Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108020003/gz3150sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270108020003/gz3150Isup2.hkl |
CCDC reference: 700022
2-Aminoterephthalic acid (10 g, 55 mmol), methyliodide (62.5 g, 440 mmol), potassium carbonate (30.4 g) and 58 ml N,N-dimethylformamide were stirred at room temperature for 4 d in a round-bottomed flask equipped with a condenser connected to air through a CaCl2 trap. The inorganic solid was then filtered off and the solution was poured into 200 ml of water at 273–278 K with stirring. Within some minutes a pasty solid formed. The solution was filtered, the solid was dissolved in chloroform and anhydrified over sodium sulfate, and the excess chloroform was distilled off. A yellow oil of (I) was finally obtained, which crystallized after several days (m.p. 322 K). Crystals of (I) suitable for structure determination were obtained by slow evaporation of a dichloromethane solution at room temperature. 1H NMR (200 MHz, 298 K, CDCl3): δ 2.89 (s, 6H, NCH3), 3.91 (s, 6H, OCH3), 7.45 (d, 1H, J1 = 8.0 Hz, J2 = 1.2 Hz, Ph), 7.598 (s, 1H, Ph), 7.66 (d, 1H, J1 = 8.0 Hz, Ph).
H atoms were positioned stereochemically and constrained using a riding model, with Uiso(H) set at 1.2Ueq of the carrier atom for ring H atoms or 1.5Ueq of the carrier atom for methyl H atoms. For H atoms of methyl groups, the conformation was defined on the basis of difference maps. The H atoms of the two ester methyl groups and methylamine group (C11) are disordered over two sites rotated by 60° with respect to each other.
Data collection: COLLECT (Nonius, 1999); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level. Only one position is shown for H atoms of disordered methyl groups. |
C12H15NO4 | F(000) = 252 |
Mr = 237.25 | Dx = 1.352 Mg m−3 |
Triclinic, P1 | Melting point: 322 K |
a = 7.7120 (7) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 7.9190 (8) Å | Cell parameters from 180 reflections |
c = 9.989 (3) Å | θ = 4.7–26.3° |
α = 74.624 (14)° | µ = 0.10 mm−1 |
β = 82.576 (16)° | T = 173 K |
γ = 85.663 (9)° | Prism, yellow |
V = 582.7 (2) Å3 | 0.38 × 0.33 × 0.28 mm |
Z = 2 |
Bruker–Nonius KappaCCD diffractometer | 2622 independent reflections |
Radiation source: normal focus sealed tube | 1977 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
Detector resolution: 9 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
CCD rotation images, thick slices scans | h = −9→10 |
Absorption correction: multi-scan SADABS (Bruker–Nonius, 2002) | k = −10→8 |
