Chiral conflict among different helicenes suppresses formation of one enantiomorph in 2D crystallization

Article abstract of DOI:10.1021/ja402012j

Diastereomeric interactions in 2D crystals formed at solid surfaces serve as excellent models for understanding molecular recognition in biomineralization. Adsorption of a pentahelicene racemate on a Au(111) surface leads to 2D conglomerate crystallization, i.e., homochiral mirror domains, as observed by scanning tunneling microscopy. Upon mixing 26% of (M)-heptahelicene into the racemate monolayer, only the (M)-pentahelicene enantiomorph is observed. This effect is explained by a preferred heterochiral interaction between the different helicene species, suppressing the formation of the pure (P)-pentahelicene enantiomorph. These results shine new light onto stereoselective molecular recognition mediated by van der Waals forces.

Full text of DOI:10.1021/ja402012j

Supporting Information
Chira l c o nflict among d ifferent helic en es su p presses
formatio n o f o ne ena ntiomo rph in 2D crystallizatio n
Johannes Seibel,† Oliver Allemann,‡ Jay S. Siegel,‡ and Karl-Heinz Ernst*,†,‡
† Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
‡ Department of Chemistry, University of Zurich, 8057 Zürich, Switzerland
Supporting Information Figure S1. Models for homochiral and heterochiral packing for db[5]H. If
heterochiral dimers are constructed at the same packing density as for the homochiral dimer (a), one
combination has a priori a too strong overlap (b, red ellipse). A second combination (c) can be packed
with equal density, but its combinations do not fit to the experimentally observed packing (d,
heterochiral arrangements are presented with higher transparency.): Although one arrangement (P-
M1) fits the bright protrusions, it contradicts the STM contrast at the lower molecular edge (d, yellow
ellipse). In particular, it is not possible to build an extended layer due to strong overlap among the unit
cells (P-M1, red ellipse). Like for the homochiral combination the P-M2 arrangement fits the STM
contrast at the lower molecular edge (blue ellipses), but not the bright protrusion pattern. In order to
fit into the unit cell, however, the pair of dimers has to pack so close, that the lower parts of the
molecules in the middle show a too strong overlap (P-M2 red ellipse). The STM image (d) is identical
to the one shown as Fig. 2d (10 nm × 10 nm, U = 2.051 V, I = 28 pA).
S1

Supporting Information
Supporting Information Figure S2. Model of a 2 × 3 arrangement of unit cells. A single unit cell
consists of two dimers, rotated by 180 degrees with respect to each other. This allows along the [1 0]
1
direction a close arrangement by overlap to one side, but not to the other side. No overlap is observed
along the [11
2
] direction (viz. perpendicular to [1
1
0]). The transformation matrix between
"
%
6
2
adsorbate lattice and gold substrate is
. A unit cell contains 4 molecules and covers 78 Au
$
'
0 13
#
&
atoms. The lengths of the unit cell vectors are 1.52 nm and 3.74 nm.
Supporting Information Figure S3. STM image (150 nm × 150 nm, U = –2.725 V, I = 31 pA) of a
monolayer consisting of 90% rac-db[5]H and 10% (M)-[7]H. The (P)-db[5]H enantiomorph
(yellow) covers a smaller area than the (M)-db[5]H enantiomorph (blue).
S2

Supporting Information
Supporting Information Figure S4. Dependence of excess of M-db[5]H domains (blue) and
overall ordered area (red) on the amount of [7]H mixed into the monolayer. The amount of [7]H
is given in percentage of the area covered (coverage, bottom axis) and the relative molar
amount of [7]H in the layer (‘diastereomeric excess-de’).
Supporting Information Table S1. Summary of the statistical analyses.
Nr of
200 x 200 nm
Percen-
tage M
domains
50
54
67
86
100
Avg.
Domain
Size (M)
1091
655
1119
Avg.
Domain
Size (P)
Coverage
doping
Amount of
M-7[H]
Total area
Ordered
Percentage of
ordered area
probed /nm2
area /nm2
images
10
10
10
10
0 %
5 %
10 %
15 %
20 %
0.00 %
6.60 %
13.20 %
19.80 %
26.40 %
400’000
400’000
400’000
400’000
400’000
17627
10876
9815
6860
2576
44 ± 5
27 ± 10
25 ± 8
17 ± 11
6 ± 3
498
714
250
689
447
10
S3

