |
N14—H14C···O1Diii | 0.89 | 1.81 | 2.687 (4) | 168 |
O2B—H2B···O5D | 0.82 | 2.20 | 2.914 (6) | 145 |
N24—H24A···O2Civ | 0.89 | 2.63 | 3.490 (5) | 164 |
N24—H24C···O3C | 0.89 | 1.92 | 2.787 (5) | 166 |
N24—H24B···O1Cv | 0.89 | 1.89 | 2.737 (5) | 159 |
O3C—H3C···O1A | 0.82 | 2.11 | 2.841 (5) | 149 |
O4C—H4C···O1Cvi | 0.82 | 2.12 | 2.877 (5) | 154 |
O6C—H6C···O2Cv | 0.82 | 1.80 | 2.608 (4) | 171 |
O3D—H3D···O5Dvi | 0.82 | 2.11 | 2.715 (4) | 131 |
O4D—H4D···O2Cvii | 0.82 | 2.06 | 2.782 (4) | 146 |
O6D—H6D···O2Dii | 0.82 | 1.70 | 2.515 (4) | 175 |
Symmetry codes: (i) x+1, y, z; (ii) x, y, z−1; (iii) x+1, y, z−1; (iv) x+1, y, z+1; (v) x, y, z+1; (vi) x−1, y, z; (vii) −x, y−1/2, −z. |
C7H7NO2 | F(000) = 576 |
Mr = 137.14 | Dx = 1.373 Mg m−3 Dm = 1.36 (2) Mg m−3 Dm measured by flotation using a liquid mixture of xylene and carbon tetrachloride |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 25 reflections |
a = 18.5712 (8) Å | θ = 9.1–13.6° |
b = 3.8431 (3) Å | µ = 0.10 mm−1 |
c = 18.6321 (9) Å | T = 293 K |
β = 93.670 (11)° | Needle, light pink |
V = 1327.06 (13) Å3 | 0.23 × 0.14 × 0.12 mm |
Z = 8 |
Nonius MACH-3 sealed-tube diffractometer | 1746 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.038 |
Graphite monochromator | θmax = 27.0°, θmin = 2.2° |
ω/2θ scans | h = 0→22 |
Absorption correction: ψ scan (North et al., 1968) | k = −1→4 |
Tmin = 0.945, Tmax = 0.985 | l = −22→22 |
3787 measured reflections | 3 standard reflections every 60 min |
2845 independent reflections | intensity decay: none |
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)] = 0.066 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.227 | H-atom parameters constrained |
S = 1.17 | w = 1/[σ2(Fo2) + (0.076P)2 + 1.6498P] where P = (Fo2 + 2Fc2)/3 |
2845 reflections | (Δ/σ)max < 0.001 |
183 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.27 e Å−3 |
C7H7NO2 | V = 1327.06 (13) Å3 |
Mr = 137.14 | Z = 8 |
Monoclinic, P21/n | Mo Kα radiation |
a = 18.5712 (8) Å | µ = 0.10 mm−1 |
b = 3.8431 (3) Å | T = 293 K |
c = 18.6321 (9) Å | 0.23 × 0.14 × 0.12 mm |
β = 93.670 (11)° |
Nonius MACH-3 sealed-tube diffractometer | 1746 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.038 |
Tmin = 0.945, Tmax = 0.985 | 3 standard reflections every 60 min |
3787 measured reflections | intensity decay: none |
2845 independent reflections |
R[F2 > 2σ(F2)] = 0.066 | 0 restraints |
wR(F2) = 0.227 | H-atom parameters constrained |
S = 1.17 | Δρmax = 0.37 e Å−3 |
2845 reflections | Δρmin = −0.27 e Å−3 |
183 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C11 | 0.84596 (17) | 0.2725 (10) | 0.57151 (17) | 0.0421 (8) | |
C111 | 0.91218 (19) | 0.1701 (11) | 0.53878 (18) | 0.0463 (9) | |
