Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805038791/su6250sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536805038791/su6250Isup2.hkl |
CCDC reference: 281106
Crystals of the title compound, (I), were grown from a mixture of L-histidine and trifluoroacetic acid, in the stoichiometric ratio of 1:1, by slow evaporation at room temperature.
The tertiary CH and secondary CH2 H atoms of the histidinium cations were included in calculated positions and treated as riding atoms, with C—H = 0.97–0.98 Å and Uiso(H) = 1.2Ueq(parent C atom). All other H atoms were located in difference Fourier maps and refined freely [N—H = 0.75 (7)–1.00 (6) Å and C—H = 0.847 (11)–0.85 (6) Å].
Data collection: CAD-4 Software (Enraf–Nonius, 1997); cell refinement: CAD-4 Software; data reduction: XCAD4 in WinGX (Farrugia, 1999); program(s) used to solve structure: SIR92 (Burla et al., 1989); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-32 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.
C6H10N3O2+·C2F3O2− | Z = 2 |
Mr = 269.19 | F(000) = 276 |
Triclinic, P1 | Dx = 1.649 Mg m−3 |
Hall symbol: P 1 | Cu Kα radiation, λ = 1.54180 Å |
a = 5.1724 (6) Å | Cell parameters from 25 reflections |
b = 8.8183 (12) Å | θ = 20–30° |
c = 12.481 (3) Å | µ = 1.46 mm−1 |
α = 96.193 (17)° | T = 293 K |
β = 99.853 (13)° | Block, brown |
γ = 102.106 (13)° | 0.2 × 0.2 × 0.1 mm |
V = 542.26 (16) Å3 |
Enraf–Nonius CAD-4 diffractometer | 2053 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.001 |
Graphite monochromator | θmax = 68.0°, θmin = 3.6° |
ω/2θ scans | h = −6→6 |
Absorption correction: ψ scan (North et al., 1968) | k = −10→10 |
Tmin = 0.790, Tmax = 0.864 | l = −14→15 |
2064 measured reflections | 2 standard reflections every 60 min |
2063 independent reflections | intensity decay: none |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.038 | w = 1/[σ2(Fo2) + (0.0775P)2 + 0.22P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.108 | (Δ/σ)max < 0.001 |
S = 1.01 | Δρmax = 0.42 e Å−3 |
2063 reflections | Δρmin = −0.32 e Å−3 |
382 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
13 restraints | Extinction coefficient: 0.055 (4) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 92 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.04 (2) |
C6H10N3O2+·C2F3O2− | γ = 102.106 (13)° |
Mr = 269.19 | V = 542.26 (16) Å3 |
Triclinic, P1 | Z = 2 |
a = 5.1724 (6) Å | Cu Kα radiation |
b = 8.8183 (12) Å | µ = 1.46 mm−1 |
c = 12.481 (3) Å | T = 293 K |
α = 96.193 (17)° | 0.2 × 0.2 × 0.1 mm |
β = 99.853 (13)° |
