Di­chloro­[(η⁵-cyclo­penta­dien­yl)dimeth­yl(η⁵-3-phenyl­inden­yl)silane]hafnium(IV): a powder study

The title compound, [Hf(C₂₂H₂₀Si)Cl₂], was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature. The mol­ecular structure comprises a hafnium dichloride centre, coordinated by a η⁵-cyclo­penta­dienyl and a η⁵-3-phenyl­indenyl unit, which are connected through a shared dimethyl­silicon linkage.

Comment

For approximately two decades, there has been substantial inter­est in group 4 metallocenes, driven by their ability, in combination with methyl­alumoxane, to catalyse the isotactic polymerization of propyl­ene [for a recent review see Resconi et al. (2000)] and ethyl­ene [for reviews see Alt & Köppl (2000) and Möhring & Coville (2006)]. For ansa-bridged indenyl-derived mol­ecules, the stereoselectivity and regioselectivity of the propyl­ene monomer are strongly influenced by substitution at the indenyl ring system. Characterization of these mol­ecules through crystallography is clearly desirable in order to elucidate fully the relationship between the structure of the catalyst and both the stereoregularity and the mol­ecular weight of the polymer it produces. For many of these compounds, growth of single crystals suitable for diffraction analysis can be difficult or impossible. Here we employed laboratory X-ray powder diffraction to solve and refine the crystal structure of an Hf-containing cyclo­penta­dien­yl–indenyl catalyst, (I), in which the ligand presents heterotopic faces to the active Hf site.

The Hf ion in (I) is linked to two Cl ions at distances of 2.305 (3) and 2.303 (3) Å (this distance was restrained in the Rietveld refinement to be 2.3 Å) (Fig. 1). The coordination of Hf is completed by an η⁵-cyclo­penta­dienyl and an η⁵-phenyl­indenyl unit, which are connected through a dimethyl­silicon linkage at an angle φ of 100.3 (1)° through the Si atom, which can be compared with 94.6 (1)° in the bis­indenyl zirconocene analogue. The Si atom is bonded to the indenyl unit in the 1-position. The distances between the Hf and the cyclo­penta­dienyl centroid are 2.26 (3) Å for the indenyl residue and 2.170 (3) Å for the cyclo­penta­dienyl; these distances were not constrained at the refinement stage. The indenyl and cyclo­penta­dienyl rings are tilted at an angle β of 55 (2)° with respect to each other, which can be compared with an angle of 61.8° in the bis-indenyl zirconocene analogue (Dang et al., 1999). The angles δ (hafnium–cyclo­penta­dienyl centroid–carbon α to silicon) are 92.4 (2) and 87.3 (2)° for the cyclo­penta­dienyl and indenyl rings, respectively. The phenyl residue is twisted out of plane with respect to the indenyl residue by a torsion angle of 24.1 (2)°.

The mol­ecules pack so that the indenyl rings on neighbouring mol­ecules are parallel and in contact (Fig. 2). Excluding H⋯H contacts, two short contacts (less than the sum of the van der Waals radii) exist. Between the indenyl ring systems, the C7⋯C10 distance of 3.37 (3) Å is only slightly shorter than the value of 3.4 Å derived from the sum of the carbon van der Waals radii (Bondi, 1964). There also exists a contact C5⋯C21 of 3.35 (3) Å between the cyclo­penta­dienyl residue and a phenyl ring on a neighbouring mol­ecule. Both of these contacts are only marginally shorter than expected and it is not clear that they indicate the presence of any strong directional inter­actions between mol­ecules or that the crystal structure adopted can be rationally based on the close packing of mol­ecules.

Figure 1 The asymmetric unit of (I), showing the atom-labelling scheme. Displacement ellipsoids are shown at the 50% probability level. H atoms are not shown for clarity. Hf green, Cl yellow, Si blue and C grey.

Figure 2 Crystal packing in (I), viewed parallel to the a axis. Hf green, Cl yellow, Si blue and C grey. H atoms have been omitted.

Figure 3 Final observed (points), calculated (line), difference [(yobs − ycalc)] and weighted difference [(yobs − ycalc)/σ] profiles for the Rietveld refinement of (I).

Experimental

All manipulations were performed under argon using conventional Schlenk techniques. Solvents were dried and distilled under argon prior to use. 1-Phenyl­indenyl lithium, cyclo­penta­dienyl lithium and hafnium tetra­chloride (zirconium content < 0.5%) are commercial products from https://www.mcat.de.

