Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113009098/yf3029sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113009098/yf3029Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113009098/yf3029IIsup3.hkl | |
Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113009098/yf3029Isup4.cml | |
Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113009098/yf3029IIsup5.cml |
CCDC references: 950373; 950374
For related literature, see: Abonía et al. (2001); Beaulieu et al. (2007); Bernstein et al. (1995); Bondi (1964); Castillo et al. (2010, 2013); Cremer & Pople (1975); Desplat et al. (2010); Glidewell & Lloyd (1984, 1986); Grande et al. (2007); Guillon et al. (2007); Lancelot et al. (1994); Maeba et al. (1990); Neale et al. (1987); Wood et al. (2009).
For the synthesis of (I), a mixture of 1-(2-aminophenyl)pyrrole (0.63 mmol), 2-chlorobenzaldehyde (0.63 mmol) and palladium/charcoal (10%, 0.63 mmol) was dissolved in acetonitrile (2 ml). The solution was stirred at ambient temperature for 48 h until the starting materials were no longer detected by thin-layer chromatography. The palladium/charcoal was then removed by filtration, the solvent was removed under reduced pressure and the crude product was purified by column chromatography on silica gel using a 3:1 v/v chloroform–hexane mixture as eluent. Colourless crystals of (I) suitable for single-crystal X-ray diffraction were grown by slow evaporation, at ambient temperature and in air, of a solution in ethanol (yield 91%, m.p. 453 K). MS (70 eV) m/z (%): 280/278 (34/100) [M+], 254/252 (8/25), 121 (41); analysis, found: C 73.3, H 3.9, N 10.1%; C17H11ClN2 requires: C 73.3, H 4.0, N 10.1%. For the synthesis of (II), a mixture of 1-(2-aminophenyl)pyrrole (0.63 mmol) and piperonal (0.63 mmol) was dissolved in a mixture of acetonitrile and water (2:1 v/v; 1.5 ml). The mixture was left at ambient temperature without stirring for 6 d; the resulting solid product was collected by filtration and washed with hexane. Yellow crystals of (II) suitable for single-crystal X-ray diffraction were grown by slow evaporation, at ambient temperature and in air, of a solution in ethanol (yield 86%, m.p. 434 K). MS (70 eV) m/z (%): 290 (42) [M+], 229 (7), 169 (100), 157 (9), 115 (8); analysis, found: C 74.3, H 4.9, N 9.4%; C18H14N2O2 requires: C 74.5, H 4.9, N 9.7%.
All H atoms were located in difference maps. C-bound H atoms were then treated as riding in geometrically idealized positions, with C—H = 0.95 (aromatic and pyrrole), 0.99 (CH2) or 1.00 Å (aliphatic), and with Uiso(H) = 1.2Ueq(C). The N-bound H atom in (II) was permitted to ride at the position found in a difference map, with Uiso(H) = 1.2Ueq(N), giving N—H = 0.88 Å.
For both compounds, data collection: COLLECT (Nonius, 1998); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003). Program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) for (I); SIR2004 (Burla et al., 2005) for (II). For both compounds, program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
C17H11ClN2 | F(000) = 576 |
Mr = 278.73 | Dx = 1.433 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2984 reflections |
a = 13.5649 (13) Å | θ = 3.0–27.5° |
b = 11.8142 (11) Å | µ = 0.29 mm−1 |
c = 8.1678 (12) Å | T = 120 K |
β = 99.281 (10)° | Block, colourless |
V = 1291.8 (3) Å3 | 0.42 × 0.25 × 0.22 mm |
Z = 4 |
Bruker Nonius KappaCCD area-detector diffractometer | 2984 independent reflections |
Radiation source: Bruker Nonius FR591 rotating anode | 2187 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.047 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.0° |
ϕ and ω scans | h = −17→17 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −14→15 |
Tmin = 0.890, Tmax = 0.940 | l = −10→10 |
18171 measured reflections |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.116 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0544P)2 + 0.6625P] where P = (Fo2 + 2Fc2)/3 |
2984 reflections | (Δ/σ)max = 0.001 |
181 parameters | Δρmax = 0.31 e Å−3 |
0 restraints | Δρmin = −0.33 e Å−3 |
