Halogen bonding stabilizes a cis-azobenzene derivative in the solid state: a crystallographic study

Crystals of trans- and cis-isomers of a fluorinated azobenzene derivative have been prepared and characterized by single-crystal X-ray diffraction. The presence of F atoms on the aromatic core of the azobenzene increases the lifetime of the metastable cis-isomer, allowing single crystals of the cis-azobenzene to be grown. Structural analysis on the cis-azobenzene, complemented with density functional theory calculations, highlights the active role of the halogen-bond contact (N...I synthon) in promoting the stabilization of the cis-isomer. The presence of a long aliphatic chain on the azobenzene unit induces a phase segregation that stabilizes the molecular arrangement for both the trans- and cis-isomers. Due to the rarity of cis-azobenzene crystal structures in the literature, our paper makes a step towards understanding the role of non-covalent interactions in driving the packing of metastable azobenzene isomers. This is expected to be important in the future rational design of solid-state, photoresponsive materials based on halogen bonding.

Computing details

For both compounds, data collection: Bruker APEX2; cell refinement: Bruker SAINT; data reduction: Bruker SAINT; program(s) used to solve structure: SHELXS (Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122). Program(s) used to refine structure: SHELXL97 (Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122) for ico231; SHELXL (Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122) for ico281_4. For both compounds, molecular graphics: ORTEP-3 (Farrugia, L.J. (1997) Jour. Appl. Cryst. 30, 565) Mercury (Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457. Software used to prepare material for publication: SHELXL97 for ico231; SHELXL for ico281_4.

(ico231)

Crystal data

C24H29F4IN2O	Z = 2
Mr = 564.39	F(000) = 568
Triclinic, P1	Dx = 1.587 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.4374 (9) Å	Cell parameters from 9935 reflections
b = 10.2935 (12) Å	θ = 2.6–34.9°
c = 16.536 (2) Å	µ = 1.41 mm^−1
α = 105.237 (10)°	T = 103 K
β = 101.641 (10)°	Flat Prism, orange
γ = 95.607 (12)°	0.40 × 0.25 × 0.05 mm
V = 1181.0 (2) Å^3

Data collection

Bruker APEX-II CCD diffractometer	10045 independent reflections
Radiation source: fine-focus sealed tube	8800 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
φ and ω scans	θmax = 35.7°, θmin = 2.1°
Absorption correction: multi-scan Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.	h = −12→12
Tmin = 0.553, Tmax = 0.706	k = −16→16
39236 measured reflections	l = −26→26

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.080	H-atom parameters not refined
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0425P)^2 + 0.3826P] where P = (Fo^2 + 2Fc^2)/3
10045 reflections	(Δ/σ)max = 0.001
290 parameters	Δρmax = 1.39 e Å^−3
0 restraints	Δρmin = −1.72 e Å^−3