(Cyclo­penta­dien­yl)(3-phenyl­inden-1-yl)dimethyl­silane: To a solution of dichloro­dimethyl­silane (6.80 g, 6.4 ml, 52.68 mmol) in 200 ml of diethyl ether, 1-phenyl­indenyl lithium (3.48 g, 17.56 mmol) was added at 195 K. The mixture was slowly warmed to ambient temperature and stirred for 1 h. The solvent was removed under vacuum and the oily residue extracted with pentane. The combined extracts were filtered through celite, the solvent removed and the residual oil dried under high vacuum to obtain 17.51 mmol (99.7%) of crude product as a red oil. The crude product was used without further purification in the next step. The red oil was dissolved in toluene (30 ml) and cyclo­penta­dienyl lithium (1.32 g) was added. After 2 d the reaction was complete (determined by ¹H NMR). Water and saturated NH₄Cl were added and the mixture extracted several times with diethyl ether. The combined organic fractions were dried over Na₂SO₄ and the solvent was removed under vacuum. (Cyclo­penta­dien­yl)(3-phenyl­inden-1-yl)dimethyl­silane was obtained as a yellow oil as a mixture of isomers which was used directly in the next step.

(η⁵-Cyclo­penta­dien­yl)(η⁵-3-phenyl­inden­yl)dimethyl­silane­hafnium(IV) dichloride: To a solution of (cyclo­penta­dien­yl)(3-phenyl­inden-1-yl)­dimethyl­silane (4.91 g, 15.61 mmol) in 150 ml of diethyl ether, 2.5 M n-butyl ­lithium (12.5 ml, 31.25 mmol) in hexane was added at 195 K. The mixture was slowly warmed to ambient temperature and stirred overnight. The dark-yellow mixture was then cooled to 195 K and HfCl₄ (5.00 g, 31.25 mmol) was added over a period of 1 h. The mixture was then warmed to ambient temperature and stirred for 1 h. The solvent was removed and the oily residue extracted twice with dichloro­methane. The combined extracts were filtered through celite, the solvent removed and the residual oil dried under high vacuum to obtain 14.62 mmol (93.7%) of crude product. Analytically pure product was obtained by recrystallization from toluene/hexane (1:2).

Crystal data

• [Hf(C₂₂H₂₀Si)Cl₂]

• M_r = 561.88

• Triclinic,

• a = 10.1894 (4) Å

• b = 11.0993 (4) Å

• c = 9.6940 (4) Å

• α = 91.974 (2)°

• β = 108.693 (2)°

• γ = 80.501 (3)°

• V = 1024.07 (7) ų

• Z = 2

• D_x = 1.822 Mg m⁻³

• Co Kα radiation

• T = 293 K

• Specimen shape: cylinder

• 0.7 × 0.1 mm

• Particle morphology: finely ground powder, yellow

Data collection

• Stoe Stadi-P diffractometer

• Specimen mounting: 0.3 mm Lindemann glass capillary

• Specimen mounted in transmission mode

• Scan method: step

• 2θ_min = 2.0, 2θ_max = 60.0°

• Increment in 2θ = 0.01°

Refinement

• R_p = 0.046

• R_wp = 0.059

• R_exp = 0.059

• R_B = 0.068

• S = 1.04

• Wavelength of incident radiation: 1.78892 Å

• Excluded region(s): none

• The GSAS profile function number 3 was employed, which utilizes a pseudo-Voigt description of the peak shape which allows for angle-dependent asymmetry. The function is fully documented in the GSAS technical manual which is distributed with the software package. Peak tails were ignored when the intensity was 0.1 % of the overall peak. Refined parameters were GV (3.996), LX (3.016) and LY (16.261), with S/L and H/L set fixed at 0.013 and 0.035, which are generally suitable values for the diffractometer in question.

• 169 parameters

• All H-atom parameters refined subject to stereochemical restraints

• (Δ/σ)_max = 0.03

• Preferred orientation correction: March–Dollase AXIS 1 Ratio = 1.08679, h = 0.000, k = 0.000, l= 1.000. Prefered orientation correction range: Min = 0.77904, Max = 1.13297