C17H11ClN2 | V = 1291.8 (3) Å3 |
Mr = 278.73 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 13.5649 (13) Å | µ = 0.29 mm−1 |
b = 11.8142 (11) Å | T = 120 K |
c = 8.1678 (12) Å | 0.42 × 0.25 × 0.22 mm |
β = 99.281 (10)° |
Bruker Nonius KappaCCD area-detector diffractometer | 2984 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2187 reflections with I > 2σ(I) |
Tmin = 0.890, Tmax = 0.940 | Rint = 0.047 |
18171 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.116 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.31 e Å−3 |
2984 reflections | Δρmin = −0.33 e Å−3 |
181 parameters |
x | y | z | Uiso*/Ueq | ||
C1 | 0.34705 (14) | 0.75957 (17) | 0.4570 (2) | 0.0252 (4) | |
H1 | 0.3527 | 0.8382 | 0.4357 | 0.030* | |
C2 | 0.40865 (14) | 0.67575 (17) | 0.4147 (2) | 0.0270 (4) | |
H2 | 0.4642 | 0.6868 | 0.3591 | 0.032* | |
C3 | 0.37595 (14) | 0.57131 (17) | 0.4673 (2) | 0.0247 (4) | |
H3 | 0.4048 | 0.4993 | 0.4538 | 0.030* | |
C3a | 0.29317 (13) | 0.59319 (16) | 0.5431 (2) | 0.0210 (4) | |
C4 | 0.22842 (13) | 0.52535 (16) | 0.6229 (2) | 0.0216 (4) | |
N5 | 0.15083 (11) | 0.56487 (13) | 0.68203 (19) | 0.0219 (3) | |
C5a | 0.13447 (13) | 0.68197 (16) | 0.6709 (2) | 0.0213 (4) | |
C6 | 0.05335 (14) | 0.72742 (17) | 0.7364 (2) | 0.0251 (4) | |
H6 | 0.0103 | 0.6782 | 0.7840 | 0.030* | |
C7 | 0.03527 (15) | 0.84232 (18) | 0.7328 (2) | 0.0277 (4) | |
H7 | −0.0197 | 0.8718 | 0.7780 | 0.033* | |
C8 | 0.09805 (15) | 0.91530 (17) | 0.6624 (2) | 0.0276 (4) | |
H8 | 0.0854 | 0.9944 | 0.6601 | 0.033* | |
C9 | 0.17847 (15) | 0.87330 (16) | 0.5960 (2) | 0.0256 (4) | |
H9 | 0.2208 | 0.9231 | 0.5480 | 0.031* | |
C9a | 0.19646 (13) | 0.75749 (16) | 0.6006 (2) | 0.0210 (4) | |
N9b | 0.27628 (11) | 0.70985 (13) | 0.53517 (18) | 0.0209 (3) | |
C41 | 0.24779 (14) | 0.40080 (16) | 0.6382 (2) | 0.0217 (4) | |
C42 | 0.33173 (14) | 0.35660 (16) | 0.7397 (2) | 0.0230 (4) | |
Cl42 | 0.41717 (4) | 0.44616 (4) | 0.85870 (6) | 0.03018 (16) | |
C43 | 0.34865 (15) | 0.24091 (16) | 0.7547 (2) | 0.0262 (4) | |
H43 | 0.4060 | 0.2126 | 0.8251 | 0.031* | |
C44 | 0.28068 (15) | 0.16737 (17) | 0.6655 (2) | 0.0287 (4) | |
H44 | 0.2917 | 0.0880 | 0.6741 | 0.034* | |
C45 | 0.19673 (15) | 0.20885 (17) | 0.5637 (2) | 0.0275 (4) | |
H45 | 0.1502 | 0.1580 | 0.5033 | 0.033* | |
C46 | 0.18072 (14) | 0.32427 (17) | 0.5504 (2) | 0.0247 (4) | |
H46 | 0.1231 | 0.3520 | 0.4802 | 0.030* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0244 (10) | 0.0283 (10) | 0.0233 (9) | −0.0063 (8) | 0.0048 (8) | 0.0025 (8) |
C2 | 0.0226 (10) | 0.0330 (11) | 0.0262 (10) | −0.0027 (8) | 0.0068 (8) | 0.0011 (8) |
C3 | 0.0215 (9) | 0.0282 (11) | 0.0249 (9) | 0.0015 (8) | 0.0048 (8) | −0.0016 (8) |
C3a | 0.0219 (9) | 0.0202 (9) | 0.0204 (9) | 0.0003 (7) | 0.0019 (7) | −0.0010 (7) |
C4 | 0.0191 (9) | 0.0266 (10) | 0.0177 (9) | −0.0005 (8) | −0.0006 (7) | −0.0018 (7) |
N5 | 0.0196 (8) | 0.0240 (8) | 0.0217 (8) | −0.0024 (6) | 0.0023 (6) | −0.0002 (6) |
C5a | 0.0202 (9) | 0.0241 (10) | 0.0187 (9) | 0.0003 (8) | 0.0003 (7) | 0.0008 (7) |
C6 | 0.0207 (9) | 0.0308 (11) | 0.0237 (10) | −0.0011 (8) | 0.0029 (8) | −0.0004 (8) |
C7 | 0.0243 (10) | 0.0338 (11) | 0.0244 (10) | 0.0054 (9) | 0.0019 (8) | −0.0026 (8) |
C8 | 0.0313 (11) | 0.0229 (10) | 0.0281 (10) | 0.0034 (8) | 0.0030 (8) | −0.0014 (8) |
C9 | 0.0289 (10) | 0.0235 (10) | 0.0241 (10) | −0.0021 (8) | 0.0034 (8) | −0.0006 (8) |
C9a | 0.0191 (9) | 0.0253 (10) | 0.0181 (9) | −0.0002 (7) | 0.0009 (7) | −0.0019 (7) |
N9b | 0.0212 (8) | 0.0206 (8) | 0.0206 (7) | −0.0012 (6) | 0.0027 (6) | 0.0003 (6) |
C41 | 0.0217 (9) | 0.0236 (9) | 0.0210 (9) | −0.0022 (8) | 0.0073 (7) | 0.0006 (7) |
C42 | 0.0242 (9) | 0.0225 (9) | 0.0225 (9) | −0.0022 (8) | 0.0044 (7) | −0.0032 (7) |
Cl42 | 0.0299 (3) | 0.0247 (3) | 0.0324 (3) | −0.0005 (2) | −0.00563 (19) | −0.0037 (2) |
C43 | 0.0283 (10) | 0.0253 (10) | 0.0255 (10) | 0.0009 (8) | 0.0057 (8) | 0.0002 (8) |
C44 | 0.0365 (11) | 0.0211 (10) | 0.0299 (10) | −0.0019 (9) | 0.0093 (9) | −0.0003 (8) |
