Perfluorinated 6-isopropyl-2,4,5-trimethyl­benzonitrile

Batsanov, A.S.; Richmond, P.; Sandford, G.; Chambers, R.D.

doi:10.1107/S1600536804031745

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 61| Part 1| January 2005| Pages o45-o46

https://doi.org/10.1107/S1600536804031745

Perfluorinated 6-isopropyl-2,4,5-trimethylbenzonitrile

Andrei S. Batsanov,^a ^* Paul Richmond,^a Graham Sandford ^a and Richard D. Chambers ^a

^aDepartment of Chemistry, University of Durham, South Road, Durham DH1 3LE, England
^*Correspondence e-mail: a.s.batsanov@durham.ac.uk

(Received 24 November 2004; accepted 30 November 2004; online 11 December 2004)

In the title compound, 3-fluoro-6-[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-2,4,5-tris(trifluoromethyl)benzonitrile, C₁₃F₁₇N, the benzene ring is puckered due to steric repulsion between substituents.

Comment

The title compound, (I), was obtained as a by-product during our studies concerning fluoride-ion induced perfluoro-alkylation reactions of highly fluorinated aromatic systems (Chambers & Sargent, 1981 ; Brooke, 1997 ; Richmond, 2001 ).

The molecule of (I) (Fig. 1) is sterically overcrowded, resulting in some very short intramolecular non-bonded distances, viz. F1⋯F2 = 2.467 (4) Å, F1⋯F8 = 2.503 (4) Å, F6⋯F10 = 2.503 (4) Å, F9⋯F12 = 2.430 (4) Å, F11⋯F12 = 2.547 (4) Å, C7⋯F4 = 2.681 (4) Å, C7⋯F15 = 2.606 (4) Å and C7⋯F18 = 2.962 (4) Å, cf. the standard van der Waals contact distances (Rowland & Taylor, 1996 ) F⋯F = 2.90 Å and C⋯F = 3.22 Å. As a result, the substituents tilt out of the benzene plane and induce some puckering of the ring itself. Thus atoms C1, C2, C3 and C4 of the ring are coplanar within 0.012 (2) Å, but C5 and C6 deviate from the plane by −0.102 (6) and 0.052 (6) Å, respectively. The deviations of the substituent atoms are −0.196 (6) (C7), −0.467 (7) (N), −0.073 (7) (C8), −0.035 (6) (F1), 0.119 (7) (C9), −0.69 (1) (C10) and 0.35 (1) Å (C11).

The C—F bond distances in the trifluoromethyl groups range from 1.316 (4) to 1.342 (4) Å, with an average of 1.330 (7) Å.

Figure 1
Molecular structure of (I)

. Atomic displacement ellipsoids are drawn at the 50% probability level.

Experimental

A mixture containing tetrafluorophthalonitrile (5.0 g, 25 mmol) and dried KF (2.2 g, 100 mmol) in anhydrous DMF (25 ml) was heated to 323 K under dry N₂ with a cold-finger condenser attached, containing acetone/CO₂. Me₃SiCF₃ (14 g, 100 ml) in anhydrous DMF (5 ml) was added slowly to the reaction vessel via a syringe. The mixture was stirred at 323 K for 6 h. The deep red solution was transferred to an autoclave (160 ml) under dry N₂. Hexafluoropropene (15 g, 90 mmol) was transferred into the autoclave under vacuum. The autoclave was sealed and heated to 358 K over a period of 48 h, and then opened in a vacuum. 7.0 g (41 mmol) of hexafluoropropene was recovered. Continuous extraction into perfluoromethylcyclohexane followed by evaporation of the solvent on a rotary evaporator gave a very small quantity of (I) as a white solid. Analysis found: C 31.6, N 2.8%; C₁₃F₁₇N requires: C 31.4, N 2.8%. The ¹⁹F NMR data (field strength 376 MHz) are listed in Table 2. The very broad peak at −55.0 p.p.m. can be interpreted as a poorly resolved multiplet of the C10F₃ group, resulting from unusual rotation of this group and the adjacent perfluoroisopropyl group.