Enraf–Nonius CAD-4 diffractometer | 2053 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.001 |
Tmin = 0.790, Tmax = 0.864 | 2 standard reflections every 60 min |
2064 measured reflections | intensity decay: none |
2063 independent reflections |
R[F2 > 2σ(F2)] = 0.038 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.108 | Δρmax = 0.42 e Å−3 |
S = 1.01 | Δρmin = −0.32 e Å−3 |
2063 reflections | Absolute structure: Flack (1983), 92 Friedel pairs |
382 parameters | Absolute structure parameter: 0.04 (2) |
13 restraints |
Experimental. psi-scan absorption correction: North et al. (1968) Number of psi-scan sets used was 4 Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied. |
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 | ||
C1 | 0.8441 (8) | 0.2285 (5) | −0.2787 (4) | 0.0460 (9) | |
C2 | 1.1001 (11) | 0.1445 (4) | −0.1522 (4) | 0.0524 (11) | |
C3 | 1.0878 (7) | 0.3327 (4) | −0.2536 (3) | 0.0331 (7) | |
C4 | 1.1832 (8) | 0.4790 (4) | −0.2996 (3) | 0.0379 (8) | |
H4A | 1.0329 | 0.4972 | −0.3507 | 0.045* | |
H4B | 1.3199 | 0.4626 | −0.3411 | 0.045* | |
C5 | 1.3010 (6) | 0.6273 (3) | −0.2138 (3) | 0.0272 (6) | |
H5A | 1.4381 | 0.6052 | −0.1568 | 0.033* | |
C6 | 1.4345 (6) | 0.7612 (4) | −0.2695 (3) | 0.0289 (6) | |
C7 | 1.0914 (8) | 0.4240 (4) | 0.0842 (3) | 0.0412 (8) | |
C8 | 0.8156 (7) | 0.3716 (4) | 0.0061 (3) | 0.0369 (7) | |
C9 | 0.9856 (9) | 0.9431 (6) | 0.5115 (4) | 0.0523 (10) | |
C10 | 0.6365 (9) | 0.7805 (5) | 0.4043 (4) | 0.0467 (9) | |
C11 | 0.8024 (8) | 0.8432 (4) | 0.3391 (3) | 0.0402 (8) | |
C12 | 0.7871 (10) | 0.8073 (4) | 0.2184 (3) | 0.0462 (9) | |
H12A | 0.6122 | 0.7387 | 0.1858 | 0.055* | |
H12B | 0.9228 | 0.7497 | 0.2067 | 0.055* | |
C13 | 0.8268 (6) | 0.9487 (4) | 0.1569 (3) | 0.0303 (6) | |
H13 | 0.9902 | 1.0259 | 0.1958 | 0.036* | |
C14 | 0.8615 (7) | 0.8969 (4) | 0.0390 (3) | 0.0345 (7) | |
C15 | 0.7585 (11) | 1.3651 (5) | 0.3768 (5) | 0.0661 (14) | |
C16 | 0.5426 (10) | 1.2437 (6) | 0.4187 (4) | 0.0568 (12) | |
N1 | 0.8581 (8) | 0.1136 (4) | −0.2154 (4) | 0.0566 (10) | |
N2 | 1.2439 (7) | 0.2766 (3) | −0.1733 (3) | 0.0378 (6) | |
N3 | 1.0882 (6) | 0.6752 (3) | −0.1614 (2) | 0.0313 (6) | |
N4 | 1.0179 (8) | 0.9436 (5) | 0.4079 (3) | 0.0476 (8) | |
N5 | 0.7568 (8) | 0.8435 (5) | 0.5115 (3) | 0.0503 (9) | |
N6 | 0.5937 (6) | 1.0230 (3) | 0.1517 (2) | 0.0339 (6) | |
O1 | 1.6392 (5) | 0.7386 (3) | −0.3067 (2) | 0.0394 (6) | |
O2 | 1.3431 (5) | 0.8785 (3) | −0.2730 (2) | 0.0411 (6) | |
O3 | 0.6610 (6) | 0.2548 (4) | 0.0239 (3) | 0.0614 (9) | |