C45 | 0.0322 (11) | 0.0244 (10) | 0.0260 (10) | −0.0086 (8) | 0.0046 (8) | −0.0044 (8) |
C46 | 0.0218 (9) | 0.0290 (10) | 0.0234 (9) | −0.0029 (8) | 0.0044 (7) | 0.0000 (8) |
C1—C2 | 1.375 (3) | C9—H9 | 0.9500 |
C1—H1 | 0.9500 | C9a—N9b | 1.401 (2) |
C2—C3 | 1.402 (3) | N9b—C1 | 1.368 (2) |
C2—H2 | 0.9500 | C3a—N9b | 1.397 (2) |
C3—C3a | 1.391 (3) | C5a—C9a | 1.410 (3) |
C3—H3 | 0.9500 | C4—C41 | 1.497 (3) |
C3a—C4 | 1.422 (3) | C41—C46 | 1.396 (3) |
C4—N5 | 1.313 (2) | C41—C42 | 1.397 (3) |
N5—C5a | 1.402 (2) | C42—C43 | 1.388 (3) |
C5a—C6 | 1.405 (3) | C42—Cl42 | 1.7448 (19) |
C6—C7 | 1.379 (3) | C43—C44 | 1.385 (3) |
C6—H6 | 0.9500 | C43—H43 | 0.9500 |
C7—C8 | 1.399 (3) | C44—C45 | 1.386 (3) |
C7—H7 | 0.9500 | C44—H44 | 0.9500 |
C8—C9 | 1.386 (3) | C45—C46 | 1.382 (3) |
C8—H8 | 0.9500 | C45—H45 | 0.9500 |
C9—C9a | 1.389 (3) | C46—H46 | 0.9500 |
N9b—C1—C2 | 107.96 (17) | C8—C9—C9a | 119.21 (18) |
N9b—C1—H1 | 126.0 | C8—C9—H9 | 120.4 |
C2—C1—H1 | 126.0 | C9a—C9—H9 | 120.4 |
C1—C2—C3 | 108.77 (17) | C9—C9a—N9b | 121.92 (17) |
C1—C2—H2 | 125.6 | C9—C9a—C5a | 121.36 (17) |
C3—C2—H2 | 125.6 | N9b—C9a—C5a | 116.73 (16) |
C3a—C3—C2 | 106.91 (17) | C1—N9b—C3a | 108.85 (15) |
C3a—C3—H3 | 126.5 | C1—N9b—C9a | 130.49 (16) |
C2—C3—H3 | 126.5 | C3a—N9b—C9a | 120.65 (15) |
C3—C3a—N9b | 107.51 (16) | C46—C41—C42 | 117.65 (17) |
C3—C3a—C4 | 134.56 (18) | C46—C41—C4 | 120.19 (17) |
N9b—C3a—C4 | 117.93 (16) | C42—C41—C4 | 122.16 (16) |
N5—C4—C3a | 124.00 (17) | C43—C42—C41 | 121.85 (17) |
N5—C4—C41 | 117.36 (16) | C43—C42—Cl42 | 117.54 (15) |
C3a—C4—C41 | 118.63 (16) | C41—C42—Cl42 | 120.57 (14) |
C4—N5—C5a | 117.08 (16) | C44—C43—C42 | 118.98 (19) |
N5—C5a—C6 | 118.55 (17) | C44—C43—H43 | 120.5 |
N5—C5a—C9a | 123.51 (17) | C42—C43—H43 | 120.5 |
C6—C5a—C9a | 117.92 (17) | C43—C44—C45 | 120.41 (18) |
C7—C6—C5a | 121.02 (18) | C43—C44—H44 | 119.8 |
C7—C6—H6 | 119.5 | C45—C44—H44 | 119.8 |
C5a—C6—H6 | 119.5 | C46—C45—C44 | 119.96 (18) |
C6—C7—C8 | 119.85 (19) | C46—C45—H45 | 120.0 |
C6—C7—H7 | 120.1 | C44—C45—H45 | 120.0 |
C8—C7—H7 | 120.1 | C45—C46—C41 | 121.14 (18) |
C9—C8—C7 | 120.65 (19) | C45—C46—H46 | 119.4 |
C9—C8—H8 | 119.7 | C41—C46—H46 | 119.4 |
C7—C8—H8 | 119.7 | ||
N9b—C1—C2—C3 | 0.0 (2) | C2—C1—N9b—C9a | −179.42 (17) |
C1—C2—C3—C3a | −0.2 (2) | C3—C3a—N9b—C1 | −0.2 (2) |
C2—C3—C3a—N9b | 0.2 (2) | C4—C3a—N9b—C1 | 178.91 (16) |
C2—C3—C3a—C4 | −178.7 (2) | C3—C3a—N9b—C9a | 179.37 (15) |
C3—C3a—C4—N5 | −177.53 (19) | C4—C3a—N9b—C9a | −1.5 (2) |
N9b—C3a—C4—N5 | 3.6 (3) | C9—C9a—N9b—C1 | −1.2 (3) |
C3—C3a—C4—C41 | 1.1 (3) | C5a—C9a—N9b—C1 | 178.48 (18) |
N9b—C3a—C4—C41 | −177.72 (15) | C9—C9a—N9b—C3a | 179.32 (17) |
C3a—C4—N5—C5a | −2.8 (3) | C5a—C9a—N9b—C3a | −1.0 (2) |
C41—C4—N5—C5a | 178.51 (15) | N5—C4—C41—C46 | 66.5 (2) |
C4—N5—C5a—C6 | −178.58 (16) | C3a—C4—C41—C46 | −112.3 (2) |
C4—N5—C5a—C9a | 0.0 (3) | C3a—C4—C41—C42 | 68.1 (2) |
N5—C5a—C6—C7 | 178.30 (17) | N5—C4—C41—C42 | −113.1 (2) |
C9a—C5a—C6—C7 | −0.3 (3) | C46—C41—C42—C43 | −0.3 (3) |
C5a—C6—C7—C8 | 0.3 (3) | C4—C41—C42—C43 | 179.27 (17) |
C6—C7—C8—C9 | 0.0 (3) | C46—C41—C42—Cl42 | −177.96 (13) |
C7—C8—C9—C9a | −0.2 (3) | C4—C41—C42—Cl42 | 1.6 (2) |
C8—C9—C9a—N9b | 179.79 (17) | C41—C42—C43—C44 | 0.5 (3) |
C8—C9—C9a—C5a | 0.2 (3) | Cl42—C42—C43—C44 | 178.18 (14) |
N5—C5a—C9a—C9 | −178.45 (17) | C42—C43—C44—C45 | −0.4 (3) |
C6—C5a—C9a—C9 | 0.1 (3) | C43—C44—C45—C46 | 0.3 (3) |
N5—C5a—C9a—N9b | 1.9 (3) | C44—C45—C46—C41 | −0.1 (3) |
C6—C5a—C9a—N9b | −179.53 (16) | C42—C41—C46—C45 | 0.1 (3) |
C2—C1—N9b—C3a | 0.1 (2) | C4—C41—C46—C45 | −179.45 (17) |
C18H14N2O2 | F(000) = 1216 |
Mr = 290.31 | Dx = 1.377 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3225 reflections |
a = 26.590 (3) Å | θ = 2.6–27.5° |
b = 6.2890 (9) Å | µ = 0.09 mm−1 |
c = 17.2655 (19) Å | T = 120 K |
β = 104.017 (11)° | Block, yellow |
V = 2801.3 (6) Å3 | 0.45 × 0.24 × 0.16 mm |
Z = 8 |
Bruker Nonius KappaCCD area-detector diffractometer | 3225 independent reflections |
Radiation source: Bruker Nonius FR591 rotating anode | 2350 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.046 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 2.6° |