Crystal data

C₁₃F₁₇N
M_r = 493.14
Monoclinic, P2₁/n
a = 9.521 (1) Å
b = 9.410 (1) Å
c = 17.426 (2) Å
β = 103.44 (1)°
V = 1518.5 (3) Å³
Z = 4
D_x = 2.157 Mg m⁻³
Mo Kα radiation
Cell parameters from 692 reflections
θ = 10.2–21.4°
μ = 0.28 mm⁻¹
T = 100 (2) K
Needle, colourless
0.55 × 0.08 × 0.02 mm

Data collection

Bruker SMART 1K CCD area detector diffractometer
ω scans
Absorption correction: none
10 711 measured reflections
3497 independent reflections
1972 reflections with I > 2σ(I)
R_int = 0.106
θ_max = 27.5°
h = −12 → 12
k = −12 → 12
l = −22 → 22

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.134
S = 1.02
3497 reflections
280 parameters
w = 1/[σ²(F_o²) + (0.0488P)² + 0.8197P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Table 1
Selected interatomic distances (Å)

N—C7	1.148 (5)
F1—C3	1.336 (4)
F12—C11	1.377 (4)
C1—C2	1.403 (5)
C1—C6	1.407 (5)
C1—C7	1.443 (5)
C2—C3	1.384 (5)
C2—C8	1.520 (5)
C3—C4	1.386 (5)
C4—C5	1.400 (5)
C4—C9	1.532 (5)
C5—C6	1.405 (5)
C5—C10	1.542 (5)
C6—C11	1.539 (5)
C11—C12	1.559 (5)
C11—C13	1.578 (5)

Table 2
¹⁹F NMR spectrum of (I)

δ (p.p.m.)	Intensity	Multiplicity	Coupling (Hz)	Assignment
−55.0	3	br m	–	C10F₃
−56.5	3	dq	⁴J_FF 28, ⁵J_FF 4	C9F₃
−57.2	3	d	⁴J_FF 28	C8F₃
−69.2	6	br s	–	C12F₃, C13F₃
−100.6	1	sept	⁴J_FF 28	F1
−163.5	1	q	³J_FF 54	F12

Data collection: SMART (Bruker, 1997 ); cell refinement: SAINT (Bruker, 1999 ); data reduction: SAINT; program(s) used to solve structure: SHELXTL(Bruker, 2001 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536804031745/lh6327sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536804031745/lh6327Isup2.hkl

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXTL(Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

3-fluoro-6-[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-2,4,5- tris(trifluoromethyl)benzonitrile top

Crystal data top

C₁₃F₁₇N	F(000) = 952
M_r = 493.14	D_x = 2.157 Mg m⁻³
Monoclinic, P2₁/n	Melting point = 351–352 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 9.521 (1) Å	Cell parameters from 692 reflections
b = 9.410 (1) Å	θ = 10.2–21.4°
c = 17.426 (2) Å	µ = 0.28 mm⁻¹
β = 103.44 (1)°	T = 100 K
V = 1518.5 (3) Å³	Needle, colourless
Z = 4	0.55 × 0.08 × 0.02 mm

Data collection top

Bruker SMART 1K CCD area detector diffractometer	1972 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.106
Graphite monochromator	θ_max = 27.5°, θ_min = 2.3°
Detector resolution: 8 pixels mm^-1	h = −12→12
ω scans	k = −12→12
10711 measured reflections	l = −22→22
3497 independent reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F² > 2σ(F²)] = 0.057	Secondary atom site location: difference Fourier map
wR(F²) = 0.134	w = 1/[σ²(F_o²) + (0.0488P)² + 0.8197P] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max < 0.001
3497 reflections	Δρ_max = 0.34 e Å⁻³
280 parameters	Δρ_min = −0.35 e Å⁻³

