Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270112025589/lg3082sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270112025589/lg3082Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270112025589/lg3082IIsup3.hkl | |
Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270112025589/lg3082Isup4.cml | |
Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270112025589/lg3082IIsup5.cml |
CCDC references: 899063; 899064
A solution of N,N-dimethyl-p-phenylenediamine (0.68 g, 5 mmol) and 2-hydroxy-5-nitrobenzaldehyde (0.83 g, 5 mmol) in ethanol (20 ml) was refluxed for 15 min. The precipitated solid from the cooled reaction mixture was filtered off and recrystallized twice from ethanol to give crystals.
Analysis for compound (I): yield 91%; brown crystals [Red in CIF - please clarify], m.p. 488–491 K. Elemental analysis for C15H15N3O3 (Mr = 285.30), calculated: C 63.15, H 5.30, N 14.73%; found: C 63.01, H 5.49, N 14.59%. Spectroscopic analysis: 1H NMR (CDCl3, δ, p.p.m.): 15.19 (br. s, 1H, OH/NH), 8.65 (s, 1H, H7), 8.31 (s, 1H, H5), 8.19 (d, J = 9.0 Hz, 1H, H3), 7.32 (d, J = 9.0 Hz, 2H, H10 and H14), 7.02 (d, J = 9.2 Hz, 1H, H2), 6.75 (d, J = 9.0 Hz, 2H, H11 and H13), 3.03 (s, 6H, 2× CH3); 13C NMR (CDCl3, δ, p.p.m.): 167.4 (C1), 154.5 (C7), 150.6 (C12), 139.6 (C9), 134.4 (C4), 127.5 (C5), 127.4 (C3), 122.4 (C10 and C14), 118.5 (C6), 118.2 (C2), 112.6 (C11 and C13), 40.4 (C16 and C18); 15N NMR (CDCl3/ext. CH3NO2, δ, p.p.m.): -13.1 (N4), -93.8 (N8), -331.3 (N15).
Analysis for compound (II): yield 89%; red crystals, m.p. 441–443 K. Elemental analysis for C17H19N3O3 (Mr = 313.36), calculated: C 65.16, H 6.11, N 13.41%; found: C 65.11, H 6.17, N 13.37%. Spectroscopic analysis: 1H NMR (CDCl3, δ, p.p.m.): 15.30 (br. s, 1H, OH/NH), 8.63 (s, 1H, H7), 8.30 (s, 1H, H5), 8.18 (d, J = 9.0 Hz, 1H, H3), 7.30 (d, J = 9.0 Hz, 2H, H10 and H14), 7.01 (d, J = 9.2 Hz, 1H, H2), 6.70 (d, J = 9.0 Hz, 2H, H11 and H13), 3.41 (q, J = 7.1 Hz, 4H, 2× CH2), 1.21 (t, J = 7.1, 6H, 2 × CH3); 13C NMR (CDCl3, δ, p.p.m.): 167.5 (C1), 153.7 (C7), 148.1 (C12), 139.5 (C9), 133.3 (C4), 127.5 (C5), 127.2 (C3), 122.7 (C10 and C14), 118.6 (C6), 118.2 (C2), 111.9 (C11 and C13), 44.58 (C16 and C18), 12.56 (C17 and C19); 15N NMR (CDCl3/ext. CH3NO2, δ, p.p.m.): -13.4 (N4), -95.3 (N8), -302.3 (N15).
Single crystals of both compounds suitable for X-ray diffraction were obtained by very slow evaporation of analytical samples from NMR tubes, where CDCl3 was used as solvent.
All H atoms were located from electron-density maps, but they were calculated at their idealized positions and allowed to ride on their parent atoms, with C—H = 0.95 (aromatic), 0.98 (methyl) or 0.99 Å (methylene) and O—H = 0.84 Å, and with Uiso(H) = 1.2Ueq(C) for aromatic or methylene groups or 1.5Ueq(C,O) for methyl or hydroxyl groups. The treatment of disorder in (II) required the use of restraints to equalize the bonding distances N15—C16 and N15—C16B, and also the C16—C17 and C16B—C17B distances (s.u. = 0.02 Å). Restraints were also applied for the minor component to make the anisotropic displacement parameters of C16B and C17B more similar (s.u. = 0.02).
