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The title compound, C
24H
24N
2O
2, crystallizes as a triclinic polymorph from dimethylformamide and a monoclinic polymorph from ethanol. In both forms, the molecule displays crystallographic inversion symmetry, and the packing involves translationally related `ladders' of molecules connected by N—H
O=C hydrogen bonds. Differences between the structures can be rationalized in terms of weak C—H
O contacts. Powder and differential scanning calorimetry investigations of new samples gave no evidence for the triclinic form, and it seems to represent a disappearing polymorph.
Supporting information
CCDC references: 616125; 616126
The title compound was prepared according to Jones et al. (2002). The resulting white solid was washed several times with toluene and methanol and dried in air [yield 80%, m.p. 543–545 K for form M (form T is no longer availale)]. Analysis calculated: C 77.39, H 6.49, N 7.52%; found C 77.43, H 6.54, N 7.55%. 1H NMR (DMSO-d6/TMS): δ 8.66 (bs, 2H), 7.87 (s, 4H), 7.32–7.18 (m, 10H), 3.49 (q, 4H), 2.85 (t, 4H). IR (cm−1, KBr pellets): 3301, 3085, 3064, 3030, 2969, 2933, 2868, 1630, 1544, 1497, 1465, 1455, 1372, 1323, 1290, 1194, 1161, 1120, 1088, 1053, 1032, 1022, 910, 857, 749, 700. ESI MS (m/z, intensity): 170 (24) [M+2H]2+, 339 (100) [M+H]+, 677 (30) [2M+H]+. Single crystals were obtained from the relevant solvent (see Comment) by slow evaporation.
Amide H atoms were refined freely. Other H atoms were included at calculated positions and refined using a riding model with fixed C—H bond lengths of 0.95 (CH) and 0.99 Å (CH2) for the triclinic form, and 0.94 (CH) and 0.98 Å (CH2) for the monoclinic form; Uiso(H) values were fixed at 1.2 times Ueq(C) of the parent C atom.
For both compounds, data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.
(T)
N,
N'-Diphenethylterephthalamide
top
Crystal data top
C24H24N2O2 | Z = 1 |
Mr = 372.45 | F(000) = 198 |
Triclinic, P1 | Dx = 1.272 Mg m−3 |
a = 5.1845 (12) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.719 (2) Å | Cell parameters from 3748 reflections |
c = 10.041 (2) Å | θ = 2.8–30.5° |
α = 95.305 (5)° | µ = 0.08 mm−1 |
β = 98.541 (5)° | T = 133 K |
γ = 101.663 (5)° | Tablet, colourless |
V = 486.08 (18) Å3 | 0.4 × 0.2 × 0.1 mm |
Data collection top
Bruker SMART 1000 CCD area detector diffractometer | 2271 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.033 |
Graphite monochromator | θmax = 30.5°, θmin = 2.1° |
Detector resolution: 8.192 pixels mm-1 | h = −7→7 |
ω scan | k = −13→13 |
5728 measured reflections | l = −14→13 |
2899 independent reflections | |
Refinement top
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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0648P)2 + 0.1016P] where P = (Fo2 + 2Fc2)/3 |