A powder diffraction pattern was collected using a monochromated Stoe Stadi-P instrument operating in Debye–Scherrer geometry with the sample contained in a 0.3 mm Lindemann glass capillary which was spun during the measurement to minimize preferred orientation effects. The pattern was indexed using TREOR (Werner et al., 1985), employing 18 low-angle reflections. A triclinic unit cell of reasonable volume (assuming Z = 2) gave indexing figures of merit M₁₈=84, F₁₈=178. The crystal structure was solved using the simulated annealing algorithms as implemented in both PSSP (Stephens & Huq, 2002) and DASH (David et al., 2006). The crystal structure was assumed to be centrosymmetric (space group P, Z′= 1), and this approach led to a chemically reasonable starting model for Rietveld refinement. For the refinement, suitable restraints were imposed on bond lengths, angles and planar groups, including bonds to H atoms. The CH and CH₃ distances were constrained to be 0.93 and 0.96 Å, respectively. Three independent atomic displacement parameters were employed: one for the Hf, one for the two Cl atoms, one for all C and Si, and one for the H atoms which was was set equal to 1.2 times that for the C and Si atoms. Trials were made employing preferred orientation in directions suggested by a basic BFDH calculation of likely crystal morphology, which indicated that a small degree of preferred orientation existed in the sample [refined ratio=1.09 (4)], with plate-like crystallites being preferentially oriented normal to the diffraction plane. Given the air-sensitive nature of the sample, we did not try to confirm this through visual microscopy. The refinement, using the GSAS software suite (Larson & Von Dreele, 2000), converged readily to yield acceptable figures of merit of χ² = 1.08, R_wp = 0.059, R_p = 0.046, DWd = 1.43 and R_Bragg = 0.068, and a visually acceptable fit (Fig. 3). Standard deviations are taken from the program employed and represent statistical uncertainties rather than estimates of the absolute error, which are likely to be considerably greater.

Data collection: WinXpow (Stoe & Cie, 1999); data reduction: WinXpow; program(s) used to solve structure: DASH (David et al., 2006) and PSSP (Stephens & Huq, 2002); program(s) used to refine structure: GSAS (Larson & Von Dreele, 2000); molecular graphics: PLATON (Spek, 2003).

Supporting information

Computing details

Data collection: Stoe software; data reduction: Stoe software; program(s) used to solve structure: please supply; program(s) used to refine structure: GSAS; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: please supply.

Dichloro[(η⁵-cyclopentadienyl)dimethyl(η⁵-3- phenylindenyl)silane]hafnium(IV)

Crystal data

[Hf(C22H20Si)Cl2]	γ = 80.501 (3)°
Mr = 561.88	V = 1024.07 (7) Å^3
Triclinic, P1	Z = 2
Hall symbol: -P 1	F(000) = 544
a = 10.1894 (4) Å	Dx = 1.822 Mg m^−3
b = 11.0993 (4) Å	Co Kα radiation, λ = 1.78892 Å
c = 9.6940 (4) Å	T = 293 K
α = 91.974 (2)°	yellow
β = 108.693 (2)°	cylinder, 0.7 mm × 0.1 mm mm

Data collection

Stoe Stadi-P diffractometer	Data collection mode: transmission
Primary focussing, Ge 111 monochromator	Scan method: step
Specimen mounting: 0.3 mm Lindemann glass capillary	2θmin = 2.0°, 2θmax = 60.0°, 2θstep = 0.01°

Refinement

Least-squares matrix: full	169 parameters
Rp = 0.046	166 restraints
Rwp = 0.059	All H-atom parameters refined
Rexp = 0.059	(Δ/σ)max = 0.03
R(F^2) = 0.068	Background function: GSAS Background function number 1 with 10 terms. Shifted Chebyshev function of 1st kind 1: 248.915 2: -209.686 3: 57.0023 4: -4.01480 5: 6.91473 6: -5.10485 7: -2.21704 8: 2.85278 9: 1.09751 10: -3.29532
Excluded region(s): none	Preferred orientation correction: March-Dollase AXIS 1 Ratio= 1.08679 h= 0.000 k= 0.000 l= 1.000 Prefered orientation correction range: Min= 0.77904, Max= 1.13297
Profile function: The GSAS profile function number 3 was employed, which utilises a pseudo-Voigt description of the peak shape which allows for angle-dependent asymmetry. The function is fully documented in the GSAS technical manual which is distributed with the software package. Peak tails were ignored when the intensity was 0.1 % of the overall peak. Refined parameters were GV (3.996), LX (3.016) and LY (16.261), with S/L and H/L set fixed at 0.013 and 0.035, which are generally suitable values for the diffractometer in question.

Special details

Experimental. The nuclear magnetic resonance spectra were recorded on a Jeol 400 MHz s pectrometer.