O4 | 0.7704 (5) | 0.4498 (3) | −0.0692 (2) | 0.0475 (7) | |
O5 | 1.0912 (5) | 0.8762 (4) | 0.0320 (2) | 0.0484 (7) | |
O6 | 0.6702 (6) | 0.8824 (4) | −0.0369 (2) | 0.0556 (8) | |
O7 | 0.4911 (11) | 1.2820 (8) | 0.5071 (3) | 0.1013 (17) | |
O8 | 0.4445 (7) | 1.1223 (4) | 0.3506 (3) | 0.0530 (7) | |
F1 | 1.0849 (7) | 0.5183 (4) | 0.1742 (2) | 0.0693 (8) | |
F2 | 1.2823 (5) | 0.5032 (3) | 0.0376 (2) | 0.0600 (7) | |
F3 | 1.1793 (6) | 0.3021 (3) | 0.1180 (3) | 0.0637 (7) | |
F4 | 0.9327 (8) | 1.2950 (5) | 0.3359 (5) | 0.1025 (14) | |
F5 | 0.6422 (8) | 1.4234 (5) | 0.2938 (3) | 0.0916 (11) | |
F6 | 0.8936 (13) | 1.4847 (5) | 0.4500 (4) | 0.130 (2) | |
H1 | 0.710 (12) | 0.017 (7) | −0.223 (5) | 0.058 (14)* | |
H1' | 0.694 (9) | 0.218 (10) | −0.323 (6) | 0.11 (3)* | |
H2 | 1.407 (11) | 0.327 (6) | −0.141 (4) | 0.044 (12)* | |
H2' | 1.183 (9) | 0.101 (6) | −0.104 (3) | 0.050 (13)* | |
H3A | 0.996 (8) | 0.596 (4) | −0.128 (3) | 0.036 (10)* | |
H3B | 0.970 (9) | 0.714 (6) | −0.210 (4) | 0.063 (15)* | |
H3C | 1.163 (10) | 0.758 (4) | −0.104 (3) | 0.059 (14)* | |
H4 | 1.141 (12) | 0.986 (7) | 0.389 (5) | 0.057 (16)* | |
H5 | 0.727 (11) | 0.816 (6) | 0.567 (5) | 0.055 (14)* | |
H6A | 0.440 (5) | 0.965 (4) | 0.103 (3) | 0.033 (10)* | |
H6B | 0.614 (9) | 1.110 (3) | 0.115 (3) | 0.037 (10)* | |
H6C | 0.578 (15) | 1.067 (8) | 0.221 (3) | 0.09 (2)* | |
H9' | 1.104 (10) | 0.982 (7) | 0.569 (3) | 0.075 (18)* | |
H10' | 0.489 (6) | 0.713 (5) | 0.377 (4) | 0.054 (14)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.040 (2) | 0.0367 (18) | 0.052 (2) | −0.0070 (15) | 0.0130 (18) | −0.0066 (16) |
C2 | 0.084 (3) | 0.0276 (17) | 0.055 (3) | 0.0163 (19) | 0.029 (2) | 0.0160 (17) |
C3 | 0.0343 (16) | 0.0264 (14) | 0.0362 (17) | 0.0007 (12) | 0.0120 (13) | −0.0009 (13) |
C4 | 0.050 (2) | 0.0297 (16) | 0.0325 (17) | 0.0021 (14) | 0.0119 (15) | 0.0039 (13) |
C5 | 0.0297 (14) | 0.0246 (14) | 0.0265 (14) | 0.0023 (11) | 0.0062 (11) | 0.0082 (11) |
C6 | 0.0275 (14) | 0.0292 (14) | 0.0252 (14) | −0.0027 (11) | 0.0011 (11) | 0.0088 (11) |
C7 | 0.0461 (19) | 0.0408 (18) | 0.042 (2) | 0.0143 (15) | 0.0142 (16) | 0.0109 (16) |
C8 | 0.0408 (18) | 0.0362 (17) | 0.0415 (19) | 0.0124 (14) | 0.0183 (15) | 0.0174 (15) |
C9 | 0.057 (2) | 0.074 (3) | 0.0308 (19) | 0.018 (2) | 0.0151 (18) | 0.0149 (19) |
C10 | 0.059 (2) | 0.044 (2) | 0.045 (2) | 0.0155 (18) | 0.0230 (19) | 0.0195 (17) |
C11 | 0.059 (2) | 0.0395 (17) | 0.0339 (18) | 0.0221 (16) | 0.0195 (16) | 0.0208 (15) |
C12 | 0.076 (3) | 0.0374 (18) | 0.0330 (18) | 0.0198 (18) | 0.0196 (18) | 0.0114 (15) |