Supporting Information
Supporting Information Figure S5. Models for diastereomeric interactions between (P)-db[5]H and
(M)-[7]H (a-c) and (M)-db[5]H and (M)-[7]H (d-f). The six examples show the closest
arrangements possible for P-M and M-M combinations. The largest overlap between both species is
achieved for the P-M pair shown in b.
S4

Supporting Information
Syntheses
Supporting Scheme 1. Scheme of synthesis of db[5]H.
Reaction Conditions and Chemicals
The C–F activation reaction was set up in an MBraun glovebox under a nitrogen atmosphere
with O2, H2O < 0.1 ppm. The reaction mixture was heated outside the glovebox, but still under a
nitrogen atmosphere. All glassware was dried at 150 °C for at least 12 hrs and allowed to cool in
vacuo. The substrates and reagents used for the C–F activation reaction were synthesized and
purified. Chlorobenzene was filtered through dry Al2O3 and stored over 4 Å molecular sieves.
The Negishi cross-coupling reactions were conducted in water- and oxygen-free atmosphere.
Dry THF from the solvent system was used, ZnCl2 was melted under vacuum in order to
eliminate water residue, Palldium catalysts were synthesized in the Siegel group. For work-up
and purification outside the glovebox, distilled solvents of technical grade were used.
Table S1. Suppliers and grade of used chemicals.
Compound
chlorobenzene
Quality
puriss.
99 %
Supplier
Fluka
Fluorochem
Acros
Aldrich
Alfa Aesar
Sigma Aldrich
1-bromo-2-iodobenzene
n-BuLi (2.5 M in hexane)
1,4-diiodobenzene
1-fluoro-2-bromobenzene
zinc chloride
99 %
99 %
puriss.
Instruments
19
1
13
NMR spectra were recorded on Bruker AV-400 ( F), and Bruker AV-500 ( H, C) instruments.
13
C NMR spectra are proton decoupled. Data are reported as follows: chemical shift in ppm,
multiplicity (s = singlet, d = doublet, m = multiplet, ddd = doublet of doublet of doublet, etc.),
n
coupling constant J in Hz, and integration. The signals were referenced against solvent peaks
1
13
19
( H: residual CHCl3 7.26 ppm; C, CDCl3 77.16 ppm) or external standards ( F: CCl3F in CDCl3
0 ppm).
Mass spectra were recorded by the Laboratory for Mass Spectroscopy of the Organic
S5