Special details top

Experimental. The data collection nominally covered over a hemisphere of reciprocal space, by a combination of 4 sets of exposures; each set had a different φ and/or 2θ angles and each exposure (50 s) covered 0.3° in ω. Crystal decay was monitored by repeating 50 initial frames at the end of data collection and comparing 78 duplicate reflections. Crystal to detector distance 4.53 cm.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N	0.2327 (4)	0.6948 (3)	0.2402 (2)	0.0301 (8)
F1	0.0004 (2)	0.2198 (2)	0.04015 (13)	0.0293 (5)
F2	−0.1394 (3)	0.4289 (3)	0.06439 (15)	0.0451 (7)
F3	−0.0544 (2)	0.4634 (2)	0.18788 (13)	0.0328 (6)
F4	−0.0287 (3)	0.6210 (2)	0.10331 (15)	0.0378 (6)
F6	0.3691 (3)	0.0630 (2)	0.00157 (14)	0.0346 (6)
F7	0.2104 (3)	−0.0262 (2)	0.05958 (15)	0.0378 (6)
F8	0.1453 (3)	0.1025 (2)	−0.04488 (13)	0.0352 (6)
F9	0.5879 (2)	0.2270 (2)	0.21283 (12)	0.0229 (5)
F10	0.4727 (2)	0.0556 (2)	0.14733 (13)	0.0269 (5)
F11	0.6071 (2)	0.1887 (2)	0.09313 (13)	0.0265 (5)
F12	0.6279 (2)	0.4431 (2)	0.14449 (13)	0.0245 (5)
F13	0.4826 (3)	0.6219 (2)	0.04560 (13)	0.0341 (6)
F14	0.6437 (3)	0.7132 (2)	0.13983 (15)	0.0361 (6)
F15	0.4183 (2)	0.7475 (2)	0.13403 (14)	0.0312 (6)
F16	0.7056 (2)	0.4894 (2)	0.28607 (14)	0.0331 (6)
F17	0.5644 (3)	0.6689 (2)	0.28107 (14)	0.0350 (6)
F18	0.4884 (2)	0.4594 (2)	0.29882 (12)	0.0296 (5)
C1	0.2450 (4)	0.4827 (3)	0.1475 (2)	0.0162 (8)
C2	0.1146 (4)	0.4156 (4)	0.1118 (2)	0.0170 (8)
C3	0.1224 (4)	0.2883 (4)	0.0732 (2)	0.0200 (8)
C4	0.2527 (4)	0.2237 (3)	0.0719 (2)	0.0171 (8)
C5	0.3818 (4)	0.2856 (4)	0.1133 (2)	0.0168 (8)
C6	0.3790 (4)	0.4234 (3)	0.14396 (19)	0.0151 (7)
C7	0.2380 (4)	0.6051 (4)	0.1964 (2)	0.0208 (8)
C8	−0.0287 (4)	0.4813 (4)	0.1170 (2)	0.0222 (8)
C9	0.2446 (5)	0.0883 (4)	0.0222 (2)	0.0275 (9)
C10	0.5157 (4)	0.1899 (4)	0.1405 (2)	0.0213 (8)
C11	0.5182 (4)	0.5116 (4)	0.1689 (2)	0.0190 (8)
C12	0.5138 (4)	0.6530 (4)	0.1218 (2)	0.0266 (9)
C13	0.5710 (4)	0.5318 (4)	0.2610 (2)	0.0237 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N	0.035 (2)	0.0232 (18)	0.034 (2)	0.0063 (15)	0.0119 (17)	−0.0049 (16)
F1	0.0223 (12)	0.0271 (12)	0.0356 (13)	−0.0059 (10)	0.0006 (10)	−0.0036 (10)