Special details

Experimental. Bruker KRYOFLEX low temperature device.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
I1	−1.032228 (12)	0.233555 (10)	−0.130000 (6)	0.02364 (3)
F1	−0.38325 (13)	0.06570 (9)	−0.04237 (6)	0.02267 (17)
F2	−0.72409 (13)	0.03719 (9)	−0.13340 (6)	0.02432 (18)
F3	−0.78666 (13)	0.47590 (9)	0.02874 (6)	0.02363 (18)
F4	−0.44186 (13)	0.50605 (9)	0.12306 (6)	0.02269 (17)
O1	0.59484 (15)	0.36006 (11)	0.29865 (7)	0.0229 (2)
N1	−0.21713 (17)	0.32153 (13)	0.09942 (8)	0.0194 (2)
N2	−0.11712 (17)	0.22878 (13)	0.08737 (8)	0.0200 (2)
C1	−0.47714 (19)	0.16927 (14)	−0.02183 (9)	0.0174 (2)
C2	−0.6567 (2)	0.15381 (14)	−0.07001 (9)	0.0187 (2)
C3	−0.76610 (19)	0.25559 (15)	−0.05494 (9)	0.0185 (2)
C4	−0.6888 (2)	0.37353 (14)	0.01176 (9)	0.0183 (2)
C5	−0.50994 (19)	0.38927 (14)	0.06028 (9)	0.0176 (2)
C6	−0.39736 (19)	0.28853 (14)	0.04520 (9)	0.0168 (2)
C7	0.06324 (19)	0.26716 (14)	0.14248 (9)	0.0174 (2)
C8	0.1734 (2)	0.16420 (15)	0.13852 (10)	0.0200 (2)
H8	0.1252	0.0757	0.1000	0.024*
C9	0.3531 (2)	0.18983 (15)	0.19033 (9)	0.0192 (2)
H9	0.4270	0.1193	0.1882	0.023*
C10	0.4229 (2)	0.32103 (14)	0.24541 (9)	0.0185 (2)
C11	0.3134 (2)	0.42484 (15)	0.24785 (10)	0.0214 (3)
H11	0.3629	0.5142	0.2848	0.026*
C12	0.1352 (2)	0.39889 (15)	0.19741 (9)	0.0203 (2)
H12	0.0615	0.4696	0.1998	0.024*
C13	0.7167 (2)	0.26024 (15)	0.30047 (9)	0.0196 (2)
H13A	0.7363	0.2203	0.2421	0.023*
H13B	0.6624	0.1859	0.3202	0.023*
C14	0.8984 (2)	0.33278 (15)	0.36217 (10)	0.0202 (2)
H14A	0.8747	0.3772	0.4190	0.024*
H14B	0.9519	0.4051	0.3405	0.024*
C15	1.03874 (19)	0.23712 (15)	0.37353 (10)	0.0199 (2)
H15A	0.9854	0.1651	0.3955	0.024*
H15B	1.0617	0.1923	0.3166	0.024*
C16	1.22276 (19)	0.30984 (15)	0.43527 (10)	0.0199 (2)
H16A	1.1983	0.3587	0.4911	0.024*
H16B	1.2783	0.3789	0.4117	0.024*
C17	1.3630 (2)	0.21589 (15)	0.45142 (10)	0.0207 (3)
H17A	1.3862	0.1657	0.3956	0.025*
H17B	1.3091	0.1481	0.4763	0.025*
C18	1.5474 (2)	0.29147 (15)	0.51204 (10)	0.0213 (3)
H18A	1.5233	0.3451	0.5669	0.026*
H18B	1.6037	0.3564	0.4859	0.026*
C19	1.6860 (2)	0.19764 (15)	0.53182 (10)	0.0214 (3)
H19A	1.6290	0.1326	0.5577	0.026*
H19B	1.7095	0.1440	0.4769	0.026*
C20	1.8718 (2)	0.27090 (15)	0.59251 (10)	0.0206 (3)
H20A	1.9311	0.3350	0.5666	0.025*
H20B	1.8497	0.3249	0.6477	0.025*
C21	2.0034 (2)	0.17184 (15)	0.61045 (10)	0.0222 (3)
H21A	2.0183	0.1146	0.5546	0.027*
H21B	1.9449	0.1107	0.6384	0.027*
C22	2.1960 (2)	0.23800 (15)	0.66732 (10)	0.0200 (2)
H22A	2.2586	0.2963	0.6389	0.024*
H22B	2.1831	0.2969	0.7231	0.024*
C23	2.3148 (2)	0.13084 (16)	0.68374 (11)	0.0244 (3)