2899 reflections | (Δ/σ)max < 0.001 |
131 parameters | Δρmax = 0.41 e Å−3 |
0 restraints | Δρmin = −0.23 e Å−3 |
Crystal data top
C24H24N2O2 | γ = 101.663 (5)° |
Mr = 372.45 | V = 486.08 (18) Å3 |
Triclinic, P1 | Z = 1 |
a = 5.1845 (12) Å | Mo Kα radiation |
b = 9.719 (2) Å | µ = 0.08 mm−1 |
c = 10.041 (2) Å | T = 133 K |
α = 95.305 (5)° | 0.4 × 0.2 × 0.1 mm |
β = 98.541 (5)° | |
Data collection top
Bruker SMART 1000 CCD area detector diffractometer | 2271 reflections with I > 2σ(I) |
5728 measured reflections | Rint = 0.033 |
2899 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.41 e Å−3 |
2899 reflections | Δρmin = −0.23 e Å−3 |
131 parameters | |
Special details top
Experimental. H NMR: Bruker 400 MHz IR: Nicolet FT–IR Magna 560 spectrometer |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.20205 (16) | 0.32616 (10) | 0.26726 (9) | 0.0277 (2) | |
N1 | 0.63551 (19) | 0.30544 (11) | 0.29535 (11) | 0.0245 (2) | |
H1 | 0.783 (3) | 0.3201 (16) | 0.2636 (16) | 0.030 (4)* | |
C1 | 0.4699 (2) | 0.42616 (11) | 0.11183 (11) | 0.0183 (2) | |
C2 | 0.7147 (2) | 0.51500 (12) | 0.10553 (11) | 0.0200 (2) | |
H2 | 0.8614 | 0.5254 | 0.1775 | 0.024* | |
C3 | 0.2556 (2) | 0.41176 (12) | 0.00574 (12) | 0.0207 (2) | |
H3 | 0.0886 | 0.3516 | 0.0096 | 0.025* | |
C4 | 0.4242 (2) | 0.34843 (12) | 0.23175 (11) | 0.0199 (2) | |
C5 | 0.6235 (2) | 0.22751 (13) | 0.41224 (12) | 0.0252 (2) | |
H5A | 0.6548 | 0.1319 | 0.3879 | 0.030* | |
H5B | 0.4423 | 0.2159 | 0.4359 | 0.030* | |
C6 | 0.8290 (3) | 0.30203 (14) | 0.53544 (13) | 0.0292 (3) | |
H6A | 1.0106 | 0.3154 | 0.5120 | 0.035* | |
H6B | 0.7953 | 0.3966 | 0.5622 | 0.035* | |
C7 | 0.8129 (2) | 0.21525 (12) | 0.65279 (11) | 0.0219 (2) | |
C8 | 0.9578 (2) | 0.10983 (13) | 0.66794 (12) | 0.0262 (3) | |
H8 | 1.0736 | 0.0944 | 0.6058 | 0.031* | |
C9 | 0.9343 (3) | 0.02702 (14) | 0.77316 (14) | 0.0310 (3) | |
H9 | 1.0340 | −0.0445 | 0.7824 | 0.037* | |
C10 | 0.7663 (3) | 0.04841 (15) | 0.86445 (13) | 0.0324 (3) | |
H10 | 0.7497 | −0.0086 | 0.9360 | 0.039* | |
C11 | 0.6226 (3) | 0.15343 (15) | 0.85077 (13) | 0.0322 (3) | |
H11 | 0.5082 | 0.1691 | 0.9135 | 0.039* | |
C12 | 0.6454 (2) | 0.23592 (13) | 0.74555 (13) | 0.0274 (3) | |
H12 | 0.5454 | 0.3074 | 0.7368 | 0.033* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0161 (4) | 0.0382 (5) | 0.0334 (5) | 0.0084 (3) | 0.0088 (3) | 0.0157 (4) |
N1 | 0.0151 (4) | 0.0353 (6) | 0.0263 (5) | 0.0069 (4) | 0.0055 (4) | 0.0150 (4) |
C1 | 0.0150 (5) | 0.0207 (5) | 0.0211 (5) | 0.0056 (4) | 0.0044 (4) | 0.0054 (4) |
C2 | 0.0136 (4) | 0.0242 (5) | 0.0215 (5) | 0.0037 (4) | 0.0005 (4) | 0.0046 (4) |