For both compounds, data collection: COLLECT (Bruker, 2008); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
C15H15N3O3 | F(000) = 1200 |
Mr = 285.30 | Dx = 1.402 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3324 reflections |
a = 31.688 (2) Å | θ = 0.4–28.3° |
b = 6.7674 (5) Å | µ = 0.10 mm−1 |
c = 13.146 (1) Å | T = 123 K |
β = 106.545 (6)° | Plate, red |
V = 2702.4 (3) Å3 | 0.15 × 0.13 × 0.03 mm |
Z = 8 |
Bruker Kappa APEXII CCD area-detector diffractometer | 2467 independent reflections |
Radiation source: fine-focus sealed tube | 1242 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.108 |
Detector resolution: 9 pixels mm-1 | θmax = 25.4°, θmin = 3.1° |
ϕ and ω scans | h = −38→37 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −7→8 |
Tmin = 0.985, Tmax = 0.997 | l = −15→15 |
4611 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)] = 0.082 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.167 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0415P)2 + 5.4351P] where P = (Fo2 + 2Fc2)/3 |
2467 reflections | (Δ/σ)max < 0.001 |
193 parameters | Δρmax = 0.27 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
C15H15N3O3 | V = 2702.4 (3) Å3 |
Mr = 285.30 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 31.688 (2) Å | µ = 0.10 mm−1 |
b = 6.7674 (5) Å | T = 123 K |
c = 13.146 (1) Å | 0.15 × 0.13 × 0.03 mm |
β = 106.545 (6)° |
Bruker Kappa APEXII CCD area-detector diffractometer | 2467 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1242 reflections with I > 2σ(I) |
Tmin = 0.985, Tmax = 0.997 | Rint = 0.108 |
4611 measured reflections |
R[F2 > 2σ(F2)] = 0.082 | 0 restraints |
wR(F2) = 0.167 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.27 e Å−3 |
2467 reflections | Δρmin = −0.25 e Å−3 |
193 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | ||
O1 | 0.52621 (9) | 1.0161 (4) | 0.6531 (3) | 0.0392 (9) | |
H1 | 0.5043 | 0.9460 | 0.6235 | 0.059* | |
O4A | 0.71055 (9) | 0.6370 (5) | 0.8492 (2) | 0.0353 (8) | |
O4B | 0.67200 (9) | 0.3711 (4) | 0.7984 (2) | 0.0297 (7) | |
N4 | 0.67536 (11) | 0.5524 (5) | 0.8074 (3) | 0.0271 (9) | |
N8 | 0.48098 (11) | 0.6959 (5) | 0.5994 (3) | 0.0226 (8) | |
N15 | 0.31176 (10) | 0.3775 (5) | 0.4226 (3) | 0.0288 (9) | |
C1 | 0.56150 (13) | 0.9003 (6) | 0.6902 (3) | 0.0258 (10) | |
C2 | 0.60210 (14) | 0.9886 (6) | 0.7378 (4) | 0.0324 (12) | |
H2 | 0.6039 | 1.1284 | 0.7440 | 0.039* | |
C3 | 0.63947 (13) | 0.8768 (6) | 0.7759 (3) | 0.0282 (11) | |
H3 | 0.6671 | 0.9379 | 0.8075 | 0.034* | |
C4 | 0.63598 (12) | 0.6738 (6) | 0.7670 (3) | 0.0203 (10) | |
C5 | 0.59640 (12) | 0.5812 (6) | 0.7212 (3) | 0.0203 (10) | |
H5 | 0.5953 | 0.4411 | 0.7166 | 0.024* | |
C6 | 0.55827 (13) | 0.6899 (6) | 0.6818 (3) | 0.0207 (10) | |
C7 | 0.51652 (12) | 0.5931 (6) | 0.6357 (3) | 0.0227 (10) | |
H7 | 0.5152 | 0.4530 | 0.6319 | 0.027* | |
C9 | 0.43969 (13) | 0.6029 (6) | 0.5577 (3) | 0.0221 (10) | |
C10 | 0.43060 (12) | 0.4040 (6) | 0.5674 (3) | 0.0218 (10) | |
H10 | 0.4535 | 0.3171 | 0.6036 | 0.026* | |
C11 | 0.38834 (13) | 0.3317 (6) | 0.5246 (3) | 0.0237 (10) | |
H11 | 0.3828 | 0.1954 | 0.5326 | 0.028* | |
C12 | 0.35325 (13) | 0.4541 (6) | 0.4695 (3) | 0.0231 (10) | |
C13 | 0.36290 (13) | 0.6552 (6) | 0.4624 (3) | 0.0250 (10) | |
H13 | 0.3401 | 0.7438 | 0.4276 | 0.030* | |
C14 | 0.40491 (13) | 0.7256 (6) | 0.5054 (3) | 0.0244 (10) | |
H14 | 0.4104 | 0.8624 | 0.4992 | 0.029* | |
C16 | 0.27433 (12) | 0.5130 (7) | 0.3847 (4) | 0.0320 (12) | |
H16A | 0.2703 | 0.5892 | 0.4447 | 0.048* | |
H16B | 0.2476 | 0.4368 | 0.3522 | 0.048* | |
H16C | 0.2801 | 0.6034 | 0.3321 | 0.048* | |
C18 | 0.30268 (15) | 0.1728 (6) | 0.4367 (4) | 0.0378 (12) | |
H18A | 0.3230 | 0.0898 | 0.4114 | 0.057* | |
H18B | 0.2723 | 0.1425 | 0.3962 | 0.057* | |
H18C | 0.3066 | 0.1464 | 0.5121 | 0.057* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0297 (18) | 0.0243 (18) | 0.057 (2) | 0.0043 (14) | 0.0009 (17) | 0.0084 (16) |