H23A	2.2495	0.0720	0.7110	0.029*
H23B	2.3263	0.0725	0.6275	0.029*
C24	2.5089 (2)	0.18819 (17)	0.74072 (11)	0.0266 (3)
H24A	2.5781	0.2418	0.7127	0.040*
H24B	2.5741	0.1130	0.7497	0.040*
H24C	2.4997	0.2467	0.7965	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.01525 (5)	0.02909 (6)	0.02601 (5)	0.00334 (3)	0.00098 (3)	0.01008 (4)
F1	0.0194 (4)	0.0195 (4)	0.0257 (4)	0.0069 (3)	0.0037 (3)	0.0007 (3)
F2	0.0218 (4)	0.0201 (4)	0.0237 (4)	0.0008 (3)	−0.0002 (3)	−0.0011 (3)
F3	0.0217 (4)	0.0216 (4)	0.0289 (5)	0.0098 (3)	0.0061 (4)	0.0071 (4)
F4	0.0242 (4)	0.0170 (4)	0.0224 (4)	0.0029 (3)	0.0028 (3)	0.0002 (3)
O1	0.0180 (5)	0.0201 (5)	0.0245 (5)	0.0046 (4)	−0.0033 (4)	0.0021 (4)
N1	0.0161 (5)	0.0216 (5)	0.0192 (5)	0.0037 (4)	0.0024 (4)	0.0046 (4)
N2	0.0161 (5)	0.0206 (5)	0.0222 (6)	0.0036 (4)	0.0016 (4)	0.0063 (4)
C1	0.0164 (5)	0.0167 (5)	0.0190 (6)	0.0044 (4)	0.0046 (4)	0.0042 (5)
C2	0.0170 (6)	0.0188 (6)	0.0178 (6)	0.0007 (4)	0.0024 (5)	0.0028 (5)
C3	0.0148 (5)	0.0213 (6)	0.0202 (6)	0.0035 (4)	0.0033 (4)	0.0079 (5)
C4	0.0168 (6)	0.0183 (5)	0.0210 (6)	0.0047 (4)	0.0051 (5)	0.0067 (5)
C5	0.0183 (6)	0.0163 (5)	0.0170 (6)	0.0024 (4)	0.0038 (4)	0.0034 (4)
C6	0.0152 (5)	0.0185 (5)	0.0169 (5)	0.0034 (4)	0.0034 (4)	0.0054 (5)
C7	0.0150 (5)	0.0188 (6)	0.0172 (6)	0.0028 (4)	0.0019 (4)	0.0048 (5)
C8	0.0179 (6)	0.0180 (6)	0.0214 (6)	0.0034 (4)	0.0013 (5)	0.0032 (5)
C9	0.0174 (6)	0.0185 (6)	0.0198 (6)	0.0046 (4)	0.0016 (5)	0.0038 (5)
C10	0.0171 (6)	0.0193 (6)	0.0172 (6)	0.0037 (4)	0.0015 (4)	0.0040 (5)
C11	0.0204 (6)	0.0186 (6)	0.0205 (6)	0.0046 (5)	−0.0005 (5)	0.0014 (5)
C12	0.0197 (6)	0.0198 (6)	0.0196 (6)	0.0059 (5)	0.0019 (5)	0.0037 (5)
C13	0.0155 (6)	0.0206 (6)	0.0204 (6)	0.0042 (4)	0.0006 (5)	0.0047 (5)
C14	0.0155 (6)	0.0216 (6)	0.0214 (6)	0.0025 (4)	0.0012 (5)	0.0050 (5)
C15	0.0125 (5)	0.0231 (6)	0.0209 (6)	0.0031 (4)	−0.0006 (4)	0.0045 (5)
C16	0.0148 (5)	0.0213 (6)	0.0221 (6)	0.0024 (4)	0.0027 (5)	0.0051 (5)
C17	0.0145 (5)	0.0223 (6)	0.0214 (6)	0.0014 (4)	0.0006 (5)	0.0031 (5)
C18	0.0136 (5)	0.0231 (6)	0.0228 (6)	0.0010 (4)	0.0009 (5)	0.0023 (5)
C19	0.0154 (6)	0.0217 (6)	0.0223 (6)	0.0022 (4)	0.0001 (5)	0.0020 (5)
C20	0.0149 (6)	0.0217 (6)	0.0220 (6)	0.0019 (4)	0.0017 (5)	0.0032 (5)
C21	0.0173 (6)	0.0211 (6)	0.0228 (6)	0.0023 (5)	−0.0014 (5)	0.0021 (5)
C22	0.0157 (6)	0.0212 (6)	0.0201 (6)	0.0013 (4)	0.0013 (5)	0.0039 (5)
C23	0.0188 (6)	0.0229 (6)	0.0260 (7)	0.0031 (5)	−0.0031 (5)	0.0044 (6)
C24	0.0195 (7)	0.0276 (7)	0.0287 (8)	0.0033 (5)	−0.0014 (6)	0.0069 (6)

