Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110012850/ga3145sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270110012850/ga3145Isup2.hkl |
CCDC reference: 779962
Compound (I) was synthesized by heating together under reflux 1-(8-bromobenzo[1,2-b; 4,5-b']difuran-4-yl)-2-aminopropane (BDF) (0.29 g, 1 mmol) and 3,5-dinitrosalicylic acid (DNSA) (0.23 g, 1 mmol) in 50% ethanol–water (50 ml) for 10 min. After concentration to ca 30 ml, partial room-temperature evaporation of the hot-filtered solution gave well formed pale-yellow crystal prisms of (I) (m.p. 493–495 K). The original BDF was solvent-extracted from samples of speciality paint products (Cotton et al., 2008), the purified BDF being used for the preparation of the DNSA salt. Spectroscopic analysis of (I): 1H NMR (400 MHz, d6-DMSO, 298 K, δ, p.p.m.): 17.12 (1H, br s, OH), 8.36 (3H, br s, NH3+), 8.16 (1H, d, J = 2.3 Hz, ArH21), 8.13 (1H, d, J = 2.3 Hz, ArH51), 7.46 (1H, d, J = 2.3 Hz, ArH52), 7.01 (1H, d, J = 2.3 Hz, ArH22), 3.52 (2H, m, H2, H11), 3.303 (1H, dd, J = 12.9 and 8.5 Hz, H12), 1.14 (3H, d, J = 6.4 Hz, H13); 13C{1H} NMR (100 MHz, d6-DMSO, 298 K, δ, p.p.m.): 149.7 (C2), 148.4 (C5), 147.7 (C21), 147.2 (C51), 126.3 (C6), 125.9 (C3), 111.4 (C1), 106.8 (C52), 106.5 (C22), 92.0 (C4), 47.0 (C12), 31.7 (C11), 17.9(C13). The assignments obtained are comparable with those obtained for BDF hydrochloride (Chambers et al., 2001; Cotton et al., 2008).
H atoms involved in hydrogen-bonding interactions were located by difference methods and their positional and isotropic displacement parameters were refined. Other H atoms were positioned geometrically and treated as riding, with C—H(aromatic) = 0.93 and C—H(aliphatic) = 0.96–0.98 Å, and with Uiso = 1.2Ueq(C). The C2 (R) absolute configuration was confirmed with statistically valid certainty (Flack & Bernardinelli, 2008). The absence of a small number of reflections (16) of the 1909 possible below 2θmin is ascribed to instrumental collection limitations.
Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).
C13H13BrNO2+·C7H3N2O7− | F(000) = 528 |
Mr = 522.28 | Dx = 1.707 Mg m−3 |
Monoclinic, P21 | Melting point = 493–495 K |
Hall symbol: P 2yb | Mo Kα radiation, λ = 0.71073 Å |
a = 6.9596 (3) Å | Cell parameters from 5783 reflections |
b = 17.2201 (9) Å | θ = 3.0–32.6° |
c = 8.7147 (4) Å | µ = 2.08 mm−1 |
β = 103.315 (4)° | T = 297 K |
V = 1016.34 (8) Å3 | Prism, pale yellow |
Z = 2 | 0.50 × 0.30 × 0.25 mm |
Oxford Gemini-S Ultra CCD area-detector diffractometer | 4450 independent reflections |
Radiation source: Enhance (Mo) X-ray tube | 3733 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.053 |