Supporting Information
Chemistry Institute of the University of Zurich on a Finnigan MAT95 instrument or on a
Finnigan Trace DSQ GC-MS. Data are reported as follows: m/z (% relative intensity).
Syntheses
2-fluoro-2'-bromobiphenyl: To a solution of 1-fluoro-2-bromobenzene (1.12 g, 6.40 mmol) in
THF (10 mL) nBuLi (2.7 mL, 2.5 M in hexane, 6.75 mmol) was added at –78 °C . The slightly
yellow solution was stirred for 30 min. When ZnCl2 (952 mg, 6.99 mmol) in THF (8 mL) was
added the solution turned colorless and was allowed to warm to 0 °C. It was then transferred to
a flask charged with 1-bromo-2-iodobenzene (1.65 g, 5.83 mmol) and Pd(PPh3)4 (67 mg, 0.06
mmol) and THF (10 mL). The solution was then heated to 50 °C and stirred for 12 h. The
reaction was quenched with water. The water was then extracted with DCM (3x), the combined
organic phases were dried over MgSO4, filtered and concentrated in vacuo. Flash column
chromatography (Hex/DCM 99:1) afforded the desired product as a colorless oil (1.32 g, 90 %).
Rf (silica, Hexane)= 0.26.
1
H-NMR (500 MHz, CDCl3): δ = 7.69 (dd, J = 8.0, 1.5 Hz, 1 H), 7.41–7.35 (m, 2 H), 7.33–
7.20 (m, 3 H), 7.15 (ddd, J = 10, 8.5, 1.5 Hz, 1 H).
13
1
C-NMR (125.8 MHz, CDCl3): δ = 159.70 (d, JC–F = 247.3 Hz), 137.35, 133.01, 131.76,
3
3
2
131.71 (d, JC–F = 3.1 Hz), 129.97 (d, JC–F = 8.0 Hz), 129.55, 129.03 (d, JC–F = 16.1 Hz), 127.31,
123.99, 123.93 (d, JC–F = 3.6 Hz), 115.78 (d, JC–F = 22.1 Hz).
4
2
19
F-NMR (376.5 MHz, CDCl3): δ = –114.68.
MS (EI): m/z (%): 251.9 (80), 249.9 (84), 171.0 (42), 170.0 (100), 151.0 (20), 85.0 (24), 75.0
(20).
1,4-bis(2,2'-difluorobiphenyl-2-yl)benzene: To a solution of 2-fluoro-2'-bromobiphenyl (599
mg, 2.39 mmol) in THF (12 mL) nBuLi (1.1 mL, 2.5 M in hexane, 2.75 mmol) was added at –
78 °C . The yellow solution was stirred for 30 min. When ZnCl2 (386 mg, 2.83 mmol) in THF (4
mL) was added the solution turned almost colorless and was allowed to warm to 0 °C. It was
then transferred to a flask charged with 1,4-diiodobenzene (360 mg, 1.09 mmol) and PEPPSI-
iPr (21 mg, 0.03 mmol) and THF (4 mL). The solution was then heated to 70 °C and stirred for
13 h. The reaction was quenched with an aqueous solution of NaHCO3 (10 %). The water phase
was then extracted with DCM (3x), the combined organic phases were dried over MgSO4,
filtered and concentrated in vacuo. Flash column chromatography (Hex/DCM 98:2 to 90:10)
afforded the desired product as a white solid (276 mg, 61 %).
Rf (silica, Hex/DCM 9:1) = 0.17.
1
H-NMR (500 MHz, CDCl3): δ = 7.46–7.37 (m, 8 H), 7.22–7.16 (m, 2 H), 7.07 (ddd, J = 7.5,
S6

Supporting Information
7.5, 2.0 Hz, 2 H), 7.01 (ddd, J = 7.5, 7.5, 1.5 Hz, 2 H), 6.97 (s, 4 H), 6.91 (ddd, J = 10.0, 8.0,
1.0 Hz, 2 H).
13
1
C-NMR (125.8 MHz, CDCl3): δ = 159.55 (d, JC–F = 246.6 Hz), 141.43, 139.61, 134.51,
3
2
3
132.24 (d, JC–F = 3.5 Hz), 131.09, 130.16, 129.18 (d, JC–F = 15.6 Hz), 128.83 (d, JC–F = 7.8 Hz),
128.83 (2 C), 128.26, 127.24, 123.79 (d, JC–F = 3.6 Hz), 115.58 (d, JC–F = 22.5 Hz).
4
2
19
F-NMR (376.5 MHz, CDCl3): δ = –115.44.
MS (EI): m/z (%): 418.2 (100), 398.2 (19), 246.1 (20), 207.1 (21), 188.1 (30).
[5,6, 9,10]-dibenzopentahelicene: In the glove box, a vial was charged with 1,4-bis(2,2'-
difluorobiphenyl-2-yl)benzene (23 mg, 0.055 mmol), [iPr3Si][CHB11H5Cl6] (6 mg, 0.011 mmol)
and Me2SiMes2 (44 mg, 0.148 mmol). The mixture was dissolved in chlorobenzene (1 mL),
heated to 110 °C and stirred for 8 h. The reaction was quenched with ethyl acetate and the
solvents were evaporated. Flash column chromatography afforded the product as a white solid
(14 mg, 67 %).
Rf (silica, Hex/DCM 4:1) = 0.12.
1
H-NMR (500 MHz, CDCl3): δ = 8.68 (m, 6 H), 8.58 (d, J = 8.0 Hz, 2 H), 8.27 (d, J = 8.0 Hz,
2 H), 7.74 (m, 4 H), 7.53 (ddd, J = 8.0, 7.0, 1.5 Hz, 2 H), 7.53 (ddd, J = 8.0, 6.5, 1.0 Hz, 2 H).
13
C-NMR (125.8 MHz, CDCl3): δ = 131.13, 131.04, 130.53, 130.44, 130.05, 129.71, 127.84,
127.64, 127.44, 127.06, 125.37, 123.85, 123.66, 123.37, 121.96.
+
HR-MS (ESI): m/z: Calculated for C30H19 [M+H] : 379.14813, found: 379.14830.
Crystal-Structure Determination. – A crystal of C H was mounted on a glass fibre and
30 18
used for a low-temperature X-ray structure determination. All measurements were made on an
2
Agilent Technologies SuperNova area-detector diffractometer using Cu Kα radiation (λ =
1.54184 Å) from a micro-focus X-ray source and an Oxford Instruments Cryojet XL cooler. The
unit cell constants and an orientation matrix for data collection were obtained from a least-squares
refinement of the setting angles of 10218 reflections in the range 4° < 2θ < 148°. A total of 1884
frames were collected using ω scans with κ offsets, 1.5-10.0 seconds exposure time and a rotation
angle of 1.0° per frame, and a crystal-detector distance of 55.0 mm.
2
Data reduction was performed with CrysAlisPro . The intensities were corrected for
Lorentz and polarization effects, and an empirical absorption correction using spherical
2
harmonics was applied. The space group was uniquely determined by the systematic absences.
Equivalent reflections were merged. The data collection and refinement parameters are given in
S7