C13 | 0.0346 (15) | 0.0320 (15) | 0.0250 (15) | 0.0060 (12) | 0.0091 (12) | 0.0054 (12) |
C14 | 0.0380 (17) | 0.0360 (16) | 0.0265 (16) | 0.0012 (13) | 0.0086 (13) | 0.0025 (12) |
C15 | 0.072 (3) | 0.045 (2) | 0.067 (3) | 0.012 (2) | −0.017 (3) | −0.001 (2) |
C16 | 0.067 (3) | 0.075 (3) | 0.036 (2) | 0.039 (2) | 0.0035 (19) | 0.002 (2) |
N1 | 0.064 (2) | 0.0285 (15) | 0.072 (3) | −0.0132 (15) | 0.032 (2) | 0.0000 (16) |
N2 | 0.0411 (16) | 0.0304 (13) | 0.0410 (16) | 0.0032 (12) | 0.0113 (13) | 0.0069 (12) |
N3 | 0.0371 (14) | 0.0268 (12) | 0.0321 (14) | 0.0051 (10) | 0.0120 (11) | 0.0101 (11) |
N4 | 0.054 (2) | 0.064 (2) | 0.0331 (17) | 0.0189 (17) | 0.0187 (15) | 0.0212 (15) |
N5 | 0.068 (2) | 0.064 (2) | 0.0354 (17) | 0.0283 (18) | 0.0267 (16) | 0.0268 (16) |
N6 | 0.0382 (14) | 0.0367 (14) | 0.0284 (14) | 0.0082 (12) | 0.0094 (11) | 0.0079 (11) |
O1 | 0.0350 (12) | 0.0497 (14) | 0.0389 (13) | 0.0068 (10) | 0.0166 (10) | 0.0215 (11) |
O2 | 0.0462 (13) | 0.0314 (11) | 0.0503 (14) | 0.0079 (10) | 0.0146 (11) | 0.0208 (11) |
O3 | 0.0518 (16) | 0.0565 (18) | 0.080 (2) | 0.0037 (13) | 0.0146 (16) | 0.0421 (17) |
O4 | 0.0412 (13) | 0.0536 (15) | 0.0528 (16) | 0.0075 (11) | 0.0136 (12) | 0.0299 (13) |
O5 | 0.0405 (13) | 0.0647 (17) | 0.0360 (14) | 0.0072 (12) | 0.0134 (11) | −0.0089 (12) |
O6 | 0.0502 (16) | 0.083 (2) | 0.0282 (13) | 0.0158 (15) | 0.0020 (12) | −0.0051 (13) |
O7 | 0.115 (3) | 0.161 (5) | 0.0402 (19) | 0.070 (3) | 0.017 (2) | −0.010 (2) |
O8 | 0.0631 (17) | 0.0536 (16) | 0.0461 (15) | 0.0097 (14) | 0.0271 (14) | 0.0060 (13) |
F1 | 0.0872 (19) | 0.0697 (17) | 0.0504 (15) | 0.0236 (15) | 0.0151 (14) | −0.0059 (13) |
F2 | 0.0432 (13) | 0.0721 (17) | 0.0599 (15) | −0.0005 (11) | 0.0103 (11) | 0.0160 (13) |
F3 | 0.0614 (15) | 0.0599 (15) | 0.0738 (18) | 0.0265 (12) | 0.0020 (13) | 0.0210 (13) |
F4 | 0.078 (2) | 0.079 (2) | 0.160 (4) | 0.0144 (18) | 0.047 (3) | 0.031 (3) |
F5 | 0.107 (3) | 0.082 (2) | 0.070 (2) | 0.0078 (19) | −0.0181 (19) | 0.0230 (17) |
F6 | 0.189 (5) | 0.072 (2) | 0.079 (3) | −0.006 (3) | −0.047 (3) | −0.0087 (19) |
C1—N1 | 1.357 (6) | C10—H10' | 0.85 (5) |
C1—C3 | 1.360 (5) | C11—N4 | 1.363 (6) |
C1—H1' | 0.85 (6) | C11—C12 | 1.491 (5) |
C2—N1 | 1.317 (7) | C12—C13 | 1.530 (5) |
C2—N2 | 1.323 (5) | C12—H12A | 0.9700 |
C2—H2' | 0.847 (11) | C12—H12B | 0.9700 |
C3—N2 | 1.378 (5) | C13—N6 | 1.483 (4) |
C3—C4 | 1.492 (5) | C13—C14 | 1.544 (4) |
C4—C5 | 1.539 (4) | C13—H13 | 0.9800 |
C4—H4A | 0.9700 | C14—O6 | 1.222 (5) |
C4—H4B | 0.9700 | C14—O5 | 1.255 (5) |