1H-NMR (400 MHz, CDCl3. 20°C): d 7.92 (d, 1H), 7.60 (d, 2H), 7.13–7.50 (m, 5H), 6.70 (dd, 2H), 6.16 (s, 1H), 5.94 (dd, 1H), 5.81 (dd, 1H), 1.09 (s, 3H), 0.85 (s, 3H). 13 C-NMR (400 MHz, CDCl3. 20°C): d 134.3 (C), 133.8 (C), 129.3 (Cp), 128.6 (Cp), 127.7 (CH), 127.6 (CH), 125.9 (CH), 124.6 (CH), 124.5 (CH), 123.1 (C) 121.9 (CH), 117.9 (C), 114.7 (CH), 107.7 (CH), 106.6 (C), 89.1 (C) -1.7 (CH3), -4.9 (CH3).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
HF1	−0.0022 (5)	0.2027 (3)	0.2495 (6)	0.175 (3)*
CL1	0.1623 (16)	0.2207 (14)	0.138 (2)	0.147 (7)*
CL2	0.1050 (15)	0.0123 (8)	0.3496 (17)	0.147 (7)*
SI1	−0.2918 (15)	0.3441 (12)	0.3001 (14)	0.135 (6)*
C1	−0.2674 (15)	0.2374 (11)	0.1562 (14)	0.135 (6)*
C2	−0.212 (2)	0.2703 (18)	0.0509 (18)	0.135 (6)*
C3	−0.1502 (18)	0.163 (2)	0.001 (2)	0.135 (6)*
C4	−0.156 (3)	0.0651 (17)	0.085 (3)	0.135 (6)*
C5	−0.222 (2)	0.1122 (11)	0.186 (2)	0.135 (6)*
C8	−0.1065 (11)	0.359 (2)	0.399 (2)	0.135 (6)*
C9	−0.0161 (13)	0.4173 (17)	0.339 (2)	0.135 (6)*
C10	−0.0535 (19)	0.5118 (19)	0.228 (2)	0.135 (6)*
C11	0.050 (2)	0.5542 (17)	0.191 (2)	0.135 (6)*
C12	0.194 (2)	0.5091 (17)	0.266 (2)	0.135 (6)*
C13	0.2309 (16)	0.4164 (18)	0.367 (2)	0.135 (6)*
C14	0.1272 (12)	0.3631 (16)	0.398 (2)	0.135 (6)*
C6	0.1334 (13)	0.2745 (13)	0.5056 (18)	0.135 (6)*
C7	−0.0019 (15)	0.2754 (14)	0.5121 (17)	0.135 (6)*
C15	−0.369 (2)	0.269 (2)	0.417 (2)	0.135 (6)*
C16	−0.393 (2)	0.4926 (16)	0.214 (2)	0.135 (6)*
C20	0.507 (2)	0.087 (2)	0.818 (2)	0.135 (6)*
C21	0.389 (2)	0.130 (2)	0.859 (2)	0.135 (6)*
C22	0.2678 (19)	0.193 (2)	0.7583 (17)	0.135 (6)*
C17	0.2656 (15)	0.2136 (16)	0.6159 (16)	0.135 (6)*
C18	0.3827 (16)	0.168 (2)	0.5732 (19)	0.135 (6)*
C19	0.5046 (16)	0.106 (2)	0.675 (2)	0.135 (6)*
H10	−0.147 (2)	0.544 (3)	0.182 (4)	0.161 (7)*
H11	0.026 (3)	0.616 (2)	0.122 (3)	0.161 (7)*
H12	0.263 (3)	0.539 (2)	0.240 (3)	0.161 (7)*
H14	0.3253 (15)	0.387 (3)	0.413 (4)	0.161 (7)*
H7	−0.0256 (19)	0.212 (2)	0.555 (3)	0.161 (7)*
H15a	−0.46 (2)	0.316 (16)	0.41 (5)	0.161 (7)*
H15b	−0.38 (4)	0.188 (18)	0.38 (5)	0.161 (7)*
H15c	−0.307 (19)	0.26 (4)	0.516 (7)	0.161 (7)*
H16a	−0.492 (6)	0.493 (17)	0.20 (6)	0.161 (7)*
H16b	−0.36 (5)	0.558 (6)	0.28 (1)	0.161 (7)*
H16c	−0.38 (5)	0.504 (16)	0.12 (3)	0.161 (7)*
H20	0.588 (2)	0.046 (3)	0.885 (3)	0.161 (7)*
H21	0.390 (3)	0.117 (3)	0.954 (2)	0.161 (7)*
H22	0.188 (2)	0.220 (3)	0.785 (3)	0.161 (7)*
H18	0.381 (2)	0.181 (3)	0.478 (2)	0.161 (7)*
H19	0.584 (2)	0.079 (3)	0.647 (3)	0.161 (7)*
H2	−0.223 (3)	0.349 (2)	0.013 (4)	0.161 (7)*
H3	−0.108 (5)	0.158 (3)	−0.071 (4)	0.161 (7)*
H4	−0.120 (4)	−0.0165 (19)	0.077 (5)	0.161 (7)*
H5	−0.242 (4)	0.0669 (14)	0.254 (4)	0.161 (7)*

