Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103023333/sk1668sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103023333/sk1668Isup2.hkl |
CCDC reference: 229095
A mixture of 2-aminobenzimidazole (0.20 g, 1.50 mmol), Meldrum's acid (0.22 g, 1.52 mmol) and ethanol (10 ml) was heated under reflux for 1 h. Compound (I) was formed as a white solid which was collected by filtration and washed with ethanol (84% yield; m.p. 430 K). Crystals suitable for single-crystal X-ray diffraction analysis were obtained by crystallization from ethanol. Compound (I) was also obtained by crystallization from an ethanol solution mixing equimolar amounts of 2-aminobenzimidazole and malonic acid monoethyl ester.
The space group P21/c was uniquely assigned from the systematic absences. All H atoms were located in difference maps. H atoms bonded to C atoms were subsequently treated as riding atoms, with C—H distances of 0.95 (aromatic), 0.98 (CH3) and 0.99 Å (CH2). H atoms bonded to N atoms were allowed to ride at the positions identified from the difference maps, giving N—H distances in the range 0.93–1.03 Å.
Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).
C7H8N3+·C5H7O4− | F(000) = 1120 |
Mr = 265.27 | Dx = 1.341 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 5983 reflections |
a = 12.0121 (2) Å | θ = 3.2–27.5° |
b = 10.5379 (2) Å | µ = 0.10 mm−1 |
c = 20.8249 (6) Å | T = 120 K |
β = 94.7550 (8)° | Plate, colourless |
V = 2626.99 (10) Å3 | 0.22 × 0.16 × 0.02 mm |
Z = 8 |
Nonius KappaCCD diffractometer | 5983 independent reflections |
Radiation source: rotating anode | 4204 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.115 |
ϕ scans, and ω scans with κ offsets | θmax = 27.5°, θmin = 3.2° |
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997) | h = −15→15 |
Tmin = 0.974, Tmax = 0.998 | k = −13→13 |
33691 measured reflections | l = −27→27 |
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)] = 0.061 | H-atom parameters constrained |
wR(F2) = 0.171 | w = 1/[σ2(Fo2) + (0.0837P)2 + 0.7506P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
5983 reflections | Δρmax = 0.26 e Å−3 |
346 parameters | Δρmin = −0.33 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0125 (18) |
C7H8N3+·C5H7O4− | V = 2626.99 (10) Å3 |
Mr = 265.27 | Z = 8 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.0121 (2) Å | µ = 0.10 mm−1 |
b = 10.5379 (2) Å | T = 120 K |
c = 20.8249 (6) Å | 0.22 × 0.16 × 0.02 mm |
β = 94.7550 (8)° |
Nonius KappaCCD diffractometer | 5983 independent reflections |
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997) | 4204 reflections with I > 2σ(I) |
Tmin = 0.974, Tmax = 0.998 | Rint = 0.115 |
33691 measured reflections |
R[F2 > 2σ(F2)] = 0.061 | 0 restraints |