Geometric parameters (Å, º)

I1—C3	2.0694 (14)	C14—H14B	0.9900
F1—C1	1.3380 (15)	C15—C16	1.520 (2)
F2—C2	1.3416 (16)	C15—H15A	0.9900
F3—C4	1.3398 (16)	C15—H15B	0.9900
F4—C5	1.3387 (16)	C16—C17	1.522 (2)
O1—C10	1.3533 (18)	C16—H16A	0.9900
O1—C13	1.4373 (18)	C16—H16B	0.9900
N1—N2	1.2661 (17)	C17—C18	1.522 (2)
N1—C6	1.4078 (19)	C17—H17A	0.9900
N2—C7	1.4141 (18)	C17—H17B	0.9900
C1—C2	1.381 (2)	C18—C19	1.526 (2)
C1—C6	1.4017 (19)	C18—H18A	0.9900
C2—C3	1.390 (2)	C18—H18B	0.9900
C3—C4	1.387 (2)	C19—C20	1.525 (2)
C4—C5	1.378 (2)	C19—H19A	0.9900
C5—C6	1.3987 (19)	C19—H19B	0.9900
C7—C8	1.3979 (19)	C20—C21	1.524 (2)
C7—C12	1.402 (2)	C20—H20A	0.9900
C8—C9	1.393 (2)	C20—H20B	0.9900
C8—H8	0.9500	C21—C22	1.526 (2)
C9—C10	1.396 (2)	C21—H21A	0.9900
C9—H9	0.9500	C21—H21B	0.9900
C10—C11	1.403 (2)	C22—C23	1.524 (2)
C11—C12	1.375 (2)	C22—H22A	0.9900
C11—H11	0.9500	C22—H22B	0.9900
C12—H12	0.9500	C23—C24	1.521 (2)
C13—C14	1.507 (2)	C23—H23A	0.9900
C13—H13A	0.9900	C23—H23B	0.9900
C13—H13B	0.9900	C24—H24A	0.9800
C14—C15	1.521 (2)	C24—H24B	0.9800
C14—H14A	0.9900	C24—H24C	0.9800
C10—O1—C13	118.62 (11)	H15A—C15—H15B	107.8
N2—N1—C6	115.12 (12)	C15—C16—C17	114.19 (12)
N1—N2—C7	113.08 (12)	C15—C16—H16A	108.7
F1—C1—C2	116.96 (12)	C17—C16—H16A	108.7
F1—C1—C6	121.80 (12)	C15—C16—H16B	108.7
C2—C1—C6	121.25 (12)	C17—C16—H16B	108.7
F2—C2—C1	118.10 (13)	H16A—C16—H16B	107.6
F2—C2—C3	120.09 (13)	C16—C17—C18	113.17 (12)
C1—C2—C3	121.80 (13)	C16—C17—H17A	108.9
C4—C3—C2	117.35 (13)	C18—C17—H17A	108.9
C4—C3—I1	121.22 (10)	C16—C17—H17B	108.9
C2—C3—I1	121.43 (11)	C18—C17—H17B	108.9
F3—C4—C5	118.79 (13)	H17A—C17—H17B	107.8
F3—C4—C3	120.11 (13)	C17—C18—C19	113.60 (12)
C5—C4—C3	121.08 (13)	C17—C18—H18A	108.8
F4—C5—C4	118.44 (12)	C19—C18—H18A	108.8
F4—C5—C6	119.31 (12)	C17—C18—H18B	108.8
C4—C5—C6	122.24 (13)	C19—C18—H18B	108.8
C5—C6—C1	116.27 (12)	H18A—C18—H18B	107.7
C5—C6—N1	115.16 (12)	C20—C19—C18	114.63 (12)
C1—C6—N1	128.56 (12)	C20—C19—H19A	108.6
C8—C7—C12	119.95 (13)	C18—C19—H19A	108.6
C8—C7—N2	115.66 (12)	C20—C19—H19B	108.6
C12—C7—N2	124.38 (13)	C18—C19—H19B	108.6
C9—C8—C7	120.77 (13)	H19A—C19—H19B	107.6
C9—C8—H8	119.6	C21—C20—C19	112.15 (12)
C7—C8—H8	119.6	C21—C20—H20A	109.2
C8—C9—C10	118.83 (13)	C19—C20—H20A	109.2
C8—C9—H9	120.6	C21—C20—H20B	109.2
C10—C9—H9	120.6	C19—C20—H20B	109.2
O1—C10—C9	124.98 (13)	H20A—C20—H20B	107.9