C5—N3 | 1.483 (4) | C15—F6 | 1.303 (6) |
C5—C6 | 1.535 (4) | C15—F5 | 1.316 (6) |
C5—H5A | 0.9800 | C15—F4 | 1.333 (7) |
C6—O2 | 1.226 (4) | C15—C16 | 1.577 (8) |
C6—O1 | 1.270 (4) | C16—O7 | 1.208 (6) |
C7—F3 | 1.333 (5) | C16—O8 | 1.247 (6) |
C7—F1 | 1.333 (5) | N1—H1 | 1.00 (6) |
C7—F2 | 1.340 (5) | N2—H2 | 0.87 (5) |
C7—C8 | 1.533 (5) | N3—H3A | 0.93 (5) |
C8—O3 | 1.231 (5) | N3—H3B | 0.93 (5) |
C8—O4 | 1.243 (5) | N3—H3C | 0.93 (5) |
C9—N5 | 1.318 (7) | N4—H4 | 0.75 (7) |
C9—N4 | 1.332 (6) | N5—H5 | 0.79 (6) |
C9—H9' | 0.85 (5) | N6—H6A | 0.93 (5) |
C10—C11 | 1.357 (6) | N6—H6B | 0.93 (5) |
C10—N5 | 1.377 (6) | N6—H6C | 0.93 (5) |
N1—C1—C3 | 107.6 (4) | C11—C12—H12B | 108.3 |
N1—C1—H1' | 115 (6) | C13—C12—H12B | 108.3 |
C3—C1—H1' | 137 (6) | H12A—C12—H12B | 107.4 |
N1—C2—N2 | 108.7 (4) | N6—C13—C12 | 111.0 (3) |
N1—C2—H2' | 136 (4) | N6—C13—C14 | 109.4 (3) |
N2—C2—H2' | 115 (4) | C12—C13—C14 | 109.9 (3) |
C1—C3—N2 | 105.8 (3) | N6—C13—H13 | 108.8 |
C1—C3—C4 | 129.9 (4) | C12—C13—H13 | 108.8 |
N2—C3—C4 | 124.3 (3) | C14—C13—H13 | 108.8 |
C3—C4—C5 | 115.1 (3) | O6—C14—O5 | 126.7 (3) |
C3—C4—H4A | 108.5 | O6—C14—C13 | 118.4 (3) |
C5—C4—H4A | 108.5 | O5—C14—C13 | 114.9 (3) |
C3—C4—H4B | 108.5 | F6—C15—F5 | 106.3 (4) |
C5—C4—H4B | 108.5 | F6—C15—F4 | 108.7 (6) |
H4A—C4—H4B | 107.5 | F5—C15—F4 | 104.6 (5) |
N3—C5—C6 | 109.6 (2) | F6—C15—C16 | 115.0 (5) |
N3—C5—C4 | 111.1 (3) | F5—C15—C16 | 110.5 (4) |
C6—C5—C4 | 109.4 (3) | F4—C15—C16 | 111.1 (4) |
N3—C5—H5A | 108.9 | O7—C16—O8 | 130.2 (6) |
C6—C5—H5A | 108.9 | O7—C16—C15 | 117.4 (5) |
C4—C5—H5A | 108.9 | O8—C16—C15 | 112.4 (4) |
O2—C6—O1 | 125.9 (3) | C2—N1—C1 | 109.0 (3) |
O2—C6—C5 | 119.4 (3) | C2—N1—H1 | 127 (3) |
O1—C6—C5 | 114.6 (3) | C1—N1—H1 | 124 (3) |
F3—C7—F1 | 106.8 (3) | C2—N2—C3 | 108.9 (3) |
F3—C7—F2 | 106.8 (3) | C2—N2—H2 | 128 (3) |
F1—C7—F2 | 106.2 (3) | C3—N2—H2 | 123 (3) |
F3—C7—C8 | 111.7 (3) | C5—N3—H3A | 113 (3) |
F1—C7—C8 | 112.3 (3) | C5—N3—H3B | 112 (4) |
F2—C7—C8 | 112.7 (3) | H3A—N3—H3B | 112 (4) |
O3—C8—O4 | 126.4 (4) | C5—N3—H3C | 111 (3) |
O3—C8—C7 | 116.4 (3) | H3A—N3—H3C | 104 (4) |
O4—C8—C7 | 117.2 (3) | H3B—N3—H3C | 105 (5) |
N5—C9—N4 | 108.4 (4) | C9—N4—C11 | 109.5 (4) |
N5—C9—H9' | 123 (5) | C9—N4—H4 | 126 (5) |
N4—C9—H9' | 127 (5) | C11—N4—H4 | 124 (4) |
C11—C10—N5 | 107.4 (4) | C9—N5—C10 | 108.4 (3) |
C11—C10—H10' | 121 (4) | C9—N5—H5 | 120 (4) |
N5—C10—H10' | 132 (4) | C10—N5—H5 | 130 (4) |
C10—C11—N4 | 106.2 (4) | C13—N6—H6A | 113 (3) |
C10—C11—C12 | 130.8 (4) | C13—N6—H6B | 113 (3) |
N4—C11—C12 | 122.8 (4) | H6A—N6—H6B | 96 (4) |