F2	0.0204 (13)	0.0660 (18)	0.0457 (16)	0.0075 (13)	0.0008 (11)	−0.0243 (14)
F3	0.0349 (14)	0.0364 (13)	0.0333 (13)	0.0077 (11)	0.0203 (11)	0.0024 (11)
F4	0.0336 (14)	0.0247 (13)	0.0593 (16)	0.0148 (11)	0.0195 (13)	0.0154 (12)
F6	0.0398 (14)	0.0270 (12)	0.0359 (14)	0.0090 (11)	0.0068 (11)	−0.0134 (11)
F7	0.0464 (15)	0.0125 (11)	0.0490 (16)	−0.0040 (11)	−0.0006 (13)	−0.0004 (11)
F8	0.0422 (15)	0.0261 (12)	0.0304 (13)	0.0048 (11)	−0.0055 (11)	−0.0113 (10)
F9	0.0234 (12)	0.0182 (10)	0.0257 (12)	0.0015 (9)	0.0032 (10)	−0.0006 (9)
F10	0.0303 (12)	0.0093 (10)	0.0394 (13)	0.0016 (9)	0.0046 (11)	0.0007 (9)
F11	0.0258 (12)	0.0227 (11)	0.0345 (13)	0.0081 (9)	0.0139 (11)	−0.0028 (10)
F12	0.0203 (11)	0.0196 (11)	0.0374 (13)	−0.0004 (9)	0.0141 (10)	−0.0035 (10)
F13	0.0563 (17)	0.0223 (12)	0.0271 (13)	−0.0038 (11)	0.0164 (12)	0.0038 (10)
F14	0.0347 (14)	0.0210 (12)	0.0550 (16)	−0.0124 (11)	0.0150 (13)	0.0042 (11)
F15	0.0383 (14)	0.0141 (10)	0.0448 (14)	0.0046 (10)	0.0171 (12)	0.0042 (10)
F16	0.0243 (13)	0.0316 (13)	0.0392 (14)	−0.0022 (11)	−0.0008 (11)	−0.0010 (11)
F17	0.0472 (15)	0.0201 (11)	0.0350 (13)	−0.0004 (11)	0.0038 (12)	−0.0110 (10)
F18	0.0304 (13)	0.0354 (13)	0.0226 (12)	−0.0097 (10)	0.0055 (10)	0.0012 (10)
C1	0.024 (2)	0.0104 (16)	0.0165 (18)	0.0027 (15)	0.0086 (15)	0.0012 (14)
C2	0.0191 (19)	0.0186 (18)	0.0152 (18)	0.0021 (16)	0.0077 (15)	0.0042 (15)
C3	0.024 (2)	0.0170 (18)	0.0179 (19)	−0.0049 (16)	0.0018 (16)	0.0017 (15)
C4	0.023 (2)	0.0099 (16)	0.0183 (18)	0.0032 (15)	0.0045 (16)	0.0024 (14)
C5	0.0195 (19)	0.0149 (17)	0.0187 (18)	0.0014 (15)	0.0097 (16)	−0.0006 (15)
C6	0.0224 (19)	0.0092 (16)	0.0140 (17)	0.0003 (14)	0.0049 (15)	0.0010 (14)
C7	0.019 (2)	0.0181 (19)	0.027 (2)	0.0051 (16)	0.0091 (17)	0.0005 (16)
C8	0.019 (2)	0.024 (2)	0.025 (2)	0.0027 (16)	0.0078 (17)	−0.0010 (16)
C9	0.032 (2)	0.0166 (19)	0.032 (2)	0.0031 (18)	0.0027 (19)	−0.0042 (17)
C10	0.023 (2)	0.0144 (18)	0.027 (2)	0.0022 (16)	0.0060 (18)	−0.0006 (16)
C11	0.0172 (19)	0.0155 (18)	0.027 (2)	0.0027 (15)	0.0110 (16)	0.0006 (15)
C12	0.029 (2)	0.0190 (19)	0.035 (2)	−0.0054 (17)	0.0128 (19)	−0.0008 (18)
C13	0.019 (2)	0.0181 (19)	0.031 (2)	−0.0025 (16)	−0.0003 (17)	−0.0023 (17)