O1—C10—C11	114.78 (12)	C20—C21—C22	115.23 (12)
C9—C10—C11	120.24 (13)	C20—C21—H21A	108.5
C12—C11—C10	120.82 (13)	C22—C21—H21A	108.5
C12—C11—H11	119.6	C20—C21—H21B	108.5
C10—C11—H11	119.6	C22—C21—H21B	108.5
C11—C12—C7	119.37 (13)	H21A—C21—H21B	107.5
C11—C12—H12	120.3	C23—C22—C21	111.26 (12)
C7—C12—H12	120.3	C23—C22—H22A	109.4
O1—C13—C14	106.98 (11)	C21—C22—H22A	109.4
O1—C13—H13A	110.3	C23—C22—H22B	109.4
C14—C13—H13A	110.3	C21—C22—H22B	109.4
O1—C13—H13B	110.3	H22A—C22—H22B	108.0
C14—C13—H13B	110.3	C24—C23—C22	114.72 (13)
H13A—C13—H13B	108.6	C24—C23—H23A	108.6
C13—C14—C15	112.62 (12)	C22—C23—H23A	108.6
C13—C14—H14A	109.1	C24—C23—H23B	108.6
C15—C14—H14A	109.1	C22—C23—H23B	108.6
C13—C14—H14B	109.1	H23A—C23—H23B	107.6
C15—C14—H14B	109.1	C23—C24—H24A	109.5
H14A—C14—H14B	107.8	C23—C24—H24B	109.5
C16—C15—C14	112.88 (12)	H24A—C24—H24B	109.5
C16—C15—H15A	109.0	C23—C24—H24C	109.5
C14—C15—H15A	109.0	H24A—C24—H24C	109.5
C16—C15—H15B	109.0	H24B—C24—H24C	109.5
C14—C15—H15B	109.0
C6—N1—N2—C7	179.24 (12)	N2—N1—C6—C1	−2.6 (2)
F1—C1—C2—F2	0.0 (2)	N1—N2—C7—C8	173.55 (13)
C6—C1—C2—F2	179.77 (13)	N1—N2—C7—C12	−7.7 (2)
F1—C1—C2—C3	−179.22 (13)	C12—C7—C8—C9	1.7 (2)
C6—C1—C2—C3	0.5 (2)	N2—C7—C8—C9	−179.53 (14)
F2—C2—C3—C4	179.74 (13)	C7—C8—C9—C10	−1.1 (2)
C1—C2—C3—C4	−1.0 (2)	C13—O1—C10—C9	−0.7 (2)
F2—C2—C3—I1	−1.13 (19)	C13—O1—C10—C11	179.93 (13)
C1—C2—C3—I1	178.11 (11)	C8—C9—C10—O1	−179.60 (14)
C2—C3—C4—F3	179.21 (13)	C8—C9—C10—C11	−0.3 (2)
I1—C3—C4—F3	0.07 (19)	O1—C10—C11—C12	−179.53 (14)
C2—C3—C4—C5	0.7 (2)	C9—C10—C11—C12	1.1 (2)
I1—C3—C4—C5	−178.40 (11)	C10—C11—C12—C7	−0.5 (2)
F3—C4—C5—F4	0.6 (2)	C8—C7—C12—C11	−0.9 (2)
C3—C4—C5—F4	179.11 (13)	N2—C7—C12—C11	−179.55 (14)
F3—C4—C5—C6	−178.43 (13)	C10—O1—C13—C14	177.97 (13)
C3—C4—C5—C6	0.1 (2)	O1—C13—C14—C15	177.40 (12)
F4—C5—C6—C1	−179.62 (12)	C13—C14—C15—C16	179.64 (13)
C4—C5—C6—C1	−0.6 (2)	C14—C15—C16—C17	177.19 (13)
F4—C5—C6—N1	−0.16 (19)	C15—C16—C17—C18	178.86 (13)
C4—C5—C6—N1	178.88 (13)	C16—C17—C18—C19	177.46 (13)
F1—C1—C6—C5	−179.99 (13)	C17—C18—C19—C20	−179.94 (13)
C2—C1—C6—C5	0.3 (2)	C18—C19—C20—C21	179.44 (13)
F1—C1—C6—N1	0.6 (2)	C19—C20—C21—C22	177.18 (13)
C2—C1—C6—N1	−179.08 (14)	C20—C21—C22—C23	178.26 (14)
N2—N1—C6—C5	178.07 (13)	C21—C22—C23—C24	−179.46 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9···F1^i	0.95	2.59	3.1477 (17)	118

Symmetry code: (i) −x, −y, −z.