Tmin = 0.952, Tmax = 0.972 | l = −12→12 |
8647 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)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0514P)2 + 0.1249P] where P = (Fo2 + 2Fc2)/3 |
2622 reflections | (Δ/σ)max < 0.001 |
158 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.23 e Å−3 |
C12H15NO4 | γ = 85.663 (9)° |
Mr = 237.25 | V = 582.7 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.7120 (7) Å | Mo Kα radiation |
b = 7.9190 (8) Å | µ = 0.10 mm−1 |
c = 9.989 (3) Å | T = 173 K |
α = 74.624 (14)° | 0.38 × 0.33 × 0.28 mm |
β = 82.576 (16)° |
Bruker–Nonius KappaCCD diffractometer | 2622 independent reflections |
Absorption correction: multi-scan SADABS (Bruker–Nonius, 2002) | 1977 reflections with I > 2σ(I) |
Tmin = 0.952, Tmax = 0.972 | Rint = 0.037 |
8647 measured reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.25 e Å−3 |
2622 reflections | Δρmin = −0.23 e Å−3 |
158 parameters |
Experimental. The absorption and emission spectrum of (I) has been recorded in chloroform solution, using a modular spectro-fluorimeter, with monochromators and light source from Acton Research. The fluorescence quantum yield has been measured by comparison with a quinine sulfate standard solution (0.1 M H2SO4 in water). Both the sample and the standard have been excited at 350?nm. The solvent Raman emission at ca 390?nm has been subtracted from the emission spectrum in the range 380–400?nm. The sample quantum yield Q is 0.091 and has been obtained by the expression (Lakowicz, 1999) Q=QR×(I/IR)×(ODR/OD)×(n/nR)2 in which Q is the quantum yield, I is the integrated intensity, OD is the optical density and n the refractive index. The subscript R refers to the reference fluorophore of known quantum yield (QR=0.577, Lakowicz, 1999). |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.47151 (13) | 0.20200 (14) | 0.50560 (10) | 0.0327 (3) | |
O2 | 0.22131 (13) | 0.12717 (13) | 0.44894 (9) | 0.0298 (3) | |
O3 | 0.09094 (16) | −0.40205 (14) | 1.13535 (10) | 0.0397 (3) | |
O4 | 0.20049 (14) | −0.18755 (13) | 1.20262 (9) | 0.0316 (3) | |
N1 | 0.34854 (16) | 0.29631 (14) | 0.78190 (12) | 0.0262 (3) | |
C1 | 0.2926 (2) | 0.1799 (2) | 0.30224 (14) | 0.0337 (4) | |
H1A | 0.3038 | 0.3073 | 0.2733 | 0.051* | 0.776 (18) |
H1B | 0.2138 | 0.1463 | 0.2451 | 0.051* | 0.776 (18) |
H1C | 0.4080 | 0.1217 | 0.2897 | 0.051* | 0.776 (18) |
H1D | 0.3133 | 0.0762 | 0.2654 | 0.051* | 0.224 (18) |
H1E | 0.4032 | 0.2372 | 0.2937 | 0.051* | 0.224 (18) |
H1F | 0.2091 | 0.2618 | 0.2490 | 0.051* | 0.224 (18) |