O1A | 0.91302 (13) | 0.0090 (8) | 0.48179 (14) | 0.0587 (8) | |
O1B | 0.97236 (13) | 0.2588 (9) | 0.57552 (14) | 0.0600 (8) | |
H1B | 1.0070 | 0.1883 | 0.5546 | 0.090* | |
C12 | 0.77871 (18) | 0.1918 (11) | 0.53741 (19) | 0.0483 (9) | |
H12 | 0.7767 | 0.0804 | 0.4930 | 0.058* | |
C13 | 0.71598 (19) | 0.2732 (12) | 0.5680 (2) | 0.0523 (10) | |
H13 | 0.6721 | 0.2156 | 0.5441 | 0.063* | |
C14 | 0.71662 (19) | 0.4406 (11) | 0.6341 (2) | 0.0509 (9) | |
N14 | 0.65429 (17) | 0.5140 (12) | 0.6668 (2) | 0.0708 (11) | |
H14A | 0.6132 | 0.4561 | 0.6464 | 0.085* | |
H14B | 0.6563 | 0.6180 | 0.7078 | 0.085* | |
C15 | 0.78406 (19) | 0.5267 (11) | 0.6685 (2) | 0.0497 (9) | |
H15 | 0.7859 | 0.6404 | 0.7126 | 0.060* | |
C16 | 0.84725 (19) | 0.4442 (10) | 0.63744 (19) | 0.0460 (9) | |
H16 | 0.8913 | 0.5038 | 0.6608 | 0.055* | |
C21 | 0.42867 (17) | 0.2794 (10) | 0.65205 (17) | 0.0413 (8) | |
C211 | 0.46161 (18) | 0.1748 (11) | 0.58669 (18) | 0.0476 (9) | |
O2A | 0.52138 (14) | 0.0223 (9) | 0.58821 (14) | 0.0627 (8) | |
O2B | 0.42463 (14) | 0.2369 (9) | 0.52655 (13) | 0.0618 (8) | |
H2B | 0.4477 | 0.1736 | 0.4928 | 0.093* | |
C22 | 0.36222 (19) | 0.4527 (10) | 0.64957 (19) | 0.0460 (9) | |
H22 | 0.3392 | 0.5077 | 0.6052 | 0.055* | |
C23 | 0.33051 (19) | 0.5428 (11) | 0.71138 (19) | 0.0478 (9) | |
H23 | 0.2863 | 0.6572 | 0.7085 | 0.057* | |
C24 | 0.36421 (19) | 0.4637 (11) | 0.77878 (19) | 0.0466 (9) | |
N24 | 0.33086 (18) | 0.5453 (11) | 0.84022 (17) | 0.0637 (10) | |
H24A | 0.3509 | 0.4910 | 0.8816 | 0.076* | |
H24B | 0.2899 | 0.6507 | 0.8373 | 0.076* | |
C25 | 0.43079 (19) | 0.2923 (11) | 0.78169 (19) | 0.0489 (9) | |
H25 | 0.4537 | 0.2349 | 0.8259 | 0.059* | |
C26 | 0.46226 (18) | 0.2091 (11) | 0.71935 (19) | 0.0486 (9) | |
H26 | 0.5073 | 0.1026 | 0.7221 | 0.058* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C11 | 0.0398 (17) | 0.043 (2) | 0.0425 (17) | −0.0016 (16) | −0.0010 (14) | 0.0027 (16) |
C111 | 0.0438 (18) | 0.053 (2) | 0.0416 (18) | −0.0009 (18) | −0.0033 (14) | 0.0053 (18) |
O1A | 0.0442 (14) | 0.083 (2) | 0.0485 (14) | 0.0039 (15) | −0.0020 (11) | −0.0119 (15) |
O1B | 0.0376 (13) | 0.084 (2) | 0.0575 (15) | 0.0023 (15) | −0.0035 (11) | −0.0155 (16) |
C12 | 0.0441 (18) | 0.056 (2) | 0.0436 (18) | 0.0001 (18) | −0.0033 (15) | −0.0013 (18) |
C13 | 0.0399 (18) | 0.064 (3) | 0.052 (2) | −0.0063 (19) | −0.0063 (15) | 0.008 (2) |
C14 | 0.0442 (19) | 0.054 (2) | 0.055 (2) | 0.0023 (18) | 0.0065 (16) | 0.0085 (19) |
N14 | 0.0447 (17) | 0.099 (3) | 0.070 (2) | 0.004 (2) | 0.0087 (15) | −0.004 (2) |
C15 | 0.051 (2) | 0.051 (2) | 0.0463 (19) | 0.0001 (19) | 0.0023 (15) | −0.0018 (18) |
C16 | 0.0418 (18) | 0.047 (2) | 0.0481 (19) | −0.0047 (17) | −0.0021 (14) | 0.0004 (17) |