ϕ and ω scans | h = −34→34 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −8→7 |
Tmin = 0.960, Tmax = 0.986 | l = −22→22 |
23085 measured reflections |
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)] = 0.049 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.114 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0376P)2 + 3.2029P] where P = (Fo2 + 2Fc2)/3 |
3225 reflections | (Δ/σ)max = 0.001 |
199 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
C18H14N2O2 | V = 2801.3 (6) Å3 |
Mr = 290.31 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 26.590 (3) Å | µ = 0.09 mm−1 |
b = 6.2890 (9) Å | T = 120 K |
c = 17.2655 (19) Å | 0.45 × 0.24 × 0.16 mm |
β = 104.017 (11)° |
Bruker Nonius KappaCCD area-detector diffractometer | 3225 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2350 reflections with I > 2σ(I) |
Tmin = 0.960, Tmax = 0.986 | Rint = 0.046 |
23085 measured reflections |
R[F2 > 2σ(F2)] = 0.049 | 0 restraints |
wR(F2) = 0.114 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.32 e Å−3 |
3225 reflections | Δρmin = −0.24 e Å−3 |
199 parameters |
x | y | z | Uiso*/Ueq | ||
C1 | 0.33788 (7) | 1.1611 (3) | 0.20621 (10) | 0.0301 (4) | |
H1 | 0.3143 | 1.2745 | 0.1888 | 0.036* | |
C2 | 0.37700 (7) | 1.0999 (3) | 0.17223 (11) | 0.0326 (4) | |
H2 | 0.3853 | 1.1632 | 0.1270 | 0.039* | |
C3 | 0.40297 (7) | 0.9250 (3) | 0.21654 (10) | 0.0324 (4) | |
H3 | 0.4318 | 0.8505 | 0.2066 | 0.039* | |
C3a | 0.37859 (6) | 0.8837 (3) | 0.27650 (10) | 0.0275 (4) | |
C4 | 0.38528 (6) | 0.7100 (3) | 0.33813 (10) | 0.0269 (4) | |
H4 | 0.3637 | 0.5846 | 0.3148 | 0.032* | |
N5 | 0.36709 (5) | 0.7916 (2) | 0.40552 (8) | 0.0265 (3) | |
H5 | 0.3752 | 0.7109 | 0.4484 | 0.032* | |
C5a | 0.32160 (6) | 0.9076 (3) | 0.39337 (10) | 0.0231 (4) | |
C6 | 0.29136 (6) | 0.9131 (3) | 0.44910 (10) | 0.0255 (4) | |
H6 | 0.3006 | 0.8271 | 0.4956 | 0.031* | |
C7 | 0.24801 (7) | 1.0424 (3) | 0.43741 (10) | 0.0293 (4) | |
H7 | 0.2281 | 1.0455 | 0.4762 | 0.035* | |
C8 | 0.23350 (7) | 1.1672 (3) | 0.36950 (11) | 0.0332 (4) | |
H8 | 0.2037 | 1.2554 | 0.3616 | 0.040* | |
C9 | 0.26298 (7) | 1.1623 (3) | 0.31302 (10) | 0.0297 (4) | |
H9 | 0.2531 | 1.2467 | 0.2662 | 0.036* | |
C9a | 0.30662 (6) | 1.0348 (3) | 0.32491 (10) | 0.0235 (4) | |
N9b | 0.33884 (5) | 1.0288 (2) | 0.27039 (8) | 0.0246 (3) | |
O41 | 0.59642 (4) | 0.5001 (2) | 0.45054 (7) | 0.0287 (3) | |
C42 | 0.61376 (7) | 0.7065 (3) | 0.48326 (11) | 0.0334 (4) | |
H42A | 0.6322 | 0.6926 | 0.5402 | 0.040* | |
H42B | 0.6379 | 0.7691 | 0.4540 | 0.040* | |
O43 | 0.56956 (5) | 0.8395 (2) | 0.47560 (8) | 0.0386 (3) | |
C43a | 0.52790 (6) | 0.7248 (3) | 0.43325 (10) | 0.0269 (4) | |
C44 | 0.47709 (6) | 0.7900 (3) | 0.40861 (10) | 0.0281 (4) | |
H44 | 0.4666 | 0.9287 | 0.4198 | 0.034* | |
C45 | 0.44164 (6) | 0.6418 (3) | 0.36624 (10) | 0.0269 (4) | |
C46 | 0.45736 (7) | 0.4415 (3) | 0.35024 (11) | 0.0317 (4) | |
H46 | 0.4325 | 0.3438 | 0.3214 | 0.038* | |
C47 | 0.50945 (7) | 0.3788 (3) | 0.37585 (11) | 0.0327 (4) | |
H47 | 0.5205 | 0.2409 | 0.3647 | 0.039* | |
C47a | 0.54357 (6) | 0.5245 (3) | 0.41741 (10) | 0.0244 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0308 (9) | 0.0288 (10) | 0.0271 (9) | −0.0022 (8) | 0.0002 (7) | 0.0066 (8) |
C2 | 0.0302 (9) | 0.0386 (11) | 0.0275 (9) | −0.0077 (8) | 0.0039 (7) | 0.0040 (8) |
C3 | 0.0257 (9) | 0.0447 (12) | 0.0263 (9) | 0.0008 (8) | 0.0057 (7) | −0.0009 (8) |
C3a | 0.0250 (8) | 0.0323 (10) | 0.0231 (8) | 0.0022 (7) | 0.0020 (7) | −0.0011 (7) |
C4 | 0.0241 (8) | 0.0280 (10) | 0.0273 (9) | 0.0003 (7) | 0.0038 (7) | −0.0007 (7) |
N5 | 0.0241 (7) | 0.0306 (8) | 0.0246 (7) | 0.0050 (6) | 0.0053 (6) | 0.0063 (6) |
C5a | 0.0202 (8) | 0.0210 (9) | 0.0255 (8) | −0.0016 (7) | 0.0007 (6) | −0.0023 (7) |
C6 | 0.0257 (8) | 0.0251 (9) | 0.0248 (8) | −0.0035 (7) | 0.0041 (7) | −0.0008 (7) |
C7 | 0.0287 (9) | 0.0298 (10) | 0.0306 (9) | −0.0021 (8) | 0.0097 (7) | −0.0049 (8) |