O4A | 0.0213 (16) | 0.040 (2) | 0.040 (2) | −0.0061 (15) | 0.0006 (14) | −0.0023 (17) |
O4B | 0.0276 (16) | 0.0250 (18) | 0.0339 (19) | 0.0002 (14) | 0.0045 (14) | 0.0003 (15) |
N4 | 0.027 (2) | 0.026 (2) | 0.029 (2) | −0.0033 (17) | 0.0082 (17) | −0.0010 (18) |
N8 | 0.0207 (19) | 0.030 (2) | 0.018 (2) | 0.0004 (16) | 0.0071 (16) | −0.0013 (17) |
N15 | 0.0203 (19) | 0.029 (2) | 0.034 (2) | 0.0024 (17) | 0.0030 (16) | 0.0029 (18) |
C1 | 0.028 (2) | 0.023 (3) | 0.026 (3) | 0.005 (2) | 0.006 (2) | 0.006 (2) |
C2 | 0.034 (3) | 0.017 (3) | 0.043 (3) | −0.003 (2) | 0.006 (2) | 0.001 (2) |
C3 | 0.028 (2) | 0.023 (2) | 0.030 (3) | −0.007 (2) | 0.003 (2) | −0.003 (2) |
C4 | 0.027 (2) | 0.020 (3) | 0.017 (2) | −0.0035 (18) | 0.0105 (19) | −0.0048 (19) |
C5 | 0.022 (2) | 0.022 (2) | 0.020 (2) | 0.0014 (18) | 0.0109 (19) | −0.0009 (19) |
C6 | 0.021 (2) | 0.025 (2) | 0.017 (2) | 0.0020 (19) | 0.0062 (18) | 0.004 (2) |
C7 | 0.023 (2) | 0.020 (2) | 0.027 (3) | −0.0018 (18) | 0.010 (2) | −0.0031 (19) |
C9 | 0.021 (2) | 0.026 (2) | 0.020 (2) | −0.0007 (19) | 0.0067 (19) | −0.001 (2) |
C10 | 0.022 (2) | 0.021 (2) | 0.021 (3) | 0.0028 (18) | 0.005 (2) | 0.0034 (19) |
C11 | 0.022 (2) | 0.025 (3) | 0.027 (3) | 0.0057 (19) | 0.0113 (19) | 0.004 (2) |
C12 | 0.027 (2) | 0.028 (3) | 0.016 (2) | 0.003 (2) | 0.009 (2) | 0.0037 (19) |
C13 | 0.023 (2) | 0.023 (2) | 0.029 (3) | 0.0067 (19) | 0.0083 (19) | 0.000 (2) |
C14 | 0.030 (3) | 0.018 (2) | 0.025 (3) | 0.0023 (19) | 0.008 (2) | 0.0028 (19) |
C16 | 0.016 (2) | 0.047 (3) | 0.032 (3) | 0.007 (2) | 0.005 (2) | 0.001 (2) |
C18 | 0.033 (3) | 0.036 (3) | 0.041 (3) | −0.004 (2) | 0.005 (2) | 0.000 (2) |
O1—C1 | 1.338 (5) | C6—C7 | 1.446 (5) |
O1—H1 | 0.8400 | C7—H7 | 0.9500 |
O4A—N4 | 1.235 (4) | C9—C10 | 1.390 (5) |
O4B—N4 | 1.234 (4) | C9—C14 | 1.395 (5) |
N4—C4 | 1.462 (5) | C10—C11 | 1.386 (5) |
N8—C7 | 1.294 (5) | C10—H10 | 0.9500 |
N8—C9 | 1.414 (5) | C11—C12 | 1.410 (6) |
N15—C12 | 1.384 (5) | C11—H11 | 0.9500 |
N15—C18 | 1.438 (5) | C12—C13 | 1.404 (6) |
N15—C16 | 1.470 (5) | C13—C14 | 1.374 (6) |
C1—C2 | 1.395 (6) | C13—H13 | 0.9500 |
C1—C6 | 1.430 (6) | C14—H14 | 0.9500 |
C2—C3 | 1.374 (6) | C16—H16A | 0.9800 |
C2—H2 | 0.9500 | C16—H16B | 0.9800 |
C3—C4 | 1.380 (6) | C16—H16C | 0.9800 |
C3—H3 | 0.9500 | C18—H18A | 0.9800 |
C4—C5 | 1.378 (5) | C18—H18B | 0.9800 |
C5—C6 | 1.383 (5) | C18—H18C | 0.9800 |
C5—H5 | 0.9500 | ||
C1—O1—H1 | 109.5 | C10—C9—N8 | 126.1 (4) |
O4B—N4—O4A | 123.1 (4) | C14—C9—N8 | 116.1 (4) |
O4B—N4—C4 | 118.9 (3) | C11—C10—C9 | 120.4 (4) |
O4A—N4—C4 | 118.0 (3) | C11—C10—H10 | 119.8 |
C7—N8—C9 | 121.1 (4) | C9—C10—H10 | 119.8 |
C12—N15—C18 | 120.2 (4) | C10—C11—C12 | 122.0 (4) |
C12—N15—C16 | 119.3 (4) | C10—C11—H11 | 119.0 |
C18—N15—C16 | 118.2 (3) | C12—C11—H11 | 119.0 |
O1—C1—C2 | 118.7 (4) | N15—C12—C13 | 122.1 (4) |
O1—C1—C6 | 121.4 (4) | N15—C12—C11 | 121.2 (4) |
C2—C1—C6 | 119.9 (4) | C13—C12—C11 | 116.7 (4) |
C3—C2—C1 | 121.1 (4) | C14—C13—C12 | 120.8 (4) |
C3—C2—H2 | 119.4 | C14—C13—H13 | 119.6 |
C1—C2—H2 | 119.4 | C12—C13—H13 | 119.6 |
C2—C3—C4 | 118.5 (4) | C13—C14—C9 | 122.2 (4) |
C2—C3—H3 | 120.7 | C13—C14—H14 | 118.9 |
C4—C3—H3 | 120.7 | C9—C14—H14 | 118.9 |
C5—C4—C3 | 122.0 (4) | N15—C16—H16A | 109.5 |
C5—C4—N4 | 118.7 (4) | N15—C16—H16B | 109.5 |
C3—C4—N4 | 119.3 (4) | H16A—C16—H16B | 109.5 |
C4—C5—C6 | 120.7 (4) | N15—C16—H16C | 109.5 |
C4—C5—H5 | 119.6 | H16A—C16—H16C | 109.5 |
C6—C5—H5 | 119.6 | H16B—C16—H16C | 109.5 |
C5—C6—C1 | 117.7 (4) | N15—C18—H18A | 109.5 |
C5—C6—C7 | 120.9 (4) | N15—C18—H18B | 109.5 |
C1—C6—C7 | 121.4 (4) | H18A—C18—H18B | 109.5 |
N8—C7—C6 | 120.5 (4) | N15—C18—H18C | 109.5 |
N8—C7—H7 | 119.7 | H18A—C18—H18C | 109.5 |
C6—C7—H7 | 119.7 | H18B—C18—H18C | 109.5 |
C10—C9—C14 | 117.8 (4) | ||
O1—C1—C2—C3 | −179.1 (4) | C5—C6—C7—N8 | 179.7 (4) |
C6—C1—C2—C3 | 0.9 (7) | C1—C6—C7—N8 | 0.9 (6) |
C1—C2—C3—C4 | −0.7 (7) | C7—N8—C9—C10 | 12.4 (6) |
C2—C3—C4—C5 | 0.2 (6) | C7—N8—C9—C14 | −169.9 (4) |