C21 | 0.0385 (17) | 0.040 (2) | 0.0444 (18) | −0.0026 (16) | −0.0027 (14) | −0.0009 (16) |
C211 | 0.0405 (18) | 0.056 (2) | 0.0454 (19) | −0.0059 (18) | −0.0024 (14) | 0.0014 (18) |
O2A | 0.0458 (14) | 0.091 (2) | 0.0515 (15) | 0.0130 (15) | 0.0013 (11) | −0.0020 (15) |
O2B | 0.0556 (15) | 0.086 (2) | 0.0433 (14) | 0.0146 (16) | −0.0040 (11) | −0.0023 (16) |
C22 | 0.0450 (18) | 0.049 (2) | 0.0427 (18) | −0.0037 (17) | −0.0057 (14) | 0.0042 (17) |
C23 | 0.0390 (17) | 0.052 (2) | 0.052 (2) | 0.0017 (17) | −0.0017 (15) | 0.0020 (18) |
C24 | 0.0453 (18) | 0.047 (2) | 0.0469 (19) | −0.0048 (17) | −0.0004 (15) | 0.0005 (17) |
N24 | 0.0549 (19) | 0.088 (3) | 0.0476 (18) | 0.010 (2) | 0.0024 (14) | −0.0006 (19) |
C25 | 0.0477 (19) | 0.054 (2) | 0.0437 (18) | −0.0035 (18) | −0.0081 (15) | 0.0022 (18) |
C26 | 0.0383 (17) | 0.055 (2) | 0.051 (2) | 0.0011 (17) | −0.0059 (15) | 0.0037 (19) |
C11—C16 | 1.393 (5) | C21—C26 | 1.391 (5) |
C11—C12 | 1.399 (5) | C21—C22 | 1.400 (5) |
C11—C111 | 1.461 (5) | C21—C211 | 1.454 (5) |
C111—O1A | 1.230 (4) | C211—O2A | 1.254 (4) |
C111—O1B | 1.318 (4) | C211—O2B | 1.298 (4) |
O1B—H1B | 0.8200 | O2B—H2B | 0.8200 |
C12—C13 | 1.365 (5) | C22—C23 | 1.371 (5) |
C12—H12 | 0.9300 | C22—H22 | 0.9300 |
C13—C14 | 1.389 (6) | C23—C24 | 1.400 (5) |
C13—H13 | 0.9300 | C23—H23 | 0.9300 |
C14—N14 | 1.372 (5) | C24—N24 | 1.372 (5) |
C14—C15 | 1.409 (5) | C24—C25 | 1.399 (5) |
N14—H14A | 0.8600 | N24—H24A | 0.8600 |
N14—H14B | 0.8600 | N24—H24B | 0.8600 |
C15—C16 | 1.378 (5) | C25—C26 | 1.371 (5) |
C15—H15 | 0.9300 | C25—H25 | 0.9300 |
C16—H16 | 0.9300 | C26—H26 | 0.9300 |
C16—C11—C12 | 118.0 (3) | C26—C21—C22 | 117.8 (3) |
C16—C11—C111 | 121.9 (3) | C26—C21—C211 | 120.8 (3) |
C12—C11—C111 | 120.1 (3) | C22—C21—C211 | 121.4 (3) |
O1A—C111—O1B | 121.4 (3) | O2A—C211—O2B | 121.6 (3) |
O1A—C111—C11 | 123.6 (3) | O2A—C211—C21 | 122.0 (3) |
O1B—C111—C11 | 115.0 (3) | O2B—C211—C21 | 116.4 (3) |
C111—O1B—H1B | 109.5 | C211—O2B—H2B | 109.5 |
C13—C12—C11 | 121.4 (3) | C23—C22—C21 | 121.1 (3) |
C13—C12—H12 | 119.3 | C23—C22—H22 | 119.4 |
C11—C12—H12 | 119.3 | C21—C22—H22 | 119.4 |
C12—C13—C14 | 121.1 (3) | C22—C23—C24 | 120.5 (3) |
C12—C13—H13 | 119.4 | C22—C23—H23 | 119.8 |
C14—C13—H13 | 119.4 | C24—C23—H23 | 119.8 |
N14—C14—C13 | 122.0 (4) | N24—C24—C25 | 121.3 (3) |
N14—C14—C15 | 120.0 (4) | N24—C24—C23 | 119.9 (3) |
C13—C14—C15 | 118.0 (3) | C25—C24—C23 | 118.7 (3) |
C14—N14—H14A | 120.0 | C24—N24—H24A | 120.0 |
C14—N14—H14B | 120.0 | C24—N24—H24B | 120.0 |
H14A—N14—H14B | 120.0 | H24A—N24—H24B | 120.0 |
C16—C15—C14 | 120.7 (4) | C26—C25—C24 | 120.0 (3) |
C16—C15—H15 | 119.6 | C26—C25—H25 | 120.0 |
C14—C15—H15 | 119.6 | C24—C25—H25 | 120.0 |
C15—C16—C11 | 120.8 (3) | C25—C26—C21 | 121.8 (3) |
