Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801002641/wn6003sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801002641/wn6003Isup2.hkl |
CCDC reference: 159853
Pentafluorobenzonitrile was obtained from Lancaster and crystallized in a 0.4 mm capillary tube at 268 K, cooled with an Oxford Cryosystems Cryostream cooler.
Data collection: COLLECT (Nonius BV, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1993); software used to prepare material for publication: SHELXL97.
C7F5N | Dx = 1.911 Mg m−3 |
Mr = 193.08 | Melting point: 268 K |
Orthorhombic, Cmca | Mo Kα radiation, λ = 0.71073 Å |
a = 7.6864 (5) Å | Cell parameters from 2861 reflections |
b = 9.5175 (3) Å | θ = 1.0–27.5° |
c = 18.3480 (12) Å | µ = 0.21 mm−1 |
V = 1342.25 (13) Å3 | T = 180 K |
Z = 8 | Cylinder, colourless |
F(000) = 752 | 0.35 mm (radius) |
KappaCCD diffractometer | 732 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.052 |
Horizonally-mounted graphite crystal monochromator | θmax = 27.5°, θmin = 2.2° |
Detector resolution: 9 pixels mm-1 | h = 0→9 |
CCD scans | k = −12→12 |
4072 measured reflections | l = −23→23 |
820 independent 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)] = 0.037 | w = 1/[σ2(Fo2) + (0.0592P)2 + 0.5299P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.108 | (Δ/σ)max < 0.001 |
S = 1.12 | Δρmax = 0.25 e Å−3 |
819 reflections | Δρmin = −0.24 e Å−3 |
68 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.016 (4) |
C7F5N | V = 1342.25 (13) Å3 |
Mr = 193.08 | Z = 8 |
Orthorhombic, Cmca | Mo Kα radiation |
a = 7.6864 (5) Å | µ = 0.21 mm−1 |
b = 9.5175 (3) Å | T = 180 K |
c = 18.3480 (12) Å | 0.35 mm (radius) |
KappaCCD diffractometer | 732 reflections with I > 2σ(I) |
4072 measured reflections | Rint = 0.052 |
820 independent reflections |
R[F2 > 2σ(F2)] = 0.037 | 68 parameters |
wR(F2) = 0.108 | 0 restraints |
S = 1.12 | Δρmax = 0.25 e Å−3 |
819 reflections | Δρmin = −0.24 e Å−3 |
Experimental. Crystal grown in situ at 268 K in a 0.4 mm capillary. |
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 on F2 for ALL reflections except for 1 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_obs 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 | ||
F3 | 0.19431 (11) | 0.13388 (9) | 0.65670 (5) | 0.0411 (3) | |
F4 | 0.19455 (12) | −0.09958 (10) | 0.57154 (5) | 0.0450 (3) | |
F5 | 0.5000 | −0.21505 (12) | 0.53032 (7) | 0.0459 (4) | |
N1 | 0.5000 | 0.3606 (2) | 0.73871 (10) | 0.0479 (5) | |
C1 | 0.5000 | 0.2619 (2) | 0.70317 (10) | 0.0325 (4) | |
C2 | 0.5000 | 0.1383 (2) | 0.65861 (9) | 0.0257 (4) | |
C3 | 0.3447 (2) | 0.07690 (13) | 0.63639 (7) | 0.0273 (3) | |
C4 | 0.3441 (2) | −0.04187 (13) | 0.59347 (7) | 0.0295 (4) | |
C5 | 0.5000 | −0.1014 (2) | 0.57246 (9) | 0.0298 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
F3 | 0.0277 (5) | 0.0426 (5) | 0.0531 (6) | 0.0058 (3) | 0.0084 (4) | 0.0006 (4) |
F4 | 0.0378 (5) | 0.0462 (6) | 0.0510 (6) | −0.0153 (4) | −0.0104 (4) | −0.0009 (4) |
F5 | 0.0697 (9) | 0.0305 (7) | 0.0374 (7) | 0.000 | 0.000 | −0.0114 (5) |
N1 | 0.0715 (13) | 0.0343 (9) | 0.0380 (10) | 0.000 | 0.000 | −0.0081 (7) |
C1 | 0.0419 (10) | 0.0266 (8) | 0.0290 (9) | 0.000 | 0.000 | 0.0011 (7) |
C2 | 0.0313 (9) | 0.0223 (8) | 0.0235 (8) | 0.000 | 0.000 | 0.0020 (6) |
C3 | 0.0263 (7) | 0.0268 (6) | 0.0288 (6) | 0.0023 (4) | 0.0023 (5) | 0.0048 (5) |
C4 | 0.0302 (7) | 0.0297 (7) | 0.0287 (7) | −0.0072 (5) | −0.0045 (5) | 0.0035 (5) |
C5 | 0.0434 (11) | 0.0233 (8) | 0.0229 (9) | 0.000 | 0.000 | −0.0022 (6) |