(ico281_4)

Crystal data

C24H29F4IN2O	F(000) = 1136
Mr = 564.39	Dx = 1.571 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 7540 reflections
a = 8.5802 (16) Å	θ = 2.6–26.9°
b = 33.663 (5) Å	µ = 1.39 mm^−1
c = 8.752 (2) Å	T = 103 K
β = 109.255 (16)°	Lamina, orange
V = 2386.5 (8) Å^3	0.20 × 0.10 × 0.05 mm
Z = 4

Data collection

Bruker APEX-II CCD diffractometer	5073 independent reflections
Radiation source: fine-focus sealed tube	3840 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.047
φ and ω scans	θmax = 27.5°, θmin = 2.4°
Absorption correction: multi-scan Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.	h = −11→10
Tmin = 0.791, Tmax = 0.862	k = −43→42
25224 measured reflections	l = −11→10

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.059	H-atom parameters not refined
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0132P)^2 + 3.0191P] where P = (Fo^2 + 2Fc^2)/3
5073 reflections	(Δ/σ)max = 0.004
290 parameters	Δρmax = 0.57 e Å^−3
0 restraints	Δρmin = −0.99 e Å^−3

Special details

Experimental. Crystals were orange thin plate, nearly always twinned. The champion used for data collection was an untwinned portion cut from a large twinned crystal. The experiment temperature was controlled by a Bruker KRYOFLEX low temperature device.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
I1	−0.33486 (3)	0.719707 (6)	0.50898 (2)	0.01803 (6)
C1	0.0686 (4)	0.69226 (9)	0.9478 (3)	0.0146 (7)
C2	−0.0729 (4)	0.69065 (9)	0.8160 (4)	0.0151 (7)
C3	−0.1316 (4)	0.72358 (9)	0.7209 (3)	0.0152 (6)
C4	−0.0458 (4)	0.75871 (9)	0.7667 (4)	0.0167 (7)
C5	0.0956 (4)	0.76055 (9)	0.8995 (4)	0.0162 (7)
C6	0.1587 (4)	0.72706 (8)	0.9900 (3)	0.0143 (6)
F1	0.1189 (2)	0.65949 (5)	1.0380 (2)	0.0204 (4)
F2	−0.1538 (2)	0.65581 (5)	0.7814 (2)	0.0217 (4)
F3	−0.0999 (2)	0.79237 (5)	0.6820 (2)	0.0221 (4)
F4	0.1772 (2)	0.79515 (5)	0.9384 (2)	0.0225 (4)
N1	0.2931 (3)	0.73196 (7)	1.1398 (3)	0.0166 (6)
N2	0.4156 (3)	0.70914 (7)	1.1791 (3)	0.0167 (6)
C7	0.4508 (4)	0.67991 (9)	1.0768 (3)	0.0149 (7)
C8	0.5412 (4)	0.64763 (9)	1.1593 (4)	0.0170 (7)
H8	0.5695	0.6461	1.2736	0.020*
C9	0.5899 (4)	0.61800 (9)	1.0770 (4)	0.0182 (7)
H9	0.6482	0.5956	1.1341	0.022*
C10	0.5542 (4)	0.62068 (9)	0.9107 (4)	0.0168 (7)
C11	0.4685 (4)	0.65333 (9)	0.8273 (4)	0.0162 (7)
H11	0.4451	0.6554	0.7137	0.019*
C12	0.4169 (4)	0.68300 (9)	0.9102 (3)	0.0152 (7)
H12	0.3585	0.7054	0.8533	0.018*
O1	0.6138 (3)	0.59014 (6)	0.8444 (2)	0.0206 (5)
C13	0.5739 (4)	0.58791 (9)	0.6719 (4)	0.0188 (7)
H13A	0.6000	0.6133	0.6290	0.023*
H13B	0.4549	0.5822	0.6197	0.023*
C14	0.6770 (4)	0.55465 (9)	0.6391 (4)	0.0190 (7)
H14A	0.6637	0.5307	0.6991	0.023*
H14B	0.7948	0.5624	0.6802	0.023*
C15	0.6298 (4)	0.54457 (9)	0.4600 (4)	0.0181 (7)
H15A	0.5173	0.5331	0.4228	0.022*
H15B	0.6271	0.5694	0.3982	0.022*
C16	0.7479 (4)	0.51547 (9)	0.4231 (4)	0.0200 (7)
H16A	0.7582	0.4917	0.4925	0.024*
H16B	0.8583	0.5280	0.4520	0.024*
C17	0.6956 (4)	0.50221 (9)	0.2471 (4)	0.0199 (7)
H17A	0.5931	0.4864	0.2225	0.024*
H17B	0.6703	0.5260	0.1768	0.024*
C18	0.8253 (4)	0.47760 (9)	0.2061 (4)	0.0195 (7)
H18A	0.9278	0.4934	0.2298	0.023*
H18B	0.8511	0.4538	0.2763	0.023*
C19	0.7702 (4)	0.46457 (9)	0.0302 (4)	0.0190 (7)