C3 | 0.0130 (4) | 0.0227 (5) | 0.0263 (5) | 0.0021 (4) | 0.0034 (4) | 0.0058 (4) |
C4 | 0.0151 (5) | 0.0228 (5) | 0.0223 (5) | 0.0041 (4) | 0.0031 (4) | 0.0060 (4) |
C5 | 0.0187 (5) | 0.0317 (6) | 0.0253 (6) | 0.0031 (4) | 0.0015 (4) | 0.0133 (5) |
C6 | 0.0275 (6) | 0.0299 (6) | 0.0266 (6) | −0.0018 (5) | 0.0012 (5) | 0.0093 (5) |
C7 | 0.0187 (5) | 0.0233 (5) | 0.0196 (5) | −0.0019 (4) | −0.0005 (4) | 0.0026 (4) |
C8 | 0.0213 (5) | 0.0317 (6) | 0.0245 (6) | 0.0041 (4) | 0.0040 (4) | 0.0019 (5) |
C9 | 0.0269 (6) | 0.0300 (6) | 0.0343 (7) | 0.0055 (5) | −0.0021 (5) | 0.0087 (5) |
C10 | 0.0282 (6) | 0.0380 (7) | 0.0250 (6) | −0.0055 (5) | −0.0021 (5) | 0.0122 (5) |
C11 | 0.0254 (6) | 0.0446 (7) | 0.0237 (6) | −0.0002 (5) | 0.0074 (5) | 0.0017 (5) |
C12 | 0.0231 (6) | 0.0300 (6) | 0.0280 (6) | 0.0056 (4) | 0.0031 (4) | 0.0007 (5) |
Geometric parameters (Å, º) top
O1—C4 | 1.2395 (13) | C10—C11 | 1.385 (2) |
N1—C4 | 1.3449 (14) | C11—C12 | 1.3886 (18) |
N1—C5 | 1.4568 (14) | N1—H1 | 0.864 (16) |
C1—C3 | 1.3953 (15) | C2—H2 | 0.9500 |
C1—C2 | 1.3971 (15) | C3—H3 | 0.9500 |
C1—C4 | 1.5023 (15) | C5—H5A | 0.9900 |
C2—C3i | 1.3901 (15) | C5—H5B | 0.9900 |
C3—C2i | 1.3901 (15) | C6—H6A | 0.9900 |
C5—C6 | 1.5235 (17) | C6—H6B | 0.9900 |
C6—C7 | 1.5137 (16) | C8—H8 | 0.9500 |
C7—C12 | 1.3920 (17) | C9—H9 | 0.9500 |
C7—C8 | 1.3940 (17) | C10—H10 | 0.9500 |
C8—C9 | 1.3909 (18) | C11—H11 | 0.9500 |
C9—C10 | 1.385 (2) | C12—H12 | 0.9500 |
| | | |
C4—N1—C5 | 122.93 (9) | C2i—C3—H3 | 119.8 |
C3—C1—C2 | 119.48 (10) | C1—C3—H3 | 119.8 |
C3—C1—C4 | 118.12 (9) | N1—C5—H5A | 109.1 |
C2—C1—C4 | 122.36 (9) | C6—C5—H5A | 109.1 |
C3i—C2—C1 | 120.19 (10) | N1—C5—H5B | 109.1 |
C2i—C3—C1 | 120.33 (10) | C6—C5—H5B | 109.1 |
O1—C4—N1 | 123.30 (10) | H5A—C5—H5B | 107.9 |
O1—C4—C1 | 120.55 (9) | C7—C6—H6A | 109.6 |
N1—C4—C1 | 116.15 (9) | C5—C6—H6A | 109.6 |
N1—C5—C6 | 112.32 (10) | C7—C6—H6B | 109.6 |
C7—C6—C5 | 110.25 (10) | C5—C6—H6B | 109.6 |
C12—C7—C8 | 118.48 (11) | H6A—C6—H6B | 108.1 |
C12—C7—C6 | 120.52 (11) | C9—C8—H8 | 119.7 |
C8—C7—C6 | 120.96 (11) | C7—C8—H8 | 119.7 |
C9—C8—C7 | 120.61 (12) | C10—C9—H9 | 119.8 |
C10—C9—C8 | 120.30 (12) | C8—C9—H9 | 119.8 |
C9—C10—C11 | 119.55 (12) | C9—C10—H10 | 120.2 |
C10—C11—C12 | 120.19 (12) | C11—C10—H10 | 120.2 |
C11—C12—C7 | 120.87 (12) | C10—C11—H11 | 119.9 |
C4—N1—H1 | 119.3 (10) | C12—C11—H11 | 119.9 |
C5—N1—H1 | 117.7 (10) | C11—C12—H12 | 119.6 |
C3i—C2—H2 | 119.9 | C7—C12—H12 | 119.6 |
C1—C2—H2 | 119.9 | | |
| | | |
C3—C1—C2—C3i | −0.10 (18) | N1—C5—C6—C7 | −178.62 (10) |
C4—C1—C2—C3i | −177.89 (10) | C5—C6—C7—C12 | −90.35 (14) |
C2—C1—C3—C2i | 0.10 (18) | C5—C6—C7—C8 | 87.46 (14) |
C4—C1—C3—C2i | 177.99 (10) | C12—C7—C8—C9 | 0.24 (17) |
C5—N1—C4—O1 | 0.33 (19) | C6—C7—C8—C9 | −177.61 (11) |