C15—C16—H16 | 119.6 | C25—C26—H26 | 119.1 |
C11—C16—H16 | 119.6 | C21—C26—H26 | 119.1 |
C16—C11—C111—O1A | 177.7 (4) | C26—C21—C211—O2A | −0.8 (6) |
C12—C11—C111—O1A | −0.9 (6) | C22—C21—C211—O2A | 179.4 (4) |
C16—C11—C111—O1B | −1.3 (5) | C26—C21—C211—O2B | 176.8 (4) |
C12—C11—C111—O1B | −179.9 (4) | C22—C21—C211—O2B | −3.0 (6) |
C16—C11—C12—C13 | −1.0 (6) | C26—C21—C22—C23 | −1.5 (6) |
C111—C11—C12—C13 | 177.6 (4) | C211—C21—C22—C23 | 178.3 (4) |
C11—C12—C13—C14 | 0.2 (6) | C21—C22—C23—C24 | 0.2 (6) |
C12—C13—C14—N14 | −177.7 (4) | C22—C23—C24—N24 | −177.9 (4) |
C12—C13—C14—C15 | 0.5 (6) | C22—C23—C24—C25 | 0.2 (6) |
N14—C14—C15—C16 | 177.8 (4) | N24—C24—C25—C26 | 178.9 (4) |
C13—C14—C15—C16 | −0.5 (6) | C23—C24—C25—C26 | 0.8 (6) |
C14—C15—C16—C11 | −0.3 (6) | C24—C25—C26—C21 | −2.3 (6) |
C12—C11—C16—C15 | 1.0 (6) | C22—C21—C26—C25 | 2.6 (6) |
C111—C11—C16—C15 | −177.6 (4) | C211—C21—C26—C25 | −177.2 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1B···O1Ai | 0.82 | 1.83 | 2.650 (4) | 172 |
N14—H14A···O2A | 0.86 | 2.57 | 3.369 (5) | 154 |
O2B—H2B···O2Aii | 0.82 | 1.81 | 2.616 (4) | 166 |
N24—H24A···O1Aiii | 0.86 | 2.13 | 2.969 (4) | 165 |
Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) x−1/2, −y+1/2, z+1/2. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C7H8NO2+·C4H5O6− | C7H7NO2 |
Mr | 287.22 | 137.14 |
Crystal system, space group | Monoclinic, P21 | Monoclinic, P21/n |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 6.021 (4), 28.789 (11), 7.426 (5) | 18.5712 (8), 3.8431 (3), 18.6321 (9) |
β (°) | 107.89 (4) | 93.670 (11) |
V (Å3) | 1225.0 (12) | 1327.06 (13) |
Z | 4 | 8 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.14 | 0.10 |
Crystal size (mm) | 0.22 × 0.15 × 0.13 | 0.23 × 0.14 × 0.12 |
Data collection | ||
Diffractometer | Nonius MACH-3 sealed-tube diffractometer | Nonius MACH-3 sealed-tube diffractometer |
Absorption correction | ψ scan (North et al., 1968) | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.930, 0.981 | 0.945, 0.985 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3083, 2721, 2127 | 3787, 2845, 1746 |
Rint | 0.091 | 0.038 |
(sin θ/λ)max (Å−1) | 0.639 | 0.638 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.106, 1.08 | 0.066, 0.227, 1.17 |
No. of reflections | 2721 | 2845 |
No. of parameters | 371 | 183 |
No. of restraints | 1 | 0 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.29, −0.29 | 0.37, −0.27 |
Absolute structure | Flack H D (1983), Acta Cryst. A39, 876-881 | ? |
Absolute structure parameter | 10 (10) | ? |
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXTL/PC (Bruker, 2000), SHELXTL/PC, ORTEP-3 (Farrugia, 1997), Mercury (Version 1.4.1; Macrae et al., 2006 ) and PLATON (Spek, 2003).