H19A	0.7359	0.4883	−0.0394	0.023*
H19B	0.6723	0.4472	0.0092	0.023*
C20	0.9012 (4)	0.44251 (9)	−0.0185 (4)	0.0187 (7)
H20A	0.9970	0.4603	−0.0038	0.022*
H20B	0.9395	0.4193	0.0536	0.022*
C21	0.8373 (4)	0.42840 (9)	−0.1932 (4)	0.0185 (7)
H21A	0.7895	0.4514	−0.2634	0.022*
H21B	0.7471	0.4091	−0.2046	0.022*
C22	0.9665 (4)	0.40908 (9)	−0.2537 (4)	0.0194 (7)
H22A	1.0522	0.4289	−0.2519	0.023*
H22B	1.0206	0.3872	−0.1797	0.023*
C23	0.8925 (4)	0.39274 (10)	−0.4243 (4)	0.0215 (7)
H23A	0.8372	0.4147	−0.4976	0.026*
H23B	0.8072	0.3728	−0.4254	0.026*
C24	1.0181 (5)	0.37354 (10)	−0.4895 (4)	0.0291 (8)
H24A	1.0753	0.3521	−0.4167	0.044*
H24B	1.0987	0.3935	−0.4965	0.044*
H24C	0.9615	0.3626	−0.5974	0.044*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.01436 (10)	0.02283 (11)	0.01573 (10)	0.00240 (11)	0.00336 (7)	−0.00071 (10)
C1	0.0150 (17)	0.0163 (17)	0.0141 (15)	0.0046 (14)	0.0069 (13)	0.0024 (13)
C2	0.0165 (17)	0.0133 (17)	0.0186 (16)	−0.0038 (14)	0.0099 (14)	−0.0038 (13)
C3	0.0128 (15)	0.0209 (17)	0.0127 (14)	0.0018 (15)	0.0052 (12)	−0.0016 (13)
C4	0.0207 (18)	0.0151 (17)	0.0168 (16)	0.0046 (15)	0.0095 (14)	0.0046 (13)
C5	0.0199 (18)	0.0115 (16)	0.0199 (16)	−0.0011 (15)	0.0102 (14)	−0.0022 (13)
C6	0.0135 (15)	0.0155 (17)	0.0153 (15)	0.0005 (14)	0.0067 (12)	−0.0055 (12)
F1	0.0216 (10)	0.0151 (9)	0.0224 (10)	0.0002 (8)	0.0044 (8)	0.0053 (7)
F2	0.0196 (10)	0.0185 (10)	0.0247 (10)	−0.0052 (8)	0.0041 (8)	−0.0011 (8)
F3	0.0256 (11)	0.0166 (10)	0.0231 (10)	0.0046 (8)	0.0067 (8)	0.0054 (7)
F4	0.0242 (11)	0.0129 (9)	0.0275 (10)	−0.0030 (8)	0.0047 (8)	−0.0020 (8)
N1	0.0155 (15)	0.0174 (15)	0.0150 (13)	−0.0017 (11)	0.0025 (11)	−0.0028 (10)
N2	0.0169 (15)	0.0153 (15)	0.0174 (13)	0.0008 (11)	0.0048 (11)	−0.0015 (10)
C7	0.0124 (16)	0.0164 (16)	0.0157 (15)	−0.0029 (14)	0.0044 (13)	−0.0017 (13)
C8	0.0169 (18)	0.0208 (18)	0.0123 (15)	−0.0003 (14)	0.0033 (13)	−0.0011 (13)
C9	0.0163 (18)	0.0193 (17)	0.0170 (16)	0.0011 (14)	0.0028 (13)	0.0032 (13)
C10	0.0147 (17)	0.0169 (17)	0.0197 (16)	−0.0022 (14)	0.0070 (13)	−0.0016 (13)
C11	0.0156 (17)	0.0204 (18)	0.0128 (15)	0.0008 (14)	0.0051 (13)	0.0015 (13)
C12	0.0118 (16)	0.0151 (16)	0.0175 (16)	−0.0006 (13)	0.0031 (13)	0.0028 (13)
O1	0.0285 (13)	0.0184 (12)	0.0168 (11)	0.0063 (10)	0.0101 (10)	−0.0010 (9)
C13	0.0175 (18)	0.0215 (18)	0.0179 (17)	−0.0026 (15)	0.0062 (14)	−0.0021 (13)
C14	0.0223 (19)	0.0178 (17)	0.0186 (17)	0.0028 (15)	0.0090 (14)	0.0014 (13)
C15	0.0170 (18)	0.0163 (17)	0.0204 (17)	0.0001 (14)	0.0053 (14)	−0.0019 (13)
C16	0.0221 (19)	0.0192 (18)	0.0204 (17)	0.0030 (15)	0.0092 (14)	0.0006 (13)
C17	0.0207 (18)	0.0203 (18)	0.0201 (17)	−0.0007 (15)	0.0085 (14)	−0.0014 (13)
C18	0.0254 (19)	0.0153 (17)	0.0183 (16)	0.0041 (15)	0.0081 (14)	0.0013 (13)
C19	0.0209 (19)	0.0168 (17)	0.0196 (17)	0.0012 (15)	0.0070 (14)	−0.0016 (13)
C20	0.0204 (18)	0.0172 (17)	0.0180 (16)	−0.0012 (15)	0.0057 (14)	−0.0016 (13)
C21	0.0205 (18)	0.0177 (17)	0.0180 (16)	0.0019 (14)	0.0073 (14)	0.0014 (13)
C22	0.0193 (19)	0.0180 (17)	0.0209 (17)	−0.0015 (15)	0.0067 (14)	0.0024 (13)
C23	0.0230 (19)	0.0200 (18)	0.0227 (18)	0.0015 (15)	0.0093 (15)	−0.0011 (14)
C24	0.033 (2)	0.027 (2)	0.033 (2)	−0.0037 (17)	0.0190 (17)	−0.0067 (16)