C11—C12—C13 | 116.0 (3) | C13—N6—H6C | 112 (5) |
C11—C12—H12A | 108.3 | H6A—N6—H6C | 119 (5) |
C13—C12—H12A | 108.3 | H6B—N6—H6C | 102 (5) |
N1—C1—C3—N2 | −0.5 (4) | C11—C12—C13—C14 | 168.9 (3) |
N1—C1—C3—C4 | 179.2 (3) | N6—C13—C14—O6 | −19.2 (4) |
C1—C3—C4—C5 | 126.2 (4) | C12—C13—C14—O6 | 102.9 (4) |
N2—C3—C4—C5 | −54.1 (5) | N6—C13—C14—O5 | 159.8 (3) |
C3—C4—C5—N3 | −68.5 (4) | C12—C13—C14—O5 | −78.1 (4) |
C3—C4—C5—C6 | 170.3 (3) | F6—C15—C16—O7 | 11.0 (7) |
N3—C5—C6—O2 | −5.9 (4) | F5—C15—C16—O7 | −109.4 (5) |
C4—C5—C6—O2 | 116.2 (3) | F4—C15—C16—O7 | 135.0 (5) |
N3—C5—C6—O1 | 172.8 (3) | F6—C15—C16—O8 | −171.2 (5) |
C4—C5—C6—O1 | −65.1 (3) | F5—C15—C16—O8 | 68.4 (5) |
F3—C7—C8—O3 | 33.6 (5) | F4—C15—C16—O8 | −47.2 (5) |
F1—C7—C8—O3 | −86.3 (4) | N2—C2—N1—C1 | −0.2 (5) |
F2—C7—C8—O3 | 153.9 (4) | C3—C1—N1—C2 | 0.5 (5) |
F3—C7—C8—O4 | −145.9 (4) | N1—C2—N2—C3 | −0.1 (4) |
F1—C7—C8—O4 | 94.2 (4) | C1—C3—N2—C2 | 0.4 (4) |
F2—C7—C8—O4 | −25.6 (5) | C4—C3—N2—C2 | −179.3 (3) |
N5—C10—C11—N4 | −0.5 (4) | N5—C9—N4—C11 | 0.9 (5) |
N5—C10—C11—C12 | 173.7 (4) | C10—C11—N4—C9 | −0.2 (5) |
C10—C11—C12—C13 | 132.0 (4) | C12—C11—N4—C9 | −175.0 (4) |
N4—C11—C12—C13 | −54.6 (5) | N4—C9—N5—C10 | −1.2 (5) |
C11—C12—C13—N6 | −69.9 (4) | C11—C10—N5—C9 | 1.0 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2i | 1.00 (6) | 1.99 (6) | 2.935 (4) | 157 (5) |
N2—H2···O4ii | 0.87 (5) | 1.97 (6) | 2.838 (4) | 178 (4) |
N3—H3A···O4 | 0.94 (1) | 1.86 (1) | 2.784 (4) | 172 (4) |
N3—H3B···O1iii | 0.93 (5) | 1.98 (2) | 2.884 (4) | 162 (5) |
N3—H3C···O5 | 0.93 (1) | 2.03 (3) | 2.832 (4) | 144 (5) |
N4—H4···O8ii | 0.75 (7) | 1.93 (7) | 2.681 (5) | 172 (6) |
N5—H5···O1iv | 0.79 (6) | 1.87 (6) | 2.657 (4) | 176 (6) |
N6—H6A···O5iii | 0.93 (1) | 1.84 (2) | 2.740 (4) | 165 (4) |
N6—H6B···O3v | 0.93 (1) | 1.81 (1) | 2.728 (4) | 170 (4) |
N6—H6C···O8 | 0.93 (5) | 1.92 (2) | 2.827 (4) | 164 (7) |
Symmetry codes: (i) x−1, y−1, z; (ii) x+1, y, z; (iii) x−1, y, z; (iv) x−1, y, z+1; (v) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C6H10N3O2+·C2F3O2− |
Mr | 269.19 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 5.1724 (6), 8.8183 (12), 12.481 (3) |
α, β, γ (°) | 96.193 (17), 99.853 (13), 102.106 (13) |
V (Å3) | 542.26 (16) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 1.46 |
Crystal size (mm) | 0.2 × 0.2 × 0.1 |
Data collection | |
Diffractometer | Enraf–Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.790, 0.864 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2064, 2063, 2053 |
Rint | 0.001 |
