Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010902215X/sk3328sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010902215X/sk3328Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010902215X/sk3328IIsup3.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010902215X/sk3328IIIsup4.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010902215X/sk3328IVsup5.hkl |
CCDC references: 742252; 742253; 742254; 742255
For the preparation of (I)–(IV) (Fink & Kurys, 1996), typically, the 2,4-, 2,5-, 3,4- and 3,5-difluorobenzoyl chlorides [Quantities?] in dry CH2Cl2 (20–30 ml) were added dropwise over a period of 2–3 min to a cold (273 K) 20–30 ml solution of 3-aminopyridine [In what solvent? Concentration?] containing Et3N (1.5 ml), and the reaction was stirred overnight at room temperature. Typical organic workup and washings furnished the products in reasonable yields of 40–90%. Crystals suitable for diffraction were grown from CHCl3 as colourless blocks over a period of 1–2 weeks. Compounds (I)–(IV) gave clean 1H and 13C NMR spectra in d6-DMSO and the IR spectra (in CHCl3 solution or KBr discs) are as expected.
Compounds (I) and (II) are isostructural and in the same space group [P21/n for (I) and P21/c for (II); No. 14]. They differ by >10% in their a and c unit-cell dimensions. Conversion of (I) from P21/n to a P21/c setting gives a = 13.97, b = 5.09, c = 16.03 Å and β = 119.06°, different to the values of a = 8.04, b = 5.14, c = 23.99 Å and β = 94.32° for (II). Compounds (III) and (IV) (in P21/n) differ by 9% on the a and b dimensions and 4% on the c-axis length, but they are essentially isomorphous, as the a and b unit-cell differences can be attributed to the effects of the peripheral F-atom substitution and disorder patterns.
H atoms attached to C atoms were treated as riding using the SHELXL97 (Sheldrick, 2008) defaults at 150 (1) K, with C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C). N-bound H atoms were refined freely with isotropic displacement parameters, to N—H = 0.86 (3) Å in (I), 0.89 (3) Å in (II), 0.87 (2) Å in (III) and 0.89 (2) Å in (IV).
Rotational disorder is present in the difluorophenyl group in (III), with site-occupancy factors of 0.809 (4) and 0.191 (4) for the major and minor components of disorder, respectively. As both C6 atom sites in both rings overlay and occupy the same space, only the F/H atoms were treated in the disorder.
The extinction coefficient refines to 0.006 (3) in (I), 0.015 (5) in (II), 0.017 (6) in (III) and 0.014 (5) in (IV). Refinement for (I) was finalized with no correction and, as (II)–(IV) have corrections at the 3σ level, this correction was retained.
For all compounds, data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and SORTX (McArdle, 1995); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PREP8 (Ferguson, 1998).
C12H8F2N2O | F(000) = 480 |
Mr = 234.20 | Dx = 1.560 Mg m−3 |
Monoclinic, P21/n | Melting point: 400 K |
Hall symbol: -p 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 13.9692 (5) Å | Cell parameters from 8024 reflections |
b = 5.0957 (2) Å | θ = 2.6–27.5° |
c = 15.3151 (8) Å | µ = 0.13 mm−1 |
β = 113.812 (2)° | T = 150 K |
V = 997.37 (8) Å3 | Block, colourless |
Z = 4 | 0.30 × 0.20 × 0.15 mm |
Nonius KappaCCD diffractometer | 2269 independent reflections |
Radiation source: fine-focus sealed X-ray tube | 1247 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.092 |
ϕ, ω scans with κ offsets | θmax = 27.5°, θmin = 2.6° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = −18→16 |
Tmin = 0.963, Tmax = 0.975 | k = −5→6 |
5121 measured reflections | l = −17→19 |
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) = 0.170 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0894P)2] where P = (Fo2 + 2Fc2)/3 |
2269 reflections | (Δ/σ)max < 0.001 |
158 parameters | Δρmax = 0.27 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
C12H8F2N2O | V = 997.37 (8) Å3 |
Mr = 234.20 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 13.9692 (5) Å | µ = 0.13 mm−1 |
b = 5.0957 (2) Å | T = 150 K |
c = 15.3151 (8) Å | 0.30 × 0.20 × 0.15 mm |
β = 113.812 (2)° |
Nonius KappaCCD diffractometer | 2269 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1247 reflections with I > 2σ(I) |
Tmin = 0.963, Tmax = 0.975 | Rint = 0.092 |
5121 measured reflections |
R[F2 > 2σ(F2)] = 0.056 | 0 restraints |
wR(F2) = 0.170 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 0.27 e Å−3 |
2269 reflections | Δρmin = −0.34 e Å−3 |
158 parameters |
Experimental. Analytical data for (I): m.p. 399–401 K (uncorrected); IR (νC═O, cm−1): 1660 (vs), 1595 (m) (CHCl3); 1662 (s) (KBr); 1H NMR (400 MHz, DMSO, δ, p.p.m.): 10.65 (s, 1H, N—H), 8.87 (br s, 1H, 3-pyr), 8.34 (d, 1H, 3-pyr), 8.16 (d, 1H, 3-pyr), 7.81 (q, 1H, 2,4-F2), 7.45 (td, 1H, 2,4-F2), 7.41 (m, 1H, 3-pyr), 7.27 (td, 1H, 2,4-F2); 19F NMR (400 MHz, DMSO, δ, p.p.m): −106.05, −109.98. Analytical data for (II): m.p. 383–385 K (uncorrected); IR (νC═O, cm−1): 1661 (vs), 1600 (m) (CHCl3); 1662 (s) (KBr); 1H NMR (400 MHz, DMSO, δ, p.p.m.): 10.75 (s, 1H, N—H), 8.87 (d, 1H, 3-pyr), 8.34 (d, 1H, 3-pyr), 8.16 (dt, 1H, 3-pyr), 7.58 (m, 1H, 2,5-F2), 7.47 (m, 2H, 2,5-F2), 7.43 (m, 1H, 3-pyr); 19F NMR (400 MHz, DMSO, δ, p.p.m): −118.32, −120.45. Analytical data for (III): m.p. 401–403 K (uncorrected); IR (νC═O, cm−1): 1656 (br s), 1615 (m) (CHCl3); 1673 (s) (KBr); 1H NMR (400 MHz, DMSO, δ, p.p.m.): 10.50 (br s, 1H, N—H), 8.88 (br s, 1H, 3-pyr), 8.34 (d, 1H, 3-pyr), 8.17 (dt, 1H, 3-pyr), 8.06 (td, 1H, 3,4-F2), 7.89 (m, 1H, 3,4-F2), 7.64 (q, 1H, 3,4-F2), 7.40 (dd, 1H, 3-pyr); 19F NMR (400 MHz, DMSO, δ, p.p.m.): −134.04, −138.11. Analytical data for (IV): m.p. 436–439 K (uncorrected); IR (νC═O, cm−1): 1653 (br s), 1595 (s) (CHCl3); 1667 (s), 1597 (s) (KBr); 1H NMR (400 MHz, DMSO, δ, p.p.m.): 10.57 (br s, 1H, N—H), 8.93 (s, 1H, 3-pyr), 8.34 (d, 1H, 3-pyr), 8.18 (dt, 1H, 3-pyr), 7.71 (m, 2H, 3,4-F2), 7.52 (tt, 1H, 3,4-F2), 7.41 (dd, 1H, 3-pyr); 19F NMR (400 MHz, DMSO, δ, p.p.m.): −109.15. |
x | y | z | Uiso*/Ueq | ||
F12 | 0.59600 (11) | 0.1954 (3) | −0.00023 (11) | 0.0352 (4) | |
F14 | 0.89737 (11) | 0.3804 (3) | −0.05019 (12) | 0.0441 (5) | |
O1 | 0.63823 (13) | 0.8455 (3) | 0.16779 (13) | 0.0329 (5) | |
C1 | 0.63950 (18) | 0.6191 (5) | 0.14092 (18) | 0.0266 (6) | |