Supporting Information
Table 1. A view of the molecule is shown in the Figure.
3
The structure was solved by direct methods using SHELXS97 , which revealed the positions
of all non-hydrogen atoms. The non-hydrogen atoms were refined anisotropically. All of the H-
atoms were placed in geometrically calculated positions and refined by using a riding model where
each H-atom was assigned a fixed isotropic displacement parameter with a value equal to 1.2U of
eq
2
its parent atom. The refinement of the structure was carried out on F by using full-matrix least-
2 2 2
squares procedures, which minimised the function Σw(F –F ) . The weighting scheme was
o
c
based on counting statistics and included a factor to downweight the intense reflections. Plots of
2 2 2
Σw(F –F ) versus F /F (max) and resolution showed no unusual trends. A correction for
o
c
c c
secondary extinction was applied.
Neutral atom scattering factors for non-hydrogen atoms were taken from Maslen, Fox and
4a
O'Keefe , and the scattering factors for H-atoms were taken from Stewart, Davidson and
5
Simpson . Anomalous dispersion effects were included in F ; the values for f' and f" were those
6
c
4b
of Creagh and McAuley . The values of the mass attenuation coefficients are those of Creagh
4c
and Hubbel . The SHELXL97 program was used for all calculations.
3
1
ORTEP representation of the molecule (50% probability ellipsoids; H-atoms given arbitrary
displacement parameters for clarity)
Definition of Terms
2 2 2
Function minimized: Σw(F – F ) where
o
c
S8

Supporting Information
2
w = [σ (F ) + (aP) + bP] and P = (F + 2F )/3
2
2
-1
2
2
o
o
c
2
F
o
= S(C – RB)/Lp
2
2
2
2
and σ (F ) = S (C + R B)/Lp
2
o
S = Scan rate
C = Total integrated peak count
R = Ratio of scan time to background counting time
B = Total background count
Lp = Lorentz-polarization factor
2
2
2
R-factors: R = Σ|<F > – F |/ΣF
o
summed only over reflections for which more than one
int
o
o
symmetry equivalent was measured. R(F) = Σ||F | – |F ||/Σ|F | summed over all observed
o
c
o
2
reflections. wR(F ) = [Σw(F – F ) /Σw(F ) ] summed over all reflections.
2
2 2
2 2 1/2
o
c
o
Standard deviation of an observation of unit weight (goodness of fit):
2
2 2
1/2
[Σw(F – F ) /(N – N )] where N = number of observations; N = number of variables
o
c
o
v
o
v
References
(1) Johnson, C. K. ORTEPII, Report ORNL-5138, Oak Ridge National Laboratory, Oak Ridge,
Tennessee, 1976.
(2) CrysAlisPro, Agilent Technologies, Yarnton, Oxfordshire, England, 2011.
(3) Sheldrick, G.M. Acta Crystallogr. Sect. A, 2008, 64, 112-122.
(4) a) Maslen, E. N.; Fox, A.G.; O'Keefe, M. A. in 'International Tables for
Crystallography', Ed. A. J. C. Wilson, Kluwer Academic Publishers, Dordrecht, 1992,
Vol. C, Table 6.1.1.1, pp. 477;
b) Creagh, D. C.; McAuley, W. J. ibid. Table 4.2.6.8, pp. 219;
c) Creagh, D. C.; Hubbell, J. H. ibid. Table 4.2.4.3, pp. 200.
(5) R. F. Stewart, E.R. Davidson, W.T. Simpson, J. Chem. Phys. 1965, 42, 3175.
(6) Ibers, J.A. Hamilton, W.C. Acta Crystallogr. 1964, 17, 781.
S9