Geometric parameters (Å, º)

I1—C3	2.090 (3)	C14—H14B	0.9900
C1—F1	1.343 (3)	C15—C16	1.519 (4)
C1—C2	1.372 (4)	C15—H15A	0.9900
C1—C6	1.385 (4)	C15—H15B	0.9900
C2—F2	1.345 (3)	C16—C17	1.523 (4)
C2—C3	1.378 (4)	C16—H16A	0.9900
C3—C4	1.380 (4)	C16—H16B	0.9900
C4—F3	1.350 (3)	C17—C18	1.522 (4)
C4—C5	1.378 (4)	C17—H17A	0.9900
C5—F4	1.344 (3)	C17—H17B	0.9900
C5—C6	1.381 (4)	C18—C19	1.519 (4)
C6—N1	1.442 (4)	C18—H18A	0.9900
N1—N2	1.255 (3)	C18—H18B	0.9900
N2—C7	1.429 (4)	C19—C20	1.520 (4)
C7—C8	1.391 (4)	C19—H19A	0.9900
C7—C12	1.393 (4)	C19—H19B	0.9900
C8—C9	1.374 (4)	C20—C21	1.520 (4)
C8—H8	0.9500	C20—H20A	0.9900
C9—C10	1.388 (4)	C20—H20B	0.9900
C9—H9	0.9500	C21—C22	1.524 (4)
C10—O1	1.360 (4)	C21—H21A	0.9900
C10—C11	1.389 (4)	C21—H21B	0.9900
C11—C12	1.390 (4)	C22—C23	1.520 (4)
C11—H11	0.9500	C22—H22A	0.9900
C12—H12	0.9500	C22—H22B	0.9900
O1—C13	1.435 (3)	C23—C24	1.520 (4)
C13—C14	1.512 (4)	C23—H23A	0.9900
C13—H13A	0.9900	C23—H23B	0.9900
C13—H13B	0.9900	C24—H24A	0.9800
C14—C15	1.522 (4)	C24—H24B	0.9800
C14—H14A	0.9900	C24—H24C	0.9800
F1—C1—C2	119.1 (3)	H15A—C15—H15B	107.8
F1—C1—C6	119.7 (3)	C15—C16—C17	114.2 (3)
C2—C1—C6	121.3 (3)	C15—C16—H16A	108.7
F2—C2—C1	118.1 (3)	C17—C16—H16A	108.7
F2—C2—C3	120.5 (3)	C15—C16—H16B	108.7
C1—C2—C3	121.4 (3)	C17—C16—H16B	108.7
C2—C3—C4	117.4 (3)	H16A—C16—H16B	107.6
C2—C3—I1	121.2 (2)	C18—C17—C16	113.8 (3)
C4—C3—I1	121.3 (2)	C18—C17—H17A	108.8
F3—C4—C5	118.3 (3)	C16—C17—H17A	108.8
F3—C4—C3	120.4 (3)	C18—C17—H17B	108.8
C5—C4—C3	121.3 (3)	C16—C17—H17B	108.8
F4—C5—C4	119.5 (3)	H17A—C17—H17B	107.7
F4—C5—C6	119.3 (3)	C19—C18—C17	112.9 (3)
C4—C5—C6	121.1 (3)	C19—C18—H18A	109.0
C5—C6—C1	117.3 (3)	C17—C18—H18A	109.0
C5—C6—N1	118.2 (3)	C19—C18—H18B	109.0
C1—C6—N1	123.2 (3)	C17—C18—H18B	109.0
N2—N1—C6	121.7 (2)	H18A—C18—H18B	107.8
N1—N2—C7	125.5 (2)	C18—C19—C20	114.4 (3)
C8—C7—C12	119.4 (3)	C18—C19—H19A	108.7
C8—C7—N2	114.2 (3)	C20—C19—H19A	108.7
C12—C7—N2	126.2 (3)	C18—C19—H19B	108.7
C9—C8—C7	120.6 (3)	C20—C19—H19B	108.7
C9—C8—H8	119.7	H19A—C19—H19B	107.6
C7—C8—H8	119.7	C21—C20—C19	112.3 (3)
C8—C9—C10	120.2 (3)	C21—C20—H20A	109.1
C8—C9—H9	119.9	C19—C20—H20A	109.1
C10—C9—H9	119.9	C21—C20—H20B	109.1
O1—C10—C9	114.5 (3)	C19—C20—H20B	109.1
O1—C10—C11	125.6 (3)	H20A—C20—H20B	107.9
C9—C10—C11	119.8 (3)	C20—C21—C22	114.9 (3)
C10—C11—C12	120.0 (3)	C20—C21—H21A	108.5
C10—C11—H11	120.0	C22—C21—H21A	108.5
C12—C11—H11	120.0	C20—C21—H21B	108.5
C11—C12—C7	120.0 (3)	C22—C21—H21B	108.5
C11—C12—H12	120.0	H21A—C21—H21B	107.5
C7—C12—H12	120.0	C23—C22—C21	112.3 (3)
C10—O1—C13	119.7 (2)	C23—C22—H22A	109.1
O1—C13—C14	106.7 (2)	C21—C22—H22A	109.1
O1—C13—H13A	110.4	C23—C22—H22B	109.1
C14—C13—H13A	110.4	C21—C22—H22B	109.1
O1—C13—H13B	110.4	H22A—C22—H22B	107.9
C14—C13—H13B	110.4	C22—C23—C24	113.9 (3)
H13A—C13—H13B	108.6	C22—C23—H23A	108.8
C13—C14—C15	112.8 (3)	C24—C23—H23A	108.8
C13—C14—H14A	109.0	C22—C23—H23B	108.8
C15—C14—H14A	109.0	C24—C23—H23B	108.8
C13—C14—H14B	109.0	H23A—C23—H23B	107.7
C15—C14—H14B	109.0	C23—C24—H24A	109.5
H14A—C14—H14B	107.8	C23—C24—H24B	109.5
C16—C15—C14	113.1 (2)	H24A—C24—H24B	109.5
C16—C15—H15A	109.0	C23—C24—H24C	109.5
C14—C15—H15A	109.0	H24A—C24—H24C	109.5
C16—C15—H15B	109.0	H24B—C24—H24C	109.5
C14—C15—H15B	109.0
F1—C1—C2—F2	−1.1 (4)	C6—N1—N2—C7	9.3 (4)
C6—C1—C2—F2	179.6 (3)	N1—N2—C7—C8	−152.1 (3)
F1—C1—C2—C3	178.9 (3)	N1—N2—C7—C12	34.3 (5)
C6—C1—C2—C3	−0.3 (5)	C12—C7—C8—C9	−3.2 (5)
F2—C2—C3—C4	177.7 (3)	N2—C7—C8—C9	−177.3 (3)
C1—C2—C3—C4	−2.3 (4)	C7—C8—C9—C10	2.3 (5)
F2—C2—C3—I1	−5.5 (4)	C8—C9—C10—O1	177.9 (3)
C1—C2—C3—I1	174.5 (2)	C8—C9—C10—C11	−0.3 (5)
C2—C3—C4—F3	−177.7 (3)	O1—C10—C11—C12	−178.7 (3)
I1—C3—C4—F3	5.5 (4)	C9—C10—C11—C12	−0.8 (5)
C2—C3—C4—C5	1.8 (4)	C10—C11—C12—C7	−0.2 (5)
I1—C3—C4—C5	−174.9 (2)	C8—C7—C12—C11	2.2 (4)
F3—C4—C5—F4	−1.6 (4)	N2—C7—C12—C11	175.5 (3)
C3—C4—C5—F4	178.8 (3)	C9—C10—O1—C13	175.1 (3)
F3—C4—C5—C6	−179.1 (3)	C11—C10—O1—C13	−6.9 (5)
C3—C4—C5—C6	1.3 (5)	C10—O1—C13—C14	172.0 (3)
F4—C5—C6—C1	178.6 (3)	O1—C13—C14—C15	171.5 (3)
C4—C5—C6—C1	−3.9 (5)	C13—C14—C15—C16	171.8 (3)
F4—C5—C6—N1	11.0 (4)	C14—C15—C16—C17	175.1 (3)
C4—C5—C6—N1	−171.5 (3)	C15—C16—C17—C18	172.1 (3)
F1—C1—C6—C5	−175.8 (3)	C16—C17—C18—C19	179.8 (3)
C2—C1—C6—C5	3.4 (5)	C17—C18—C19—C20	175.7 (3)
F1—C1—C6—N1	−8.9 (4)	C18—C19—C20—C21	177.2 (3)
C2—C1—C6—N1	170.4 (3)	C19—C20—C21—C22	175.2 (3)
C5—C6—N1—N2	−136.4 (3)	C20—C21—C22—C23	175.5 (3)
C1—C6—N1—N2	56.8 (4)	C21—C22—C23—C24	179.5 (3)