N1 | 0.58332 (15) | 0.4206 (4) | 0.15729 (16) | 0.0264 (5) | |
C11 | 0.70511 (17) | 0.5444 (5) | 0.08776 (18) | 0.0252 (6) | |
C12 | 0.68455 (18) | 0.3419 (5) | 0.02223 (19) | 0.0265 (6) | |
C13 | 0.74731 (19) | 0.2826 (5) | −0.02459 (18) | 0.0281 (6) | |
C14 | 0.83427 (18) | 0.4357 (5) | −0.00446 (19) | 0.0302 (6) | |
C15 | 0.85954 (18) | 0.6436 (5) | 0.0585 (2) | 0.0317 (6) | |
C16 | 0.79400 (19) | 0.6957 (5) | 0.10365 (19) | 0.0297 (6) | |
C21 | 0.50709 (17) | 0.4458 (5) | 0.19488 (18) | 0.0249 (6) | |
C22 | 0.42988 (19) | 0.2530 (5) | 0.1692 (2) | 0.0303 (6) | |
N23 | 0.35206 (16) | 0.2465 (4) | 0.19848 (17) | 0.0328 (6) | |
C24 | 0.3496 (2) | 0.4401 (5) | 0.2565 (2) | 0.0337 (7) | |
C25 | 0.4239 (2) | 0.6368 (5) | 0.2871 (2) | 0.0321 (7) | |
C26 | 0.50461 (19) | 0.6419 (5) | 0.25677 (19) | 0.0288 (6) | |
H1 | 0.597 (2) | 0.264 (6) | 0.145 (2) | 0.042 (8)* | |
H13 | 0.7312 | 0.1419 | −0.0689 | 0.034* | |
H15 | 0.9200 | 0.7472 | 0.0703 | 0.038* | |
H16 | 0.8097 | 0.8389 | 0.1469 | 0.036* | |
H22 | 0.4329 | 0.1169 | 0.1279 | 0.036* | |
H24 | 0.2943 | 0.4425 | 0.2776 | 0.040* | |
H25 | 0.4195 | 0.7689 | 0.3291 | 0.039* | |
H26 | 0.5566 | 0.7751 | 0.2776 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F12 | 0.0361 (8) | 0.0387 (9) | 0.0337 (10) | −0.0127 (7) | 0.0170 (7) | −0.0109 (7) |
F14 | 0.0412 (9) | 0.0541 (11) | 0.0472 (11) | −0.0065 (8) | 0.0284 (8) | −0.0110 (8) |
O1 | 0.0402 (11) | 0.0233 (10) | 0.0390 (12) | −0.0005 (8) | 0.0199 (9) | −0.0038 (8) |
C1 | 0.0250 (12) | 0.0284 (14) | 0.0232 (15) | 0.0017 (11) | 0.0063 (11) | 0.0031 (12) |
N1 | 0.0311 (11) | 0.0206 (11) | 0.0307 (13) | −0.0004 (9) | 0.0158 (10) | −0.0023 (10) |
C11 | 0.0261 (12) | 0.0235 (13) | 0.0242 (14) | 0.0020 (10) | 0.0083 (11) | 0.0026 (11) |
C12 | 0.0248 (12) | 0.0270 (14) | 0.0250 (15) | −0.0029 (10) | 0.0073 (11) | 0.0024 (12) |
C13 | 0.0350 (14) | 0.0281 (14) | 0.0228 (15) | −0.0030 (11) | 0.0132 (12) | −0.0026 (12) |
C14 | 0.0289 (13) | 0.0382 (15) | 0.0280 (15) | 0.0028 (12) | 0.0161 (12) | 0.0038 (13) |
C15 | 0.0278 (14) | 0.0354 (15) | 0.0308 (16) | −0.0048 (12) | 0.0106 (12) | −0.0006 (13) |
C16 | 0.0313 (14) | 0.0292 (14) | 0.0267 (16) | −0.0005 (11) | 0.0096 (12) | 0.0002 (12) |
C21 | 0.0272 (12) | 0.0254 (13) | 0.0215 (14) | 0.0031 (10) | 0.0092 (11) | 0.0032 (11) |
C22 | 0.0321 (14) | 0.0296 (14) | 0.0300 (16) | −0.0014 (11) | 0.0134 (12) | −0.0016 (12) |
N23 | 0.0347 (12) | 0.0303 (13) | 0.0381 (15) | 0.0019 (10) | 0.0195 (11) | 0.0030 (11) |
C24 | 0.0365 (14) | 0.0344 (15) | 0.0354 (17) | 0.0082 (12) | 0.0198 (13) | 0.0076 (13) |
C25 | 0.0428 (15) | 0.0290 (14) | 0.0281 (16) | 0.0072 (12) | 0.0178 (13) | 0.0017 (12) |
C26 | 0.0341 (14) | 0.0262 (14) | 0.0252 (15) | 0.0010 (11) | 0.0109 (12) | 0.0006 (12) |
F12—C12 | 1.365 (3) | C21—C26 | 1.387 (3) |
F14—C14 | 1.359 (3) | C22—N23 | 1.334 (3) |
O1—C1 | 1.227 (3) | N23—C24 | 1.337 (3) |
C1—N1 | 1.364 (3) | C24—C25 | 1.382 (4) |
C1—C11 | 1.500 (3) | C25—C26 | 1.382 (3) |
N1—C21 | 1.406 (3) | N1—H1 | 0.86 (3) |
C11—C12 | 1.386 (4) | C13—H13 | 0.9500 |
C11—C16 | 1.397 (3) | C15—H15 | 0.9500 |
C12—C13 | 1.372 (3) | C16—H16 | 0.9500 |
C13—C14 | 1.370 (3) | C22—H22 | 0.9500 |
C14—C15 | 1.379 (4) | C24—H24 | 0.9500 |
C15—C16 | 1.378 (4) | C25—H25 | 0.9500 |
C21—C22 | 1.393 (3) | C26—H26 | 0.9500 |
O1—C1—N1 | 123.2 (2) | C22—N23—C24 | 116.6 (2) |
O1—C1—C11 | 121.0 (2) | N23—C24—C25 | 122.9 (2) |
N1—C1—C11 | 115.7 (2) | C24—C25—C26 | 120.2 (3) |
C1—N1—C21 | 126.5 (2) | C25—C26—C21 | 117.7 (2) |
C1—C11—C12 | 126.1 (2) | C1—N1—H1 | 116.4 (18) |
C1—C11—C16 | 117.4 (2) | C21—N1—H1 | 117.0 (18) |
C12—C11—C16 | 116.5 (2) | C14—C13—H13 | 121.5 |
F12—C12—C11 | 119.4 (2) | C12—C13—H13 | 121.5 |
F12—C12—C13 | 117.0 (2) | C16—C15—H15 | 121.2 |
C11—C12—C13 | 123.6 (2) | C14—C15—H15 | 121.2 |
C12—C13—C14 | 116.9 (2) | C15—C16—H16 | 119.0 |
F14—C14—C13 | 117.8 (2) | C11—C16—H16 | 119.0 |
F14—C14—C15 | 118.9 (2) | N23—C22—H22 | 117.8 |
C13—C14—C15 | 123.2 (2) | C21—C22—H22 | 117.8 |
C14—C15—C16 | 117.7 (2) | N23—C24—H24 | 118.5 |
C11—C16—C15 | 122.0 (2) | C25—C24—H24 | 118.5 |
C22—C21—N1 | 116.6 (2) | C24—C25—H25 | 119.9 |
C26—C21—N1 | 125.3 (2) | C26—C25—H25 | 119.9 |
C22—C21—C26 | 118.1 (2) | C25—C26—H26 | 121.1 |
N23—C22—C21 | 124.4 (2) | C21—C26—H26 | 121.1 |
O1—C1—N1—C21 | 8.7 (4) | C13—C14—C15—C16 | 0.8 (4) |
C11—C1—N1—C21 | −171.8 (2) | C14—C15—C16—C11 | 0.5 (4) |
O1—C1—C11—C12 | −152.1 (3) | C12—C11—C16—C15 | −1.5 (4) |
N1—C1—C11—C12 | 28.3 (4) | C1—C11—C16—C15 | 180.0 (2) |
O1—C1—C11—C16 | 26.3 (3) | C1—N1—C21—C26 | −28.5 (4) |
N1—C1—C11—C16 | −153.3 (2) | C1—N1—C21—C22 | 153.3 (2) |
C16—C11—C12—F12 | −176.6 (2) | C26—C21—C22—N23 | 1.4 (4) |
C1—C11—C12—F12 | 1.8 (4) | N1—C21—C22—N23 | 179.8 (2) |
C16—C11—C12—C13 | 1.4 (4) | C21—C22—N23—C24 | 0.0 (4) |
C1—C11—C12—C13 | 179.8 (2) | C22—N23—C24—C25 | −1.2 (4) |
F12—C12—C13—C14 | 177.8 (2) | N23—C24—C25—C26 | 1.0 (4) |
C11—C12—C13—C14 | −0.3 (4) | C24—C25—C26—C21 | 0.5 (4) |
C12—C13—C14—F14 | −179.9 (2) | C22—C21—C26—C25 | −1.6 (4) |
C12—C13—C14—C15 | −0.8 (4) | N1—C21—C26—C25 | −179.8 (2) |
F14—C14—C15—C16 | 179.8 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···F12 | 0.86 (3) | 2.24 (3) | 2.741 (3) | 117 (2) |
N1—H1···O1i | 0.86 (3) | 2.20 (3) | 3.017 (3) | 158 (3) |
C26—H26···O1 | 0.95 | 2.41 | 2.911 (3) | 113 |
C22—H22···F12ii | 0.95 | 2.43 | 3.360 (3) | 168 |
Symmetry codes: (i) x, y−1, z; (ii) −x+1, −y, −z. |
C12H8F2N2O | F(000) = 480 |
Mr = 234.20 | Dx = 1.573 Mg m−3 |
Monoclinic, P21/c | Melting point: 366 K |
Hall symbol: -p 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 8.0371 (7) Å | Cell parameters from 13479 reflections |
b = 5.1425 (4) Å | θ = 2.6–27.5° |
c = 23.994 (2) Å | µ = 0.13 mm−1 |
β = 94.320 (4)° | T = 150 K |
V = 988.87 (15) Å3 | Plate, colourless |
Z = 4 | 0.20 × 0.18 × 0.05 mm |
Nonius KappaCCD diffractometer | 2181 independent reflections |
Radiation source: fine-focus sealed X-ray tube | 1346 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.061 |
ϕ, ω scans with κ offsets | θmax = 27.4°, θmin = 3.0° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = −10→10 |
Tmin = 0.724, Tmax = 0.999 | k = −6→6 |
5500 measured reflections | l = −24→31 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.052 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.146 | w = 1/[σ2(Fo2) + (0.0734P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max = 0.001 |