(sin θ/λ)max (Å−1) | 0.601 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.108, 1.01 |
No. of reflections | 2063 |
No. of parameters | 382 |
No. of restraints | 13 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.42, −0.32 |
Absolute structure | Flack (1983), 92 Friedel pairs |
Absolute structure parameter | 0.04 (2) |
Computer programs: CAD-4 Software (Enraf–Nonius, 1997), CAD-4 Software, XCAD4 in WinGX (Farrugia, 1999), SIR92 (Burla et al., 1989), SHELXL97 (Sheldrick, 1997), ORTEP-32 (Farrugia, 1997), SHELXL97.
C1—N1 | 1.357 (6) | C6—O1 | 1.270 (4) |
C2—N1 | 1.317 (7) | C7—F3 | 1.333 (5) |
C2—N2 | 1.323 (5) | C7—F1 | 1.333 (5) |
C3—N2 | 1.378 (5) | C7—F2 | 1.340 (5) |
C5—N3 | 1.483 (4) | C8—O3 | 1.231 (5) |
C6—O2 | 1.226 (4) | C8—O4 | 1.243 (5) |
N1—C1—C3 | 107.6 (4) | F3—C7—F2 | 106.8 (3) |
N1—C2—N2 | 108.7 (4) | F1—C7—F2 | 106.2 (3) |
C1—C3—N2 | 105.8 (3) | F3—C7—C8 | 111.7 (3) |
N2—C3—C4 | 124.3 (3) | F1—C7—C8 | 112.3 (3) |
N3—C5—C6 | 109.6 (2) | F2—C7—C8 | 112.7 (3) |
N3—C5—C4 | 111.1 (3) | O3—C8—O4 | 126.4 (4) |
O2—C6—O1 | 125.9 (3) | O3—C8—C7 | 116.4 (3) |
O2—C6—C5 | 119.4 (3) | O4—C8—C7 | 117.2 (3) |
O1—C6—C5 | 114.6 (3) | C2—N1—C1 | 109.0 (3) |
F3—C7—F1 | 106.8 (3) | C2—N2—C3 | 108.9 (3) |
C1—C3—C4—C5 | 126.2 (4) | C3—C4—C5—C6 | 170.3 (3) |
N2—C3—C4—C5 | −54.1 (5) | C11—C12—C13—C14 | 168.9 (3) |
C3—C4—C5—N3 | −68.5 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2i | 1.00 (6) | 1.99 (6) | 2.935 (4) | 157 (5) |
N2—H2···O4ii | 0.87 (5) | 1.97 (6) | 2.838 (4) | 178 (4) |
N3—H3A···O4 | 0.935 (11) | 1.855 (13) | 2.784 (4) | 172 (4) |
N3—H3B···O1iii | 0.93 (5) | 1.98 (2) | 2.884 (4) | 162 (5) |
N3—H3C···O5 | 0.932 (11) | 2.03 (3) | 2.832 (4) | 144 (5) |
N4—H4···O8ii | 0.75 (7) | 1.93 (7) | 2.681 (5) | 172 (6) |
N5—H5···O1iv | 0.79 (6) | 1.87 (6) | 2.657 (4) | 176 (6) |
N6—H6A···O5iii | 0.926 (11) | 1.835 (16) | 2.740 (4) | 165 (4) |
N6—H6B···O3v | 0.932 (11) | 1.806 (14) | 2.728 (4) | 170 (4) |
N6—H6C···O8 | 0.93 (5) | 1.92 (2) | 2.827 (4) | 164 (7) |
Symmetry codes: (i) x−1, y−1, z; (ii) x+1, y, z; (iii) x−1, y, z; (iv) x−1, y, z+1; (v) x, y+1, z. |
Histidine is an interesting molecule from a crystal engineering point of view. It can act as a proton donor, a proton acceptor, a nucleophilic agent and a ligand for complexation with various metal ions. It exists as both orthorhombic and monclinic polymorphic forms. The crystal structures of L-histidine (Madden, McGandy & Seeman, 1972; Madden, McGandy, Seeman, Harding & Hoy, 1972) and its complexes, such as L-histidinium