C2—C3—C4—N4 | −179.8 (4) | C14—C9—C10—C11 | 1.0 (6) |
O4B—N4—C4—C5 | 0.5 (6) | N8—C9—C10—C11 | 178.6 (4) |
O4A—N4—C4—C5 | −179.3 (4) | C9—C10—C11—C12 | 0.4 (6) |
O4B—N4—C4—C3 | −179.5 (4) | C18—N15—C12—C13 | −176.6 (4) |
O4A—N4—C4—C3 | 0.7 (6) | C16—N15—C12—C13 | −13.8 (6) |
C3—C4—C5—C6 | 0.0 (6) | C18—N15—C12—C11 | 5.2 (6) |
N4—C4—C5—C6 | −179.9 (3) | C16—N15—C12—C11 | 168.0 (4) |
C4—C5—C6—C1 | 0.1 (6) | C10—C11—C12—N15 | 176.7 (4) |
C4—C5—C6—C7 | −178.7 (4) | C10—C11—C12—C13 | −1.7 (6) |
O1—C1—C6—C5 | 179.4 (4) | N15—C12—C13—C14 | −176.8 (4) |
C2—C1—C6—C5 | −0.6 (6) | C11—C12—C13—C14 | 1.5 (6) |
O1—C1—C6—C7 | −1.8 (6) | C12—C13—C14—C9 | −0.1 (6) |
C2—C1—C6—C7 | 178.3 (4) | C10—C9—C14—C13 | −1.1 (6) |
C9—N8—C7—C6 | −177.6 (4) | N8—C9—C14—C13 | −179.0 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N8 | 0.84 | 1.84 | 2.583 (4) | 147 |
C16—H16A···O4Ai | 0.98 | 2.62 | 3.495 (5) | 148 |
C16—H16A···O4Aii | 0.98 | 2.69 | 3.062 (5) | 103 |
C16—H16C···O4Biii | 0.98 | 2.60 | 3.411 (5) | 140 |
C2—H2···O4Biv | 0.95 | 2.64 | 3.352 (5) | 132 |
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+1, −y+1, −z+1; (iv) x, y+1, z. |
C17H19N3O3 | F(000) = 664 |
Mr = 313.35 | Dx = 1.365 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3812 reflections |
a = 6.5848 (1) Å | θ = 0.4–28.3° |
b = 22.2544 (4) Å | µ = 0.10 mm−1 |
c = 10.8735 (2) Å | T = 123 K |
β = 106.811 (1)° | Plate, red |
V = 1525.31 (5) Å3 | 0.20 × 0.16 × 0.06 mm |
Z = 4 |
Bruker Kappa APEXII CCD area-detector diffractometer | 3790 independent reflections |
Radiation source: fine-focus sealed tube | 2653 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
Detector resolution: 9 pixels mm-1 | θmax = 28.3°, θmin = 2.7° |
ϕ and ω scans | h = −8→8 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −29→25 |
Tmin = 0.981, Tmax = 0.994 | l = −14→14 |
6646 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)] = 0.056 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.123 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0343P)2 + 0.8927P] where P = (Fo2 + 2Fc2)/3 |
3790 reflections | (Δ/σ)max < 0.001 |
228 parameters | Δρmax = 0.38 e Å−3 |
8 restraints | Δρmin = −0.25 e Å−3 |
C17H19N3O3 | V = 1525.31 (5) Å3 |
Mr = 313.35 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.5848 (1) Å | µ = 0.10 mm−1 |
b = 22.2544 (4) Å | T = 123 K |
c = 10.8735 (2) Å | 0.20 × 0.16 × 0.06 mm |
β = 106.811 (1)° |
Bruker Kappa APEXII CCD area-detector diffractometer | 3790 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2653 reflections with I > 2σ(I) |
Tmin = 0.981, Tmax = 0.994 | Rint = 0.030 |
6646 measured reflections |
R[F2 > 2σ(F2)] = 0.056 | 8 restraints |
wR(F2) = 0.123 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.38 e Å−3 |
3790 reflections | Δρmin = −0.25 e Å−3 |
228 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | Occ. (<1) | |
O1 | 0.62487 (19) | −0.00420 (6) | 0.65774 (11) | 0.0292 (3) | |
H1 | 0.6717 | 0.0187 | 0.6108 | 0.044* | |
O4A | 1.2373 (2) | −0.11842 (6) | 1.14921 (12) | 0.0369 (3) | |
O4B | 1.4676 (2) | −0.07660 (6) | 1.06910 (13) | 0.0371 (3) | |
N4 | 1.2831 (2) | −0.08873 (7) | 1.06541 (14) | 0.0272 (3) | |
N8 | 0.8984 (2) | 0.05530 (6) | 0.58184 (13) | 0.0219 (3) | |
N15 | 0.9700 (2) | 0.21352 (7) | 0.19249 (16) | 0.0344 (4) | |
C1 | 0.7858 (3) | −0.02429 (8) | 0.75424 (15) | 0.0224 (4) | |
C2 | 0.7423 (3) | −0.06292 (8) | 0.84506 (16) | 0.0253 (4) | |
H2 | 0.6000 | −0.0745 | 0.8365 | 0.030* | |
C3 | 0.9037 (3) | −0.08426 (8) | 0.94667 (16) | 0.0246 (4) | |
H3 | 0.8736 | −0.1102 | 1.0086 | 0.029* | |
C4 | 1.1114 (3) | −0.06732 (7) | 0.95727 (15) | 0.0221 (4) | |
C5 | 1.1597 (3) | −0.02930 (7) | 0.86918 (16) | 0.0219 (4) | |
H5 | 1.3029 | −0.0184 | 0.8788 | 0.026* | |
C6 | 0.9984 (3) | −0.00712 (7) | 0.76660 (15) | 0.0210 (4) | |
C7 | 1.0492 (3) | 0.03371 (7) | 0.67494 (16) | 0.0223 (4) | |
H7 | 1.1925 | 0.0443 | 0.6838 | 0.027* | |
C9 | 0.9309 (3) | 0.09557 (7) | 0.48881 (15) | 0.0206 (3) | |