C2 | 0.32830 (18) | 0.14155 (17) | 0.54078 (14) | 0.0237 (3) | |
C3 | 0.25481 (17) | 0.06346 (17) | 0.68881 (13) | 0.0217 (3) | |
C4 | 0.17405 (18) | −0.09610 (18) | 0.71668 (14) | 0.0245 (3) | |
H4 | 0.1443 | −0.1349 | 0.6407 | 0.029* | |
C5 | 0.13578 (18) | −0.20008 (17) | 0.85184 (13) | 0.0242 (3) | |
H5 | 0.0804 | −0.3081 | 0.8686 | 0.029* | |
C6 | 0.18083 (17) | −0.14146 (17) | 0.96195 (13) | 0.0217 (3) | |
C7 | 0.25243 (17) | 0.02053 (17) | 0.93814 (13) | 0.0227 (3) | |
H7 | 0.2792 | 0.0584 | 1.0155 | 0.027* | |
C8 | 0.28683 (17) | 0.13111 (17) | 0.80168 (13) | 0.0210 (3) | |
C9 | 0.15006 (18) | −0.25888 (17) | 1.10732 (14) | 0.0243 (3) | |
C10 | 0.1882 (2) | −0.2932 (2) | 1.34595 (14) | 0.0359 (4) | |
H10A | 0.0682 | −0.2842 | 1.3904 | 0.054* | 0.689 (19) |
H10B | 0.2686 | −0.2511 | 1.3971 | 0.054* | 0.689 (19) |
H10C | 0.2197 | −0.4159 | 1.3473 | 0.054* | 0.689 (19) |
H10D | 0.3028 | −0.3499 | 1.3661 | 0.054* | 0.311 (19) |
H10E | 0.1023 | −0.3831 | 1.3594 | 0.054* | 0.311 (19) |
H10F | 0.1513 | −0.2183 | 1.4092 | 0.054* | 0.311 (19) |
C11 | 0.2981 (2) | 0.44154 (18) | 0.66779 (15) | 0.0333 (4) | |
H11A | 0.2138 | 0.4023 | 0.6182 | 0.050* | 0.781 (18) |
H11B | 0.4021 | 0.4821 | 0.6029 | 0.050* | 0.781 (18) |
H11C | 0.2445 | 0.5379 | 0.7056 | 0.050* | 0.781 (18) |
H11D | 0.3598 | 0.5459 | 0.6663 | 0.050* | 0.219 (18) |
H11E | 0.1715 | 0.4661 | 0.6815 | 0.050* | 0.219 (18) |
H11F | 0.3291 | 0.4103 | 0.5789 | 0.050* | 0.219 (18) |
C12 | 0.3864 (2) | 0.3510 (2) | 0.90307 (15) | 0.0329 (3) | |
H12A | 0.2765 | 0.3708 | 0.9591 | 0.049* | |
H12B | 0.4498 | 0.4597 | 0.8717 | 0.049* | |
H12C | 0.4584 | 0.2591 | 0.9599 | 0.049* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0339 (6) | 0.0378 (6) | 0.0277 (5) | −0.0114 (5) | 0.0026 (4) | −0.0109 (4) |
O2 | 0.0304 (6) | 0.0390 (6) | 0.0186 (5) | −0.0058 (4) | −0.0031 (4) | −0.0037 (4) |
O3 | 0.0619 (8) | 0.0289 (6) | 0.0268 (5) | −0.0173 (5) | −0.0039 (5) | −0.0009 (4) |
O4 | 0.0445 (6) | 0.0306 (6) | 0.0192 (5) | −0.0090 (5) | −0.0052 (4) | −0.0029 (4) |
N1 | 0.0344 (7) | 0.0213 (6) | 0.0234 (6) | −0.0051 (5) | −0.0013 (5) | −0.0065 (4) |
C1 | 0.0416 (9) | 0.0403 (9) | 0.0183 (7) | −0.0047 (7) | −0.0029 (6) | −0.0055 (6) |
C2 | 0.0285 (7) | 0.0209 (6) | 0.0226 (7) | −0.0015 (6) | −0.0023 (5) | −0.0074 (5) |
C3 | 0.0219 (7) | 0.0218 (6) | 0.0206 (6) | 0.0010 (5) | −0.0017 (5) | −0.0047 (5) |
C4 | 0.0268 (7) | 0.0261 (7) | 0.0228 (7) | −0.0016 (6) | −0.0038 (5) | −0.0094 (5) |
C5 | 0.0265 (7) | 0.0206 (6) | 0.0257 (7) | −0.0036 (5) | −0.0011 (5) | −0.0063 (5) |