wR(F2) = 0.171 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.26 e Å−3 |
5983 reflections | Δρmin = −0.33 e Å−3 |
346 parameters |
x | y | z | Uiso*/Ueq | ||
O31 | 0.78600 (11) | 0.49346 (15) | 0.22748 (7) | 0.0319 (4) | |
O32 | 0.61246 (11) | 0.53116 (15) | 0.18638 (7) | 0.0330 (4) | |
O33 | 0.67315 (15) | 0.59736 (18) | 0.03519 (8) | 0.0515 (5) | |
O34 | 0.60923 (11) | 0.75745 (15) | 0.09240 (7) | 0.0328 (4) | |
O41 | 0.29905 (11) | 0.30770 (15) | 0.22946 (7) | 0.0319 (4) | |
O42 | 0.13905 (11) | 0.25111 (14) | 0.17480 (7) | 0.0320 (4) | |
O43 | 0.16559 (12) | −0.00016 (15) | 0.11187 (7) | 0.0364 (4) | |
O44 | 0.25514 (11) | 0.11340 (15) | 0.04023 (7) | 0.0339 (4) | |
N11 | 0.52969 (14) | 0.32618 (19) | 0.25327 (9) | 0.0356 (4) | |
N12 | 0.58623 (13) | 0.15722 (18) | 0.32393 (8) | 0.0308 (4) | |
N17 | 0.71491 (13) | 0.28910 (17) | 0.29607 (8) | 0.0287 (4) | |
N21 | 0.01040 (14) | 0.42118 (18) | 0.24330 (9) | 0.0355 (4) | |
N22 | 0.04014 (14) | 0.59319 (17) | 0.31636 (8) | 0.0316 (4) | |
N27 | 0.18761 (13) | 0.49189 (17) | 0.28741 (8) | 0.0292 (4) | |
C11 | 0.60504 (16) | 0.2604 (2) | 0.28875 (10) | 0.0285 (5) | |
C12A | 0.68717 (16) | 0.1179 (2) | 0.35643 (9) | 0.0288 (5) | |
C13 | 0.71161 (18) | 0.0205 (2) | 0.39919 (10) | 0.0347 (5) | |
C14 | 0.82314 (19) | 0.0074 (2) | 0.42294 (11) | 0.0401 (5) | |
C15 | 0.90515 (19) | 0.0898 (2) | 0.40439 (11) | 0.0401 (6) | |
C16 | 0.87964 (17) | 0.1895 (2) | 0.36143 (10) | 0.0339 (5) | |
C16A | 0.76873 (16) | 0.2019 (2) | 0.33809 (10) | 0.0294 (5) | |
C21 | 0.07527 (16) | 0.4983 (2) | 0.28013 (10) | 0.0292 (5) | |
C22A | 0.13293 (17) | 0.6529 (2) | 0.34778 (10) | 0.0310 (5) | |
C23 | 0.1425 (2) | 0.7536 (2) | 0.39020 (11) | 0.0398 (6) | |
C24 | 0.2500 (2) | 0.7906 (2) | 0.41207 (11) | 0.0438 (6) | |
C25 | 0.3431 (2) | 0.7281 (2) | 0.39234 (11) | 0.0432 (6) | |
C26 | 0.33395 (17) | 0.6252 (2) | 0.35070 (10) | 0.0350 (5) | |
C26A | 0.22677 (16) | 0.5883 (2) | 0.32895 (10) | 0.0301 (5) | |
C31 | 0.76122 (17) | 0.6398 (2) | 0.14043 (10) | 0.0344 (5) | |
C32 | 0.71624 (16) | 0.5467 (2) | 0.18829 (9) | 0.0275 (4) | |
C33 | 0.67865 (17) | 0.6610 (2) | 0.08345 (10) | 0.0332 (5) | |
C35 | 0.52230 (17) | 0.7772 (2) | 0.04049 (10) | 0.0346 (5) | |
C36 | 0.45300 (19) | 0.8888 (2) | 0.05781 (11) | 0.0415 (6) | |
C41 | 0.30760 (16) | 0.1483 (2) | 0.14985 (10) | 0.0311 (5) | |
C42 | 0.24258 (15) | 0.2426 (2) | 0.18757 (9) | 0.0266 (4) | |
C43 | 0.23435 (16) | 0.0780 (2) | 0.10011 (10) | 0.0286 (5) | |
C45 | 0.18627 (19) | 0.0540 (3) | −0.01227 (10) | 0.0400 (6) | |
C46 | 0.0823 (2) | 0.1300 (3) | −0.02830 (12) | 0.0475 (6) | |
H11A | 0.5558 | 0.4001 | 0.2313 | 0.043* | |
H11B | 0.4543 | 0.3042 | 0.2473 | 0.043* | |