C10 | 1.1272 (3) | 0.11697 (8) | 0.48217 (16) | 0.0223 (4) | |
H10 | 1.2536 | 0.1042 | 0.5441 | 0.027* | |
C11 | 1.1391 (3) | 0.15641 (7) | 0.38660 (16) | 0.0230 (4) | |
H11 | 1.2742 | 0.1705 | 0.3846 | 0.028* | |
C12 | 0.9561 (3) | 0.17650 (8) | 0.29146 (17) | 0.0245 (4) | |
C13 | 0.7602 (3) | 0.15488 (8) | 0.30041 (17) | 0.0260 (4) | |
H13 | 0.6329 | 0.1676 | 0.2393 | 0.031* | |
C14 | 0.7495 (3) | 0.11537 (8) | 0.39666 (16) | 0.0240 (4) | |
H14 | 0.6148 | 0.1014 | 0.3998 | 0.029* | |
C16 | 0.7773 (4) | 0.23028 (11) | 0.0887 (3) | 0.0257 (7) | 0.789 (6) |
H16A | 0.6813 | 0.1952 | 0.0666 | 0.031* | 0.789 (6) |
H16B | 0.8178 | 0.2419 | 0.0111 | 0.031* | 0.789 (6) |
C17 | 0.6615 (5) | 0.28215 (12) | 0.1294 (2) | 0.0313 (7) | 0.789 (6) |
H17A | 0.5351 | 0.2923 | 0.0591 | 0.047* | 0.789 (6) |
H17B | 0.7557 | 0.3171 | 0.1500 | 0.047* | 0.789 (6) |
H17C | 0.6191 | 0.2705 | 0.2053 | 0.047* | 0.789 (6) |
C16B | 0.7851 (15) | 0.2594 (4) | 0.1507 (9) | 0.029 (3) | 0.211 (6) |
H16C | 0.7019 | 0.2614 | 0.2133 | 0.034* | 0.211 (6) |
H16D | 0.8367 | 0.3001 | 0.1382 | 0.034* | 0.211 (6) |
C17B | 0.658 (2) | 0.2316 (5) | 0.0247 (11) | 0.051 (3) | 0.211 (6) |
H17D | 0.5326 | 0.2562 | −0.0137 | 0.076* | 0.211 (6) |
H17E | 0.6143 | 0.1909 | 0.0404 | 0.076* | 0.211 (6) |
H17F | 0.7465 | 0.2296 | −0.0341 | 0.076* | 0.211 (6) |
C18 | 1.1665 (3) | 0.24487 (8) | 0.19747 (19) | 0.0305 (4) | |
H18A | 1.1560 | 0.2607 | 0.1107 | 0.037* | |
H18B | 1.2844 | 0.2155 | 0.2198 | 0.037* | |
C19 | 1.2213 (4) | 0.29653 (10) | 0.2927 (2) | 0.0458 (6) | |
H19A | 1.3548 | 0.3150 | 0.2897 | 0.069* | |
H19B | 1.2368 | 0.2813 | 0.3795 | 0.069* | |
H19C | 1.1077 | 0.3266 | 0.2704 | 0.069* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0257 (7) | 0.0352 (7) | 0.0249 (7) | −0.0052 (6) | 0.0046 (5) | 0.0048 (5) |
O4A | 0.0429 (8) | 0.0383 (8) | 0.0310 (7) | 0.0053 (6) | 0.0132 (6) | 0.0119 (6) |
O4B | 0.0272 (7) | 0.0400 (8) | 0.0424 (8) | 0.0031 (6) | 0.0072 (6) | 0.0113 (6) |
N4 | 0.0342 (9) | 0.0231 (8) | 0.0251 (8) | 0.0033 (7) | 0.0098 (7) | 0.0021 (6) |
N8 | 0.0271 (8) | 0.0187 (7) | 0.0207 (7) | −0.0018 (6) | 0.0083 (6) | −0.0021 (6) |
N15 | 0.0257 (8) | 0.0366 (9) | 0.0404 (9) | −0.0002 (7) | 0.0087 (7) | 0.0178 (7) |
C1 | 0.0251 (9) | 0.0228 (8) | 0.0192 (8) | −0.0020 (7) | 0.0065 (7) | −0.0044 (6) |
C2 | 0.0268 (9) | 0.0270 (9) | 0.0238 (9) | −0.0067 (7) | 0.0099 (7) | −0.0038 (7) |
C3 | 0.0333 (10) | 0.0211 (8) | 0.0221 (9) | −0.0025 (7) | 0.0125 (7) | −0.0012 (7) |
C4 | 0.0282 (9) | 0.0196 (8) | 0.0181 (8) | 0.0020 (7) | 0.0059 (7) | −0.0018 (6) |
C5 | 0.0225 (8) | 0.0201 (8) | 0.0244 (8) | −0.0012 (7) | 0.0091 (7) | −0.0023 (7) |
C6 | 0.0266 (9) | 0.0188 (8) | 0.0193 (8) | −0.0010 (7) | 0.0092 (7) | −0.0032 (6) |
C7 | 0.0241 (9) | 0.0198 (8) | 0.0242 (8) | −0.0009 (7) | 0.0088 (7) | −0.0016 (7) |
C9 | 0.0252 (9) | 0.0188 (8) | 0.0191 (8) | −0.0011 (7) | 0.0084 (7) | −0.0019 (6) |
C10 | 0.0215 (8) | 0.0225 (8) | 0.0213 (8) | 0.0020 (7) | 0.0036 (7) | −0.0003 (7) |
C11 | 0.0220 (8) | 0.0225 (8) | 0.0256 (9) | −0.0020 (7) | 0.0089 (7) | −0.0002 (7) |
C12 | 0.0270 (9) | 0.0196 (8) | 0.0280 (9) | 0.0005 (7) | 0.0098 (7) | 0.0028 (7) |
C13 | 0.0211 (9) | 0.0251 (9) | 0.0299 (9) | 0.0015 (7) | 0.0045 (7) | 0.0057 (7) |
C14 | 0.0219 (8) | 0.0243 (9) | 0.0264 (9) | −0.0020 (7) | 0.0079 (7) | −0.0010 (7) |
C16 | 0.0341 (16) | 0.0242 (13) | 0.0203 (14) | −0.0001 (11) | 0.0100 (12) | 0.0004 (11) |
C17 | 0.0333 (16) | 0.0263 (13) | 0.0343 (14) | 0.0031 (12) | 0.0099 (11) | 0.0045 (10) |
C16B | 0.031 (6) | 0.021 (5) | 0.038 (5) | 0.008 (4) | 0.016 (4) | −0.003 (4) |
C17B | 0.049 (7) | 0.045 (6) | 0.042 (7) | −0.002 (5) | −0.012 (6) | 0.011 (5) |
C18 | 0.0297 (10) | 0.0283 (9) | 0.0362 (10) | −0.0006 (8) | 0.0139 (8) | 0.0077 (8) |
C19 | 0.0578 (15) | 0.0337 (11) | 0.0497 (13) | −0.0057 (10) | 0.0217 (11) | −0.0002 (10) |
O1—C1 | 1.334 (2) | C10—H10 | 0.9500 |
O1—H1 | 0.8400 | C11—C12 | 1.414 (2) |