C6 | 0.0217 (7) | 0.0212 (6) | 0.0210 (6) | 0.0006 (5) | −0.0007 (5) | −0.0044 (5) |
C7 | 0.0248 (7) | 0.0234 (7) | 0.0210 (6) | −0.0003 (5) | −0.0016 (5) | −0.0085 (5) |
C8 | 0.0195 (6) | 0.0202 (6) | 0.0234 (6) | −0.0004 (5) | −0.0002 (5) | −0.0071 (5) |
C9 | 0.0254 (7) | 0.0236 (7) | 0.0227 (7) | −0.0005 (6) | −0.0016 (5) | −0.0048 (5) |
C10 | 0.0443 (9) | 0.0412 (9) | 0.0200 (7) | −0.0087 (7) | −0.0066 (6) | −0.0005 (6) |
C11 | 0.0465 (9) | 0.0222 (7) | 0.0287 (7) | −0.0045 (6) | 0.0021 (6) | −0.0043 (6) |
C12 | 0.0413 (9) | 0.0282 (7) | 0.0325 (8) | −0.0106 (7) | −0.0028 (6) | −0.0120 (6) |
O1—C2 | 1.2095 (17) | C5—C6 | 1.3928 (19) |
O1—C11 | 2.9492 (19) | C5—H5 | 0.9500 |
O2—C2 | 1.3419 (16) | C6—C7 | 1.3851 (19) |
O2—C1 | 1.4579 (16) | C6—C9 | 1.5026 (18) |
O3—C9 | 1.2035 (17) | C7—C8 | 1.4157 (18) |
O4—C9 | 1.3381 (17) | C7—H7 | 0.9500 |
O4—C10 | 1.4494 (16) | C10—H10A | 0.9800 |
N1—C8 | 1.3819 (17) | C10—H10B | 0.9800 |
N1—C11 | 1.4577 (18) | C10—H10C | 0.9800 |
N1—C12 | 1.4581 (18) | C10—H10D | 0.9800 |
C1—H1A | 0.9800 | C10—H10E | 0.9800 |
C1—H1B | 0.9800 | C10—H10F | 0.9800 |
C1—H1C | 0.9800 | C11—H11A | 0.9800 |
C1—H1D | 0.9800 | C11—H11B | 0.9800 |
C1—H1E | 0.9800 | C11—H11C | 0.9800 |
C1—H1F | 0.9800 | C11—H11D | 0.9800 |
C2—C3 | 1.4971 (18) | C11—H11E | 0.9800 |
C3—C4 | 1.3963 (19) | C11—H11F | 0.9800 |
C3—C8 | 1.4253 (18) | C12—H12A | 0.9800 |
C4—C5 | 1.3900 (19) | C12—H12B | 0.9800 |
C4—H4 | 0.9500 | C12—H12C | 0.9800 |
C2—O1—C11 | 78.56 (9) | H10A—C10—H10B | 109.5 |
C2—O2—C1 | 115.63 (11) | O4—C10—H10C | 109.5 |
C9—O4—C10 | 117.26 (11) | H10A—C10—H10C | 109.5 |
C8—N1—C11 | 120.81 (12) | H10B—C10—H10C | 109.5 |
C8—N1—C12 | 118.93 (11) | O4—C10—H10D | 109.5 |
C11—N1—C12 | 113.52 (11) | H10A—C10—H10D | 141.1 |
O2—C1—H1A | 109.5 | H10B—C10—H10D | 56.3 |
O2—C1—H1B | 109.5 | H10C—C10—H10D | 56.3 |
H1A—C1—H1B | 109.5 | O4—C10—H10E | 109.5 |
O2—C1—H1C | 109.5 | H10A—C10—H10E | 56.3 |
H1A—C1—H1C | 109.5 | H10B—C10—H10E | 141.1 |
H1B—C1—H1C | 109.5 | H10C—C10—H10E | 56.3 |
O2—C1—H1D | 109.5 | H10D—C10—H10E | 109.5 |
H1A—C1—H1D | 141.1 | O4—C10—H10F | 109.5 |
H1B—C1—H1D | 56.3 | H10A—C10—H10F | 56.3 |
H1C—C1—H1D | 56.3 | H10B—C10—H10F | 56.3 |
O2—C1—H1E | 109.5 | H10C—C10—H10F | 141.1 |
H1A—C1—H1E | 56.3 | H10D—C10—H10F | 109.5 |
H1B—C1—H1E | 141.1 | H10E—C10—H10F | 109.5 |
H1C—C1—H1E | 56.3 | N1—C11—O1 | 80.37 (8) |
H1D—C1—H1E | 109.5 | N1—C11—H11A | 109.5 |
O2—C1—H1F | 109.5 | O1—C11—H11A | 69.4 |
H1A—C1—H1F | 56.3 | N1—C11—H11B | 109.5 |
H1B—C1—H1F | 56.3 | O1—C11—H11B | 62.4 |