H12 | 0.5202 | 0.1118 | 0.3263 | 0.037* | |
H17 | 0.7428 | 0.3638 | 0.2784 | 0.034* | |
H21A | 0.0458 | 0.3585 | 0.2182 | 0.043* | |
H21B | −0.0666 | 0.4565 | 0.2322 | 0.043* | |
H22 | −0.0418 | 0.6207 | 0.3195 | 0.038* | |
H27 | 0.2264 | 0.4259 | 0.2675 | 0.035* | |
H13 | 0.6553 | −0.0352 | 0.4120 | 0.042* | |
H14 | 0.8435 | −0.0591 | 0.4524 | 0.048* | |
H15 | 0.9803 | 0.0779 | 0.4213 | 0.048* | |
H16 | 0.9355 | 0.2459 | 0.3488 | 0.041* | |
H23 | 0.0785 | 0.7957 | 0.4038 | 0.048* | |
H24 | 0.2601 | 0.8600 | 0.4411 | 0.053* | |
H25 | 0.4154 | 0.7568 | 0.4079 | 0.052* | |
H26 | 0.3979 | 0.5823 | 0.3378 | 0.042* | |
H31A | 0.7782 | 0.7218 | 0.1623 | 0.041* | |
H31B | 0.8316 | 0.6061 | 0.1255 | 0.041* | |
H35A | 0.4749 | 0.7005 | 0.0348 | 0.042* | |
H35B | 0.5563 | 0.7939 | −0.0004 | 0.042* | |
H36A | 0.4180 | 0.8703 | 0.0977 | 0.062* | |
H36B | 0.3949 | 0.9050 | 0.0229 | 0.062* | |
H36C | 0.5009 | 0.9638 | 0.0642 | 0.062* | |
H41A | 0.3660 | 0.1943 | 0.1284 | 0.037* | |
H41B | 0.3453 | 0.0865 | 0.1802 | 0.037* | |
H45A | 0.1659 | −0.0330 | 0.0004 | 0.048* | |
H45B | 0.2291 | 0.0477 | −0.0508 | 0.048* | |
H46A | 0.0383 | 0.1329 | 0.0093 | 0.071* | |
H46B | 0.0380 | 0.0904 | −0.0645 | 0.071* | |
H46C | 0.1026 | 0.2165 | −0.0401 | 0.071* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O31 | 0.0217 (7) | 0.0426 (9) | 0.0310 (8) | 0.0028 (6) | 0.0000 (5) | 0.0059 (7) |
O32 | 0.0208 (7) | 0.0407 (9) | 0.0376 (8) | 0.0029 (6) | 0.0016 (6) | 0.0039 (7) |
O33 | 0.0653 (12) | 0.0585 (12) | 0.0303 (9) | 0.0264 (9) | 0.0022 (8) | −0.0048 (8) |
O34 | 0.0292 (8) | 0.0416 (9) | 0.0274 (7) | 0.0087 (6) | 0.0017 (6) | 0.0027 (6) |
O41 | 0.0220 (7) | 0.0390 (9) | 0.0345 (8) | −0.0004 (6) | 0.0000 (6) | −0.0066 (7) |
O42 | 0.0187 (7) | 0.0362 (9) | 0.0404 (8) | 0.0000 (6) | −0.0008 (6) | −0.0013 (7) |
O43 | 0.0349 (8) | 0.0389 (9) | 0.0350 (8) | −0.0074 (7) | 0.0000 (6) | 0.0013 (7) |
O44 | 0.0301 (8) | 0.0455 (10) | 0.0261 (7) | −0.0018 (6) | 0.0022 (6) | −0.0002 (7) |
N11 | 0.0205 (8) | 0.0482 (12) | 0.0379 (10) | −0.0036 (8) | 0.0006 (7) | 0.0033 (9) |
N12 | 0.0230 (8) | 0.0365 (11) | 0.0334 (9) | −0.0072 (7) | 0.0042 (7) | −0.0039 (8) |
N17 | 0.0207 (8) | 0.0348 (10) | 0.0307 (9) | −0.0052 (7) | 0.0019 (6) | −0.0010 (8) |
N21 | 0.0230 (9) | 0.0386 (11) | 0.0445 (11) | 0.0029 (8) | −0.0002 (7) | −0.0035 (9) |
N22 | 0.0248 (9) | 0.0348 (10) | 0.0354 (10) | 0.0037 (7) | 0.0038 (7) | 0.0016 (8) |
N27 | 0.0215 (8) | 0.0330 (10) | 0.0330 (9) | 0.0029 (7) | 0.0023 (7) | 0.0006 (8) |
C11 | 0.0221 (10) | 0.0361 (12) | 0.0277 (10) | −0.0052 (8) | 0.0048 (7) | −0.0063 (9) |
C12A | 0.0268 (10) | 0.0340 (12) | 0.0262 (10) | −0.0020 (8) | 0.0061 (7) | −0.0062 (9) |