2181 reflections | Δρmax = 0.26 e Å−3 |
159 parameters | Δρmin = −0.22 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.015 (5) |
C12H8F2N2O | V = 988.87 (15) Å3 |
Mr = 234.20 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.0371 (7) Å | µ = 0.13 mm−1 |
b = 5.1425 (4) Å | T = 150 K |
c = 23.994 (2) Å | 0.20 × 0.18 × 0.05 mm |
β = 94.320 (4)° |
Nonius KappaCCD diffractometer | 2181 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1346 reflections with I > 2σ(I) |
Tmin = 0.724, Tmax = 0.999 | Rint = 0.061 |
5500 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.146 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 0.26 e Å−3 |
2181 reflections | Δρmin = −0.22 e Å−3 |
159 parameters |
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 | ||
F12 | 0.10791 (15) | 0.2833 (2) | 0.55226 (5) | 0.0451 (4) | |
F15 | 0.50349 (17) | −0.3716 (3) | 0.68041 (5) | 0.0525 (4) | |
O1 | 0.29969 (19) | −0.3552 (3) | 0.47780 (6) | 0.0425 (4) | |
C1 | 0.2775 (3) | −0.1333 (4) | 0.49513 (9) | 0.0355 (5) | |
N1 | 0.2412 (2) | 0.0722 (4) | 0.46140 (8) | 0.0376 (5) | |
C11 | 0.2926 (3) | −0.0796 (4) | 0.55678 (9) | 0.0352 (5) | |
C12 | 0.2126 (3) | 0.1209 (4) | 0.58329 (9) | 0.0371 (5) | |
C13 | 0.2298 (3) | 0.1644 (4) | 0.64007 (9) | 0.0408 (6) | |
C14 | 0.3300 (3) | −0.0020 (4) | 0.67312 (9) | 0.0428 (6) | |
C15 | 0.4058 (3) | −0.2057 (4) | 0.64775 (10) | 0.0405 (6) | |
C16 | 0.3905 (3) | −0.2472 (4) | 0.59113 (9) | 0.0381 (5) | |
C21 | 0.2012 (3) | 0.0672 (4) | 0.40283 (9) | 0.0345 (5) | |
C22 | 0.1033 (3) | 0.2712 (4) | 0.38045 (9) | 0.0379 (5) | |
N23 | 0.0561 (2) | 0.2955 (3) | 0.32587 (8) | 0.0415 (5) | |
C24 | 0.1076 (3) | 0.1097 (4) | 0.29198 (9) | 0.0419 (6) | |
C25 | 0.2059 (3) | −0.0985 (4) | 0.31059 (9) | 0.0413 (6) | |
C26 | 0.2554 (3) | −0.1216 (4) | 0.36708 (9) | 0.0388 (6) | |
H1 | 0.233 (3) | 0.226 (5) | 0.4773 (11) | 0.063 (8)* | |
H13 | 0.1741 | 0.3055 | 0.6562 | 0.049* | |
H14 | 0.3462 | 0.0238 | 0.7124 | 0.051* | |
H16 | 0.4462 | −0.3893 | 0.5754 | 0.046* | |
H22 | 0.0679 | 0.4004 | 0.4053 | 0.045* | |
H24 | 0.0750 | 0.1214 | 0.2532 | 0.050* | |
H25 | 0.2393 | −0.2250 | 0.2848 | 0.050* | |
H26 | 0.3239 | −0.2617 | 0.3807 | 0.047* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F12 | 0.0479 (8) | 0.0437 (8) | 0.0443 (8) | 0.0101 (6) | 0.0067 (6) | 0.0013 (6) |
F15 | 0.0576 (9) | 0.0497 (8) | 0.0482 (8) | 0.0009 (7) | −0.0093 (7) | 0.0076 (7) |
O1 | 0.0558 (10) | 0.0300 (8) | 0.0414 (9) | 0.0017 (7) | 0.0009 (7) | −0.0025 (7) |
C1 | 0.0330 (12) | 0.0327 (12) | 0.0406 (13) | −0.0028 (9) | 0.0019 (9) | −0.0003 (10) |
N1 | 0.0449 (11) | 0.0309 (10) | 0.0366 (11) | −0.0005 (8) | 0.0007 (8) | −0.0023 (9) |
C11 | 0.0332 (12) | 0.0323 (11) | 0.0403 (12) | −0.0039 (9) | 0.0036 (9) | 0.0003 (10) |
C12 | 0.0373 (12) | 0.0347 (12) | 0.0391 (13) | −0.0002 (10) | 0.0024 (9) | 0.0039 (10) |
C13 | 0.0439 (13) | 0.0371 (13) | 0.0424 (14) | −0.0024 (10) | 0.0099 (10) | −0.0021 (10) |
C14 | 0.0471 (14) | 0.0456 (14) | 0.0358 (13) | −0.0103 (11) | 0.0049 (10) | −0.0019 (11) |
C15 | 0.0399 (13) | 0.0397 (12) | 0.0409 (13) | −0.0057 (10) | −0.0032 (10) | 0.0080 (11) |
C16 | 0.0363 (12) | 0.0324 (12) | 0.0454 (14) | −0.0021 (9) | 0.0015 (10) | 0.0002 (10) |
C21 | 0.0371 (12) | 0.0307 (11) | 0.0359 (12) | −0.0051 (9) | 0.0037 (9) | −0.0010 (9) |
C22 | 0.0415 (13) | 0.0332 (12) | 0.0389 (13) | −0.0023 (9) | 0.0036 (10) | −0.0026 (10) |
N23 | 0.0470 (11) | 0.0372 (11) | 0.0399 (11) | −0.0031 (9) | 0.0003 (9) | 0.0005 (9) |
C24 | 0.0475 (14) | 0.0420 (13) | 0.0358 (12) | −0.0084 (10) | 0.0006 (10) | −0.0009 (11) |
C25 | 0.0475 (14) | 0.0378 (13) | 0.0394 (13) | −0.0029 (10) | 0.0082 (10) | −0.0051 (10) |
C26 | 0.0395 (13) | 0.0357 (12) | 0.0416 (13) | −0.0005 (9) | 0.0052 (10) | −0.0003 (10) |
F12—C12 | 1.366 (2) | C21—C22 | 1.395 (3) |
F15—C15 | 1.366 (2) | C22—N23 | 1.342 (3) |
O1—C1 | 1.232 (2) | N23—C24 | 1.340 (3) |
C1—N1 | 1.350 (3) | C24—C25 | 1.384 (3) |
C1—C11 | 1.501 (3) | C25—C26 | 1.389 (3) |
N1—C21 | 1.418 (3) | N1—H1 | 0.89 (3) |
C11—C12 | 1.394 (3) | C13—H13 | 0.9500 |
C11—C16 | 1.394 (3) | C14—H14 | 0.9500 |
C12—C13 | 1.377 (3) | C16—H16 | 0.9500 |
C13—C14 | 1.383 (3) | C22—H22 | 0.9500 |
C14—C15 | 1.377 (3) | C24—H24 | 0.9500 |
C15—C16 | 1.372 (3) | C25—H25 | 0.9500 |
C21—C26 | 1.387 (3) | C26—H26 | 0.9500 |
O1—C1—N1 | 123.6 (2) | C22—N23—C24 | 116.64 (19) |
O1—C1—C11 | 120.02 (19) | N23—C24—C25 | 123.4 (2) |
N1—C1—C11 | 116.39 (18) | C24—C25—C26 | 119.7 (2) |
C1—N1—C21 | 127.05 (19) | C21—C26—C25 | 117.6 (2) |
C1—C11—C12 | 125.47 (19) | C1—N1—H1 | 117.5 (17) |
C1—C11—C16 | 117.98 (19) | C21—N1—H1 | 115.2 (17) |
C12—C11—C16 | 116.5 (2) | C12—C13—H13 | 120.7 |
F12—C12—C11 | 119.34 (19) | C14—C13—H13 | 120.7 |
F12—C12—C13 | 116.85 (19) | C13—C14—H14 | 120.8 |
C11—C12—C13 | 123.8 (2) | C15—C14—H14 | 120.8 |
C12—C13—C14 | 118.5 (2) | C11—C16—H16 | 120.2 |
C13—C14—C15 | 118.4 (2) | C15—C16—H16 | 120.2 |
F15—C15—C14 | 118.4 (2) | N23—C22—H22 | 118.1 |
F15—C15—C16 | 118.4 (2) | C21—C22—H22 | 118.1 |
C14—C15—C16 | 123.1 (2) | N23—C24—H24 | 118.3 |
C11—C16—C15 | 119.6 (2) | C25—C24—H24 | 118.3 |
C22—C21—N1 | 116.55 (19) | C24—C25—H25 | 120.1 |
C26—C21—N1 | 124.57 (19) | C26—C25—H25 | 120.1 |
C22—C21—C26 | 118.9 (2) | C21—C26—H26 | 121.2 |
N23—C22—C21 | 123.8 (2) | C25—C26—H26 | 121.2 |
O1—C1—N1—C21 | 8.8 (4) | F15—C15—C16—C11 | −179.50 (17) |
C11—C1—N1—C21 | −171.95 (19) | C14—C15—C16—C11 | −0.8 (3) |
O1—C1—C11—C12 | −153.7 (2) | C12—C11—C16—C15 | −1.2 (3) |
N1—C1—C11—C12 | 27.0 (3) | C1—C11—C16—C15 | −179.35 (19) |
O1—C1—C11—C16 | 24.3 (3) | C1—N1—C21—C26 | −27.4 (3) |
N1—C1—C11—C16 | −155.0 (2) | C1—N1—C21—C22 | 153.9 (2) |
C16—C11—C12—F12 | −176.55 (17) | C26—C21—C22—N23 | 0.7 (3) |
C1—C11—C12—F12 | 1.4 (3) | N1—C21—C22—N23 | 179.43 (19) |
C16—C11—C12—C13 | 2.1 (3) | C21—C22—N23—C24 | 0.2 (3) |
C1—C11—C12—C13 | −179.9 (2) | C22—N23—C24—C25 | −0.6 (3) |
F12—C12—C13—C14 | 177.68 (18) | N23—C24—C25—C26 | 0.1 (3) |
C11—C12—C13—C14 | −1.0 (3) | C22—C21—C26—C25 | −1.1 (3) |
C12—C13—C14—C15 | −1.0 (3) | N1—C21—C26—C25 | −179.8 (2) |
C13—C14—C15—F15 | −179.35 (18) | C24—C25—C26—C21 | 0.7 (3) |
C13—C14—C15—C16 | 1.9 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···F12 | 0.89 (3) | 2.14 (3) | 2.726 (2) | 123 (2) |