ω scans | θmax = 27.5°, θmin = 3.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→9 |
Tmin = 0.410, Tmax = 0.590 | k = −22→22 |
10418 measured reflections | l = −11→11 |
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)] = 0.048 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.112 | w = 1/[σ2(Fo2) + (0.073P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max < 0.001 |
4450 reflections | Δρmax = 0.82 e Å−3 |
315 parameters | Δρmin = −0.28 e Å−3 |
1 restraint | Absolute structure: Flack (1983), with 2047 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.038 (9) |
C13H13BrNO2+·C7H3N2O7− | V = 1016.34 (8) Å3 |
Mr = 522.28 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 6.9596 (3) Å | µ = 2.08 mm−1 |
b = 17.2201 (9) Å | T = 297 K |
c = 8.7147 (4) Å | 0.50 × 0.30 × 0.25 mm |
β = 103.315 (4)° |
Oxford Gemini-S Ultra CCD area-detector diffractometer | 4450 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3733 reflections with I > 2σ(I) |
Tmin = 0.410, Tmax = 0.590 | Rint = 0.053 |
10418 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.112 | Δρmax = 0.82 e Å−3 |
S = 1.01 | Δρmin = −0.28 e Å−3 |
4450 reflections | Absolute structure: Flack (1983), with 2047 Friedel pairs |
315 parameters | Absolute structure parameter: 0.038 (9) |
1 restraint |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles |
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 | ||
Br4 | 0.34282 (6) | 0.15378 (3) | −0.31657 (5) | 0.0614 (1) | |
O2 | 0.2808 (5) | 0.4152 (2) | −0.0534 (4) | 0.0586 (10) | |
O5 | 0.4575 (5) | 0.11118 (17) | 0.0506 (4) | 0.0536 (10) | |
N12 | 0.7647 (5) | 0.37276 (19) | 0.3442 (4) | 0.0358 (9) | |
C1 | 0.3887 (5) | 0.3118 (2) | 0.1391 (4) | 0.0369 (10) | |
C2 | 0.3336 (5) | 0.3401 (2) | −0.0143 (5) | 0.0409 (11) | |
C3 | 0.3196 (5) | 0.2955 (2) | −0.1511 (4) | 0.0406 (11) | |
C4 | 0.3631 (5) | 0.2166 (2) | −0.1383 (4) | 0.0396 (11) | |
C5 | 0.4157 (5) | 0.1867 (2) | 0.0115 (5) | 0.0362 (11) | |
C6 | 0.4285 (5) | 0.2324 (2) | 0.1483 (4) | 0.0366 (10) | |
C11 | 0.4011 (5) | 0.3619 (2) | 0.2832 (5) | 0.0415 (11) | |
C12 | 0.5753 (6) | 0.4178 (2) | 0.3164 (4) | 0.0375 (11) | |
C13 | 0.5757 (7) | 0.4678 (3) | 0.4589 (5) | 0.0501 (14) | |
C21 | 0.2332 (7) | 0.4163 (4) | −0.2158 (6) | 0.0651 (17) | |
C22 | 0.2535 (6) | 0.3465 (3) | −0.2790 (5) | 0.0510 (14) | |
C51 | 0.4978 (7) | 0.1091 (3) | 0.2125 (7) | 0.0590 (16) | |
C52 | 0.4841 (6) | 0.1799 (3) | 0.2771 (5) | 0.0486 (14) | |
O2A | 1.1484 (4) | 0.79957 (15) | −0.0779 (3) | 0.0400 (8) | |
O11A | 1.2504 (5) | 0.78262 (18) | 0.3966 (3) | 0.0533 (10) | |
O12A | 1.2305 (5) | 0.85780 (16) | 0.1892 (4) | 0.0482 (10) | |