Supporting Information
Crystallographic data
Crystallised from
Empirical formula
?
C H
30 18
-1
Formula weight [g mol ]
378.47
Crystal colour, habit
colorless, plate
0.04 ⋅ 0.28 ⋅ 0.44
100(1)
Crystal dimensions [mm]
Temperature [K]
Crystal system
monoclinic
Space group
P2 /n (#14)
1
Z
4
Reflections for cell determination
10218
4–148
19.3549(3)
5.12886(5)
19.9604(3)
90
2θ range for cell determination [°]
Unit cell parameters a [Å]
b [Å]
c [Å]
α [°]
β [°]
γ [°]
115.0553(19)
90
3
V [Å ]
1794.99(4)
792
F(000)
-3
D [g cm ]
1.400
x
-1
µ(Cu Kα) [mm ]
0.604
Scan type
ω
2θ
[°]
148.0
(max)
Transmission factors (min; max)
Total reflections measured
0.208; 1.000
18317
774977329
0.018
Symmetry independent reflections
R
int
Reflections with I > 2σ(I)
Reflections used in refinement
Parameters refined
3308
3588
272
Final R(F) [I > 2σ(I) reflections]
2
wR(F ) (all data)
0.0326
0.0894
2
2
2
-1
2
w = [σ (F ) + (0.0456P) + 0.6114P] where P = (F + 2F )/3
2
Weights:
o
o
c
Goodness of fit
1.040
S10

Supporting Information
Secondary extinction coefficient
0.0007(2)
0.004
Final Δ /σ
max
-3
Δρ (max; min) [e Å ]
σ(d ) [Å]
0.24; -0.17
0.001 – 0.002
(C– C)
TABLE S2. Bond lengths (Å) with standard uncertainties in parentheses.
C(1) -C(2)
C(1) -C(16)
C(2) -C(3)
C(3) -C(4)
C(4) -C(17)
C(5) -C(30)
C(5) -C(6)
C(5) -C(17)
C(6) -C(27)
C(6) -C(18)
C(7) -C(8)
C(7) -C(26)
C(7) -C(19)
C(8) -C(23)
C(8) -C(22)
C(9) -C(10)
C(9) -C(22)
C(10) -C(11)
1.3745(15)
1.4108(15)
1.3936(16)
1.3768(15)
1.4077(15)
1.4098(15)
1.4144(15)
1.4624(15)
1.4142(14)
1.4690(14)
1.4112(15)
1.4134(15)
1.4666(14)
1.4129(15)
1.4586(15)
1.3759(16)
1.4097(15)
1.3942(16)
C(11) -C(12)
C(12) -C(21)
C(13) -C(14)
C(13) -C(20)
C(14) -C(15)
C(15) -C(18)
C(15) -C(16)
C(16) -C(17)
C(18) -C(19)
C(19) -C(20)
C(20) -C(21)
C(21) -C(22)
C(23) -C(24)
C(24) -C(25)
C(25) -C(26)
C(27) -C(28)
C(28) -C(29)
C(29) -C(30)
1.3772(16)
1.4056(15)
1.3634(15)
1.4123(14)
1.4132(14)
1.4076(14)
1.4612(14)
1.4115(15)
1.4411(14)
1.4059(14)
1.4629(15)
1.4133(15)
1.3732(16)
1.3990(17)
1.3750(15)
1.3793(15)
1.3946(16)
1.3799(16)
TABLE S3. Bond angles (°) with standard uncertainties in parentheses.
C(2) -C(1) -C(16)
C(1) -C(2) -C(3)
C(4) -C(3) -C(2)
C(3) -C(4) -C(17)
C(30) -C(5) -C(6)
C(30) -C(5) -C(17)
C(6) -C(5) -C(17)
C(27) -C(6) -C(5)
C(27) -C(6) -C(18)
121.48(10)
119.96(10)
119.77(10)
121.46(10)
118.78(10)
120.97(10)
120.17(9)
118.21(9)
121.25(9)
C(17) -C(16) -C(15)
C(4) -C(17) -C(16)
C(4) -C(17) -C(5)
C(16) -C(17) -C(5)
C(15) -C(18) -C(19)
C(15) -C(18) -C(6)
C(19) -C(18) -C(6)
C(20) -C(19) -C(18)
C(20) -C(19) -C(7)
120.12(9)
118.80(10)
122.30(10)
118.88(9)
118.40(9)
117.93(9)
123.36(9)
118.99(9)
117.05(9)
S11