N1—H1···O1i | 0.89 (3) | 2.22 (3) | 3.003 (2) | 148 (2) |
C26—H26···O1 | 0.95 | 2.40 | 2.913 (3) | 113 |
C22—H22···F12ii | 0.95 | 2.43 | 3.339 (3) | 161 |
Symmetry codes: (i) x, y+1, z; (ii) −x, −y+1, −z+1. |
C12H8F2N2O | F(000) = 480 |
Mr = 234.20 | Dx = 1.472 Mg m−3 |
Monoclinic, P21/n | Melting point: 402 K |
Hall symbol: -p 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 7.6741 (5) Å | Cell parameters from 4309 reflections |
b = 13.7314 (6) Å | θ = 2.6–27.5° |
c = 10.3316 (8) Å | µ = 0.12 mm−1 |
β = 103.861 (3)° | T = 150 K |
V = 1057.00 (12) Å3 | Block, colourless |
Z = 4 | 0.26 × 0.24 × 0.12 mm |
Nonius KappaCCD diffractometer | 2412 independent reflections |
Radiation source: fine-focus sealed X-ray tube | 1512 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.048 |
ϕ, ω scans with κ offsets | θmax = 27.5°, θmin = 3.0° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = −9→9 |
Tmin = 0.884, Tmax = 0.987 | k = −17→17 |
7204 measured reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.050 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.142 | w = 1/[σ2(Fo2) + (0.0744P)2 + 0.0157P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
2412 reflections | Δρmax = 0.22 e Å−3 |
169 parameters | Δρmin = −0.23 e Å−3 |
1 restraint | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.017 (6) |
C12H8F2N2O | V = 1057.00 (12) Å3 |
Mr = 234.20 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 7.6741 (5) Å | µ = 0.12 mm−1 |
b = 13.7314 (6) Å | T = 150 K |
c = 10.3316 (8) Å | 0.26 × 0.24 × 0.12 mm |
β = 103.861 (3)° |
Nonius KappaCCD diffractometer | 2412 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1512 reflections with I > 2σ(I) |
Tmin = 0.884, Tmax = 0.987 | Rint = 0.048 |
7204 measured reflections |
R[F2 > 2σ(F2)] = 0.050 | 1 restraint |
wR(F2) = 0.142 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.22 e Å−3 |
2412 reflections | Δρmin = −0.23 e Å−3 |
169 parameters |
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) | |
F13 | 0.8713 (2) | 0.65663 (12) | 0.16855 (17) | 0.0578 (7) | 0.809 (4) |
F14 | 0.54283 (18) | 0.67177 (8) | 0.00741 (12) | 0.0492 (4) | |
F15 | 0.2700 (7) | 0.5640 (5) | 0.0562 (7) | 0.064 (3) | 0.191 (4) |
O1 | 0.80380 (18) | 0.44128 (9) | 0.54424 (13) | 0.0372 (4) | |
C1 | 0.6677 (2) | 0.42716 (12) | 0.45540 (18) | 0.0262 (4) | |
N1 | 0.5467 (2) | 0.35582 (11) | 0.46142 (16) | 0.0268 (4) | |
C11 | 0.6267 (2) | 0.49012 (12) | 0.33331 (17) | 0.0249 (4) | |
C12 | 0.7687 (3) | 0.54414 (13) | 0.30700 (19) | 0.0320 (5) | |
C13 | 0.7377 (3) | 0.60364 (14) | 0.1969 (2) | 0.0378 (5) | |
C14 | 0.5687 (3) | 0.61141 (13) | 0.11368 (19) | 0.0343 (5) | |
C15 | 0.4290 (3) | 0.55989 (13) | 0.13897 (19) | 0.0334 (5) | |
C16 | 0.4568 (3) | 0.49902 (13) | 0.24862 (19) | 0.0307 (5) | |
C21 | 0.5541 (2) | 0.29043 (12) | 0.56793 (17) | 0.0255 (4) | |
C22 | 0.7115 (2) | 0.26535 (13) | 0.66065 (18) | 0.0286 (5) | |
N23 | 0.7142 (2) | 0.20097 (11) | 0.75885 (15) | 0.0312 (4) | |
C24 | 0.5601 (3) | 0.15992 (14) | 0.7681 (2) | 0.0355 (5) | |
C25 | 0.3984 (3) | 0.18065 (13) | 0.6800 (2) | 0.0359 (5) | |
C26 | 0.3959 (3) | 0.24678 (13) | 0.57923 (18) | 0.0315 (5) | |
H1 | 0.456 (3) | 0.3484 (13) | 0.393 (2) | 0.033 (6)* | |
H12 | 0.8853 | 0.5398 | 0.3645 | 0.038* | |
H13 | 0.8340 | 0.6399 | 0.1779 | 0.045* | 0.191 (4) |
H15 | 0.3127 | 0.5657 | 0.0814 | 0.040* | 0.809 (4) |
H16 | 0.3593 | 0.4630 | 0.2662 | 0.037* | |
H22 | 0.8210 | 0.2949 | 0.6541 | 0.034* | |
H24 | 0.5616 | 0.1147 | 0.8379 | 0.043* | |
H25 | 0.2909 | 0.1499 | 0.6887 | 0.043* | |
H26 | 0.2861 | 0.2623 | 0.5178 | 0.038* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F13 | 0.0395 (10) | 0.0691 (11) | 0.0643 (12) | −0.0123 (8) | 0.0118 (8) | 0.0325 (9) |
F14 | 0.0578 (9) | 0.0518 (8) | 0.0378 (7) | −0.0003 (6) | 0.0112 (6) | 0.0201 (6) |
F15 | 0.058 (5) | 0.074 (5) | 0.050 (5) | 0.003 (4) | −0.011 (4) | 0.020 (4) |
O1 | 0.0318 (8) | 0.0429 (8) | 0.0323 (8) | −0.0092 (6) | −0.0018 (6) | 0.0044 (6) |
C1 | 0.0270 (10) | 0.0279 (9) | 0.0235 (9) | 0.0015 (7) | 0.0056 (8) | −0.0008 (8) |
N1 | 0.0286 (9) | 0.0278 (8) | 0.0209 (8) | −0.0012 (7) | 0.0000 (7) | 0.0015 (7) |
C11 | 0.0269 (10) | 0.0238 (9) | 0.0241 (9) | 0.0017 (7) | 0.0063 (8) | −0.0025 (8) |
C12 | 0.0302 (11) | 0.0331 (10) | 0.0321 (10) | 0.0002 (8) | 0.0064 (9) | 0.0012 (9) |
C13 | 0.0373 (12) | 0.0372 (11) | 0.0415 (12) | −0.0038 (9) | 0.0143 (10) | 0.0065 (10) |
C14 | 0.0453 (12) | 0.0308 (10) | 0.0275 (10) | 0.0025 (9) | 0.0101 (9) | 0.0073 (9) |
C15 | 0.0368 (12) | 0.0331 (10) | 0.0277 (10) | 0.0006 (9) | 0.0026 (9) | 0.0021 (9) |
C16 | 0.0326 (11) | 0.0299 (10) | 0.0298 (10) | −0.0022 (8) | 0.0078 (8) | 0.0005 (8) |
C21 | 0.0310 (11) | 0.0224 (9) | 0.0217 (9) | 0.0009 (7) | 0.0036 (8) | −0.0024 (8) |
C22 | 0.0280 (11) | 0.0281 (10) | 0.0279 (10) | 0.0017 (8) | 0.0030 (8) | −0.0010 (8) |
N23 | 0.0355 (10) | 0.0282 (8) | 0.0260 (8) | 0.0022 (7) | −0.0001 (7) | 0.0008 (7) |
C24 | 0.0437 (13) | 0.0321 (10) | 0.0276 (11) | 0.0000 (9) | 0.0027 (9) | 0.0042 (8) |
C25 | 0.0341 (12) | 0.0369 (11) | 0.0350 (11) | −0.0054 (9) | 0.0048 (9) | 0.0087 (9) |
C26 | 0.0321 (11) | 0.0324 (10) | 0.0257 (10) | −0.0016 (8) | −0.0013 (8) | 0.0024 (8) |
F13—C13 | 1.346 (2) | C21—C26 | 1.384 (3) |
F14—C14 | 1.352 (2) | C22—N23 | 1.342 (2) |
F15—C15 | 1.313 (4) | N23—C24 | 1.334 (3) |
O1—C1 | 1.229 (2) | C24—C25 | 1.381 (3) |
C1—N1 | 1.361 (2) | C25—C26 | 1.378 (3) |
C1—C11 | 1.499 (2) | N1—H1 | 0.87 (2) |
N1—C21 | 1.411 (2) | C12—H12 | 0.9500 |
C11—C12 | 1.398 (3) | C13—H13 | 0.9500 |
C11—C16 | 1.391 (3) | C15—H15 | 0.9500 |
C12—C13 | 1.374 (3) | C16—H16 | 0.9500 |
C13—C14 | 1.378 (3) | C22—H22 | 0.9500 |
C14—C15 | 1.361 (3) | C24—H24 | 0.9500 |
C15—C16 | 1.383 (3) | C25—H25 | 0.9500 |
C21—C22 | 1.393 (2) | C26—H26 | 0.9500 |
O1—C1—N1 | 123.09 (16) | C24—N23—C22 | 118.64 (16) |
O1—C1—C11 | 120.45 (16) | N23—C24—C25 | 122.53 (18) |
N1—C1—C11 | 116.45 (15) | C24—C25—C26 | 118.75 (19) |
C1—N1—C21 | 126.38 (16) | C21—C26—C25 | 119.71 (17) |
C1—C11—C12 | 116.97 (16) | C1—N1—H1 | 118.0 (13) |
C1—C11—C16 | 123.79 (16) | C21—N1—H1 | 115.6 (13) |
C12—C11—C16 | 119.22 (17) | C13—C12—H12 | 120.4 |
C11—C12—C13 | 119.21 (18) | C11—C12—H12 | 120.4 |
C12—C13—C14 | 120.88 (18) | C12—C13—H13 | 119.6 |
F13—C13—C12 | 120.8 (2) | C14—C13—H13 | 119.6 |
F13—C13—C14 | 118.34 (18) | C14—C15—H15 | 120.1 |