O31A | 0.9898 (7) | 0.7301 (2) | −0.3507 (4) | 0.0735 (13) | |
O32A | 0.9994 (7) | 0.6051 (2) | −0.3528 (4) | 0.0735 (13) | |
O51A | 0.8995 (6) | 0.4708 (2) | 0.0957 (5) | 0.0701 (13) | |
O52A | 1.0443 (5) | 0.51120 (19) | 0.3278 (4) | 0.0564 (11) | |
N3A | 1.0113 (4) | 0.6676 (2) | −0.2831 (3) | 0.0437 (10) | |
N5A | 0.9958 (6) | 0.5200 (2) | 0.1852 (5) | 0.0483 (11) | |
C1A | 1.1466 (4) | 0.72417 (19) | 0.1472 (4) | 0.0290 (9) | |
C2A | 1.1153 (5) | 0.73408 (19) | −0.0217 (4) | 0.0298 (9) | |
C3A | 1.0484 (4) | 0.6657 (2) | −0.1125 (3) | 0.0327 (9) | |
C4A | 1.0113 (5) | 0.5968 (2) | −0.0443 (5) | 0.0358 (10) | |
C5A | 1.0447 (5) | 0.59147 (19) | 0.1156 (4) | 0.0329 (10) | |
C6A | 1.1144 (4) | 0.6540 (3) | 0.2138 (3) | 0.0323 (8) | |
C11A | 1.2143 (5) | 0.7904 (2) | 0.2550 (4) | 0.0363 (11) | |
H12 | 0.56680 | 0.45140 | 0.22450 | 0.0450* | |
H21 | 0.19160 | 0.46060 | −0.27530 | 0.0780* | |
H22 | 0.22890 | 0.33420 | −0.38570 | 0.0610* | |
H51 | 0.53090 | 0.06400 | 0.27130 | 0.0710* | |
H52 | 0.50650 | 0.19170 | 0.38390 | 0.0580* | |
H111 | 0.41030 | 0.32840 | 0.37410 | 0.0500* | |
H112 | 0.28000 | 0.39160 | 0.26990 | 0.0500* | |
H121 | 0.760 (5) | 0.349 (2) | 0.255 (5) | 0.050 (9)* | |
H122 | 0.861 (6) | 0.410 (3) | 0.357 (5) | 0.047 (10)* | |
H123 | 0.773 (6) | 0.342 (3) | 0.437 (5) | 0.047 (10)* | |
H131 | 0.69210 | 0.49960 | 0.48110 | 0.0750* | |
H132 | 0.57470 | 0.43530 | 0.54810 | 0.0750* | |
H133 | 0.46060 | 0.50040 | 0.43800 | 0.0750* | |
H4A | 0.96360 | 0.55420 | −0.10710 | 0.0430* | |
H6A | 1.13890 | 0.64870 | 0.32280 | 0.0390* | |
H12A | 1.222 (6) | 0.854 (3) | 0.087 (6) | 0.050 (11)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br4 | 0.0551 (2) | 0.0804 (3) | 0.0520 (2) | −0.0214 (2) | 0.0192 (2) | −0.0302 (2) |
O2 | 0.0565 (17) | 0.0461 (17) | 0.072 (2) | 0.0007 (14) | 0.0124 (15) | 0.0034 (14) |
O5 | 0.0440 (16) | 0.0410 (17) | 0.077 (2) | −0.0007 (12) | 0.0166 (15) | −0.0108 (14) |
N12 | 0.0411 (17) | 0.0366 (17) | 0.0310 (15) | −0.0031 (14) | 0.0111 (12) | −0.0012 (13) |
C1 | 0.0284 (16) | 0.042 (2) | 0.0424 (18) | −0.0083 (14) | 0.0125 (14) | −0.0079 (15) |
C2 | 0.0289 (17) | 0.041 (2) | 0.054 (2) | −0.0062 (14) | 0.0121 (15) | −0.0025 (16) |
C3 | 0.0250 (16) | 0.054 (2) | 0.044 (2) | −0.0128 (16) | 0.0104 (14) | 0.0005 (17) |
C4 | 0.0266 (16) | 0.051 (2) | 0.0422 (19) | −0.0112 (15) | 0.0099 (14) | −0.0157 (16) |
C5 | 0.0294 (18) | 0.0346 (19) | 0.048 (2) | −0.0053 (14) | 0.0158 (15) | −0.0079 (15) |
C6 | 0.0285 (16) | 0.045 (2) | 0.0372 (18) | −0.0074 (15) | 0.0094 (14) | −0.0046 (15) |
C11 | 0.0356 (18) | 0.048 (2) | 0.045 (2) | −0.0031 (16) | 0.0178 (15) | −0.0107 (16) |