H1C—C1—H1F | 141.1 | H11A—C11—H11B | 109.5 |
H1D—C1—H1F | 109.5 | N1—C11—H11C | 109.5 |
H1E—C1—H1F | 109.5 | O1—C11—H11C | 169.4 |
O1—C2—O2 | 122.92 (12) | H11A—C11—H11C | 109.5 |
O1—C2—C3 | 124.74 (12) | H11B—C11—H11C | 109.5 |
O2—C2—C3 | 112.22 (11) | N1—C11—H11D | 109.5 |
C4—C3—C8 | 119.69 (11) | O1—C11—H11D | 117.6 |
C4—C3—C2 | 116.99 (11) | H11A—C11—H11D | 141.1 |
C8—C3—C2 | 122.65 (11) | H11B—C11—H11D | 56.3 |
C5—C4—C3 | 122.22 (12) | H11C—C11—H11D | 56.3 |
C5—C4—H4 | 118.9 | N1—C11—H11E | 109.5 |
C3—C4—H4 | 118.9 | O1—C11—H11E | 125.1 |
C4—C5—C6 | 118.14 (12) | H11A—C11—H11E | 56.3 |
C4—C5—H5 | 120.9 | H11B—C11—H11E | 141.1 |
C6—C5—H5 | 120.9 | H11C—C11—H11E | 56.3 |
C7—C6—C5 | 120.93 (12) | H11D—C11—H11E | 109.5 |
C7—C6—C9 | 120.86 (12) | N1—C11—H11F | 109.5 |
C5—C6—C9 | 118.21 (12) | O1—C11—H11F | 29.4 |
C6—C7—C8 | 121.76 (12) | H11A—C11—H11F | 56.3 |
C6—C7—H7 | 119.1 | H11B—C11—H11F | 56.3 |
C8—C7—H7 | 119.1 | H11C—C11—H11F | 141.1 |
N1—C8—C7 | 120.39 (11) | H11D—C11—H11F | 109.5 |
N1—C8—C3 | 122.74 (11) | H11E—C11—H11F | 109.5 |
C7—C8—C3 | 116.87 (12) | N1—C12—H12A | 109.5 |
O3—C9—O4 | 123.56 (12) | N1—C12—H12B | 109.5 |
O3—C9—C6 | 124.40 (12) | H12A—C12—H12B | 109.5 |
O4—C9—C6 | 112.02 (11) | N1—C12—H12C | 109.5 |
O4—C10—H10A | 109.5 | H12A—C12—H12C | 109.5 |
O4—C10—H10B | 109.5 | H12B—C12—H12C | 109.5 |
C11—O1—C2—O2 | 120.59 (13) | C11—N1—C8—C3 | 33.88 (19) |
C11—O1—C2—C3 | −63.86 (13) | C12—N1—C8—C3 | −176.74 (13) |
C1—O2—C2—O1 | 3.47 (19) | C6—C7—C8—N1 | 176.12 (12) |
C1—O2—C2—C3 | −172.58 (11) | C6—C7—C8—C3 | −3.89 (19) |
O1—C2—C3—C4 | −134.11 (15) | C4—C3—C8—N1 | −172.80 (12) |
O2—C2—C3—C4 | 41.85 (16) | C2—C3—C8—N1 | 16.9 (2) |
O1—C2—C3—C8 | 36.5 (2) | C4—C3—C8—C7 | 7.21 (19) |
O2—C2—C3—C8 | −147.57 (12) | C2—C3—C8—C7 | −163.11 (12) |
C8—C3—C4—C5 | −5.4 (2) | C10—O4—C9—O3 | 2.4 (2) |
C2—C3—C4—C5 | 165.49 (13) | C10—O4—C9—C6 | −176.01 (12) |
C3—C4—C5—C6 | −0.2 (2) | C7—C6—C9—O3 | −178.82 (14) |
C4—C5—C6—C7 | 3.7 (2) | C5—C6—C9—O3 | 1.0 (2) |
C4—C5—C6—C9 | −176.17 (12) | C7—C6—C9—O4 | −0.46 (18) |
C5—C6—C7—C8 | −1.6 (2) | C5—C6—C9—O4 | 179.41 (12) |
C9—C6—C7—C8 | 178.28 (12) | C8—N1—C11—O1 | −60.33 (12) |
C11—N1—C8—C7 | −146.13 (13) | C12—N1—C11—O1 | 148.76 (11) |
C12—N1—C8—C7 | 3.25 (19) | C2—O1—C11—N1 | 81.04 (11) |
Experimental details
Crystal data | |
Chemical formula | C12H15NO4 |
Mr | 237.25 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 173 |
a, b, c (Å) | 7.7120 (7), 7.9190 (8), 9.989 (3) |
α, β, γ (°) | 74.624 (14), 82.576 (16), 85.663 (9) |