C8 | 0.0298 (9) | 0.0299 (10) | 0.0392 (10) | 0.0070 (8) | 0.0070 (8) | −0.0033 (8) |
C9 | 0.0310 (9) | 0.0267 (10) | 0.0289 (9) | 0.0061 (8) | 0.0027 (7) | 0.0025 (8) |
C9a | 0.0231 (8) | 0.0235 (9) | 0.0220 (8) | −0.0019 (7) | 0.0018 (6) | −0.0031 (7) |
N9b | 0.0238 (7) | 0.0269 (8) | 0.0214 (7) | 0.0007 (6) | 0.0021 (5) | 0.0017 (6) |
O41 | 0.0215 (6) | 0.0298 (7) | 0.0329 (6) | 0.0005 (5) | 0.0028 (5) | −0.0024 (5) |
C42 | 0.0278 (9) | 0.0323 (11) | 0.0360 (10) | −0.0047 (8) | −0.0005 (7) | 0.0005 (8) |
O43 | 0.0252 (6) | 0.0343 (8) | 0.0547 (8) | −0.0017 (6) | 0.0065 (6) | −0.0162 (7) |
C43a | 0.0271 (8) | 0.0286 (10) | 0.0254 (8) | −0.0036 (7) | 0.0070 (7) | −0.0028 (7) |
C44 | 0.0284 (9) | 0.0234 (9) | 0.0340 (9) | 0.0036 (7) | 0.0107 (7) | −0.0001 (7) |
C45 | 0.0252 (8) | 0.0305 (10) | 0.0243 (8) | −0.0004 (7) | 0.0048 (7) | 0.0023 (7) |
C46 | 0.0279 (9) | 0.0315 (10) | 0.0338 (10) | −0.0007 (8) | 0.0036 (7) | −0.0054 (8) |
C47 | 0.0282 (9) | 0.0293 (10) | 0.0385 (10) | 0.0042 (8) | 0.0042 (8) | −0.0058 (8) |
C47a | 0.0216 (8) | 0.0267 (9) | 0.0243 (8) | 0.0031 (7) | 0.0042 (6) | 0.0028 (7) |
C1—C2 | 1.367 (3) | C9a—N9b | 1.418 (2) |
C1—H1 | 0.9500 | N9b—C1 | 1.381 (2) |
C2—C3 | 1.420 (3) | C3a—N9b | 1.381 (2) |
C2—H2 | 0.9500 | C5a—C9a | 1.403 (2) |
C3—C3a | 1.373 (2) | C4—C45 | 1.521 (2) |
C3—H3 | 0.9500 | O41—C47a | 1.3917 (19) |
C3a—C4 | 1.505 (2) | O41—C42 | 1.446 (2) |
C4—N5 | 1.457 (2) | C42—O43 | 1.423 (2) |
C4—H4 | 1.0000 | C42—H42A | 0.9900 |
N5—C5a | 1.384 (2) | C42—H42B | 0.9900 |
N5—H5 | 0.8801 | O43—C43a | 1.375 (2) |
C5a—C6 | 1.396 (2) | C43a—C47a | 1.375 (3) |
C6—C7 | 1.385 (2) | C43a—C44 | 1.377 (2) |
C6—H6 | 0.9500 | C44—C45 | 1.399 (2) |
C7—C8 | 1.386 (3) | C44—H44 | 0.9500 |
C7—H7 | 0.9500 | C45—C46 | 1.377 (3) |
C8—C9 | 1.392 (3) | C46—C47 | 1.404 (2) |
C8—H8 | 0.9500 | C46—H46 | 0.9500 |
C9—C9a | 1.384 (2) | C47—C47a | 1.364 (2) |
C9—H9 | 0.9500 | C47—H47 | 0.9500 |
C2—C1—N9b | 107.85 (16) | C9a—C9—H9 | 119.9 |
C2—C1—H1 | 126.1 | C8—C9—H9 | 119.9 |
N9b—C1—H1 | 126.1 | C9—C9a—C5a | 120.79 (16) |
C1—C2—C3 | 107.96 (16) | C9—C9a—N9b | 122.44 (15) |
C1—C2—H2 | 126.0 | C5a—C9a—N9b | 116.76 (14) |
C3—C2—H2 | 126.0 | C1—N9b—C3a | 108.94 (15) |
C3a—C3—C2 | 107.21 (16) | C1—N9b—C9a | 128.30 (15) |
C3a—C3—H3 | 126.4 | C3a—N9b—C9a | 122.74 (14) |
C2—C3—H3 | 126.4 | C47a—O41—C42 | 104.85 (13) |
C3—C3a—N9b | 108.04 (15) | O43—C42—O41 | 108.29 (13) |
C3—C3a—C4 | 132.36 (16) | O43—C42—H42A | 110.0 |
N9b—C3a—C4 | 119.41 (15) | O41—C42—H42A | 110.0 |
N5—C4—C3a | 107.66 (14) | O43—C42—H42B | 110.0 |
N5—C4—C45 | 109.66 (13) | O41—C42—H42B | 110.0 |
C3a—C4—C45 | 111.65 (14) | H42A—C42—H42B | 108.4 |
N5—C4—H4 | 109.3 | C43a—O43—C42 | 106.37 (14) |
C3a—C4—H4 | 109.3 | O43—C43a—C47a | 110.04 (15) |
C45—C4—H4 | 109.3 | O43—C43a—C44 | 127.75 (17) |
C5a—N5—C4 | 120.77 (13) | C47a—C43a—C44 | 122.21 (16) |
C5a—N5—H5 | 117.3 | C43a—C44—C45 | 116.73 (16) |
C4—N5—H5 | 114.0 | C43a—C44—H44 | 121.6 |
N5—C5a—C6 | 122.45 (15) | C45—C44—H44 | 121.6 |
N5—C5a—C9a | 119.18 (15) | C46—C45—C44 | 121.03 (16) |
C6—C5a—C9a | 118.26 (15) | C46—C45—C4 | 121.18 (16) |
C7—C6—C5a | 120.81 (16) | C44—C45—C4 | 117.79 (16) |
C7—C6—H6 | 119.6 | C45—C46—C47 | 121.19 (17) |
C5a—C6—H6 | 119.6 | C45—C46—H46 | 119.4 |
C6—C7—C8 | 120.48 (17) | C47—C46—H46 | 119.4 |
C6—C7—H7 | 119.8 | C47a—C47—C46 | 117.17 (17) |
C8—C7—H7 | 119.8 | C47a—C47—H47 | 121.4 |
C7—C8—C9 | 119.44 (17) | C46—C47—H47 | 121.4 |
C7—C8—H8 | 120.3 | C47—C47a—C43a | 121.66 (16) |
C9—C8—H8 | 120.3 | C47—C47a—O41 | 128.22 (16) |
C9a—C9—C8 | 120.21 (16) | C43a—C47a—O41 | 110.11 (15) |
N9b—C1—C2—C3 | −0.1 (2) | C4—C3a—N9b—C9a | 6.3 (2) |
C1—C2—C3—C3a | 0.3 (2) | C9—C9a—N9b—C1 | 10.1 (3) |
C2—C3—C3a—N9b | −0.4 (2) | C5a—C9a—N9b—C1 | −168.62 (16) |
C2—C3—C3a—C4 | 174.46 (18) | C9—C9a—N9b—C3a | −171.77 (16) |
C3—C3a—C4—N5 | 155.30 (18) | C5a—C9a—N9b—C3a | 9.5 (2) |
N9b—C3a—C4—N5 | −30.3 (2) | C47a—O41—C42—O43 | 5.94 (18) |
C3—C3a—C4—C45 | 34.9 (3) | O41—C42—O43—C43a | −5.37 (19) |
N9b—C3a—C4—C45 | −150.72 (15) | C42—O43—C43a—C47a | 2.70 (19) |