F14—C14—C13 | 119.17 (17) | C16—C15—H15 | 120.1 |
F14—C14—C15 | 120.37 (18) | C15—C16—H16 | 119.8 |
F15—C15—C14 | 120.3 (3) | C11—C16—H16 | 119.8 |
F15—C15—C16 | 119.8 (3) | N23—C22—H22 | 118.8 |
C13—C14—C15 | 120.45 (17) | C21—C22—H22 | 118.8 |
C14—C15—C16 | 119.82 (18) | N23—C24—H24 | 118.7 |
C11—C16—C15 | 120.42 (18) | C25—C24—H24 | 118.7 |
C22—C21—N1 | 124.04 (17) | C26—C25—H25 | 120.6 |
C26—C21—N1 | 117.99 (16) | C24—C25—H25 | 120.6 |
C22—C21—C26 | 117.95 (17) | C25—C26—H26 | 120.1 |
N23—C22—C21 | 122.42 (17) | C21—C26—H26 | 120.1 |
O1—C1—N1—C21 | 1.8 (3) | C14—C15—C16—C11 | 0.0 (3) |
C11—C1—N1—C21 | −177.69 (15) | C12—C11—C16—C15 | 0.6 (3) |
O1—C1—C11—C16 | −160.35 (18) | C1—C11—C16—C15 | 178.93 (16) |
N1—C1—C11—C16 | 19.2 (2) | C1—N1—C21—C26 | 157.96 (17) |
O1—C1—C11—C12 | 18.0 (2) | C1—N1—C21—C22 | −23.6 (3) |
N1—C1—C11—C12 | −162.47 (16) | C26—C21—C22—N23 | 0.1 (3) |
C16—C11—C12—C13 | −1.0 (3) | N1—C21—C22—N23 | −178.31 (16) |
C1—C11—C12—C13 | −179.44 (16) | C21—C22—N23—C24 | −0.3 (3) |
C11—C12—C13—C14 | 0.8 (3) | C22—N23—C24—C25 | 0.5 (3) |
C12—C13—C14—F14 | 179.06 (17) | N23—C24—C25—C26 | −0.5 (3) |
C12—C13—C14—C15 | −0.2 (3) | C24—C25—C26—C21 | 0.3 (3) |
F14—C14—C15—C16 | −179.46 (16) | C22—C21—C26—C25 | −0.1 (3) |
C13—C14—C15—C16 | −0.3 (3) | N1—C21—C26—C25 | 178.40 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N23i | 0.87 (2) | 2.14 (2) | 2.990 (2) | 164.2 (17) |
C12—H12···O1ii | 0.95 | 2.36 | 3.278 (2) | 162 |
C16—H16···N23i | 0.95 | 2.51 | 3.334 (2) | 146 |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x+2, −y+1, −z+1. |
C12H8F2N2O | F(000) = 480 |
Mr = 234.20 | Dx = 1.512 Mg m−3 |
Monoclinic, P21/n | Melting point: 437 K |
Hall symbol: -p 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 8.3784 (5) Å | Cell parameters from 3690 reflections |
b = 12.6278 (8) Å | θ = 2.6–27.5° |
c = 9.9118 (5) Å | µ = 0.12 mm−1 |
β = 101.152 (3)° | T = 150 K |
V = 1028.87 (10) Å3 | Block, colourless |
Z = 4 | 0.22 × 0.20 × 0.18 mm |
Nonius KappaCCD diffractometer | 2348 independent reflections |
Radiation source: fine-focus sealed X-ray tube | 1535 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.046 |
ϕ, ω scans with κ offsets | θmax = 27.5°, θmin = 2.6° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = −10→10 |
Tmin = 0.938, Tmax = 0.983 | k = −16→16 |
7054 measured reflections | l = −12→12 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.051 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.141 | w = 1/[σ2(Fo2) + (0.0788P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
2348 reflections | Δρmax = 0.27 e Å−3 |
159 parameters | Δρmin = −0.24 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.014 (5) |
C12H8F2N2O | V = 1028.87 (10) Å3 |
Mr = 234.20 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.3784 (5) Å | µ = 0.12 mm−1 |
b = 12.6278 (8) Å | T = 150 K |
c = 9.9118 (5) Å | 0.22 × 0.20 × 0.18 mm |
β = 101.152 (3)° |
Nonius KappaCCD diffractometer | 2348 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1535 reflections with I > 2σ(I) |
Tmin = 0.938, Tmax = 0.983 | Rint = 0.046 |
7054 measured reflections |
R[F2 > 2σ(F2)] = 0.051 | 0 restraints |
wR(F2) = 0.141 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.27 e Å−3 |
2348 reflections | Δρmin = −0.24 e Å−3 |
159 parameters |
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 | ||
F13 | 0.86046 (14) | 0.74307 (9) | 0.28043 (13) | 0.0497 (4) | |
F15 | 0.37984 (14) | 0.58544 (9) | 0.04623 (11) | 0.0440 (4) | |
O1 | 0.83831 (15) | 0.40070 (10) | 0.51724 (13) | 0.0339 (4) | |
C1 | 0.6993 (2) | 0.41253 (13) | 0.45201 (18) | 0.0255 (4) | |
N1 | 0.57409 (19) | 0.34999 (12) | 0.47156 (15) | 0.0261 (4) | |
C11 | 0.6629 (2) | 0.49972 (13) | 0.34788 (17) | 0.0256 (4) | |
C12 | 0.7771 (2) | 0.58133 (13) | 0.36008 (19) | 0.0285 (4) | |
C13 | 0.7509 (2) | 0.66224 (14) | 0.26618 (19) | 0.0327 (5) | |
C14 | 0.6196 (2) | 0.66677 (15) | 0.15852 (19) | 0.0320 (5) | |
C15 | 0.5111 (2) | 0.58467 (15) | 0.15042 (18) | 0.0302 (5) | |
C16 | 0.5279 (2) | 0.50121 (14) | 0.24170 (18) | 0.0285 (4) | |
C21 | 0.5861 (2) | 0.26335 (14) | 0.56326 (17) | 0.0258 (4) | |
C22 | 0.7137 (2) | 0.24926 (14) | 0.67524 (18) | 0.0295 (4) | |
N23 | 0.72100 (19) | 0.16792 (12) | 0.76305 (15) | 0.0330 (4) | |
C24 | 0.5983 (2) | 0.09807 (15) | 0.7421 (2) | 0.0339 (5) | |
C25 | 0.4674 (2) | 0.10642 (16) | 0.6348 (2) | 0.0366 (5) | |
C26 | 0.4613 (2) | 0.18984 (15) | 0.54430 (19) | 0.0317 (5) | |
H1 | 0.480 (2) | 0.3590 (16) | 0.415 (2) | 0.032 (5)* | |
H12 | 0.8706 | 0.5808 | 0.4317 | 0.034* | |
H14 | 0.6052 | 0.7232 | 0.0940 | 0.038* | |
H16 | 0.4493 | 0.4462 | 0.2322 | 0.034* | |
H22 | 0.7994 | 0.2997 | 0.6899 | 0.035* | |
H24 | 0.6019 | 0.0403 | 0.8039 | 0.041* | |
H25 | 0.3825 | 0.0554 | 0.6234 | 0.044* | |
H26 | 0.3720 | 0.1968 | 0.4695 | 0.038* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F13 | 0.0463 (8) | 0.0401 (7) | 0.0594 (8) | −0.0156 (6) | 0.0022 (6) | 0.0155 (6) |
F15 | 0.0399 (7) | 0.0461 (7) | 0.0396 (7) | 0.0043 (5) | −0.0084 (5) | 0.0057 (5) |
O1 | 0.0258 (8) | 0.0310 (7) | 0.0411 (8) | −0.0027 (6) | −0.0031 (6) | 0.0058 (6) |
C1 | 0.0250 (10) | 0.0232 (9) | 0.0274 (9) | 0.0010 (7) | 0.0031 (8) | −0.0057 (7) |
N1 | 0.0236 (9) | 0.0272 (8) | 0.0260 (8) | 0.0000 (6) | 0.0006 (6) | 0.0020 (6) |
C11 | 0.0253 (10) | 0.0243 (9) | 0.0274 (9) | 0.0009 (7) | 0.0059 (8) | −0.0022 (8) |
C12 | 0.0264 (10) | 0.0293 (10) | 0.0294 (9) | 0.0002 (8) | 0.0048 (8) | 0.0001 (8) |
C13 | 0.0321 (11) | 0.0287 (10) | 0.0383 (11) | −0.0053 (8) | 0.0095 (9) | 0.0015 (9) |
C14 | 0.0364 (11) | 0.0286 (10) | 0.0324 (10) | 0.0054 (8) | 0.0098 (9) | 0.0058 (8) |
C15 | 0.0277 (10) | 0.0340 (11) | 0.0270 (9) | 0.0066 (8) | 0.0003 (8) | −0.0020 (8) |
C16 | 0.0264 (10) | 0.0272 (10) | 0.0314 (10) | −0.0002 (8) | 0.0048 (8) | −0.0020 (8) |
C21 | 0.0255 (10) | 0.0255 (9) | 0.0266 (9) | 0.0015 (7) | 0.0054 (7) | −0.0009 (7) |
C22 | 0.0284 (10) | 0.0299 (10) | 0.0289 (10) | −0.0014 (8) | 0.0025 (7) | 0.0014 (8) |
N23 | 0.0319 (9) | 0.0344 (9) | 0.0312 (9) | 0.0016 (7) | 0.0026 (7) | 0.0017 (7) |
C24 | 0.0358 (11) | 0.0306 (10) | 0.0346 (10) | −0.0011 (8) | 0.0050 (9) | 0.0060 (9) |
C25 | 0.0322 (11) | 0.0338 (11) | 0.0407 (11) | −0.0086 (9) | −0.0008 (9) | 0.0044 (9) |
C26 | 0.0286 (10) | 0.0340 (10) | 0.0298 (10) | −0.0051 (8) | −0.0013 (7) | 0.0038 (8) |