C13 | 0.0323 (11) | 0.0359 (13) | 0.0364 (12) | −0.0048 (9) | 0.0066 (9) | −0.0015 (10) |
C14 | 0.0417 (13) | 0.0401 (14) | 0.0387 (13) | 0.0047 (10) | 0.0042 (9) | 0.0056 (10) |
C15 | 0.0307 (11) | 0.0483 (15) | 0.0410 (13) | 0.0010 (10) | 0.0015 (9) | 0.0035 (11) |
C16 | 0.0252 (10) | 0.0406 (13) | 0.0362 (12) | −0.0030 (9) | 0.0036 (8) | 0.0001 (10) |
C16A | 0.0289 (10) | 0.0310 (12) | 0.0286 (10) | −0.0022 (9) | 0.0048 (8) | −0.0030 (9) |
C21 | 0.0227 (10) | 0.0324 (12) | 0.0328 (11) | 0.0028 (8) | 0.0037 (8) | 0.0055 (9) |
C22A | 0.0306 (11) | 0.0332 (12) | 0.0290 (10) | 0.0008 (9) | 0.0012 (8) | 0.0064 (9) |
C23 | 0.0474 (14) | 0.0351 (13) | 0.0372 (12) | 0.0043 (10) | 0.0051 (10) | 0.0032 (10) |
C24 | 0.0563 (15) | 0.0384 (14) | 0.0356 (12) | −0.0051 (11) | −0.0027 (10) | 0.0008 (11) |
C25 | 0.0437 (13) | 0.0486 (16) | 0.0362 (12) | −0.0122 (11) | −0.0039 (10) | 0.0084 (11) |
C26 | 0.0296 (11) | 0.0444 (14) | 0.0305 (11) | −0.0035 (9) | −0.0003 (8) | 0.0069 (10) |
C26A | 0.0291 (10) | 0.0332 (12) | 0.0279 (10) | −0.0007 (9) | 0.0024 (8) | 0.0062 (9) |
C31 | 0.0255 (11) | 0.0440 (14) | 0.0343 (11) | 0.0042 (9) | 0.0053 (8) | 0.0070 (10) |
C32 | 0.0227 (10) | 0.0336 (12) | 0.0261 (10) | 0.0062 (8) | 0.0025 (7) | −0.0009 (9) |
C33 | 0.0316 (11) | 0.0387 (13) | 0.0300 (11) | 0.0058 (9) | 0.0068 (8) | 0.0052 (10) |
C35 | 0.0304 (11) | 0.0460 (14) | 0.0268 (10) | 0.0053 (10) | −0.0009 (8) | 0.0059 (10) |
C36 | 0.0399 (12) | 0.0497 (15) | 0.0351 (12) | 0.0123 (11) | 0.0045 (9) | 0.0098 (11) |
C41 | 0.0225 (10) | 0.0416 (13) | 0.0289 (10) | 0.0000 (9) | 0.0013 (7) | −0.0009 (9) |
C42 | 0.0228 (10) | 0.0299 (11) | 0.0271 (10) | −0.0014 (8) | 0.0017 (7) | 0.0039 (8) |
C43 | 0.0253 (10) | 0.0329 (12) | 0.0273 (10) | 0.0061 (9) | 0.0003 (8) | 0.0005 (9) |
C45 | 0.0400 (12) | 0.0525 (15) | 0.0269 (11) | −0.0028 (11) | −0.0009 (9) | −0.0067 (10) |
C46 | 0.0436 (14) | 0.0527 (16) | 0.0437 (14) | −0.0050 (11) | −0.0108 (10) | 0.0075 (12) |
O31—C32 | 1.253 (2) | C15—C16 | 1.397 (3) |
O32—C32 | 1.255 (2) | C15—H15 | 0.95 |
O33—C33 | 1.205 (3) | C16—C16A | 1.386 (3) |
O34—C33 | 1.338 (3) | C16—H16 | 0.95 |
O34—C35 | 1.454 (2) | C22A—C23 | 1.380 (3) |
O41—C42 | 1.262 (2) | C22A—C26A | 1.400 (3) |
O42—C42 | 1.253 (2) | C23—C24 | 1.390 (3) |
O43—C43 | 1.206 (3) | C23—H23 | 0.95 |
O44—C43 | 1.345 (2) | C24—C25 | 1.389 (4) |
O44—C45 | 1.457 (3) | C24—H24 | 0.95 |
C11—N11 | 1.317 (3) | C25—C26 | 1.387 (3) |
C11—N12 | 1.341 (3) | C25—H25 | 0.95 |
C11—N17 | 1.350 (2) | C26—C26A | 1.385 (3) |
N12—C12A | 1.401 (3) | C26—H26 | 0.95 |
N17—C16A | 1.390 (3) | C31—C33 | 1.499 (3) |
N11—H11A | 0.9683 | C31—C32 | 1.529 (3) |
N11—H11B | 0.9335 | C31—H31A | 0.99 |
N12—H12 | 0.9313 | C31—H31B | 0.99 |
N17—H17 | 0.9420 | C35—C36 | 1.502 (3) |