C3a—C4—N5—C5a | 43.5 (2) | C42—O43—C43a—C44 | −177.50 (18) |
C45—C4—N5—C5a | 165.13 (15) | O43—C43a—C44—C45 | −179.76 (16) |
C4—N5—C5a—C6 | 152.41 (16) | C47a—C43a—C44—C45 | 0.0 (3) |
C4—N5—C5a—C9a | −31.5 (2) | C43a—C44—C45—C46 | −0.2 (3) |
N5—C5a—C6—C7 | 175.53 (16) | C43a—C44—C45—C4 | −179.83 (15) |
C9a—C5a—C6—C7 | −0.6 (2) | C3a—C4—C45—C44 | 65.8 (2) |
C5a—C6—C7—C8 | 0.7 (3) | C3a—C4—C45—C46 | −113.83 (19) |
C6—C7—C8—C9 | −0.2 (3) | N5—C4—C45—C44 | −53.4 (2) |
C7—C8—C9—C9a | −0.4 (3) | N5—C4—C45—C46 | 126.93 (17) |
C8—C9—C9a—C5a | 0.5 (3) | C44—C45—C46—C47 | 0.0 (3) |
C8—C9—C9a—N9b | −178.08 (16) | C4—C45—C46—C47 | 179.67 (16) |
N5—C5a—C9a—C9 | −176.30 (15) | C45—C46—C47—C47a | 0.3 (3) |
C6—C5a—C9a—C9 | 0.0 (2) | C46—C47—C47a—C43a | −0.4 (3) |
N5—C5a—C9a—N9b | 2.4 (2) | C46—C47—C47a—O41 | 178.36 (16) |
C6—C5a—C9a—N9b | 178.68 (14) | O43—C43a—C47a—C47 | −179.89 (16) |
C2—C1—N9b—C3a | −0.20 (19) | C44—C43a—C47a—C47 | 0.3 (3) |
C2—C1—N9b—C9a | 178.18 (16) | O43—C43a—C47a—O41 | 1.11 (19) |
C3—C3a—N9b—C1 | 0.38 (19) | C44—C43a—C47a—O41 | −178.70 (15) |
C4—C3a—N9b—C1 | −175.26 (14) | C42—O41—C47a—C47 | 176.75 (18) |
C3—C3a—N9b—C9a | −178.11 (15) | C42—O41—C47a—C43a | −4.34 (18) |
Cg1 represents the centroid of the C5a/C6–C9/C9a ring and Cg2 represents the centroid of the C1–C3/C3a/N9b ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N5—H5···O41i | 0.88 | 2.18 | 3.052 (2) | 173 |
C1—H1···Cg1ii | 0.95 | 2.95 | 3.878 (2) | 165 |
C8—H8···Cg2ii | 0.95 | 2.70 | 3.568 (2) | 152 |
C42—H42A···Cg1iii | 0.99 | 2.99 | 3.628 (2) | 123 |
C46—H46···Cg2iv | 0.95 | 2.90 | 3.845 (2) | 173 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1/2, y+1/2, −z+1/2; (iii) −x+1, −y+2, −z+1; (iv) x, y−1, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C17H11ClN2 | C18H14N2O2 |
Mr | 278.73 | 290.31 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, C2/c |
Temperature (K) | 120 | 120 |
a, b, c (Å) | 13.5649 (13), 11.8142 (11), 8.1678 (12) | 26.590 (3), 6.2890 (9), 17.2655 (19) |
β (°) | 99.281 (10) | 104.017 (11) |
V (Å3) | 1291.8 (3) | 2801.3 (6) |
Z | 4 | 8 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.29 | 0.09 |
Crystal size (mm) | 0.42 × 0.25 × 0.22 | 0.45 × 0.24 × 0.16 |
Data collection | ||
Diffractometer | Bruker Nonius KappaCCD area-detector diffractometer | Bruker Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.890, 0.940 | 0.960, 0.986 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 18171, 2984, 2187 | 23085, 3225, 2350 |
Rint | 0.047 | 0.046 |
(sin θ/λ)max (Å−1) | 0.650 | 0.650 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.116, 1.06 | 0.049, 0.114, 1.08 |
No. of reflections | 2984 | 3225 |
No. of parameters | 181 | 199 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.31, −0.33 | 0.32, −0.24 |
Computer programs: COLLECT (Nonius, 1998), DIRAX/LSQ (Duisenberg et al., 2000), EVALCCD (Duisenberg et al., 2003), SHELXS97 (Sheldrick, 2008), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
C1—C2 | 1.375 (3) | C7—C8 | 1.399 (3) |
C2—C3 | 1.402 (3) | C8—C9 | 1.386 (3) |
C3—C3a | 1.391 (3) | C9—C9a | 1.389 (3) |
C3a—C4 | 1.422 (3) | C9a—N9b | 1.401 (2) |
C4—N5 | 1.313 (2) | N9b—C1 | 1.368 (2) |
N5—C5a | 1.402 (2) | C3a—N9b | 1.397 (2) |
C5a—C6 | 1.405 (3) | C5a—C9a | 1.410 (3) |
C6—C7 | 1.379 (3) | ||
C3a—C4—C41—C42 | 68.1 (2) | N5—C4—C41—C42 | −113.1 (2) |
C1—C2 | 1.367 (3) | C7—C8 | 1.386 (3) |
C2—C3 | 1.420 (3) | C8—C9 | 1.392 (3) |
C3—C3a | 1.373 (2) | C9—C9a | 1.384 (2) |
C3a—C4 | 1.505 (2) | C9a—N9b | 1.418 (2) |
C4—N5 | 1.457 (2) | N9b—C1 | 1.381 (2) |
N5—C5a | 1.384 (2) | C3a—N9b | 1.381 (2) |
C5a—C6 | 1.396 (2) | C5a—C9a | 1.403 (2) |
C6—C7 | 1.385 (2) | ||
C3a—C4—C45—C44 | 65.8 (2) | N5—C4—C45—C44 | −53.4 (2) |
C3a—C4—C45—C46 | −113.83 (19) | N5—C4—C45—C46 | 126.93 (17) |
Cg1 represents the centroid of the C5a/C6–C9/C9a ring and Cg2 represents the centroid of the C1–C3/C3a/N9b ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N5—H5···O41i | 0.88 | 2.18 | 3.052 (2) | 173 |
C1—H1···Cg1ii | 0.95 | 2.95 | 3.878 (2) | 165 |