F13—C13 | 1.361 (2) | C21—C26 | 1.384 (2) |
F15—C15 | 1.355 (2) | C22—N23 | 1.340 (2) |
O1—C1 | 1.227 (2) | N23—C24 | 1.340 (2) |
C1—N1 | 1.357 (2) | C24—C25 | 1.376 (3) |
C1—C11 | 1.500 (2) | C25—C26 | 1.378 (3) |
N1—C21 | 1.413 (2) | N1—H1 | 0.89 (2) |
C11—C12 | 1.395 (2) | C12—H12 | 0.9500 |
C11—C16 | 1.388 (2) | C14—H14 | 0.9500 |
C12—C13 | 1.371 (2) | C16—H16 | 0.9500 |
C13—C14 | 1.378 (3) | C22—H22 | 0.9500 |
C14—C15 | 1.371 (3) | C24—H24 | 0.9500 |
C15—C16 | 1.378 (3) | C25—H25 | 0.9500 |
C21—C22 | 1.395 (2) | C26—H26 | 0.9500 |
O1—C1—N1 | 122.36 (16) | C24—N23—C22 | 117.80 (16) |
O1—C1—C11 | 119.86 (16) | N23—C24—C25 | 122.86 (18) |
N1—C1—C11 | 117.77 (16) | C24—C25—C26 | 119.03 (18) |
C1—N1—C21 | 125.55 (16) | C25—C26—C21 | 119.48 (17) |
C16—C11—C12 | 120.00 (17) | C1—N1—H1 | 117.0 (13) |
C16—C11—C1 | 123.99 (16) | C21—N1—H1 | 116.9 (13) |
C12—C11—C1 | 115.98 (16) | C11—C12—H12 | 120.8 |
C13—C12—C11 | 118.37 (17) | C13—C12—H12 | 120.8 |
F13—C13—C12 | 118.20 (17) | C13—C14—H14 | 122.1 |
F13—C13—C14 | 118.06 (16) | C15—C14—H14 | 122.1 |
C12—C13—C14 | 123.74 (17) | C11—C16—H16 | 120.9 |
C15—C14—C13 | 115.80 (17) | C15—C16—H16 | 120.9 |
F15—C15—C14 | 118.06 (16) | C21—C22—H22 | 118.4 |
F15—C15—C16 | 118.09 (16) | N23—C22—H22 | 118.4 |
C14—C15—C16 | 123.85 (17) | N23—C24—H24 | 118.6 |
C15—C16—C11 | 118.24 (17) | C25—C24—H24 | 118.6 |
C26—C21—C22 | 117.71 (16) | C24—C25—H25 | 120.5 |
C26—C21—N1 | 118.27 (15) | C26—C25—H25 | 120.5 |
C22—C21—N1 | 123.97 (16) | C25—C26—H26 | 120.3 |
N23—C22—C21 | 123.12 (17) | C21—C26—H26 | 120.3 |
O1—C1—N1—C21 | −2.1 (3) | F15—C15—C16—C11 | 179.47 (15) |
C11—C1—N1—C21 | 178.88 (15) | C14—C15—C16—C11 | −0.3 (3) |
O1—C1—C11—C16 | 159.62 (16) | C12—C11—C16—C15 | 0.0 (3) |
N1—C1—C11—C16 | −21.3 (2) | C1—C11—C16—C15 | −178.17 (15) |
O1—C1—C11—C12 | −18.6 (2) | C1—N1—C21—C26 | −161.81 (17) |
N1—C1—C11—C12 | 160.44 (15) | C1—N1—C21—C22 | 20.7 (3) |
C16—C11—C12—C13 | 0.7 (3) | C26—C21—C22—N23 | 0.8 (3) |
C1—C11—C12—C13 | 179.01 (15) | N1—C21—C22—N23 | 178.32 (15) |
C11—C12—C13—F13 | 178.39 (15) | C21—C22—N23—C24 | −0.8 (3) |
C11—C12—C13—C14 | −1.2 (3) | C22—N23—C24—C25 | 0.3 (3) |
F13—C13—C14—C15 | −178.64 (15) | N23—C24—C25—C26 | 0.2 (3) |
C12—C13—C14—C15 | 1.0 (3) | C24—C25—C26—C21 | −0.2 (3) |
C13—C14—C15—F15 | −179.94 (15) | C22—C21—C26—C25 | −0.3 (3) |
C13—C14—C15—C16 | −0.2 (3) | N1—C21—C26—C25 | −177.94 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N23i | 0.89 (2) | 2.41 (2) | 3.272 (2) | 164.5 (18) |
C22—H22···O1 | 0.95 | 2.21 | 2.799 (2) | 119 |
C12—H12···O1ii | 0.95 | 2.40 | 3.225 (2) | 144 |
C16—H16···N23i | 0.95 | 2.46 | 3.381 (2) | 163 |
C14—H14···O1iii | 0.95 | 2.58 | 3.482 (2) | 158 |
C24—H24···O1iv | 0.95 | 2.48 | 3.420 (2) | 170 |
C25—H25···F15v | 0.95 | 2.52 | 3.120 (2) | 121 |
C26—H26···F15v | 0.95 | 2.52 | 3.117 (2) | 121 |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x+2, −y+1, −z+1; (iii) −x+3/2, y+1/2, −z+1/2; (iv) −x+3/2, y−1/2, −z+3/2; (v) −x+1/2, y−1/2, −z+1/2. |
Experimental details
(I) | (II) | (III) | (IV) | |
Crystal data | ||||
Chemical formula | C12H8F2N2O | C12H8F2N2O | C12H8F2N2O | C12H8F2N2O |
Mr | 234.20 | 234.20 | 234.20 | 234.20 |
Crystal system, space group | Monoclinic, P21/n | Monoclinic, P21/c | Monoclinic, P21/n | Monoclinic, P21/n |
Temperature (K) | 150 | 150 | 150 | 150 |
a, b, c (Å) | 13.9692 (5), 5.0957 (2), 15.3151 (8) | 8.0371 (7), 5.1425 (4), 23.994 (2) | 7.6741 (5), 13.7314 (6), 10.3316 (8) | 8.3784 (5), 12.6278 (8), 9.9118 (5) |
β (°) | 113.812 (2) | 94.320 (4) | 103.861 (3) | 101.152 (3) |
V (Å3) | 997.37 (8) | 988.87 (15) | 1057.00 (12) | 1028.87 (10) |
Z | 4 | 4 | 4 | 4 |
Radiation type | Mo Kα | Mo Kα | Mo Kα | Mo Kα |
µ (mm−1) | 0.13 | 0.13 | 0.12 | 0.12 |
Crystal size (mm) | 0.30 × 0.20 × 0.15 | 0.20 × 0.18 × 0.05 | 0.26 × 0.24 × 0.12 | 0.22 × 0.20 × 0.18 |
Data collection | ||||
Diffractometer | Nonius KappaCCD diffractometer | Nonius KappaCCD diffractometer | Nonius KappaCCD diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) | Multi-scan (SORTAV; Blessing, 1995) | Multi-scan (SORTAV; Blessing, 1995) | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.963, 0.975 | 0.724, 0.999 | 0.884, 0.987 | 0.938, 0.983 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5121, 2269, 1247 | 5500, 2181, 1346 | 7204, 2412, 1512 | 7054, 2348, 1535 |
Rint | 0.092 | 0.061 | 0.048 | 0.046 |
(sin θ/λ)max (Å−1) | 0.649 | 0.647 | 0.650 | 0.649 |
Refinement | ||||
R[F2 > 2σ(F2)], wR(F2), S | 0.056, 0.170, 1.02 | 0.052, 0.146, 1.02 | 0.050, 0.142, 1.05 | 0.051, 0.141, 1.03 |
No. of reflections | 2269 | 2181 | 2412 | 2348 |
No. of parameters | 158 | 159 | 169 | 159 |
No. of restraints | 0 | 0 | 1 | 0 |
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 | 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) | 0.27, −0.34 | 0.26, −0.22 | 0.22, −0.23 | 0.27, −0.24 |
Computer programs: KappaCCD Server Software (Nonius, 1997), DENZO-SMN (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and SORTX (McArdle, 1995), PLATON (Spek, 2003), SHELXL97 (Sheldrick, 2008) and PREP8 (Ferguson, 1998).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···F12 | 0.86 (3) | 2.24 (3) | 2.741 (3) | 117 (2) |
N1—H1···O1i | 0.86 (3) | 2.20 (3) | 3.017 (3) | 158 (3) |
C26—H26···O1 | 0.95 | 2.41 | 2.911 (3) | 113 |
C22—H22···F12ii | 0.95 | 2.43 | 3.360 (3) | 168 |
Symmetry codes: (i) x, y−1, z; (ii) −x+1, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···F12 | 0.89 (3) | 2.14 (3) | 2.726 (2) | 123 (2) |
N1—H1···O1i | 0.89 (3) | 2.22 (3) | 3.003 (2) | 148 (2) |
C26—H26···O1 | 0.95 | 2.40 | 2.913 (3) | 113 |
C22—H22···F12ii | 0.95 | 2.43 | 3.339 (3) | 161 |
Symmetry codes: (i) x, y+1, z; (ii) −x, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N23i | 0.87 (2) | 2.14 (2) | 2.990 (2) | 164.2 (17) |
C12—H12···O1ii | 0.95 | 2.36 | 3.278 (2) | 162 |
C16—H16···N23i | 0.95 | 2.51 | 3.334 (2) | 146 |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x+2, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N23i | 0.89 (2) | 2.41 (2) | 3.272 (2) | 164.5 (18) |
C22—H22···O1 | 0.95 | 2.21 | 2.799 (2) | 119 |
C12—H12···O1ii | 0.95 | 2.40 | 3.225 (2) | 144 |
C16—H16···N23i | 0.95 | 2.46 | 3.381 (2) | 163 |
C14—H14···O1iii | 0.95 | 2.58 | 3.482 (2) | 158 |
C24—H24···O1iv | 0.95 | 2.48 | 3.420 (2) | 170 |
C25—H25···F15v | 0.95 | 2.52 | 3.120 (2) | 121 |