Geometric parameters (Å, º) top

N—C7	1.148 (5)	F17—C13	1.342 (4)
F1—C3	1.336 (4)	F18—C13	1.326 (4)
F2—C8	1.321 (4)	C1—C2	1.403 (5)
F3—C8	1.325 (4)	C1—C6	1.407 (5)
F4—C8	1.336 (4)	C1—C7	1.443 (5)
F6—C9	1.337 (5)	C2—C3	1.384 (5)
F7—C9	1.337 (4)	C2—C8	1.520 (5)
F8—C9	1.329 (5)	C3—C4	1.386 (5)
F9—C10	1.335 (4)	C4—C5	1.400 (5)
F10—C10	1.342 (4)	C4—C9	1.532 (5)
F11—C10	1.332 (4)	C5—C6	1.405 (5)
F12—C11	1.377 (4)	C5—C10	1.542 (5)
F13—C12	1.324 (5)	C6—C11	1.539 (5)
F14—C12	1.329 (5)	C11—C12	1.559 (5)
F15—C12	1.325 (4)	C11—C13	1.578 (5)
F16—C13	1.316 (4)

C2—C1—C6	121.3 (3)	F8—C9—C4	110.2 (3)
C2—C1—C7	117.6 (3)	F6—C9—C4	111.7 (3)
C6—C1—C7	120.6 (3)	F7—C9—C4	112.4 (3)
C3—C2—C1	117.6 (3)	F11—C10—F9	108.6 (3)
C3—C2—C8	122.1 (3)	F11—C10—F10	107.7 (3)
C1—C2—C8	120.3 (3)	F9—C10—F10	105.3 (3)
F1—C3—C2	119.2 (3)	F11—C10—C5	115.3 (3)
F1—C3—C4	118.2 (3)	F9—C10—C5	110.2 (3)
C2—C3—C4	122.4 (3)	F10—C10—C5	109.3 (3)
C3—C4—C5	119.4 (3)	F12—C11—C6	109.0 (3)
C3—C4—C9	116.5 (3)	F12—C11—C12	99.6 (3)
C5—C4—C9	124.0 (3)	C6—C11—C12	113.3 (3)
C4—C5—C6	119.2 (3)	F12—C11—C13	106.6 (3)
C4—C5—C10	118.7 (3)	C6—C11—C13	113.7 (3)
C6—C5—C10	120.6 (3)	C12—C11—C13	113.4 (3)
C5—C6—C1	118.7 (3)	F13—C12—F15	107.9 (3)
C5—C6—C11	120.9 (3)	F13—C12—F14	108.1 (3)
C1—C6—C11	120.2 (3)	F15—C12—F14	108.2 (3)
N—C7—C1	174.4 (4)	F13—C12—C11	108.2 (3)
F2—C8—F3	108.0 (3)	F15—C12—C11	115.0 (3)
F2—C8—F4	106.1 (3)	F14—C12—C11	109.2 (3)
F3—C8—F4	107.4 (3)	F16—C13—F18	108.9 (3)
F2—C8—C2	112.9 (3)	F16—C13—F17	107.8 (3)
F3—C8—C2	111.5 (3)	F18—C13—F17	107.2 (3)
F4—C8—C2	110.7 (3)	F16—C13—C11	110.9 (3)
F8—C9—F6	106.0 (3)	F18—C13—C11	111.0 (3)
F8—C9—F7	107.8 (3)	F17—C13—C11	110.9 (3)
F6—C9—F7	108.6 (3)

C3—C2—C8—F2	−17.8 (5)	C5—C6—C11—F12	9.3 (4)
C3—C4—C9—F7	−79.9 (4)	F12—C11—C12—F14	−56.6 (4)
C4—C5—C10—F11	96.9 (4)	F12—C11—C13—F16	5.3 (4)

¹⁹F NMR spectrum of (I) top

δ (p.p.m.)	Intensity	Multiplicity	Coupling (Hz)	Assignement
-55.0	3	br m	–	C10F₃
-56.5	3	dq	⁴J_FF 28, ⁵J_FF 4	C9F₃
-57.2	3	d	⁴J_FF 28	C8F₃
-69.2	6	br s	–	C12F₃, C13F₃
-100.6	1	sept	⁴J_FF 28	F1
-163.5	1	q	³J_FF 54	F12

Acknowledgements

We thank EPSRC (Quota studentship to PR) for funding.

References

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