C111—O1A | 1.196 (7) | C1C—O2C | 1.261 (5) |
C111—O1B | 1.318 (7) | C4C—O5C | 1.202 (5) |
C14—N14 | 1.464 (6) | C4C—O6C | 1.306 (5) |
C211—O2A | 1.205 (10) | C1D—O1D | 1.232 (5) |
C211—O2B | 1.344 (10) | C1D—O2D | 1.276 (5) |
C24—N24 | 1.476 (5) | C4D—O5D | 1.219 (5) |
C1C—O1C | 1.236 (5) | C4D—O6D | 1.301 (5) |
C12—C11—C111—O1B | 1.3 (7) | C22—C21—C211—O2B | 6.2 (8) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1B···O5Ci | 0.82 | 2.20 | 2.901 (6) | 143 |
O1B—H1B···O4Ci | 0.82 | 2.25 | 2.949 (6) | 143 |
N14—H14A···O2Dii | 0.89 | 1.91 | 2.790 (5) | 170 |
N14—H14B···O3Di | 0.89 | 1.93 | 2.788 (4) | 163 |
N14—H14C···O1Diii | 0.89 | 1.81 | 2.687 (4) | 168 |
O2B—H2B···O5D | 0.82 | 2.20 | 2.914 (6) | 145 |
N24—H24A···O2Civ | 0.89 | 2.63 | 3.490 (5) | 164 |
N24—H24C···O3C | 0.89 | 1.92 | 2.787 (5) | 166 |
N24—H24B···O1Cv | 0.89 | 1.89 | 2.737 (5) | 159 |
O3C—H3C···O1A | 0.82 | 2.11 | 2.841 (5) | 149 |
O4C—H4C···O1Cvi | 0.82 | 2.12 | 2.877 (5) | 154 |
O6C—H6C···O2Cv | 0.82 | 1.80 | 2.608 (4) | 171 |
O3D—H3D···O5Dvi | 0.82 | 2.11 | 2.715 (4) | 131 |
O4D—H4D···O2Cvii | 0.82 | 2.06 | 2.782 (4) | 146 |
O6D—H6D···O2Dii | 0.82 | 1.70 | 2.515 (4) | 175 |
Symmetry codes: (i) x+1, y, z; (ii) x, y, z−1; (iii) x+1, y, z−1; (iv) x+1, y, z+1; (v) x, y, z+1; (vi) x−1, y, z; (vii) −x, y−1/2, −z. |
C111—O1A | 1.230 (4) | C211—O2A | 1.254 (4) |
C111—O1B | 1.318 (4) | C211—O2B | 1.298 (4) |
C14—N14 | 1.372 (5) | C24—N24 | 1.372 (5) |
C16—C11—C111—O1B | −1.3 (5) | C22—C21—C211—O2B | −3.0 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1B···O1Ai | 0.82 | 1.83 | 2.650 (4) | 172 |
N14—H14A···O2A | 0.86 | 2.57 | 3.369 (5) | 154 |
O2B—H2B···O2Aii | 0.82 | 1.81 | 2.616 (4) | 166 |
N24—H24A···O1Aiii | 0.86 | 2.13 | 2.969 (4) | 165 |
Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) x−1/2, −y+1/2, z+1/2. |
4-Aminobenzoic acid (PABA) is an essential biological molecule, acting as a bacterial cofactor involved in the synthesis of folic acid (Robinson, 1966). PABA is also a starting material in the synthesis of target esters, salts, folic acid, azo dyes and many other organic compounds. It is used in medicine for preparing local anaesthetics and ointments. It helps to protect the skin from sunburn and cancer. Fibrotic skin disorders can also be treated with PABA (Osgood et al., 1982). As PABA can donate and also accept hydrogen, it has proved to be a versatile reagent for structure extension by linear hydrogen-bonding associations, through both the carboxylic acid and amine functional groups. The crystallographic study of PABA compounds was started by Pant (1965), who studied the crystal structure of 3,5-dibromo-4-aminobenzoic acid. Later, Lai & Marsh (1967) studied this structure extensively using photographic/visual data. In fact, PABA exists in two different polymorphs, the α- and β-forms. The β-form has recently been reinvestigated by Gracin & Fischer (2005). The absence of diffractometer data for the α-form of this compound, (II), stimulated us to carry out the redetermination of this structure.