O4A—N4 | 1.2316 (19) | C11—H11 | 0.9500 |
O4B—N4 | 1.233 (2) | C12—C13 | 1.406 (2) |
N4—C4 | 1.456 (2) | C13—C14 | 1.384 (2) |
N8—C7 | 1.289 (2) | C13—H13 | 0.9500 |
N8—C9 | 1.413 (2) | C14—H14 | 0.9500 |
N15—C12 | 1.379 (2) | C16—C17 | 1.518 (4) |
N15—C18 | 1.457 (2) | C16—H16A | 0.9900 |
N15—C16 | 1.481 (3) | C16—H16B | 0.9900 |
N15—C16B | 1.553 (9) | C17—H17A | 0.9800 |
C1—C2 | 1.400 (2) | C17—H17B | 0.9800 |
C1—C6 | 1.420 (2) | C17—H17C | 0.9800 |
C2—C3 | 1.377 (2) | C16B—C17B | 1.515 (13) |
C2—H2 | 0.9500 | C16B—H16C | 0.9900 |
C3—C4 | 1.391 (2) | C16B—H16D | 0.9900 |
C3—H3 | 0.9500 | C17B—H17D | 0.9800 |
C4—C5 | 1.382 (2) | C17B—H17E | 0.9800 |
C5—C6 | 1.389 (2) | C17B—H17F | 0.9800 |
C5—H5 | 0.9500 | C18—C19 | 1.519 (3) |
C6—C7 | 1.457 (2) | C18—H18A | 0.9900 |
C7—H7 | 0.9500 | C18—H18B | 0.9900 |
C9—C14 | 1.390 (2) | C19—H19A | 0.9800 |
C9—C10 | 1.399 (2) | C19—H19B | 0.9800 |
C10—C11 | 1.380 (2) | C19—H19C | 0.9800 |
C1—O1—H1 | 109.5 | C14—C13—C12 | 121.18 (16) |
O4A—N4—O4B | 122.88 (15) | C14—C13—H13 | 119.4 |
O4A—N4—C4 | 118.29 (15) | C12—C13—H13 | 119.4 |
O4B—N4—C4 | 118.83 (14) | C13—C14—C9 | 121.70 (16) |
C7—N8—C9 | 123.82 (15) | C13—C14—H14 | 119.2 |
C12—N15—C18 | 121.03 (15) | C9—C14—H14 | 119.2 |
C12—N15—C16 | 120.63 (16) | N15—C16—C17 | 111.1 (2) |
C18—N15—C16 | 117.62 (16) | N15—C16—H16A | 109.4 |
C12—N15—C16B | 113.4 (4) | C17—C16—H16A | 109.4 |
C18—N15—C16B | 108.0 (4) | N15—C16—H16B | 109.4 |
O1—C1—C2 | 118.84 (15) | C17—C16—H16B | 109.4 |
O1—C1—C6 | 121.43 (15) | H16A—C16—H16B | 108.0 |
C2—C1—C6 | 119.73 (15) | C16—C17—H17A | 109.5 |
C3—C2—C1 | 120.65 (16) | C16—C17—H17B | 109.5 |
C3—C2—H2 | 119.7 | H17A—C17—H17B | 109.5 |
C1—C2—H2 | 119.7 | C16—C17—H17C | 109.5 |
C2—C3—C4 | 119.03 (16) | H17A—C17—H17C | 109.5 |
C2—C3—H3 | 120.5 | H17B—C17—H17C | 109.5 |
C4—C3—H3 | 120.5 | C17B—C16B—N15 | 100.1 (8) |
C5—C4—C3 | 121.75 (16) | C17B—C16B—H16C | 111.8 |
C5—C4—N4 | 118.65 (15) | N15—C16B—H16C | 111.8 |
C3—C4—N4 | 119.59 (15) | C17B—C16B—H16D | 111.8 |
C4—C5—C6 | 119.89 (16) | N15—C16B—H16D | 111.8 |
C4—C5—H5 | 120.1 | H16C—C16B—H16D | 109.5 |
C6—C5—H5 | 120.1 | C16B—C17B—H17D | 109.5 |
C5—C6—C1 | 118.95 (15) | C16B—C17B—H17E | 109.5 |
C5—C6—C7 | 119.82 (15) | H17D—C17B—H17E | 109.5 |
C1—C6—C7 | 121.22 (15) | C16B—C17B—H17F | 109.5 |
N8—C7—C6 | 119.51 (15) | H17D—C17B—H17F | 109.5 |
N8—C7—H7 | 120.2 | H17E—C17B—H17F | 109.5 |
C6—C7—H7 | 120.2 | N15—C18—C19 | 114.89 (16) |
C14—C9—C10 | 117.97 (15) | N15—C18—H18A | 108.5 |
C14—C9—N8 | 116.11 (15) | C19—C18—H18A | 108.5 |
C10—C9—N8 | 125.91 (15) | N15—C18—H18B | 108.5 |
C11—C10—C9 | 120.65 (16) | C19—C18—H18B | 108.5 |
C11—C10—H10 | 119.7 | H18A—C18—H18B | 107.5 |
C9—C10—H10 | 119.7 | C18—C19—H19A | 109.5 |
C10—C11—C12 | 122.02 (16) | C18—C19—H19B | 109.5 |
C10—C11—H11 | 119.0 | H19A—C19—H19B | 109.5 |
C12—C11—H11 | 119.0 | C18—C19—H19C | 109.5 |
N15—C12—C13 | 121.84 (16) | H19A—C19—H19C | 109.5 |
N15—C12—C11 | 121.65 (16) | H19B—C19—H19C | 109.5 |
C13—C12—C11 | 116.47 (15) | ||
O1—C1—C2—C3 | −179.48 (15) | N8—C9—C10—C11 | −179.88 (15) |
C6—C1—C2—C3 | 0.3 (3) | C9—C10—C11—C12 | −0.5 (3) |
C1—C2—C3—C4 | −0.6 (3) | C18—N15—C12—C13 | 167.89 (17) |
C2—C3—C4—C5 | 0.5 (3) | C16—N15—C12—C13 | −2.1 (3) |
C2—C3—C4—N4 | 178.95 (15) | C16B—N15—C12—C13 | 37.1 (4) |
O4A—N4—C4—C5 | 173.99 (15) | C18—N15—C12—C11 | −14.6 (3) |
O4B—N4—C4—C5 | −6.2 (2) | C16—N15—C12—C11 | 175.41 (18) |
O4A—N4—C4—C3 | −4.5 (2) | C16B—N15—C12—C11 | −145.4 (4) |
O4B—N4—C4—C3 | 175.30 (15) | C10—C11—C12—N15 | −176.66 (16) |
C3—C4—C5—C6 | −0.1 (2) | C10—C11—C12—C13 | 1.0 (2) |
N4—C4—C5—C6 | −178.58 (14) | N15—C12—C13—C14 | 176.75 (17) |
C4—C5—C6—C1 | −0.2 (2) | C11—C12—C13—C14 | −0.9 (3) |
C4—C5—C6—C7 | 179.04 (15) | C12—C13—C14—C9 | 0.3 (3) |
O1—C1—C6—C5 | 179.86 (15) | C10—C9—C14—C13 | 0.2 (2) |
C2—C1—C6—C5 | 0.1 (2) | N8—C9—C14—C13 | 179.99 (15) |
O1—C1—C6—C7 | 0.6 (2) | C12—N15—C16—C17 | 82.2 (2) |
C2—C1—C6—C7 | −179.09 (15) | C18—N15—C16—C17 | −88.1 (2) |