C5—N1—C4—C1 | −179.32 (11) | C7—C8—C9—C10 | −0.03 (19) |
C3—C1—C4—O1 | −31.21 (16) | C8—C9—C10—C11 | −0.35 (19) |
C2—C1—C4—O1 | 146.61 (12) | C9—C10—C11—C12 | 0.51 (19) |
C3—C1—C4—N1 | 148.45 (11) | C10—C11—C12—C7 | −0.30 (19) |
C2—C1—C4—N1 | −33.72 (16) | C8—C7—C12—C11 | −0.08 (17) |
C4—N1—C5—C6 | −122.89 (13) | C6—C7—C12—C11 | 177.78 (11) |
Symmetry code: (i) −x+1, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1ii | 0.864 (16) | 2.155 (16) | 2.9606 (14) | 155.1 (14) |
C6—H6A···O1ii | 0.99 | 2.79 | 3.5395 (17) | 133 |
C9—H9···O1iii | 0.95 | 2.73 | 3.3351 (18) | 122 |
Symmetry codes: (ii) x+1, y, z; (iii) −x+1, −y, −z+1. |
(M)
N,
N'-Diphenethylterephthalamide
top
Crystal data top
C24H24N2O2 | F(000) = 396 |
Mr = 372.45 | Dx = 1.247 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 19.688 (2) Å | Cell parameters from 3384 reflections |
b = 5.0178 (6) Å | θ = 3.1–26.2° |
c = 10.1344 (11) Å | µ = 0.08 mm−1 |
β = 97.762 (2)° | T = 203 K |
V = 992.03 (19) Å3 | Lath, colourless |
Z = 2 | 0.50 × 0.20 × 0.08 mm |
Data collection top
Bruker SMART 1000 CCD area-detector diffractometer | 1091 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.078 |
Graphite monochromator | θmax = 26.4°, θmin = 2.1° |
Detector resolution: 8.192 pixels mm-1 | h = −24→24 |
ω scans | k = −6→6 |
11272 measured reflections | l = −12→12 |
2029 independent reflections | |
Refinement top
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)] = 0.053 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.134 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0622P)2 + 0.0804P] where P = (Fo2 + 2Fc2)/3 |
2029 reflections | (Δ/σ)max < 0.001 |
131 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.17 e Å−3 |
Crystal data top
C24H24N2O2 | V = 992.03 (19) Å3 |
Mr = 372.45 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 19.688 (2) Å | µ = 0.08 mm−1 |
b = 5.0178 (6) Å | T = 203 K |
c = 10.1344 (11) Å | 0.50 × 0.20 × 0.08 mm |
β = 97.762 (2)° | |
Data collection top
Bruker SMART 1000 CCD area-detector diffractometer | 1091 reflections with I > 2σ(I) |
11272 measured reflections | Rint = 0.078 |
2029 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.053 | 0 restraints |
wR(F2) = 0.134 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.18 e Å−3 |
2029 reflections | Δρmin = −0.17 e Å−3 |
131 parameters | |
Special details top
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
N1 | 0.15923 (10) | 0.5748 (4) | 0.24018 (18) | 0.0366 (5) | |
H1 | 0.1476 (10) | 0.733 (5) | 0.221 (2) | 0.034 (6)* | |
O1 | 0.14505 (8) | 0.1419 (3) | 0.18378 (16) | 0.0441 (5) | |
C1 | 0.06035 (10) | 0.4462 (4) | 0.0852 (2) | 0.0283 (5) | |
C2 | 0.01771 (11) | 0.6550 (4) | 0.1125 (2) | 0.0341 (6) | |