Geometric parameters (Å, º)

HF1—CL1	2.305 (3)	C13—C14	1.407 (3)
HF1—CL2	2.303 (3)	C13—H14	0.930 (3)
HF1—SI1	3.279 (16)	C14—HF1	2.522 (19)
HF1—C1	2.526 (14)	C14—C9	1.421 (3)
HF1—C2	2.40 (2)	C14—C13	1.407 (3)
HF1—C3	2.468 (16)	C14—C6	1.438 (3)
HF1—C4	2.52 (2)	C6—HF1	2.595 (16)
HF1—C5	2.495 (19)	C6—C14	1.438 (3)
HF1—C8	2.54 (2)	C6—C7	1.397 (3)
HF1—C9	2.50 (2)	C6—C17	1.497 (3)
HF1—C14	2.522 (19)	C7—HF1	2.642 (15)
HF1—C6	2.595 (16)	C7—C8	1.477 (3)
HF1—C7	2.642 (15)	C7—C6	1.397 (3)
CL1—HF1	2.305 (3)	C7—H7	0.930 (3)
CL1—CL2	3.384 (16)	C15—SI1	1.858 (3)
CL2—HF1	2.303 (3)	C15—H15a	0.960 (3)
CL2—CL1	3.384 (16)	C15—H15b	0.960 (3)
SI1—HF1	3.279 (16)	C15—H15c	0.960 (3)
SI1—C1	1.849 (3)	C16—SI1	1.860 (3)
SI1—C8	1.855 (3)	C16—H16a	0.960 (3)
SI1—C15	1.859 (3)	C16—H16b	0.960 (3)
SI1—C16	1.8607 (3)	C16—H16c	0.960 (3)
C1—HF1	2.526 (14)	C20—C21	1.400 (3)
C1—SI1	1.849 (3)	C20—C19	1.400 (3)
C1—C2	1.399 (3)	C20—H20	0.930 (3)
C1—C5	1.399 (3)	C21—C20	1.400 (3)
C2—HF1	2.40 (2)	C21—C22	1.400 (3)
C2—C1	1.399 (3)	C21—H21	0.930 (3)
C2—C3	1.400 (3)	C22—C21	1.400 (3)
C2—H2	0.939 (3)	C22—C17	1.400 (3)
C3—HF1	2.468 (16)	C22—H22	0.930 (3)
C3—C2	1.401 (3)	C17—C6	1.497 (3)
C3—C4	1.340 (3)	C17—C22	1.400 (3)
C3—H3	0.930 (3)	C17—C18	1.398 (3)
C4—HF1	2.52 (2)	C18—C19	1.400 (3)
C4—C3	1.401 (3)	C18—H18	0.930 (3)
C4—C5	1.400 (3)	C19—C20	1.400 (3)
C4—H4	0.930 (3)	C19—C18	1.400 (3)
C5—HF1	2.495 (19)	C19—H19	0.930 (3)
C5—C1	1.399 (3)	H10—C10	0.930 (3)
C5—C4	1.400 (3)	H11—C11	0.930 (3)
C5—H5	0.930 (3)	H12—C12	0.930 (3)
C8—HF1	2.54 (2)	H14—C13	0.930 (3)
C8—SI1	1.855 (3)	H7—C7	0.930 (3)
C8—C9	1.480 (3)	H15a—C15	0.960 (3)
C8—C7	1.477 (3)	H15b—C15	0.960 (3)
C9—HF1	2.50 (2)	H15c—C15	0.960 (3)
C9—C8	1.480 (3)	H16a—C16	0.960 (3)
C9—C10	1.446 (3)	H16b—C16	0.960 (3)
C9—C14	1.421 (3)	H16c—C16	0.960 (3)
C10—C9	1.446 (3)	H20—C20	0.930 (3)
C10—C11	1.362 (3)	H21—C21	0.930 (3)
C10—H10	0.930 (3)	H22—C22	0.930 (3)
C11—C10	1.362 (3)	H18—C18	0.930 (3)
C11—C12	1.425 (3)	H19—C19	0.930 (3)
C11—H11	0.930 (3)	H2—C2	0.930 (3)
C12—C11	1.425 (3)	H3—C3	0.930 (3)
C12—C13	1.363 (3)	H4—C4	0.930 (3)