C21—N21 | 1.325 (3) | C35—H35A | 0.99 |
C21—N22 | 1.342 (3) | C35—H35B | 0.99 |
C21—N27 | 1.347 (3) | C36—H36A | 0.98 |
N22—C22A | 1.395 (3) | C36—H36B | 0.98 |
N27—C26A | 1.391 (3) | C36—H36C | 0.98 |
N21—H21A | 0.9638 | C41—C43 | 1.498 (3) |
N21—H21B | 1.0060 | C41—C42 | 1.522 (3) |
N22—H22 | 1.0337 | C41—H41A | 0.99 |
N27—H27 | 0.9512 | C41—H41B | 0.99 |
C12A—C13 | 1.374 (3) | C45—C46 | 1.498 (3) |
C12A—C16A | 1.397 (3) | C45—H45A | 0.99 |
C13—C14 | 1.396 (3) | C45—H45B | 0.99 |
C13—H13 | 0.95 | C46—H46A | 0.98 |
C14—C15 | 1.391 (3) | C46—H46B | 0.98 |
C14—H14 | 0.95 | C46—H46C | 0.98 |
C33—O34—C35 | 115.00 (16) | C24—C25—H25 | 119.0 |
C43—O44—C45 | 116.05 (17) | C26A—C26—C25 | 116.6 (2) |
C11—N11—H11A | 117.0 | C26A—C26—H26 | 121.7 |
C11—N11—H11B | 123.9 | C25—C26—H26 | 121.7 |
H11A—N11—H11B | 119.0 | C26—C26A—N27 | 131.8 (2) |
C11—N12—C12A | 109.00 (16) | C26—C26A—C22A | 121.3 (2) |
C11—N12—H12 | 128.9 | N27—C26A—C22A | 106.90 (17) |
C12A—N12—H12 | 122.0 | C33—C31—C32 | 111.42 (17) |
C11—N17—C16A | 108.81 (17) | C33—C31—H31A | 109.3 |
C11—N17—H17 | 121.2 | C32—C31—H31A | 109.3 |
C16A—N17—H17 | 129.5 | C33—C31—H31B | 109.3 |
C21—N21—H21A | 118.0 | C32—C31—H31B | 109.3 |
C21—N21—H21B | 113.1 | H31A—C31—H31B | 108.0 |
H21A—N21—H21B | 124.5 | O31—C32—O32 | 124.83 (19) |
C21—N22—C22A | 108.89 (17) | O31—C32—C31 | 117.30 (17) |
C21—N22—H22 | 126.2 | O32—C32—C31 | 117.85 (17) |
C22A—N22—H22 | 124.9 | O33—C33—O34 | 123.2 (2) |
C21—N27—C26A | 108.52 (17) | O33—C33—C31 | 124.4 (2) |
C21—N27—H27 | 120.6 | O34—C33—C31 | 112.47 (18) |
C26A—N27—H27 | 130.8 | O34—C35—C36 | 108.15 (18) |
N11—C11—N12 | 126.45 (18) | O34—C35—H35A | 110.1 |
N11—C11—N17 | 124.4 (2) | C36—C35—H35A | 110.1 |
N12—C11—N17 | 109.10 (18) | O34—C35—H35B | 110.1 |
C13—C12A—C16A | 122.24 (19) | C36—C35—H35B | 110.1 |
C13—C12A—N12 | 131.58 (18) | H35A—C35—H35B | 108.4 |
C16A—C12A—N12 | 106.17 (18) | C35—C36—H36A | 109.5 |
C12A—C13—C14 | 116.8 (2) | C35—C36—H36B | 109.5 |
C12A—C13—H13 | 121.6 | H36A—C36—H36B | 109.5 |
C14—C13—H13 | 121.6 | C35—C36—H36C | 109.5 |
C15—C14—C13 | 121.4 (2) | H36A—C36—H36C | 109.5 |
C15—C14—H14 | 119.3 | H36B—C36—H36C | 109.5 |
C13—C14—H14 | 119.3 | C43—C41—C42 | 112.50 (16) |
C14—C15—C16 | 121.6 (2) | C43—C41—H41A | 109.1 |
C14—C15—H15 | 119.2 | C42—C41—H41A | 109.1 |
C16—C15—H15 | 119.2 | C43—C41—H41B | 109.1 |
C16A—C16—C15 | 116.7 (2) | C42—C41—H41B | 109.1 |
C16A—C16—H16 | 121.7 | H41A—C41—H41B | 107.8 |
C15—C16—H16 | 121.7 | O42—C42—O41 | 125.09 (19) |
C16—C16A—N17 | 131.8 (2) | O42—C42—C41 | 118.66 (18) |
C16—C16A—C12A | 121.3 (2) | O41—C42—C41 | 116.24 (16) |
N17—C16A—C12A | 106.91 (17) | O43—C43—O44 | 124.12 (19) |
N21—C21—N22 | 125.80 (18) | O43—C43—C41 | 124.76 (19) |