C26—H26···F15v | 0.95 | 2.52 | 3.117 (2) | 121 |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x+2, −y+1, −z+1; (iii) −x+3/2, y+1/2, −z+1/2; (iv) −x+3/2, y−1/2, −z+3/2; (v) −x+1/2, y−1/2, −z+1/2. |
Angle (°) | (I) | (II) | (III) | (IV) |
O1-C1-N1-C21 | 8.7 (4) | 8.8 (4) | 1.8 (3) | -2.1 (3) |
O1-C1-C11-C12 | -152.1 (3) | -153.7 (2) | 18.0 (2) | -18.6 (2) |
C11-C1-N1-C21 | -171.8 (2) | -172.0 (2) | -177.69 (15) | 178.88 (15) |
C1-N1-C21-C22 | 153.3 (2) | 153.9 (2) | -23.6 (2) | 20.7 (3) |
Benzene-pyridine | 4.48 (18) | 3.66 (11) | 3.63 (11) | 2.94 (11) |
Benzene-amide | 27.3 (3) | 25.39 (10) | 18.64 (25) | 20.0 (2) |
Pyridine-amide | 23.3 (4) | 22.23 (11) | 21.6 (2) | 18.0 (2) |
C-C(F)-Ca | 123.6 (2) | 123.8 (2) | 120.88 (18) | 123.74 (17) |
C-C(F)-Ca | 123.3 (2) | 123.1 (2) | 120.45 (17) | 123.85 (17) |
(a) ipso angle (internal) at F atom. |
Structural systematic studies are at the core of drug-design programmes. The ability to synthesize and study closely related compounds and then monitor and correlate their chemical or biological effects in guest–host interactions is at the heart of understanding how small molecules (guests or drugs) interact with biological hosts as potential novel inhibitors or activators. In structural chemistry, a multitude of crystal structure studies have been reported to date on a variety of organic molecular classes and with a particular emphasis on polymorphism, pseudopolymorphism and isomers (Gelbrich et al., 2007; Wardell et al., 2007, 2008; Chopra & Row, 2008). The variety and sizes of structural series reported are expanding rapidly and notable examples include benzoate esters (Gowda, Foro, Sowmya & Fuess, 2008) and both mono-/dimethyl- and chlorobenzamides (Gowda, Foro, Babitha & Fuess, 2008). Series such as these provide a `goldmine' of structural data for on-going data analyses.
Our group has recently initiated a structural systematic study of (mono/di)fluoro-N'-(pyridyl)benzamide isomers (Donnelly et al., 2008; Gallagher et al., 2008; McMahon et al., 2008). In the difluoro-N-(pyridyl)benzamide series (see first scheme), a total of 18 isomers are possible through condensation of the 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-difluorobenzoyl chlorides with the 4-, 3- or 2-aminopyridines. We have reported four isomers to date, namely the 23p, 24p, 25p and 23o derivatives, where 2–6 represents the F2 substitution pattern on the benzene ring and p, m and o represent the N-atom pyridine ring position (McMahon et al., 2008; Gallagher et al., 2008). We report herein the molecular and crystal structures of the isomers 2,4-difluoro-N'-(3-pyridyl)benzamide, (I), 2,5-difluoro-N'-(3-pyridyl)benzamide, (II), 3,4-difluoro-N'-(3-pyridyl)benzamide, (III) and 3,5-difluoro-N'-(3-pyridyl)benzamide, (IV).
The four isomers (I)–(IV) are depicted in Figs. 1–4, and in the packing diagrams (Figs. 6–9) and molecular overlays (Figs. 10–11). The geometric data (bond lengths and angles) are normal and are not discussed, except for comparisons with related systems (Fig. 5), and the hydrogen bonding/packing interactions (Tables 1–4) and torsion/interplanar angles (Table 5). Differences in bond lengths and angles between the four structures are typically <0.02 Å and <2°, and are influenced by the position of the F-atom substitution pattern on both the ipso (at F-atom sites) and ortho (to F) C—C—C angles; they are typical of the F-atom ring location (Luthe et al., 2007; Klösener et al., 2008). In (III), benzene rotational disorder is observed in the 3,4-difluorobenzene group, with the 3-F atom occupying both 3- and 5-F atom positions,with site occupancies 0.809 (4) and 0.191 (4) for the major and minor components of disorder, respectively. Interestingly, a molecular difference between the (I)/(II) and (III)/(IV) pairs is that the C═O group and N atoms are oriented transoid to each other in the former and cisoid in the latter (Figs. 1–4; see also first scheme).
The defining feature of the molecular conformation in these four isomers is the dihedral angle between the benzene and pyridine rings, which are mutally oriented at between 4.48 (18)° in (I) and 2.94 (11)° in (IV) (Figs. 1–4, Table 5), while the three-atom amide unit is rotated by <30° from either the six-membered C6 or C5N plane [18.0 (2)–27.3 (3)° for all four structures]. An overlay of (I) and (II) (Fig. 10) highlights the similar conformations for the two structures, and Fig. 11 shows an overlay for (III) and (IV). In (I) and (II) the ortho-F atom is positioned transoid to the carbonyl O atom, with two intramolecular contacts involving C26···O1 and N1···F12 [both with S(6) motifs; Bernstein et al., 1995]. The C26···O1 distances are invariant, at 2.910 (3) Å in (I) and 2.913 (3) Å for (II) [C—H···O = 113° for both (I) and (II)]. However, N1···F1 varies slightly from 2.741 (3) Å in (I) to 2.726 (2) Å in (II), with angles of 117 (2)° in (I) and 123 (2)° in (II) [as the C1—N1—C21—(C22/C26) torsion angle decreases; Table 5].
Compounds (III) and (IV) are essentially isomorphous (their a and b unit-cell lengths differ by 9%) and are quasi-isostructural at the primary hydrogen-bonding level. Overlay of the unit cells indicates that (III) and (IV) occupy similar three-dimensional volume elements within their respective unit cells but that the atoms (and rings) are sufficiently displaced in each molecular structure to effect a packing situation whereby the N—H group involved in a strong interaction in (III) only forms a weaker analogous interaction in (IV) (Fig. 11). Differences arise principally from the steric effects of the 3,4-F2 (disordered) and 3,5-F2 substitution patterns at the molecular sites on the packing and resultant unit-cell parameters. The 3,5-F2 group causes a longer a dimension in (IV) and the 4-F substitution in (III) lengthens b, with a resulting impact on the observed and different geometric values of the principal N—H···N interaction. A variable-temperature study would be useful to ascertain how similar the crystal structures of (III) and (IV) are over a range of temperatures; Threlfall & Gelbrich (2007) have described the pitfalls of accrediting great significance to structural differences which can be readily explained by normal changes of lattice expansion over a range of temperatures.