C9—N8—C7—C6 | 179.41 (14) | C12—N15—C16B—C17B | −106.0 (6) |
C5—C6—C7—N8 | −178.28 (15) | C18—N15—C16B—C17B | 117.0 (6) |
C1—C6—C7—N8 | 0.9 (2) | C12—N15—C18—C19 | −72.0 (2) |
C7—N8—C9—C14 | −178.65 (15) | C16—N15—C18—C19 | 98.3 (2) |
C7—N8—C9—C10 | 1.1 (3) | C16B—N15—C18—C19 | 61.1 (4) |
C14—C9—C10—C11 | −0.1 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N8 | 0.84 | 1.81 | 2.557 (2) | 148 |
C14—H14···O1i | 0.95 | 2.64 | 3.421 (2) | 139 |
C17—H17B···O4Aii | 0.98 | 2.60 | 3.195 (3) | 119 |
C5—H5···O4Biii | 0.95 | 2.56 | 3.328 (2) | 138 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+2, y+1/2, −z+3/2; (iii) −x+3, −y, −z+2. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C15H15N3O3 | C17H19N3O3 |
Mr | 285.30 | 313.35 |
Crystal system, space group | Monoclinic, C2/c | Monoclinic, P21/c |
Temperature (K) | 123 | 123 |
a, b, c (Å) | 31.688 (2), 6.7674 (5), 13.146 (1) | 6.5848 (1), 22.2544 (4), 10.8735 (2) |
β (°) | 106.545 (6) | 106.811 (1) |
V (Å3) | 2702.4 (3) | 1525.31 (5) |
Z | 8 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.10 | 0.10 |
Crystal size (mm) | 0.15 × 0.13 × 0.03 | 0.20 × 0.16 × 0.06 |
Data collection | ||
Diffractometer | Bruker Kappa APEXII CCD area-detector diffractometer | Bruker Kappa APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.985, 0.997 | 0.981, 0.994 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4611, 2467, 1242 | 6646, 3790, 2653 |
Rint | 0.108 | 0.030 |
(sin θ/λ)max (Å−1) | 0.602 | 0.667 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.082, 0.167, 1.02 | 0.056, 0.123, 1.04 |
No. of reflections | 2467 | 3790 |
No. of parameters | 193 | 228 |
No. of restraints | 0 | 8 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.25 | 0.38, −0.25 |
Computer programs: COLLECT (Bruker, 2008), DENZO-SMN (Otwinowski & Minor, 1997), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N8 | 0.84 | 1.84 | 2.583 (4) | 147 |
C16—H16A···O4Ai | 0.98 | 2.62 | 3.495 (5) | 148 |
C16—H16A···O4Aii | 0.98 | 2.69 | 3.062 (5) | 103 |
C16—H16C···O4Biii | 0.98 | 2.60 | 3.411 (5) | 140 |
C2—H2···O4Biv | 0.95 | 2.64 | 3.352 (5) | 132 |
Symmetry codes: (i) −x+1, y, −z+3/2; (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+1, −y+1, −z+1; (iv) x, y+1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N8 | 0.84 | 1.81 | 2.557 (2) | 148 |
C14—H14···O1i | 0.95 | 2.64 | 3.421 (2) | 139 |
C17—H17B···O4Aii | 0.98 | 2.60 | 3.195 (3) | 119 |
C5—H5···O4Biii | 0.95 | 2.56 | 3.328 (2) | 138 |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+2, y+1/2, −z+3/2; (iii) −x+3, −y, −z+2. |
The title compounds, (I) and (II), are products from the condensation reaction of N,N-dimethyl-p-phenylenediamine or N,N-diethyl-p-phenylenediamine, respectively, with 2-hydroxy-5-nitrobenzaldehyde. These two compounds have the potential to occur in two tautomeric forms, and they were prepared in order to check whether increased acidity of OH (due to the presence of an NO2 group in the para-position) and increased basicity of the –N═CH– N atom would result in the enamine form of these compounds. This study shows that they occur in the solid state in the imine form (Figs. 1 and 2). However, in solution there is a fast H-atom exchange observed from the chemical shifts of atoms C1, C6, C7 and N4, between the imine (–OH) and enaminone [enamine?] (–NH) forms. As previously observed with similar compounds (Gawinecki et al., 2007), the enaminone [enamine?] form predominates in chloroform solution. Recently, (I) was studied to obtain novel Grubbs-type bidentate Schiff base ruthenium catalysts, but its pKa value was too low for it to be utilized by that method (Drozdzak & Nishioka, 2010). Previously, the electronic properties of (I) were investigated (Avramovici et al., 1973, 1974) and it was also studied for the preparation of organometallic GaIII complexes (Chesnut et al., 1998). To the best of our knowledge, (II) has not previously been discussed in the literature.