C8—H8···Cg2ii | 0.95 | 2.70 | 3.568 (2) | 152 |
C42—H42A···Cg1iii | 0.99 | 2.99 | 3.628 (2) | 123 |
C46—H46···Cg2iv | 0.95 | 2.90 | 3.845 (2) | 173 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1/2, y+1/2, −z+1/2; (iii) −x+1, −y+2, −z+1; (iv) x, y−1, z. |
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Pyrrolo[1,2-a]quinoxalines and their 4,5-dihydro-derivatives exhibit interesting pharmacological properties (Maeba et al., 1990; Lancelot et al., 1994; Grande et al., 2007). Some compounds containing this system have shown activity as potent IkappaB kinase (IKK) inhibitors (Beaulieu et al., 2007), as potent and selective serotonin-1B agonists (Neale et al., 1987), as antileishmanial agents (Guillon et al., 2007) and antiproliferative activity against human leukaemia and breast cancer (Desplat et al., 2010). Here, we report the molecular and supramolecular structures of the title compounds, (I) (Fig. 1) and (II) (Fig. 2), as representative examples of these classes of compound, prepared as part of our current programme related to the synthesis of novel quinoxaline derivatives of biological interest (Abonía et al., 2001; Castillo et al., 2010).
Compound (I) contains a formally aromatic six-membered heterocyclic ring, while (II) contains a reduced 4,5-dihydro-ring in the corresponding position. We also compare the structures of (I) and (II) with those of their analogues, (III) (Castillo et al., 2010) and (IV) (Castillo et al., 2013) (see scheme). Compounds (I) and (III) contain the same fused ring system but differ in the substituents carried by the pendent aryl ring; (II) and (IV) both contain the same reduced ring system, but (II) contains a benzodioxolyl substituent where (IV) contains a dimethoxyphenyl substituent.
The crystallization characteristics of (I)–(IV), despite their rather similar constitutions, are all different. Thus, (I), (II) and (IV) all crystallize with Z' = 1, but in three different space groups (P21/c, C2/c and Pbca, respectively), while (III) crystallizes with Z' = 2. Despite the absence in (III) of any crystallographic symmetry in addition to that of the space group P21/c, where it crystallizes as a pseudo-merohedral twin emulating a metrically orthorhombic cell, the two independent molecules are nonetheless related by an approximate, but non-crystallographic, pseudo-screw axis parallel to the [100] direction of the monoclinic unit cell (Castillo et al., 2010). The molecules of (II) contain a stereogenic centre at atom C4 and the reference molecule was selected as one having the R configuration at C4. Likewise, there is a stereogenic centre at atom C4 in (IV), but this compound exhibits configurational disorder, with a given molecular site occupied by a fraction 0.692 (5) of one enantiomer and 0.308 (5) of the other (Castillo et al., 2013).
The bond distances in (I) and (II) (Tables 1 and 2) show some interesting contrasts, consequent upon the difference in the oxidation level of their respective six-membered heterocyclic rings. In (I), the C—C distances in the five-membered ring span a range of less than 0.03 Å, despite the fact that the C1—C2 and C3—C3a bonds are formally double, while C2—C3 is formally a single bond. These distances thus indicate some degree of electron delocalization in this ring. By contrast, in (II) the C—C distances in the pyrrole ring show a much clearer distinction between single and double bonds. At the same time, the bond distances for the fused carbocyclic ring of (I), but not for that of (II), indicate some slight bond fixation in the C6—C7 and C8—C9 bonds, while in the central fused ring of (I) there is a clearly localized double bond at C4—N5. The overall pattern of the distances in (I) indicates the presence of 6π circuits in the two outer rings of the fused system and a localized double bond in the central ring, analogous to the electronic structure of phenanthrene (Glidewell & Lloyd, 1984, 1986). This pattern of distances in (I) is fairly similar to that found for (III) (Castillo et al., 2010).