C12 | 0.0452 (19) | 0.0308 (18) | 0.0387 (18) | −0.0005 (15) | 0.0143 (15) | −0.0036 (14) |
C13 | 0.068 (3) | 0.038 (2) | 0.044 (2) | 0.0032 (19) | 0.0125 (19) | −0.0100 (16) |
C21 | 0.055 (3) | 0.070 (3) | 0.070 (3) | −0.003 (2) | 0.014 (2) | 0.023 (3) |
C22 | 0.042 (2) | 0.072 (3) | 0.038 (2) | −0.011 (2) | 0.0071 (17) | 0.0088 (19) |
C51 | 0.048 (2) | 0.056 (3) | 0.072 (3) | 0.004 (2) | 0.012 (2) | 0.018 (2) |
C52 | 0.041 (2) | 0.057 (3) | 0.048 (2) | 0.0014 (17) | 0.0106 (16) | 0.0076 (18) |
O2A | 0.0523 (15) | 0.0327 (14) | 0.0385 (13) | −0.0052 (11) | 0.0174 (11) | 0.0011 (10) |
O11A | 0.074 (2) | 0.0508 (18) | 0.0349 (14) | −0.0022 (15) | 0.0119 (13) | −0.0091 (12) |
O12A | 0.0645 (18) | 0.0369 (16) | 0.0451 (16) | −0.0092 (13) | 0.0168 (13) | −0.0089 (12) |
O31A | 0.108 (3) | 0.069 (2) | 0.0384 (16) | −0.027 (2) | 0.0066 (17) | 0.0088 (15) |
O32A | 0.102 (3) | 0.067 (2) | 0.0454 (18) | 0.005 (2) | 0.0042 (18) | −0.0173 (16) |
O51A | 0.097 (3) | 0.0351 (17) | 0.086 (2) | −0.0207 (17) | 0.037 (2) | −0.0034 (16) |
O52A | 0.071 (2) | 0.0434 (17) | 0.060 (2) | 0.0030 (15) | 0.0260 (17) | 0.0182 (14) |
N3A | 0.0381 (15) | 0.055 (2) | 0.0365 (14) | −0.0095 (15) | 0.0055 (12) | −0.0065 (15) |
N5A | 0.054 (2) | 0.0314 (19) | 0.067 (2) | 0.0058 (16) | 0.0294 (18) | 0.0061 (16) |
C1A | 0.0198 (14) | 0.0317 (17) | 0.0371 (17) | 0.0013 (13) | 0.0101 (12) | −0.0019 (13) |
C2A | 0.0248 (15) | 0.0304 (18) | 0.0363 (16) | 0.0021 (13) | 0.0112 (12) | −0.0007 (13) |
C3A | 0.0283 (14) | 0.039 (2) | 0.0309 (14) | 0.0008 (14) | 0.0073 (11) | 0.0001 (13) |
C4A | 0.0249 (16) | 0.0285 (17) | 0.056 (2) | −0.0018 (13) | 0.0136 (15) | −0.0058 (14) |
C5A | 0.0267 (16) | 0.0250 (17) | 0.051 (2) | 0.0006 (13) | 0.0170 (14) | 0.0029 (14) |
C6A | 0.0288 (13) | 0.0375 (16) | 0.0313 (13) | 0.0063 (16) | 0.0086 (10) | 0.0029 (16) |
C11A | 0.0335 (17) | 0.037 (2) | 0.0398 (19) | 0.0017 (15) | 0.0116 (14) | −0.0056 (15) |
Br4—C4 | 1.872 (3) | C5—C6 | 1.414 (5) |
O2—C2 | 1.366 (5) | C6—C52 | 1.424 (6) |
O2—C21 | 1.377 (6) | C11—C12 | 1.523 (5) |
O5—C5 | 1.359 (5) | C12—C13 | 1.511 (6) |
O5—C51 | 1.374 (7) | C21—C22 | 1.343 (8) |
O2A—C2A | 1.272 (4) | C51—C52 | 1.355 (7) |
O11A—C11A | 1.209 (4) | C11—H111 | 0.9700 |
O12A—C11A | 1.311 (5) | C11—H112 | 0.9700 |
O31A—N3A | 1.220 (5) | C12—H12 | 0.9800 |
O32A—N3A | 1.229 (5) | C13—H133 | 0.9600 |
O51A—N5A | 1.239 (6) | C13—H132 | 0.9600 |
O52A—N5A | 1.220 (5) | C13—H131 | 0.9600 |
O12A—H12A | 0.88 (5) | C21—H21 | 0.9300 |
N12—C12 | 1.500 (5) | C22—H22 | 0.9300 |
N12—H123 | 0.96 (5) | C51—H51 | 0.9300 |
N12—H122 | 0.92 (5) | C52—H52 | 0.9300 |
N12—H121 | 0.87 (4) | C1A—C6A | 1.381 (6) |