N21—C21—N27 | 124.75 (19) | O44—C43—C41 | 111.12 (18) |
N22—C21—N27 | 109.44 (18) | O44—C45—C46 | 110.4 (2) |
C23—C22A—N22 | 131.9 (2) | O44—C45—H45A | 109.6 |
C23—C22A—C26A | 121.8 (2) | C46—C45—H45A | 109.6 |
N22—C22A—C26A | 106.24 (18) | O44—C45—H45B | 109.6 |
C22A—C23—C24 | 116.8 (2) | C46—C45—H45B | 109.6 |
C22A—C23—H23 | 121.6 | H45A—C45—H45B | 108.1 |
C24—C23—H23 | 121.6 | C45—C46—H46A | 109.5 |
C25—C24—C23 | 121.3 (2) | C45—C46—H46B | 109.5 |
C25—C24—H24 | 119.3 | H46A—C46—H46B | 109.5 |
C23—C24—H24 | 119.3 | C45—C46—H46C | 109.5 |
C26—C25—C24 | 122.1 (2) | H46A—C46—H46C | 109.5 |
C26—C25—H25 | 119.0 | H46B—C46—H46C | 109.5 |
C12A—N12—C11—N11 | −177.9 (2) | C26A—C22A—C23—C24 | 1.8 (3) |
C12A—N12—C11—N17 | 1.0 (2) | C22A—C23—C24—C25 | −0.5 (3) |
C16A—N17—C11—N11 | 178.29 (19) | C23—C24—C25—C26 | −0.8 (4) |
C16A—N17—C11—N12 | −0.7 (2) | C24—C25—C26—C26A | 0.7 (3) |
C11—N12—C12A—C13 | 178.0 (2) | C25—C26—C26A—N27 | 179.5 (2) |
C11—N12—C12A—C16A | −1.0 (2) | C25—C26—C26A—C22A | 0.6 (3) |
C16A—C12A—C13—C14 | −1.2 (3) | C21—N27—C26A—C26 | −178.0 (2) |
N12—C12A—C13—C14 | 179.9 (2) | C21—N27—C26A—C22A | 1.0 (2) |
C12A—C13—C14—C15 | 0.4 (3) | C23—C22A—C26A—C26 | −2.0 (3) |
C13—C14—C15—C16 | 0.3 (4) | N22—C22A—C26A—C26 | 178.75 (19) |
C14—C15—C16—C16A | −0.2 (3) | C23—C22A—C26A—N27 | 178.91 (19) |
C15—C16—C16A—N17 | 179.3 (2) | N22—C22A—C26A—N27 | −0.4 (2) |
C15—C16—C16A—C12A | −0.6 (3) | O31—C32—C31—C33 | 160.1 (2) |
C11—N17—C16A—C16 | −179.8 (2) | C32—C31—C33—O34 | 89.9 (2) |
C11—N17—C16A—C12A | 0.1 (2) | C32—C31—C33—O33 | −88.7 (3) |
C13—C12A—C16A—C16 | 1.3 (3) | C31—C33—O34—C35 | −176.0 (2) |
N12—C12A—C16A—C16 | −179.58 (19) | C33—O34—C35—C36 | −179.5 (2) |
C13—C12A—C16A—N17 | −178.57 (19) | C33—C31—C32—O32 | −21.3 (3) |
N12—C12A—C16A—N17 | 0.5 (2) | C35—O34—C33—O33 | 2.7 (3) |
C22A—N22—C21—N21 | −179.7 (2) | O41—C42—C41—C43 | −178.5 (2) |
C22A—N22—C21—N27 | 1.1 (2) | C42—C41—C43—O44 | 110.5 (2) |
C26A—N27—C21—N21 | 179.4 (2) | C42—C41—C43—O43 | −69.5 (3) |
C26A—N27—C21—N22 | −1.3 (2) | C41—C43—O44—C45 | −178.2 (2) |
C21—N22—C22A—C23 | −179.6 (2) | C43—O44—C45—C46 | 89.1 (2) |
C21—N22—C22A—C26A | −0.4 (2) | C43—C41—C42—O42 | 0.9 (3) |
N22—C22A—C23—C24 | −179.1 (2) | C45—O44—C43—O43 | 1.8 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N11—H11A···O32 | 0.97 | 1.83 | 2.797 (2) | 175 |
N11—H11B···O41 | 0.93 | 1.87 | 2.781 (2) | 164 |
N12—H12···O32i | 0.93 | 1.81 | 2.724 (2) | 168 |
N17—H17···O31 | 0.94 | 1.83 | 2.759 (2) | 168 |
N21—H21A···O42 | 0.96 | 1.88 | 2.829 (2) | 170 |
N21—H21B···O31ii | 1.01 | 1.81 | 2.794 (2) | 166 |
N22—H22···O42iii | 1.03 | 1.81 | 2.739 (2) | 147 |
N22—H22···O43iii | 1.03 | 2.50 | 3.150 (2) | 121 |