For a comparison of structures (I)–(IV) with literature data, a survey and analysis of the relevant bond lengths and angles was undertaken. Luthe and co-workers have reported a comprehensive study of fluorinated 4-chlorobiphenyls (PCB 3) (Luthe et al., 2007) and 4-bromodiphenyl ethers (PBDE 3) (Klösener et al., 2008), where the interior aromatic C—C—C ring angles (due to the ipso-F position) are shown to increase by 2–3° (or decrease from 120° for ortho-related angles) from the ideal 120°, as also demonstrated by computational calculations at the 3–21 level using SPARTAN (Shao et al., 2006). The ipso ring-angle increase is attributed to hyperconjugation of the fluorine 2p orbitals with the π-orbitals of the aromatic ring system; neighbouring (ortho) C—C—C ring angles deviate from 120° to compensate. The effect of fluorine 'tagging' has an impact on the internal aromatic angles, dihedral angles, packing and neighbouring groups, although less than for Cl substitution (Luthe et al., 2007; Klösener et al., 2008).
The 4-fluorophenyl FC6H4—Z moiety (Z = any atom but H) was selected as a model group, giving 1276 hits (2322 observations; see Fig. 5) in a search of the Cambridge Structural Database (CSD, Version 5.30 plus two updates; Allen, 2002). The ipso-F angle for 4-F derivatives expands to 123 (1)°, while angles ortho to F contract to 118 (1)° [meta angles to F increase slightly to 121 (1)°]. Analysis of the C—F bond lengths with ipso-C—C—C angles shows a trend line whereby increasing C—F bond lengths (from 1.35 to 1.38°) correlate well with increasing C—C—C angles (from 120 to 126°). Influences include the effects of both intra- and intermolecular interactions on the F-atom geometric data. The F-atom position on the aromatic ring influences distinct geometric patterns at both the ipso and ortho C—C—C angles (Fig. 5). The molecular analysis results and calculations (Luthe et al., 2007; Klösener et al., 2008) agree with both our CSD analysis and previous results from the 4-/3-/2-fluoro-N'-(4-pyridinyl)benzamides (Donnelly et al., 2008), where 4–5° differences in the internal aromatic C—C—C angles are observed.
This F-atom effect was analysed for related C6H3F2—Z moieties in the CSD for comparison with the 4-F study (above) and molecules (I)–(IV). Difluorobenzene fragments are rare in structural chemistry (Fig. 1 in McMahon et al., 2008) compared with the vast plethora of both mono-substituted fluoro- and pentafluorobenzene derivatives reported in the CSD.
Analysis of the 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-difluorobenzene groups in the CSD provides indicators for particular trends and for comparisons with (I)–(IV), but the data available are too few to allow comprehensive comparisons in three cases, namely the 2,3- (with 15 structures out of 17 observations), 2,5- (with 28/40 data) and 3,4- (with 30/48 data) structures. The CSD data for the 2,4-difluorobenzene fragment (121/170 data), and 2,6- (195/388 data) and 3,5-disubstituted fragments (66/146 data), provide average C—F bond lengths of 1.35 Å and ca 4–5° differences in the internal C—C—C angles, depending on whether the F is ipso (with C—C—C > 120°) or ortho (with C—C—C < 120°) (Fig. 5).
Analysis of the 2,4-difluorobenzene fragment in the CSD gives typical C—F bond lengths of 1.36 (1) Å, comparable with the values of 1.365 (3) and 1.359 (3) Å in (I). The variation in internal C—C—C angles within the 2,4-difluorobenzene ring shows the largest C—C—C angles of 124 (1) and 123 (1)° at the 2,4-ipso-F sites [123.6 (2) and 123.2 (2)° in (I)]. The three smallest C—C—C angles [In what?] are positioned ortho to the 2-/4-F atoms and are similar to the average CSD values (Fig. 5); in (I) these angles are 116.5 (2) (at Z), 116.9 (2) and 117.7 (2)°. In the symmetrical 2,6-difluorobenzenes, the ipso-F angles expand to 124 (2)° and the ortho angle (at Z) between the two C—F groups contracts to 115 (2)°. The two remaining ortho angles decrease to 118 (1)°. In both the 2,4-F2 and 2,6-F2 case studies, increasing C—F bond length correlates with increasing ipso-C—C—C angle (and ortho-C—C—C angle contracting from 120°). The symmetrical 3,5-difluorobenzenes and (IV) contrast remarkably with the 2,6-F2 results in terms of angle changes relative to the Z group (Fig. 5). The ipso angles expand to 123 (2)° [123.74 (17) and 123.85 (17)° in (IV)] as the ortho C14 angle contracts to 116 (2)° [115.80 (17)° in (IV)], two ortho angles decrease to 118 (2) [118.37 (17) and 118.24 (17)° in (IV)] and there is a symmetrical 120 (2)° angle at C11 [120.00 (17)° in (IV)]. [In the above discussion, it is not always obvious what is being compared, e.g. average data from the CSD, subgroup data from the CSD, average data from the title compounds, etc. Please check the text is as unambiguous as possible]
The CSD analyses and comparisons with (I)–(IV) [Only (I) and (IV) are explicitly compared - please check text above is complete] serve to highlight distinct trends in how fluoro-aromatic substitution patterns affect the internal aromatic C—C—C angles in difluorobenzene fragments. It should be noted that there are no significant deviations from planarity in the C6 (or C5N) rings, with all C atoms within 0.01 Å of the mean plane. No trends are seen in the aromatic C—C bond lengths, nor are they influenced by the fluoro substitution, although the aromatic C—C bond lengths are slightly shorter closer to the F-atom ring positions.
The hydrogen bonding in (I)–(IV) is of interest. Compounds (I) and (II) are isostructural at the primary hydrogen-bonding level but are not isomorphous. In both (I) and (II), N—H···O═C intermolecular interactions form one-dimensional chains along [010], with N···Oi = 3.017 (3) and 3.003 (2) Å, respectively (see Figs. 6 and 7 and Tables 1 and 2 for symmetry code). Pairs of molecules of (I) aggregate about inversion centres via centrosymmetric C—H···F interactions [H···F = 2.43 Å and C—H···F = 168° in (I); H···F = 2.43 Å and C—H···F = 161° in (II)]. It is of note that the pyridyl N atom is not engaged in hydrogen bonding: the closest contacts are H···Npy = 2.71 Å in (I) and 2.69 Å in (II). In (II), the closest π–π stacking interaction is C15···C26ii = 3.243 (3) Å [symmetry code: (ii) 1 − x, −y, 1 − z]. The overall effect is that the N—H···O═C one-dimensional chain is further linked into pairs via H···F interactions and forms a herringbone network via weaker stacking, as stacked columns in (I) and side-by-side in (II).
A CSD search (Version 5.30, February 2009 [Different version to that above?]; Allen, 2002) was performed to analyse the types of interactions involving F atoms with H···F distances similar in magnitude to those in (I) and (II). Parameter restrictions were for C6—H···F—C6 with H···F = 1.0–2.5 Å and an angle of 150–180° with coordinates, to yield a total of 117 hits (see second scheme). The interactions can be categorized as follows (and in combination), with 85% as metal-containing, 84% with C6F5, 33% as salts and 59% as intramolecular interactions. Given that the C—H···F interaction in both (I) and (II) is organic and neutral, structures with comparable interactions of comparable dimensions are relatively uncommon, and examples include 7-(3,5-di-t-butyldiphenyl)-2,12-bis(pentafluorophenyl)-5,6,8,9-tetrahydro dibenzo[c,h]acridine (CSD refcode CEDFOH; Korenaga et al., 2005) and trans-(ethane-1,2- diamine-N,N'-bis(7-methylsalicylideneiminato))di(2,4-difluorophenyldiboronate (NERTIN; Sanchez et al., 2001).
In (III), N—H···Npy interactions form one-dimensional chains [2.990 (2) Å] in tandem with a C—H···Npy contact [C···Npy = 3.334 (2) Å]. C—H···O═C interactions about inversion centres form R22(10) rings with C···O = 3.278 (2) Å. Molecules of (III) stack via π–π(arene) interactions about inversion centres. Closest C···ring distances are 3.38 and 3.44 Å, with Cg1···Cg2 = 3.574 (1) Å (Cg1 and Cg2 are the centroids of the C11–C16 and N24/C21–C23/C25/C26 rings, respectively). However, in (IV), there are no strong intermolecular interactions; the N—H···Npy interaction is 0.3 Å longer than in (III) [N···Npy = 3.272 (2) Å]. Weaker interactions include six C—H···N/O/F interactions with H···N/O/F distances in the range 2.40 to 2.58 Å. The C═ O group only participates in a weak interaction, with C···O = 3.225 (2) Å in (IV) [3.278 (2) Å in (III)]. The carbonyl group in (IV) is involved in three intermolecular interactions, with H···O distances in the range 2.40–2.58 Å. Differences between (III) and (IV) highlight the subtle interplay and competition between strong and weaker N—H···Npy hydrogen bonding originating from subtle packing differences in their respective molecular structures.
The range in densities of (I)–(IV) is 1.472–1.573 Mg m−3, compared with an average of 1.53 Mg m−3 for all eight C12H8F2N2O compounds reported to date (McMahon et al., 2008; Gallagher et al., 2008), including the present study. It is of note that the lowest values of 1.465 and 1.472 Mg m−3 correspond to the 23o derivative (Gallagher et al., 2008), which crystallizes with Z' = 2, and (III) or the 34m derivative, which is disordered in the C6 ring.