N3A—C3A | 1.450 (4) | C1A—C11A | 1.484 (5) |
N5A—C5A | 1.447 (5) | C1A—C2A | 1.448 (5) |
C1—C6 | 1.394 (5) | C2A—C3A | 1.435 (5) |
C1—C2 | 1.391 (5) | C3A—C4A | 1.378 (5) |
C1—C11 | 1.510 (5) | C4A—C5A | 1.362 (5) |
C2—C3 | 1.403 (5) | C5A—C6A | 1.391 (5) |
C3—C22 | 1.410 (6) | C4A—H4A | 0.9300 |
C3—C4 | 1.391 (5) | C6A—H6A | 0.9300 |
C4—C5 | 1.372 (5) | ||
C2—O2—C21 | 104.9 (4) | C1—C11—H112 | 109.00 |
C5—O5—C51 | 105.3 (3) | C12—C11—H112 | 109.00 |
C11A—O12A—H12A | 113 (3) | H111—C11—H112 | 108.00 |
H121—N12—H123 | 118 (4) | C1—C11—H111 | 109.00 |
C12—N12—H122 | 104 (3) | C11—C12—H12 | 109.00 |
C12—N12—H123 | 108 (3) | N12—C12—H12 | 109.00 |
C12—N12—H121 | 104 (2) | C13—C12—H12 | 109.00 |
H121—N12—H122 | 108 (4) | H132—C13—H133 | 109.00 |
H122—N12—H123 | 113 (4) | C12—C13—H131 | 109.00 |
O32A—N3A—C3A | 117.6 (3) | C12—C13—H132 | 110.00 |
O31A—N3A—C3A | 119.2 (3) | C12—C13—H133 | 109.00 |
O31A—N3A—O32A | 123.2 (3) | H131—C13—H132 | 109.00 |
O51A—N5A—O52A | 122.6 (4) | H131—C13—H133 | 109.00 |
O51A—N5A—C5A | 117.6 (4) | C22—C21—H21 | 124.00 |
O52A—N5A—C5A | 119.7 (4) | O2—C21—H21 | 124.00 |
C6—C1—C11 | 122.7 (3) | C21—C22—H22 | 127.00 |
C2—C1—C6 | 114.0 (3) | C3—C22—H22 | 127.00 |
C2—C1—C11 | 123.3 (3) | O5—C51—H51 | 124.00 |
C1—C2—C3 | 125.1 (3) | C52—C51—H51 | 124.00 |
O2—C2—C3 | 110.1 (3) | C51—C52—H52 | 127.00 |
O2—C2—C1 | 124.8 (4) | C6—C52—H52 | 127.00 |
C2—C3—C22 | 106.1 (3) | C2A—C1A—C6A | 122.0 (3) |
C2—C3—C4 | 119.7 (3) | C2A—C1A—C11A | 120.3 (3) |
C4—C3—C22 | 134.2 (4) | C6A—C1A—C11A | 117.7 (3) |
C3—C4—C5 | 116.6 (3) | O2A—C2A—C3A | 125.4 (3) |
Br4—C4—C3 | 121.6 (3) | C1A—C2A—C3A | 114.7 (3) |
Br4—C4—C5 | 121.7 (3) | O2A—C2A—C1A | 119.9 (3) |
O5—C5—C4 | 126.3 (4) | N3A—C3A—C2A | 120.4 (3) |
O5—C5—C6 | 110.7 (3) | C2A—C3A—C4A | 122.5 (3) |
C4—C5—C6 | 123.0 (3) | N3A—C3A—C4A | 117.1 (3) |
C5—C6—C52 | 105.3 (3) | C3A—C4A—C5A | 119.6 (3) |
C1—C6—C5 | 121.6 (3) | N5A—C5A—C6A | 118.9 (3) |
C1—C6—C52 | 133.1 (3) | C4A—C5A—C6A | 122.0 (3) |
C1—C11—C12 | 114.2 (3) | N5A—C5A—C4A | 119.0 (3) |
N12—C12—C13 | 109.1 (3) | C1A—C6A—C5A | 119.1 (3) |
N12—C12—C11 | 109.6 (3) | O11A—C11A—C1A | 121.5 (3) |
C11—C12—C13 | 111.5 (3) | O12A—C11A—C1A | 116.8 (3) |
O2—C21—C22 | 112.7 (5) | O11A—C11A—O12A | 121.7 (3) |
C3—C22—C21 | 106.2 (4) | C3A—C4A—H4A | 120.00 |
O5—C51—C52 | 112.7 (4) | C5A—C4A—H4A | 120.00 |
C6—C52—C51 | 106.0 (4) | C1A—C6A—H6A | 120.00 |
C12—C11—H111 | 109.00 | C5A—C6A—H6A | 121.00 |
C21—O2—C2—C1 | −178.3 (4) | Br4—C4—C5—O5 | −0.4 (5) |
C21—O2—C2—C3 | 0.3 (4) | Br4—C4—C5—C6 | −178.7 (3) |
C2—O2—C21—C22 | 0.0 (5) | C3—C4—C5—O5 | 177.7 (4) |
C51—O5—C5—C4 | −178.8 (4) | C3—C4—C5—C6 | −0.7 (5) |