N27—H27···O41 | 0.95 | 1.75 | 2.699 (2) | 179 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) x−1, y, z; (iii) −x, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C7H8N3+·C5H7O4− |
Mr | 265.27 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 120 |
a, b, c (Å) | 12.0121 (2), 10.5379 (2), 20.8249 (6) |
β (°) | 94.7550 (8) |
V (Å3) | 2626.99 (10) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.22 × 0.16 × 0.02 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (DENZO-SMN; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.974, 0.998 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 33691, 5983, 4204 |
Rint | 0.115 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.061, 0.171, 1.03 |
No. of reflections | 5983 |
No. of parameters | 346 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.26, −0.33 |
Computer programs: KappaCCD Server Software (Nonius, 1997), DENZO-SMN (Otwinowski & Minor, 1997), DENZO-SMN, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), SHELXL97 and PRPKAPPA (Ferguson, 1999).
O31—C32 | 1.253 (2) | N12—C12A | 1.401 (3) |
O32—C32 | 1.255 (2) | N17—C16A | 1.390 (3) |
O41—C42 | 1.262 (2) | C21—N21 | 1.325 (3) |
O42—C42 | 1.253 (2) | C21—N22 | 1.342 (3) |
C11—N11 | 1.317 (3) | C21—N27 | 1.347 (3) |
C11—N12 | 1.341 (3) | N22—C22A | 1.395 (3) |
C11—N17 | 1.350 (2) | N27—C26A | 1.391 (3) |
O31—C32—C31—C33 | 160.1 (2) | O41—C42—C41—C43 | −178.5 (2) |
C32—C31—C33—O34 | 89.9 (2) | C42—C41—C43—O44 | 110.5 (2) |
C32—C31—C33—O33 | −88.7 (3) | C42—C41—C43—O43 | −69.5 (3) |
C31—C33—O34—C35 | −176.0 (2) | C41—C43—O44—C45 | −178.2 (2) |
C33—O34—C35—C36 | −179.5 (2) | C43—O44—C45—C46 | 89.1 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N11—H11A···O32 | 0.97 | 1.83 | 2.797 (2) | 175 |
N11—H11B···O41 | 0.93 | 1.87 | 2.781 (2) | 164 |
N12—H12···O32i | 0.93 | 1.81 | 2.724 (2) | 168 |
N17—H17···O31 | 0.94 | 1.83 | 2.759 (2) | 168 |
N21—H21A···O42 | 0.96 | 1.88 | 2.829 (2) | 170 |
N21—H21B···O31ii | 1.01 | 1.81 | 2.794 (2) | 166 |
N22—H22···O42iii | 1.03 | 1.81 | 2.739 (2) | 147 |
N27—H27···O41 | 0.95 | 1.75 | 2.699 (2) | 179 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) x−1, y, z; (iii) −x, y+1/2, −z+1/2. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
The title adduct, (I), was isolated as a direct intermediate in the synthesis of dihydropyrimido[1,2-a]benzimidazolones from a three-component reaction of 2-aminobenzimidazole with Meldrum's acid and arylaldehydes. In fact, compound (I) is formed without participation of the arylaldehyde component and results simply from the reaction between 2-aminobenzimidazole and Meldrum's acid. It can also be obtained directly by reaction of 2-aminobenzothiazole with malonic acid monoethyl ester (see reaction scheme below).