Supporting Information
C(5) -C(6) -C(18)
C(8) -C(7) -C(26)
C(8) -C(7) -C(19)
C(26) -C(7) -C(19)
C(7) -C(8) -C(23)
C(7) -C(8) -C(22)
C(23) -C(8) -C(22)
C(10) -C(9) -C(22)
C(9) -C(10) -C(11)
C(12) -C(11) -C(10)
C(11) -C(12) -C(21)
C(14) -C(13) -C(20)
C(13) -C(14) -C(15)
C(18) -C(15) -C(14)
C(18) -C(15) -C(16)
C(14) -C(15) -C(16)
C(1) -C(16) -C(17)
C(1) -C(16) -C(15)
120.04(9)
118.48(9)
120.24(9)
120.75(10)
118.83(10)
119.79(9)
121.15(10)
121.13(10)
119.87(10)
120.01(11)
121.41(10)
121.01(10)
121.24(10)
118.55(9)
120.25(9)
121.19(9)
118.53(10)
121.29(10)
C(18) -C(19) -C(7)
C(19) -C(20) -C(13)
C(19) -C(20) -C(21)
C(13) -C(20) -C(21)
C(12) -C(21) -C(22)
C(12) -C(21) -C(20)
C(22) -C(21) -C(20)
C(9) -C(22) -C(21)
C(9) -C(22) -C(8)
C(21) -C(22) -C(8)
C(24) -C(23) -C(8)
C(23) -C(24) -C(25)
C(26) -C(25) -C(24)
C(25) -C(26) -C(7)
C(28) -C(27) -C(6)
C(27) -C(28) -C(29)
C(30) -C(29) -C(28)
C(29) -C(30) -C(5)
123.63(9)
118.36(10)
120.08(9)
121.56(9)
118.52(10)
121.48(10)
119.91(9)
118.99(10)
122.37(10)
118.47(9)
121.41(10)
119.63(10)
120.16(10)
121.23(10)
121.66(10)
119.78(10)
119.72(10)
121.56(10)
TABLE S4. Torsion angles (°) with standard uncertainties in parentheses.
C(16) -C(1) -C(2) -C(3) 0.6(2) C(15) -C(18) -C(19) -C(7) -151.2(1)
C(1) -C(2) -C(3) -C(4) -0.2(2)
C(2) -C(3) -C(4) -C(17) -0.1(2)
C(30) -C(5) -C(6) -C(27) -5.7(1)
C(6) -C(18) -C(19) -C(7)
C(8) -C(7) -C(19) -C(20)
35.2(2)
20.0(1)
C(26) -C(7) -C(19) -C(20) -151.5(1)
C(17) -C(5) -C(6) -C(27) 171.22(9) C(8) -C(7) -C(19) -C(18) -166.75(9)
C(30) -C(5) -C(6) -C(18) -177.71(9) C(26) -C(7) -C(19) -C(18) 21.8(2)
C(17) -C(5) -C(6) -C(18) -0.8(1) C(18) -C(19) -C(20) -C(13) -15.0(1)
C(26) -C(7) -C(8) -C(23) -5.9(1) C(7) -C(19) -C(20) -C(13) 158.64(9)
C(19) -C(7) -C(8) -C(23) -177.56(9) C(18) -C(19) -C(20) -C(21) 165.00(9)
C(26) -C(7) -C(8) -C(22) 168.70(9) C(7) -C(19) -C(20) -C(21) -21.4(1)
C(19) -C(7) -C(8) -C(22) -3.0(1)
C(22) -C(9) -C(10) -C(11) 0.3(2)
C(9) -C(10) -C(11) -C(12) 1.3(2)
C(10) -C(11) -C(12) -C(21) -0.6(2)
C(20) -C(13) -C(14) -C(15) 9.6(2)
C(13) -C(14) -C(15) -C(18) -2.4(2)
C(13) -C(14) -C(15) -C(16) 176.7(1)
C(2) -C(1) -C(16) -C(17) -0.7(2)
C(2) -C(1) -C(16) -C(15) 176.3(1)
C(14) -C(13) -C(20) -C(19)
C(14) -C(13) -C(20) -C(21) 179.4(1)
C(11) -C(12) -C(21) -C(22) -1.7(2)
-0.7(2)
C(11) -C(12) -C(21) -C(20) 174.8(1)
C(19) -C(20) -C(21) -C(12) -170.4(1)
C(13) -C(20) -C(21) -C(12)
C(19) -C(20) -C(21) -C(22)
9.6(2)
6.1(2)
C(13) -C(20) -C(21) -C(22) -173.94(9)
C(10) -C(9) -C(22) -C(21) -2.5(2)
S12