C51—O5—C5—C6 | −0.3 (4) | O5—C5—C6—C1 | −178.9 (3) |
C5—O5—C51—C52 | −0.3 (5) | O5—C5—C6—C52 | 0.7 (4) |
O31A—N3A—C3A—C2A | −17.9 (5) | C4—C5—C6—C52 | 179.3 (4) |
O31A—N3A—C3A—C4A | 160.4 (4) | C4—C5—C6—C1 | −0.3 (6) |
C2A—C3A—N3A—O32A | 163.5 (4) | C5—C6—C52—C51 | −0.8 (5) |
O32A—N3A—C3A—C4A | −18.3 (5) | C1—C6—C52—C51 | 178.7 (4) |
O51A—N5A—C5A—C6A | 166.4 (4) | C1—C11—C12—N12 | −60.8 (4) |
C4A—C5A—N5A—O52A | 172.1 (4) | C1—C11—C12—C13 | 178.3 (3) |
O51A—N5A—C5A—C4A | −10.2 (6) | O2—C21—C22—C3 | −0.3 (5) |
O52A—N5A—C5A—C6A | −11.4 (6) | O5—C51—C52—C6 | 0.7 (5) |
C6—C1—C2—C3 | −0.8 (5) | C6A—C1A—C2A—O2A | −179.4 (3) |
C11—C1—C2—O2 | −1.4 (6) | C6A—C1A—C2A—C3A | 0.2 (5) |
C6—C1—C2—O2 | 177.6 (4) | C11A—C1A—C2A—O2A | 0.9 (5) |
C6—C1—C11—C12 | 108.9 (4) | C11A—C1A—C2A—C3A | −179.5 (3) |
C11—C1—C2—C3 | −179.8 (3) | C2A—C1A—C6A—C5A | −1.8 (5) |
C2—C1—C6—C5 | 1.0 (5) | C11A—C1A—C6A—C5A | 177.9 (3) |
C2—C1—C6—C52 | −178.4 (4) | C2A—C1A—C11A—O11A | −176.5 (4) |
C11—C1—C6—C5 | 180.0 (3) | C2A—C1A—C11A—O12A | 4.4 (5) |
C11—C1—C6—C52 | 0.5 (6) | C6A—C1A—C11A—O11A | 3.9 (5) |
C2—C1—C11—C12 | −72.2 (5) | C6A—C1A—C11A—O12A | −175.3 (3) |
O2—C2—C3—C22 | −0.4 (4) | O2A—C2A—C3A—N3A | −0.5 (5) |
C1—C2—C3—C4 | −0.1 (6) | O2A—C2A—C3A—C4A | −178.6 (3) |
C1—C2—C3—C22 | 178.2 (4) | C1A—C2A—C3A—N3A | −180.0 (3) |
O2—C2—C3—C4 | −178.7 (3) | C1A—C2A—C3A—C4A | 1.9 (5) |
C2—C3—C4—Br4 | 178.9 (3) | N3A—C3A—C4A—C5A | 179.6 (3) |
C2—C3—C4—C5 | 0.9 (5) | C2A—C3A—C4A—C5A | −2.2 (5) |
C22—C3—C4—C5 | −176.8 (4) | C3A—C4A—C5A—N5A | 177.0 (3) |
C2—C3—C22—C21 | 0.4 (5) | C3A—C4A—C5A—C6A | 0.5 (5) |
C22—C3—C4—Br4 | 1.2 (6) | N5A—C5A—C6A—C1A | −175.0 (3) |
C4—C3—C22—C21 | 178.3 (4) | C4A—C5A—C6A—C1A | 1.5 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
O12A—H12A···O2A | 0.88 (5) | 1.69 (5) | 2.477 (4) | 147 (5) |
O12A—H12A···O51Ai | 0.88 (5) | 2.58 (5) | 3.120 (5) | 120 (4) |
N12—H121···O2Aii | 0.87 (4) | 1.99 (4) | 2.826 (4) | 160 (3) |
N12—H122···O51A | 0.92 (5) | 2.58 (4) | 3.059 (5) | 114 (3) |
N12—H122···O52A | 0.92 (5) | 2.21 (5) | 3.101 (5) | 165 (4) |
N12—H123···O11Aiii | 0.96 (5) | 1.81 (5) | 2.763 (4) | 172 (4) |
Symmetry codes: (i) −x+2, y+1/2, −z; (ii) −x+2, y−1/2, −z; (iii) −x+2, y−1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C13H13BrNO2+·C7H3N2O7− |
Mr | 522.28 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 297 |
a, b, c (Å) | 6.9596 (3), 17.2201 (9), 8.7147 (4) |
β (°) | 103.315 (4) |
V (Å3) | 1016.34 (8) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.08 |
Crystal size (mm) | 0.50 × 0.30 × 0.25 |
Data collection | |