H2 | 0.0295 | 0.7604 | 0.1888 | 0.041* | |
C3 | 0.04166 (11) | 0.2922 (4) | −0.0282 (2) | 0.0337 (6) | |
H3 | 0.0699 | 0.1504 | −0.0474 | 0.040* | |
C4 | 0.12475 (11) | 0.3761 (4) | 0.1737 (2) | 0.0319 (5) | |
C5 | 0.22517 (12) | 0.5337 (5) | 0.3199 (2) | 0.0435 (6) | |
H5A | 0.2613 | 0.5715 | 0.2648 | 0.052* | |
H5B | 0.2291 | 0.3456 | 0.3459 | 0.052* | |
C6 | 0.23727 (13) | 0.7010 (5) | 0.4426 (2) | 0.0504 (7) | |
H6A | 0.2015 | 0.6656 | 0.4988 | 0.060* | |
H6B | 0.2350 | 0.8900 | 0.4181 | 0.060* | |
C7 | 0.30657 (12) | 0.6392 (5) | 0.5192 (2) | 0.0424 (6) | |
C8 | 0.36484 (17) | 0.7695 (6) | 0.4943 (3) | 0.0745 (9) | |
H8 | 0.3614 | 0.9091 | 0.4319 | 0.089* | |
C9 | 0.42883 (16) | 0.6982 (7) | 0.5598 (4) | 0.0843 (10) | |
H9 | 0.4681 | 0.7892 | 0.5410 | 0.101* | |
C10 | 0.43489 (16) | 0.4992 (6) | 0.6502 (3) | 0.0652 (8) | |
H10 | 0.4783 | 0.4520 | 0.6946 | 0.078* | |
C11 | 0.37847 (16) | 0.3684 (6) | 0.6766 (3) | 0.0663 (8) | |
H11 | 0.3825 | 0.2295 | 0.7395 | 0.080* | |
C12 | 0.31463 (14) | 0.4383 (6) | 0.6113 (2) | 0.0565 (7) | |
H12 | 0.2758 | 0.3452 | 0.6307 | 0.068* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0461 (13) | 0.0191 (10) | 0.0424 (12) | 0.0042 (9) | −0.0024 (10) | 0.0011 (8) |
O1 | 0.0476 (10) | 0.0210 (8) | 0.0606 (11) | 0.0047 (7) | −0.0043 (8) | 0.0012 (7) |
C1 | 0.0343 (13) | 0.0201 (10) | 0.0307 (12) | 0.0007 (9) | 0.0059 (10) | 0.0046 (9) |
C2 | 0.0428 (14) | 0.0286 (11) | 0.0309 (13) | 0.0036 (10) | 0.0048 (11) | −0.0042 (10) |
C3 | 0.0381 (14) | 0.0224 (11) | 0.0406 (13) | 0.0070 (9) | 0.0058 (11) | −0.0020 (10) |
C4 | 0.0402 (13) | 0.0208 (11) | 0.0351 (13) | 0.0007 (10) | 0.0060 (11) | 0.0023 (10) |
C5 | 0.0448 (16) | 0.0336 (12) | 0.0491 (15) | 0.0038 (11) | −0.0049 (13) | −0.0053 (11) |
C6 | 0.0608 (18) | 0.0426 (15) | 0.0441 (15) | 0.0140 (12) | −0.0062 (13) | −0.0102 (12) |
C7 | 0.0513 (16) | 0.0365 (12) | 0.0368 (14) | 0.0024 (12) | −0.0032 (12) | −0.0116 (11) |
C8 | 0.078 (2) | 0.0546 (17) | 0.083 (2) | −0.0174 (17) | −0.0161 (19) | 0.0193 (16) |
C9 | 0.059 (2) | 0.084 (2) | 0.105 (3) | −0.0253 (18) | −0.005 (2) | 0.012 (2) |
C10 | 0.0562 (19) | 0.0708 (19) | 0.0634 (19) | 0.0082 (17) | −0.0110 (15) | −0.0110 (17) |
C11 | 0.067 (2) | 0.0748 (19) | 0.0534 (18) | 0.0077 (17) | −0.0057 (16) | 0.0149 (15) |
C12 | 0.0542 (17) | 0.0719 (18) | 0.0431 (16) | 0.0008 (14) | 0.0057 (14) | 0.0126 (14) |
Geometric parameters (Å, º) top
O1—C4 | 1.241 (2) | C10—C11 | 1.348 (4) |
N1—C4 | 1.336 (3) | C11—C12 | 1.384 (4) |
N1—C5 | 1.448 (3) | N1—H1 | 0.84 (2) |
C1—C3 | 1.392 (3) | C2—H2 | 0.9400 |
C1—C2 | 1.393 (3) | C3—H3 | 0.9400 |
C1—C4 | 1.493 (3) | C5—H5A | 0.9800 |
C2—C3i | 1.377 (3) | C5—H5B | 0.9800 |
C3—C2i | 1.377 (3) | C6—H6A | 0.9800 |
C5—C6 | 1.493 (3) | C6—H6B | 0.9800 |