F3—C3 | 1.3299 (15) | C2—C3 | 1.390 (2) |
F4—C4 | 1.3360 (14) | C2—C3i | 1.3905 (15) |
F5—C5 | 1.330 (2) | C3—C4 | 1.378 (2) |
N1—C1 | 1.144 (3) | C4—C5 | 1.381 (2) |
C1—C2 | 1.432 (2) | C5—C4i | 1.381 (2) |
N1—C1—C2 | 180.0 (2) | F4—C4—C3 | 120.82 (11) |
C3—C2—C3i | 118.3 (2) | F4—C4—C5 | 119.60 (12) |
C3—C2—C1 | 120.83 (8) | C3—C4—C5 | 119.57 (12) |
C3i—C2—C1 | 120.83 (8) | F5—C5—C4i | 119.75 (8) |
F3—C3—C4 | 119.46 (11) | F5—C5—C4 | 119.75 (8) |
F3—C3—C2 | 119.51 (12) | C4i—C5—C4 | 120.5 (2) |
C4—C3—C2 | 121.02 (11) | ||
N1—C1—C2—C3 | −90.100 | C2—C3—C4—F4 | −179.20 (12) |
N1—C1—C2—C3i | 90.100 | F3—C3—C4—C5 | −179.85 (13) |
C3i—C2—C3—F3 | −179.78 (9) | C2—C3—C4—C5 | 0.3 (2) |
C1—C2—C3—F3 | 0.1 (2) | F4—C4—C5—F5 | 0.4 (2) |
C3i—C2—C3—C4 | 0.0 (2) | C3—C4—C5—F5 | −179.19 (13) |
C1—C2—C3—C4 | 179.94 (14) | F4—C4—C5—C4i | 178.82 (9) |
F3—C3—C4—F4 | 0.6 (2) | C3—C4—C5—C4i | −0.7 (3) |
Symmetry code: (i) −x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C7F5N |
Mr | 193.08 |
Crystal system, space group | Orthorhombic, Cmca |
Temperature (K) | 180 |
a, b, c (Å) | 7.6864 (5), 9.5175 (3), 18.3480 (12) |
V (Å3) | 1342.25 (13) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.21 |
Crystal size (mm) | 0.35 (radius) |
Data collection | |
Diffractometer | KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4072, 820, 732 |
Rint | 0.052 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.108, 1.12 |
No. of reflections | 819 |
No. of parameters | 68 |
Δρmax, Δρmin (e Å−3) | 0.25, −0.24 |
Computer programs: COLLECT (Nonius BV, 1998), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO and SCALEPACK, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP (Sheldrick, 1993), SHELXL97.
Halogen–cyano interactions have been utilized in supramolecular synthons for crystal engineering (Desiraju & Harlow, 1989). For the heavier halogens (X = I, Br) the CN···X interaction is strongly structure-directing. We have recently investigated a series of perfluoro-aromatics of general formula, para-XC6F4CN. For the heavier halogens (X = Cl, Br, I), the compounds are solids at room temperature, whereas C6F5CN, (I), is a liquid (m.p. = 275.4 K; Fluorochem). The crystal was grown in a 0.4 mm capillary tube (GLAS) at 268 K, cooled with an Oxford Cryosystems Cryostream (Cosier & Glazer, 1986), and cooled further to 180 K for data collection.
Compound (I) is isostructural with the isocyanide, C6F5NC (Lentz & Preugschat, 1993), crystallizing in the orthorhombic space group Cmca with the molecule lying on a mirror plane bisecting the C6F5 ring and the cyano group (Figure 2). Compound (I) does not exhibit CN···F-type interactions. Instead, neighbouring molecules adopt a coplanar arrangement in which the F atom para to the cyano group is located over the centroid of the adjacent aromatic ring [d(F···centroid) = 3.263 Å]. The cyanide group aproaches the opposite face in a direction approximately perpendicular to the plane of the aromatic ring [d(N···centroid) = 3.071 Å] (Fig. 3). This interaction with the π-electron density of the phenyl ring presumably accommodates the complementary electronic demands of both the electronegative F and sp-hybridized N atoms.
It is interesting to note that the melting point of the isocyanide, C6F5NC, is some 10° higher than that of (I) (m.p. = 286 K) (Lentz & Preugschat, 1993). This suggests that the NC···π interactions in the isocyanide are stronger than the CN···π interactions in (I).