V (Å3) | 582.7 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.38 × 0.33 × 0.28 |
Data collection | |
Diffractometer | Bruker–Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan SADABS (Bruker–Nonius, 2002) |
Tmin, Tmax | 0.952, 0.972 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8647, 2622, 1977 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.109, 1.05 |
No. of reflections | 2622 |
No. of parameters | 158 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.23 |
Computer programs: COLLECT (Nonius, 1999), DIRAX/LSQ (Duisenberg et al., 2000), EVALCCD (Duisenberg et al., 2003), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
O1—C2 | 1.2095 (17) | C2—C3 | 1.4971 (18) |
O3—C9 | 1.2035 (17) | C6—C9 | 1.5026 (18) |
N1—C8 | 1.3819 (17) | ||
C8—N1—C11 | 120.81 (12) | C8—C3—C2 | 122.65 (11) |
C8—N1—C12 | 118.93 (11) | N1—C8—C7 | 120.39 (11) |
C11—N1—C12 | 113.52 (11) | N1—C8—C3 | 122.74 (11) |
C4—C3—C8 | 119.69 (11) | C7—C8—C3 | 116.87 (12) |
C4—C3—C2 | 116.99 (11) | ||
O1—C2—C3—C8 | 36.5 (2) | C11—N1—C8—C3 | 33.88 (19) |
C4—C5—C6—C9 | −176.17 (12) | C2—C3—C8—C7 | −163.11 (12) |
C12—N1—C8—C7 | 3.25 (19) | C5—C6—C9—O3 | 1.0 (2) |
(I)a | CUNJEAb | ISOGOMc | |
O1—C2—C3—C8 | 36.5 (2) | 43.8 | -61.5 |
C2—C3—C8—C7 | -163.11 (12) | 166.7 | -175.7 |
C11—N1—C8—C3 | 33.88 (19) | 44.0 | -21.7 |
C12—N1—C8—C7 | 3.25 (19) | 6.5 | -14.9 |
τN1d | 353.3 (1) | 349.2 | 359.5 |
O1···C11 | 2.950 (2) | 3.06 | 3.01 |
(a) This work; (b) Swisher et al. (1984); (c) Davies et al. (2004); (d) τN1 is the sum of the valence angles at N1. |
O1—C2 | 1.219 |
O3—C9 | 1.217 |
N1—C8 | 1.383 |
C2—C3 | 1.489 |
C6—C9 | 1.494 |
C8—N1—C11 | 122.19 |
C8—N1—C12 | 120.37 |
C11—N1—C12 | 114.54 |
C4—C3—C8 | 119.44 |
C4—C3—C2 | 117.54 |
C8—C3—C2 | 122.45 |
N1—C8—C7 | 119.59 |
N1—C8—C3 | 123.10 |
C7—C8—C3 | 117.30 |
O1—C2—C3—C8 | 23.5 |
C4—C5—C6—C9 | -179 |
C12—N1—C8—C7 | 18.4 |
C11—N1—C8—C3 | 38.1 |
C2—C3—C8—C7 | -165.6 |
C5—C6—C9—O3 | -0.5 |
The title compound, (I), has been prepared as an electron-rich intermediate in the synthesis of new polymeric materials for electronics and photonics. In many of these systems, π conjugation between electron-rich and electron-poor moieties along the polymer chain is required (Dhanabalan et al., 2001).
The determination of the X-ray structure of (I) was undertaken on the basis of the presumed effects of steric overcrowding due to the location of the ester and dimethylamine groups ortho to one another; these effects could affect the planarity of the molecule and hence the π conjugation and performance of the derived compounds.