Diffractometer | Oxford Gemini-S Ultra CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.410, 0.590 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10418, 4450, 3733 |
Rint | 0.053 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.112, 1.01 |
No. of reflections | 4450 |
No. of parameters | 315 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.82, −0.28 |
Absolute structure | Flack (1983), with 2047 Friedel pairs |
Absolute structure parameter | 0.038 (9) |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999), PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O12A—H12A···O2A | 0.88 (5) | 1.69 (5) | 2.477 (4) | 147 (5) |
O12A—H12A···O51Ai | 0.88 (5) | 2.58 (5) | 3.120 (5) | 120 (4) |
N12—H121···O2Aii | 0.87 (4) | 1.99 (4) | 2.826 (4) | 160 (3) |
N12—H122···O51A | 0.92 (5) | 2.58 (4) | 3.059 (5) | 114 (3) |
N12—H122···O52A | 0.92 (5) | 2.21 (5) | 3.101 (5) | 165 (4) |
N12—H123···O11Aiii | 0.96 (5) | 1.81 (5) | 2.763 (4) | 172 (4) |
Symmetry codes: (i) −x+2, y+1/2, −z; (ii) −x+2, y−1/2, −z; (iii) −x+2, y−1/2, −z+1. |
The bromo-substituted difuran amphetamine derivative 1-(8-bromobenzo[1,2-b;4,5-b']difuran-4-yl)-2-aminopropane (BDF), with the common trivial name of `bromodragonfly' due to its visual molecular configuration, was first synthesized in the racemic form by the Nichols group (Parker et al., 1998), who described it as a potent hallucinogen with an activity significantly enhanced compared with that of LSD (d-lysergic acid, N,N-diethylamide). It is in fact the first compound with LSD activity having an aromatic nucleus other than benzene or indole and is recognized as the most potent known ligand for agonist binding to both the serotonin 5-HT2A and 5-HT2C receptors (5-HT = 5-hydroxytryptamine) (Chambers et al., 2001). With amphetamines generally, the (R)-enantiomer is the most physiologically active form with respect to hallucinogenic activity, whereas the S form is more active as a central nervous system (CNS) stimulant (Hardman et al., 1996). Both the (R)- and the (S)-enantiomers of BDF have subsequently been synthesized and their relative physiological activities tested, also by the Nichols group (Chambers et al., 2001). It is therefore remarkable, considering the physiological activity of this compound, that it is not currently on the list of restricted substances in many countries. This is despite the detection of this enantiopure (R) compound in a number of commercial products, e.g. speciality paints and paint materials imported into Australia. The enantiopure BDF was isolated without resolution from such products as part of this determination (Cotton et al., 2008) and the reason for its presence in them can only be speculated upon.