C6—C7 | 1.508 (3) | C8—H8 | 0.9400 |
C7—C12 | 1.368 (3) | C9—H9 | 0.9400 |
C7—C8 | 1.373 (4) | C10—H10 | 0.9400 |
C8—C9 | 1.389 (4) | C11—H11 | 0.9400 |
C9—C10 | 1.350 (4) | C12—H12 | 0.9400 |
| | | |
C4—N1—C5 | 122.07 (19) | C2i—C3—H3 | 119.6 |
C3—C1—C2 | 118.79 (19) | C1—C3—H3 | 119.6 |
C3—C1—C4 | 118.26 (18) | N1—C5—H5A | 108.6 |
C2—C1—C4 | 122.94 (19) | C6—C5—H5A | 108.6 |
C3i—C2—C1 | 120.34 (19) | N1—C5—H5B | 108.6 |
C2i—C3—C1 | 120.87 (19) | C6—C5—H5B | 108.6 |
O1—C4—N1 | 122.0 (2) | H5A—C5—H5B | 107.6 |
O1—C4—C1 | 120.69 (19) | C5—C6—H6A | 109.6 |
N1—C4—C1 | 117.35 (18) | C7—C6—H6A | 109.6 |
N1—C5—C6 | 114.51 (19) | C5—C6—H6B | 109.6 |
C5—C6—C7 | 110.15 (19) | C7—C6—H6B | 109.6 |
C12—C7—C8 | 116.9 (2) | H6A—C6—H6B | 108.1 |
C12—C7—C6 | 121.1 (2) | C7—C8—H8 | 119.5 |
C8—C7—C6 | 121.9 (2) | C9—C8—H8 | 119.5 |
C7—C8—C9 | 121.1 (3) | C10—C9—H9 | 119.8 |
C10—C9—C8 | 120.4 (3) | C8—C9—H9 | 119.8 |
C11—C10—C9 | 119.7 (3) | C11—C10—H10 | 120.2 |
C10—C11—C12 | 120.1 (3) | C9—C10—H10 | 120.2 |
C7—C12—C11 | 121.8 (3) | C10—C11—H11 | 120.0 |
C4—N1—H1 | 119.0 (14) | C12—C11—H11 | 120.0 |
C5—N1—H1 | 117.2 (14) | C7—C12—H12 | 119.1 |
C3i—C2—H2 | 119.8 | C11—C12—H12 | 119.1 |
C1—C2—H2 | 119.8 | | |
| | | |
C3—C1—C2—C3i | −0.2 (3) | N1—C5—C6—C7 | 179.0 (2) |
C4—C1—C2—C3i | −179.00 (19) | C5—C6—C7—C12 | −87.7 (3) |
C2—C1—C3—C2i | 0.2 (3) | C5—C6—C7—C8 | 88.3 (3) |
C4—C1—C3—C2i | 179.06 (19) | C12—C7—C8—C9 | 0.2 (4) |
C5—N1—C4—O1 | 5.0 (3) | C6—C7—C8—C9 | −175.8 (3) |
C5—N1—C4—C1 | −174.68 (19) | C7—C8—C9—C10 | −0.3 (5) |
C3—C1—C4—O1 | −30.5 (3) | C8—C9—C10—C11 | 0.2 (5) |
C2—C1—C4—O1 | 148.3 (2) | C9—C10—C11—C12 | −0.1 (4) |
C3—C1—C4—N1 | 149.2 (2) | C8—C7—C12—C11 | −0.1 (4) |
C2—C1—C4—N1 | −32.0 (3) | C6—C7—C12—C11 | 176.1 (2) |
C4—N1—C5—C6 | −145.1 (2) | C10—C11—C12—C7 | 0.0 (4) |
Symmetry code: (i) −x, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1ii | 0.84 (2) | 2.08 (2) | 2.908 (2) | 165.7 (19) |
C6—H6A···O1iii | 0.98 | 2.77 | 3.664 (3) | 151 |
C12—H12···O1iii | 0.94 | 2.70 | 3.537 (3) | 149 |
Symmetry codes: (ii) x, y+1, z; (iii) x, −y+1/2, z+1/2. |
Experimental details
| (T) | (M) |
Crystal data |
Chemical formula | C24H24N2O2 | C24H24N2O2 |
Mr | 372.45 | 372.45 |
Crystal system, space group | Triclinic, P1 | Monoclinic, P21/c |
Temperature (K) | 133 | 203 |
a, b, c (Å) | 5.1845 (12), 9.719 (2), 10.041 (2) | 19.688 (2), 5.0178 (6), 10.1344 (11) |
α, β, γ (°) | 95.305 (5), 98.541 (5), 101.663 (5) | 90, 97.762 (2), 90 |
V (Å3) | 486.08 (18) | 992.03 (19) |
Z | 1 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.08 | 0.08 |
Crystal size (mm) | 0.4 × 0.2 × 0.1 | 0.50 × 0.20 × 0.08 |
|
Data collection |