PABA complexes such as 4-carboxyphenylammonium nitrate and perchlorate monohydrate, and bis(4-carboxyphenylammonium) sulfate (Athimoolam & Natarajan, 2006), have already been studied in our laboratory to understand their structure–extension properties via their linear and cyclic hydrogen-bonding associations. Also, the structures of 4-carboxyanilinium dihydrogenmonoarsenate monohydrate (Tordjman et al., 1988), 2,4,6-trinitrobenzoic acid 4-aminobenzoic acid monohydrate (Lynch et al., 1992), bis(4-aminobenzoic acid-N)dichlorocadmium(II) (Le Fur & Masse, 1996) and bis(4-aminobenzoic acid-N)silver(I) nitrate (Wang et al., 2004) have been reported earlier. Hu and co-workers have already reported the structure of PABA with tartaric acid in hydrated form (Hu et al., 2002). Here, we present the crystal structure of an anhydrous form of PABA–tartaric acid complex, (I).
The asymmetric parts of (I) and (II) consist of two crystallographically independent PABA molecules oriented with angles of 1.7 (3) and 38.4 (1)°, respectively, between themselves (Figs. 1 and 2). Protonation on the N site of the PABA cation and deprotonation on the –COOH group of the anion in (I) are evident from the C—N and C—O bond distances (Table 1). Twisting out of the carboxyl plane from the aromatic ring plane is a common feature found in PABA complexes [in 27 complexes of PABA adducts in the Cambridge Structural Database (CSD; Version 5.28; Allen, 2002)]. The angles of this twisting are 1.1 (2) and 6.8 (2)° in (I), and 3.0 (4) and 4.3 (4)° in (II).
As discussed above, the structure–extension property of PABA via hydrogen bonds is recognized as a possible tool for promoting co-crystallization, with the aim of designing noncentrosymmetric organic materials (Etter & Frankenbach, 1989). However, among the many reported adducts of PABA, only a few have been found to crystallize in noncentrosymmetric space groups (only four out of 27 complexes of PABA adducts in the CSD), and complex (I) is another such case.
In (II), the bond distances and angles (Table 3) are in agreement with the reported values (Lai & Marsh, 1967). Even though the molecular structure of (II) is already known, the aim of the present work is to elucidate the structure with precision, and to study the crystal packing of the molecule via hydrogen bonds and their visualization through graph-set notation (Etter et al., 1990; Bernstein et al., 1995).
As discussed in our previous publication (Athimoolam & Natarajan, 2006), the head-to-tail hydrogen-bonding association (head = NH2/NH3+; tail = COOH) and carboxylic acid group dimerization are characteristic interactions found between the PABA residues in many PABA complexes in the CSD. In (I), these interactions are observed through the anions because of dominant hydrogen-bonding sites in the tartrates, and correspondingly the crystal packing can be described by an intricate three-dimensional hydrogen-bonding network (Fig. 3). In (II), head-to-tail interaction is seen through a discrete D11(2) motif via an N14···O2A hydrogen bond and carboxylic acid group dimerization is observed through centrosymmetrically related R22(8) motifs (in both residues in the asymmetric unit) around the inversion centres of the unit cell. Hence, in short, the crystal packing of (II) can be readily described with three primary motifs [two R22(8) and one D11(2)] and two discrete secondary motifs [D23(7) and D33(19)] (Table 3; Fig 4).
Alternate hydrophobic and hydrophilic layers are observed in (I) as a result of the column-like arrangement of the aromatic rings of the cations and the anions. Each tartrate anion forms a self-association of S(5) motif via O—H···O intramolecular bonds. Even though tartrates form extensive intermolecular hydrogen bonds between themselves and with PABA, it is more sensible to discuss the characteristic hydrogen-bonding features than all the intricate hydrogen bonds (Table 4). The NH3+ group of the cationic residues of (I) and (II) form two sets of C22(7) chain motifs through the tartrate anions via N—H···O hydrogen bonds. Also, the tartrate anions are themselves connected via O—H···O bonds of another C22(7) chain motif. One of the two C22(7) chain motifs of the N—H···O hydrogen bonds and the O—H···O C22(7) chain motif lead to a ring of R33(12) motif in both cationic residues (Fig. 5). Fig. 6 shows the aggregation of the tartrates through O—H···O chain motifs of C11(6) and C11(7) running along the a and c axes of the unit cell, respectively. These chain motifs form a closed secondary R44(22) ring motif in both anions.