In terephthalic or benzoic acid derivatives, the carbonyl group is generally found to be coplanar with the phenyl ring (Centore et al., 1991; Centore & Tuzi, 1998). Deviations from coplanarity are observed as a result of steric overcrowding, e.g. for 2,6-disubstituted benzoic acids (Anca et al., 1967; Florencio & Smith, 1970).
Of the two carbonyl groups of (I), C9/O3 is essentially coplanar with the ring, as expected, while C2/O1, located ortho to the dimethylamine group, is not. The torsion of the carbonyl group does not fully relax the steric overcrowding, because of the contact between atom O1 and one of the H atoms bonded to atom C11. The dimethylamine group is also involved in the pattern of deformations.
In the absence of steric overcrowding, N,N-dialkyl groups are often found to be essentially coplanar with phenyl rings, and the geometry about the N atom is trigonal–planar, the sp2-hybridization favouring interaction of the lone pair with the π electrons of the ring (Centore et al., 1997, 2002; Centore & Tuzi, 2001; Castaldo et al., 2002). In (I), the N atom is in a pyramidal configuration [the sum of the valence angles around N1 is 353.3 (1)°]. Moreover, the disposition of the dimethylamine group is not symmetric with respect to the phenyl ring. In fact, the methyl group not involved in the close contact (C12) is essentially coplanar with the phenyl ring [0.133 (3) Å below the mean plane], while the other is not [0.874 (3) Å below the mean plane]. On the other hand, atom O1 lies 1.176 (3) Å above the mean plane of the phenyl ring.
An additional structural evidence probably still related to the steric overcrowding is the out-of-plane deformation of carbonyl atom C2. Actually, the phenyl ring is planar within 0.039 (1) Å, and atom C2 lies 0.378 (2) Å above the mean plane of the phenyl ring. It is worth noticing that the same type of deformation is not observed for atom N1, probably because of the π–π interaction between the N atom and the phenyl ring.
In summary, all of the deformations described above drive the nonbonded distance O1···C11 to 2.950 (2) Å.
We have searched the Cambridge Structural Database (CSD; Version 5.29; Allen, 2002) for compounds having an N,N-dimethylamine and a COO group ortho to one another. Out of the four hits found (refcodes CUNJEA, DOZDAX, ISOGOM and XERCOM), two are significant in this context (see Table 2). In one case (refcode CUNJEA; Swisher et al., 1984) the pattern of deformations is very similar to the present one. In the other (refcode ISOGOM; Davies et al., 2004) the pattern is different. In fact, the N atom has a trigonal–planar geometry, with the plane twisted with respect to the phenyl ring (by about 20°); a higher twist of the carbonyl group is observed and the carbonyl C atom is essentially coplanar with the phenyl ring. The different pattern observed in ISOGOM is probably due to the nitro group being in the para position with respect to the dimethylamine group (push–pull effect).
In view of the different deformations found in the X-ray structures, we have performed a theoretical quantum mechanical calculation of the gas phase molecular structure of (I) in order to verify the equilibrium geometry of the isolated molecule.
The gas phase equilibrium geometry of (I) has been computed by using Density Functional Theory, using the hybrid B3LYP exchange- correlation functional and the standard 6-31++G** basis set. All computations have been performed using the GAUSSIAN03 package (Frisch et al., 2003).
There is a good agreement between the experimental and the computed molecular geometry (see Table 3); the bond lengths do not differ by more than 0.016 Å and the bond angles differ by a maximum of 1.6°. The three main structural effects related to the steric overcrowding, i.e. the torsion angle of the carbonyl group around C2—C3, the deformation of the dimethylamine group and the out-of-plane displacement of atom C2, are found also in the calculated geometry.
The UV–VIS characterization of (I) in chloroform solution shows the HOMO–LUMO band centered at λmax = 350 nm, with a tail in the visible region, responsible for the yellow colour of (I). By exciting the compound at 350 nm, emission at 425 nm is observed (blue fluorescence). The measured quantum yield is 0.091.