Diffractometer | Bruker SMART 1000 CCD area detector diffractometer | Bruker SMART 1000 CCD area-detector diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5728, 2899, 2271 | 11272, 2029, 1091 |
Rint | 0.033 | 0.078 |
(sin θ/λ)max (Å−1) | 0.714 | 0.625 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.127, 1.03 | 0.053, 0.134, 1.01 |
No. of reflections | 2899 | 2029 |
No. of parameters | 131 | 131 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.41, −0.23 | 0.18, −0.17 |
Selected geometric parameters (Å, º) for (T) topO1—C4 | 1.2395 (13) | C5—C6 | 1.5235 (17) |
N1—C4 | 1.3449 (14) | C6—C7 | 1.5137 (16) |
N1—C5 | 1.4568 (14) | | |
| | | |
C3—C1—C4 | 118.12 (9) | C2—C1—C4 | 122.36 (9) |
| | | |
C5—N1—C4—C1 | −179.32 (11) | N1—C5—C6—C7 | −178.62 (10) |
C3—C1—C4—O1 | −31.21 (16) | C5—C6—C7—C8 | 87.46 (14) |
Hydrogen-bond geometry (Å, º) for (T) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.864 (16) | 2.155 (16) | 2.9606 (14) | 155.1 (14) |
C6—H6A···O1i | 0.99 | 2.79 | 3.5395 (17) | 133 |
C9—H9···O1ii | 0.95 | 2.73 | 3.3351 (18) | 122 |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y, −z+1. |
Selected geometric parameters (Å, º) for (M) topO1—C4 | 1.241 (2) | C5—C6 | 1.493 (3) |
N1—C4 | 1.336 (3) | C6—C7 | 1.508 (3) |
N1—C5 | 1.448 (3) | | |
| | | |
C3—C1—C4 | 118.26 (18) | C2—C1—C4 | 122.94 (19) |
| | | |
C5—N1—C4—C1 | −174.68 (19) | N1—C5—C6—C7 | 179.0 (2) |
C3—C1—C4—O1 | −30.5 (3) | C5—C6—C7—C8 | 88.3 (3) |
Hydrogen-bond geometry (Å, º) for (M) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.84 (2) | 2.08 (2) | 2.908 (2) | 165.7 (19) |
C6—H6A···O1ii | 0.98 | 2.77 | 3.664 (3) | 151 |
C12—H12···O1ii | 0.94 | 2.70 | 3.537 (3) | 149 |
Symmetry codes: (i) x, y+1, z; (ii) x, −y+1/2, z+1/2. |
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We are interested in the amides of terephthalic acid, and have synthesized several such compounds from dimethyl terephthalate and published their crystal structures (Jones et al., 2002). In six of the seven structures, the molecules crystallized with crystallographic inversion symmetry. Compounds with free NH functional groups formed ladder-like chains of molecules by intermolecular N—H···O═C hydrogen bonding of the expected form (two donors and two acceptors per molecule), and a related single chain was observed in N-cyclohexyl-4-(methoxycarbonyl)benzamide, with only one O═CNH group per molecule (Jones & Kuś, 2004). We present here the structures of two polymorphs of N,N'-di(phenethyl)terephthalamide. The crystals were obtained from dimethylformamide (DMF) (thick tablets, triclinic form, henceforth `T') and ethanol (laths, monoclinic form, henceforth `M'). Measurements for T were conducted at 133 K and for M at 203 K; below this temperature, crystals of M disintegrate.