In (II), the dioxolane ring is essentially planar, with a maximum deviation from the mean plane of the five ring atoms of only 0.034 (2) Å for atom O43. For the central ring of the fused tricyclic system, the ring-puckering parameters (Cremer & Pople, 1975) for the atom sequence N5/C4/C3a/N9b/C9a/C5a are Q = 0.345 (2) Å, θ = 118.2 (3)° and ϕ = 216.4 (3)°, indicative of a conformation intermediate between screw-boat and half-chair forms, for which the idealized values of θ are 112.5 and 129.2°, respectively, with both forms having an idealized value for ϕ of (60k + 30)°, where k represents an integer. For the major and minor disorder forms of (IV) (Castillo et al., 2013), the ring-puckering angles for the atom sequences corresponding to that of (II) are, respectively, θ = 121 (2) and 62 (4)°, and ϕ = 212 (2) and 29 (4)°, showing the close conformational similarity between (II) and the major form of (IV). It also confirms the enantiomeric nature of the two disorder components of (IV), since a change of absolute configuration transforms θ into (180 - θ) and ϕ into (180 + ϕ). Consequent upon the puckering of the central fused ring of (II), the dihedral angle between the planes of the two outer rings of the fused tricyclic system is 10.0 (2)°, whereas the corresponding dihedral angle in (I) is only 1.3 (2)°. In (I), the dihedral angle between the pendent aryl ring and the adjacent heterocyclic ring is 67.2 (2)°, and in (II) the corresponding angle is 87.1 (2)°.
The supramolecular assembly in the crystal structure of (I) is very simple, as there are no hydrogen bonds of any type present. The principal direction-specific intermolecular interaction is a π–π stacking interaction between the five-membered ring of the molecule at (x, y, z) and the fused aryl ring of the molecule at (x, -y + 3/2, z - 1/2). The planes of these two rings make a dihedral angle of less than 1°, with a ring-centroid separation of 3.690 (2) Å. The shortest interplanar spacing is ca 3.45 Å, with a ring-centroid offset of ca 1.32 Å, and the shortest of the individual atom···atom distances associated with this contact is C1···C9ai = 3.282 (3) Å [symmetry code: (i) x, -y + 3/2, z - 1/2]. By this means, molecules related by the c-glide plane at y = 3/4 are linked into a chain running parallel to the [001] direction (Fig. 3). The only other direction-specific interaction between the molecules is a Cl···Cl contact of 3.213 (2) Å involving the molecules at (x, y, z) and (-x + 1, -y + 1, -z + 2). While this distance is certainly less than the van der Waals sum (Bondi, 1964), the expected partial negative charges on the two atoms involved, together with their rather low polarizability, makes it unclear whether this contact is attractive or repulsive.
The supramolecular assembly in (II) takes the form of a sheet built from a combination of N—H···O and C—H···π(arene) hydrogen bonds (Table 3). Inversion-related pairs of molecules are linked by paired N—H···O hydrogen bonds to form a cyclic centrosymmetric dimer characterized by an R22(16) motif (Bernstein et al., 1995) and centred at (1/2, 1/2, 1/2) (Fig. 4). This dimeric unit can conveniently be regarded as the key building block for the sheet formation. Within the reference dimer, the atoms of type C1 at (x, y, z) and (-x + 1, -y + 1, -z + 1) act as hydrogen-bond donors to, respectively, the fused aryl rings C5a/C6–C8/C9/C9a in the molecules at (-x + 1/2, y + 1/2, -z + 1/2) and (x + 1/2, -y + 1/2, z + 1/2), which themselves form part of the cyclic dimers centred at (0, 1, 0) and (1, 0, 1). Similarly, the fused aryl rings at (x, y, z) and (-x + 1, -y + 1, -z + 1) accept hydrogen bonds from the atoms of type C1 in the molecules at, respectively, (-x + 1/2, y - 1/2, -z + 1/2) and (x + 1/2, -y + 3/2, z + 1/2), which form part of the cyclic dimers centred at (0, 0, 0) and (1, 1, 1). In this manner, a single C—H···π(arene) hydrogen bond links the cyclic R22(16) dimers into a sheet lying parallel to (101) (Fig. 5).
A number of other C—H···π contacts can be identified in the structure of (II) (Table 3), all of which lie within the reference sheet described above, so that, even if they were regarded as structurally significant, they could not affect the dimensionality of the supramolecular aggregation but would merely increase its complexity. The contact involving atom C42 has a C—H···(ring centroid) angle of only 123° and the corresponding interaction energy is thus likely to be very small (Wood et al., 2009). The two contacts from atoms C8 and C46 both involve the pyrrole ring where, as noted above, there is a considerable degree of bond fixation, so that the delocalized aromatic character of this ring is likely to be rather modest.
It is of interest briefly to compare the supramolecular assembly in (I) and (II) with that in, respectively, (III) and (IV) (Castillo et al., 2010, 2013). The presence of both hydroxyl and methoxy substituents in the molecules of (III) naturally leads to a more complex mode of supramolecular assembly for (III) than was found for (I). In (III), where Z' = 2, a combination of two independent O—H···N hydrogen bonds and four independent C—H···O hydrogen bonds gives rise to a complex sheet structure. By contrast with the structure of (I), there are no π–π stacking interactions in the structure of (III). For both the major and minor disorder components of (IV), the molecules are linked by pairs of N—H···O hydrogen bonds to form cyclic centrosymmetric R22(14) dimers, somewhat similar to the dimer formed in (II), but reinforced in (IV) by a π–π interaction within the dimer involving the pendent phenyl rings. By contrast, there are no π–π stacking interactions in the structure of (II).