C12—H12	0.930 (3)	H5—C5	0.930 (3)
C13—C12	1.363 (3)
CL1—HF1—CL2	94.5 (6)	C8—C9—C10	130.0 (3)
CL1—HF1—C2	99.1 (7)	C8—C9—C14	111.2 (2)
CL1—HF1—C3	84.0 (7)	C10—C9—C14	118.6 (4)
CL1—HF1—C5	135.8 (7)	C9—C10—C11	119.6 (3)
CL2—HF1—C2	132.5 (6)	C9—C10—H10	120.2 (5)
CL2—HF1—C3	104.8 (7)	C11—C10—H10	120.2 (5)
CL2—HF1—C5	84.2 (5)	C10—C11—C12	120.4 (3)
C2—HF1—C3	33.4 (2)	C10—C11—H11	119.7 (5)
C2—HF1—C5	55.0 (3)	C12—C11—H11	119.7 (4)
C3—HF1—C5	54.3 (3)	C11—C12—C13	120.8 (3)
C1—SI1—C8	100.3 (11)	C11—C12—H12	119.5 (3)
C1—SI1—C15	108.8 (4)	C13—C12—H12	119.5 (4)
C1—SI1—C16	109.2 (4)	C12—C13—C14	120.4 (3)
C8—SI1—C15	110.9 (4)	C12—C13—H14	119.8 (6)
C8—SI1—C16	110.8 (3)	C14—C13—H14	119.8 (4)
C15—SI1—C16	115.7 (10)	C9—C14—C13	119.3 (3)
SI1—C1—C2	121.3 (3)	C9—C14—C6	106.5 (2)
SI1—C1—C5	121.1 (5)	C13—C14—C6	132.8 (5)
C2—C1—C5	107.9 (2)	C14—C6—C7	108.9 (2)
HF1—C2—C1	78.4 (8)	C14—C6—C17	124.7 (2)
HF1—C2—C3	75.9 (7)	C7—C6—C17	124.8 (4)
HF1—C2—H2	117 (3)	C8—C7—C6	110.9 (2)
C1—C2—C3	107.8 (2)	C8—C7—H7	122.7 (2)
C1—C2—H2	126.0 (6)	C6—C7—H7	122.7 (3)
C3—C2—H2	126.0 (9)	C21—C20—C19	120.0 (4)
HF1—C3—C2	70.7 (7)	C21—C20—H20	120.0 (5)
HF1—C3—C4	75.7 (12)	C19—C20—H20	120.0 (3)
HF1—C3—H3	116 (3)	C20—C21—C22	120.0 (4)
C2—C3—C4	107.9 (2)	C20—C21—H21	120.0 (6)
C2—C3—H3	126.0 (6)	C22—C21—H21	120.0 (4)
C4—C3—H3	126.0 (8)	C21—C22—C17	120.0 (3)
C3—C4—C5	107.9 (2)	C21—C22—H22	120.0 (6)
C3—C4—H4	126.0 (14)	C17—C22—H22	120.0 (7)
C5—C4—H4	126.0 (15)	C6—C17—C22	120.9 (3)
HF1—C5—C1	75.0 (6)	C6—C17—C18	119.8 (4)
HF1—C5—C4	74.8 (9)	C22—C17—C18	120.0 (3)
HF1—C5—H5	121 (3)	C17—C18—C19	120.0 (4)
C1—C5—C4	107.8 (3)	C17—C18—H18	120.0 (4)
C1—C5—H5	125.9 (3)	C19—C18—H18	120.0 (5)
C4—C5—H5	125.9 (4)	C20—C19—C18	120.0 (3)
SI1—C8—C9	124.6 (11)	C20—C19—H19	120.0 (7)
SI1—C8—C7	128.1 (10)	C18—C19—H19	120.0 (6)
C9—C8—C7	101.94 (19)

 

Footnotes

‡Present address: Leicester School of Pharmacy, De Montfort University, Hawthorn Building, The Gateway, Leicester LE1 9BH, England.

§Present address: Borealis Polymer Oy, R&D, PO Box 330, FIN-06101, Porvoo, Finland.