The crystal structure of (I) is ordered (Fig. 1), but in (II) a small static disorder exists in one ethyl group (Fig. 2), with the occupancy of the major component equal to 0.788 (6). The molecules of both compounds are rather planar. However, the dihedral angle between the two aromatic rings in (I) is 13.44 (19)°, significantly larger than that in (II), which is 2.57 (8)°. Furthermore, the dimethylamine group shows dihedral angles of -13.8 (6) (C16—N15—C12—C13) and 5.2 (6)° (C18—N15—C12—C11) with respect to the parent benzene ring in (I). The corresponding angles in (II) are -2.1 (3) [major component; for the minor C16B—N15—C12—C13 component the angle is 37.1 (4)°] and -14.6 (3)°, respectively. Overall, the structure of (II) is more planar than (I) and the only significant deviation from the plane is found for the diethylamine group.
The presence of an intramolecular hydrogen bond in (I) was predicted according to previous studies on salicylideneanilines and proved by spectroscopic methods in solution about 40 years ago (Avramovici et al., 1973). Due to the conjugated system and the intramolecular hydrogen bond with an S(6) graph-set motif (Bernstein et al., 1995) in the solid state, the benzylideneamine group becomes closely planar, as demonstrated by the dihedral angles of 179.7 (4) (C5—C6—C7—N8) and 0.9 (6)° (C1—C6—C7—N8) between the imine bond and the phenolic ring in (I). In (II), these torsion angles are similar, with values of -178.28 (15) and 0.9 (2)°, respectively.
The H atom in both compounds was found from an electron-density map within bonding distance (~1 Å) of the O atom, before being refined at its geometrically idealized position. Although this shows signs of the structures occurring in the imine form, determination of the exact H-atom position using X-ray diffraction is not possible. More evidence of the predominant imine form can be seen from the bond distances. The O1—C1 distance in both compounds [1.338 (5) Å in (I) and 1.334 (2) Å in (II)] is close to normal values reported for single C—O bonds in phenols and salicylideneamines (e.g. Ozeryanskii et al., 2006). Also, the N8—C7 bond is short in both compounds [1.294 (5) Å in (I) and 1.289 (2) Å in (II)], strongly indicating the existence of a conjugated C═N bond, while the long C6—C7 bond [1.446 (5) Å in (I) and 1.457 (2) Å in (II)] implies a single bond. Based on these facts, the presence of an intramolecular O—H···N bond (Tables 1 and 2) and the pure (E)-isomer in both compounds are justified. These features are similar to what has been observed in related N-salicylidene-(4-dimethylamino)anilines (Filipenko et al., 1983; Aldoshin et al., 1984; Wozniak et al., 1995; Pizzala et al., 2000; Gül et al., 2007). Whereas these structures, including the present, ones show phenolic imine forms, the related 4,5-bis(dimethylamino)-1-[(2-hydroxy-5-nitrobenzylidene)amino]naphthalene is reported to have the enaminone [enamine?] form (Ozeryanskii et al., 2006).
The molecule of (I) has intermolecular C—H···O contacts between the methyl groups and the nitro group (Fig. 3), and between atom C2 and the nitro group (Table 1). There are also two different weak π–π stacking interactions with rather long centroid–centroid distances between the phenol (C1–C6) and phenylenediamine (C9–C14) rings at (-x+1, y, -z+3/2) [3.759 (2) Å] and (-x+1, -y+1, -z+1) [3.878 (2) Å] (Fig. 3). These π–π interactions and two C—H···O interactions connect the molecules into antiparallel stacks. The other three C—H···O contacts connect the stacks to neighbouring ones.
There is only one C—H···O contact between the methyl groups and the nitro group in (II) (Table 2). Arylic atoms C5 and C14 donate C—H···O contacts, which are accepted by nitro and hydroxyl groups, respectively. In (II), there are π–π stacking interactions between the phenol (C1–C6) and phenylenediamine (C9–C14) rings at (-x+2, -y, -z+1) [centroid–centroid distance = 3.5826 (10) Å] and between two phenol (C1–C6) rings [3.6267 (9) Å; symmetry code for the second ring (-x+2, -y, -z+2)]. Due to the different intermolecular interactions, the packing in (II) is different, as can be seen from Fig. 4. Furthermore, the only C—H···O contact between a methyl (C17) and a nitro group is not sufficiently strong to hold the C16—C17 ethyl group completely in one conformation. The minor component does not show a similar close contact.