Although the crystal structures of amphetamine and a number of variously ring-substituted analogues, in particular the 2,5-dimethoxy-substituted amphetamines, have been determined (e.g. rac-4-ethyl-2,5-dimethoxyamphetamine; Kennard et al., 1974), no structures of the bis-furan-substituted types are known. With the bromo analogues, the bis-furan derivatives exhibit enhanced physiological activity compared with the dimethoxy derivatives (Chambers et al., 2001). The problem with BDF has been that of obtaining crystalline samples suitable for X-ray analysis. From a number of preparations of salts of BDF with carboxylic acids, we obtained suitable crystals with only one, the relatively strong 3,5-dinitrosalicylic acid (DNSA) (pKa 2.2), from aqueous ethanolic solution. This acid has proved to be particularly effective for the generation of stable and mainly anhydrous 1:1 crystalline salts with both aliphatic and aromatic Lewis bases and we have determined the crystal structures of a large number of these (e.g. Smith et al., 2002, 2003, 2007). Additional notable structures are of the 1:1 proton-transfer compounds with the alkaloids strychnine (Smith et al., 2005) and brucine (Smith et al., 2006). The chemically stable crystalline anhydrous 1:1 salt of BDF with DNSA, R-1-(8-bromobenzo[1,2-b; 4,5-b']difuran-4-yl)-2-ammoniopropane 2-carboxy-4,6-dinitrophenolate, C13H13BrNO2+ C7H3N2O7-, (I), provided the structure which is reported here.
In the structure of (I), as expected, DNSA protonates the amine group of the isopropane side chain of BDF. Fig. 1 shows the BDF cation and the DNSA anion (the A molecule), which associate via a linear N—H···Onitro hydrogen-bonding interaction. The same H donor has a second but geometrically less favoured contact with respect to hydrogen-bonding, with the second nitro O atom [N12—H···O51A] (see Table 1). The second and third aminium H donors also give associations with both carboxyl O and phenolate O acceptors, resulting in a two-dimensional sheet structure. Undulating one-dimensional chain substructures [graph set C(8) (Etter et al., 1990)], comprising head-to-tail linked DNSA anions formed through carboxyl O—H···Onitro hydrogen bonds, extend along the b cell direction (Fig. 2). The aminium groups of the cations are incorporated within these chains, closing a cyclic R33(8) hydrogen-bonding interaction incorporating the previously mentioned cation–anion N—H···Onitro hydrogen bond (Fig. 3). The aromatic body of the BDF cation folds back under the DNSA benzene rings, layering down the a direction in the unit cell (Figs. 3 and 4). This gives cation–anion π–π interactions [minimum centroid separation for rings C1–C6 to C1A–C6A 3.566 (2) Å; inter-ring dihedral angle 5.13 (1)°]. The two-dimensional sheet structure is generated through single aminium N—H···Ocarboxyl C(8) extensions along the c axial direction. The O atoms of the second nitro group of the anion (at C3A) are unassociated, as are the O atoms of the furan `wings' of the cation. The primary DNSA anion–aminium group interactive pattern found in (I) has been categorized previously (Smith et al., 2007): the primary N+—H···O carboxyl association is Type 1 [linear C(n)], found in a large number of DNSA proton-transfer compounds. However, the secondary structure-extending interaction mode is unusual for DNSA, particularly with respect to the cyclic proximal group R33(8) association formed, along with the linear C(8) interchain association.
Because of the layered structural features found in (I), the aminium group of the BDF cation lies approximately normal to the plane of the BDF ring system [torsion angles C2—C1—C11—C12 = -72.2 (5)° and C1—C11—C12—N12 = -60.8 (4)°]. The DNSA anions have the expected short intramolecular hydrogen bond between the carboxyl and phenolate groups [O···O = 2.477 (4) Å], with the H atom localized on the carboxylate O atom rather than on the phenolic O atom. This is the case for ca 80% of the DNSA anions in the structures of over 60 proton-transfer compounds of the acid (Smith et al., 2007). This hydrogen bond results in the carboxyl group being essentially coplanar with the benzene ring [C2A—C1A—C11A—O11A = -176.5 (4)°]. Both nitro groups are rotated slightly out of the benzene plane [C2A—C3A—N3A—O32A = 163.5 (4)° and C4A—C5A—N5A—O52A = 172.1 (4)°].
The structure of (I) reported here represents the first one of any form of this bis(furan)-substituted hallucinogenically potent amphetamine, which has in the past presented problems with respect to crystal structure analysis because of its lack of crystallinity, both in the parent compound and in its salts with a number of organic acids. However, with (I), from the reaction with 3,5-dinitrosalicylic acid in ethanol–water, crystals are particularly well formed and chemically stable. The crystal structure determination not only provides a key to the stability of the crystal in the hydrogen-bonded two-dimensional network structure, but confirms that this compound is the enantiopure (R) configurational isomer, which is known to be the more hallucinogenically active form.