Compound (I) is a salt crystallizing with Z' = 2 in space group P21/c. The C—C and C—N distances in the two independent cations are very similar (Table 1) and both cations approximate to local C2v (mm2) symmetry. The C—C distances in the cations span a rather narrow range, from 1.374 (3) to 1.400 (3) Å, consistent with classical aromatic delocalization. The C—N distances are indicative of guanidinium-type delocalization and this can be further explored in terms of the corresponding bond orders, calculated using the recent recalibration by Kotelevskii & Prezhdo (2001) of the original equation relating bond order to bond length (Gordy, 1947). If, for this purpose, the dimensions of the two cations are averaged together under assumed local C2v symmetry, the averaged C—NH2 bond has a bond order of 1.77, the averaged endocyclic guanidinium bond has a bond order of 1.63, while the C—N bond exocyclic to the aromatic ring has a bond order of only 1.37. These values indicate strong guanidinium delocalization, isoelectronic with carbonate, with only modest interaction between the aromatic 6π system and the guanidinium 6π system. A similar pattern of C—N distances was found in 2-aminobenzimidazolium nitrate, where there are four independent cations in the asymmetric unit (Bats et al., 1999). The bond distances within the two anions of (I) show no unusual values, but the conformations of the anions are different, particularly in respect of the O-ethyl groups, as demonstrated by the principal torsion angles (Table 1).
The four independent ions are linked by eight N—H···O hydrogen bonds (Table 2) into a two-dimensional structure of some complexity. With such a number of independent molecular components, there is considerable flexibility in the selection of the asymmetric unit. For simplicity of analysis and description of the supramolecular aggregation, it has been found convenient to specify the asymmetric unit in terms of the formation of two neutral ion-pair aggregates (Fig. 1), in each of which a cation is linked to an anion by means of two N—H···O hydrogen bonds, all four of which are nearly linear. Cation 1 (containing atom N11) and anion 1 (containing atom O31) form neutral aggregate 1 (Fig. 1a), while cation 2 (containing atom N21) and anion 2 (containing atom O41) form neutral aggregate 2 (Fig. 1 b). There are then four N—H···O hydrogen bonds which link these aggregates into sheets and it is convenient to consider the action of each of these in turn.
Amino atom N11 in the type 1 aggregate at (x, y, z) acts as hydrogen-bond donor, via H11B, to carboxylate atom O41 in the type 2 aggregate also at (x, y, z); N21 in aggregate 2 at (x, y, z) in turn acts as hydrogen-bond donor, via H21B, to carboxylate atom O31 in the type 1 aggregate at (−1 + x, y, z). Propagation of these two hydrogen bonds then generates by translation a C42(12)[R22(8)][R22(8)] chain of rings (Bernstein et al., 1995) running parallel to the [100] direction (Fig. 2).
There are two further N—H···O hydrogen bonds, one of which involves only the type 1 aggregates, while the other involves only type 2 aggregates. Atom N12 in the type 1 aggregate at (x, y, z) acts as hydrogen-bond donor to carboxylate atom O32 at (1 − x, −0.5 + y, 0.5 − z), so producing a C21(6)[R22(8)] chain of rings running parallel to the [010] direction and generated by the 21 screw axis along (1/2, y, 1/4) (Fig. 3). In a similar way, atom N22 in the type 2 aggregate at (x, y, z) acts as hydrogen-bond donor to carboxylate atom O42 at (-x, 0.5 + y, 0.5 − z), so generating a second C21(6)[R22(8)] chain of rings around the 21 axis along (0, y, 1/4) (Fig. 4). This last hydrogen bond is accompanied by, and possibly weakly augmented by, a long contact between H22 at (x, y, z) and O43 at (-x, 0.5 + y, 0.5 − z) [H···O = 2.50 Å, N···O = 3.150 (2) Å and N—H···O = 121°], although it is doubtful if this can be regarded as a hydrogen bond.
The combination of [100] and [010] chains generates a (001) sheet. Two such sheets, related to one another by inversion, pass through each unit cell in the domains −0.03 < z < 0.53 and 0.47 < z < 1.03, but there are no direction-specific interactions between adjacent sheets. The two-dimensional supramolecular structure of (I) may be contrasted with the ribbon-type structure formed by 2-aminobenzimidazolium nitrate (Bats et al., 1999).