hydrochloride (Fuess & Bartunik 1976; Donohue & Caron 1964), L-histidinium dinitrate (Benali-Cherif et al., 2002), L-histidinium sulfate (Kumar et al., 2005) and L-histidinium tetrafluorosuccinate (Akkurt et al., 2004), have been reported, and recently the crystal structure of L-histidinium trichloroacetate (Gokulraj et al., 2005) has also been published. In the present study, we report the crystal structure of L-histidinium trifluoroacetate, (I).
The molecular structure of (I) is illustrated in Fig. 1, and selected bond distances and angles are given in Table 1. Compound (I) crystallizes with two histidine cations (A and B) and two trifluoroacetate anions in the unit cell of the non-centrosymmetric triclinic space group P1. The α-amino and imidazole groups of the L-histidine cations are protonated and positively charged, while the carboxyl groups are in the ionized state and are negatively charged. Moreover, the zwitterionic cation carries a net positive charge. The conformation angles of the histidine side chain (IUPAC–IUB Commission on Biochemical Nomenclature, 1970) are χ1 [−68.5 (4) and −69.9 (4)°], χ21 [−54.5 (5) and 54.1 (5)°] and χ22 [126.2 (4) and 132.0 (4)° for cations A and B, respectively]. The conformation ψ1 is such that it is in a gauche II form for both molecules, having a closed conformation (Pratap et al., 2000) (see Table 1). The difference in the absolute values of χ21 and χ22 is about 180°, indicating the planarity of the imidazole group. The deviations in the preferred torsion angles of χ21 at −90 and 90° are due to the interactions of the imidazole ring with other groups in the structure. The imidazole group of L-histidine is in a trans conformation, for both A [C3—C4—C5—C6 = 170.3 (3)°] and B [C11—C12—C13—C14 = 168.9 (3)°], with respect to the carboxyl group, and gauche with respect to the amino N atom. The corresponding gauche II conformation angles observed in other complexes are −60 and −60.9° in L-histidine formate formic acid, −60 and −67.5° in DL-histidine formate monohydrate, −60.2 (3)° in L-histidine dinitrate, 58.2 and −96.8° in L-histidine glycolate, −61.2 (5) and 99.2 (5)° in monoclinic L-histidine acetate and 37.1 (6) and −78.8 (6)° in L-histidinium trichloroacetate.
The trifluoroacetate anions play a vital role in the hydrogen bonding with the histidinium cation via the amine N atom and the N atom of the imidazole ring. The three-dimensional network of N—H···O bonds links the cations and trifluoroacetate anions stabilizing the crystal packing as shown in Fig. 2.