Both molecules (Figs. 1 and 2) show the expected inversion symmetry; the origins were chosen such that the inversion centres lie at (1/2, 1/2, 0) (T) and (0, 1/2, 0) (M). They are closely similar, although the bond lengths in M are consistently slightly shorter, presumably attributable to libration effects at the higher measurement temperature. Corresponding torsion angles also show only minor differences, e.g. the rotation of the carbonyl group by ca 30° out of the central ring plane, the extended side chain conformation and the perpendicular position of the terminal ring relative to the chain (Tables 1 and 3). The molecular dimensions may be regarded as normal. A search of the Cambridge Structural Database (Allen, 2002; Version 5.27) for the structural subunit Ph—C(═ O)—NH—CH2 showed a mean C—C—C═O torsion angle of 24.1 (6)°; the C—C—C angle corresponding to C2—C1—C4 of the current structures (syn to the NH function) was consistently greater than 120°, whereas that corresponding to C3—C1—C4 was narrower [122.46 (8) and 118.34 (8)°, respectively].
Both compounds show only one symmetry-independent classical hydrogen bond (Tables 2 and 4), but this suffices to form the usual ladder motif (Figs. 3 and 4) involving rings of graph set R22(18) (Etter, 1990). Neighbouring molecules in the ladder are related by translation. In T, the repeat distance of the chain, ca 5 Å, corresponds to the short x axis; in M, to the short y axis, whereby the adjacent ladders in Fig. 4 are related by 21 and c-glide operators. The same repeat distance was observed in two of our earlier structures, namely N,N'-di-n-butyl- and N,N'-di-n-hexyl-terephthalamide (Jones et al., 2002). In the related benzamide (Jones & Kuś, 2004), the crystal repeat distance was ca 10 Å, but there were two symmetry-independent molecules in the chain.
In the hope of explaining or at least rationalizing the existence of two polymorphs, an analysis of the packing differences needs to be conducted. The projection of T along the short axis (Fig. 5) shows that the molecules lie parallel to the (021) planes. Neighbouring `ladders' are connected across inversion centres (1/2, 0, 1/2) by a borderline `weak' C—H···O interaction (Desiraju & Steiner, 1999) involving a meta H atom of the terminal ring (Table 2). The horizontal rows of molecules in Fig. 5 are appreciably offset. There is a consistent directionality of the C═O groups, whereby the groups at the left of each molecule point out of the paper.
The projection of M along the short axis (Fig. 6) shows that the molecules lie in planes parallel to (302). Neighbouring ladders are connected via a bifurcated (C—H)2···O interaction (Table 4), involving a methylene H atom and an ortho H atom of the terminal ring, via a c-glide operator and align parallel to the z axis; the offset is much less than in T. The C═O groups alternate in direction, in and out of the paper, in contrast to T.
There are no significant C—H···π or stacking interactions in either form. It could be surmised that the different packing patterns, although distinguishable in terms of C—H···O contacts, might be more subtly determined by the sum of many much weaker van der Waals-type interactions. It might be instructive to predict the packing of this compound (Day et al., 2005), although such methods are still in their infancy.
After determining the structures, it seemed worthwhile to investigate more closely the relative stability of the two phases and any possible phase changes. Unfortunately, the samples used for the single-crystal measurements were no longer available. A new synthesis and new recrystallizations were undertaken. Although the same conditions were used, the new samples seemed optically to contain only the M phase (poorly formed and intergrown laths, in contrast to the well formed and generally larger and thicker tablets of form T). Powder investigations based on the new samples confirmed that only the M phase was present. The powder pattern was not changed by either (i) heating to temperatures slightly below the melting point and recooling, (ii) melting and recooling, (iii) stirring a suspension for one week and re-isolating, or (iv) rapid (kinetically controlled) crystallization from ethanol or DMF. Cooling the samples to liquid nitrogen temperature gave inconclusive results; two new reflections at low angle arose in the powder pattern, but the overall pattern did not correspond to form T. Differential scanning calorimetry measurements gave no indication of any phase change up to the melting point. We are therefore unable to form any conclusions as to possible phase interchanges between forms T and M. Form T seems to represent a `disappearing polymorph' (Dunitz & Bernstein, 1995) and may thus be metastable, whereas form M, now found exclusively, is presumably the stable form.