Supporting Information
C(18) -C(15) -C(16) -C(1) -168.10(9) C(10) -C(9) -C(22) -C(8)
172.6(1)
3.2(2)
C(14) -C(15) -C(16) -C(1) 12.9(2)
C(18) -C(15) -C(16) -C(17) 8.8(2)
C(12) -C(21) -C(22) -C(9)
C(20) -C(21) -C(22) -C(9) -173.39(9)
C(14) -C(15) -C(16) -C(17) -170.19(9) C(12) -C(21) -C(22) -C(8) -172.15(9)
C(3) -C(4) -C(17) -C(16) 0.1(2)
C(3) -C(4) -C(17) -C(5) 178.3(1)
C(20) -C(21) -C(22) -C(8)
C(7) -C(8) -C(22) -C(9)
C(23) -C(8) -C(22) -C(9)
11.3(1)
172.16(9)
-13.4(2)
C(1) -C(16) -C(17) -C(4)
0.3(1)
C(15) -C(16) -C(17) -C(4) -176.69(9) C(7) -C(8) -C(22) -C(21) -12.7(1)
C(1) -C(16) -C(17) -C(5) -177.95(9) C(23) -C(8) -C(22) -C(21) 161.8(1)
C(15) -C(16) -C(17) -C(5)
5.0(1)
C(7) -C(8) -C(23) -C(24)
3.3(2)
C(30) -C(5) -C(17) -C(4) -10.3(2)
C(22) -C(8) -C(23) -C(24) -171.2(1)
C(6) -C(5) -C(17) -C(4) 172.90(9) C(8) -C(23) -C(24) -C(25)
C(30) -C(5) -C(17) -C(16) 167.95(9) C(23) -C(24) -C(25) -C(26)
1.0(2)
-2.7(2)
-0.1(2)
4.4(2)
C(6) -C(5) -C(17) -C(16) -8.9(1)
C(24) -C(25) -C(26) -C(7)
C(14) -C(15) -C(18) -C(19) -13.2(1) C(8) -C(7) -C(26) -C(25)
C(16) -C(15) -C(18) -C(19) 167.79(9) C(19) -C(7) -C(26) -C(25) 176.0(1)
C(14) -C(15) -C(18) -C(6) 160.73(9) C(5) -C(6) -C(27) -C(28) 4.9(2)
C(16) -C(15) -C(18) -C(6) -18.3(1) C(18) -C(6) -C(27) -C(28) 176.83(9)
C(27) -C(6) -C(18) -C(15) -157.39(9) C(6) -C(27) -C(28) -C(29)
-0.5(2)
-3.1(2)
2.2(2)
2.3(2)
C(5) -C(6) -C(18) -C(15) 14.4(1)
C(27) -C(6) -C(18) -C(19) 16.2(2)
C(27) -C(28) -C(29) -C(30)
C(28) -C(29) -C(30) -C(5)
C(5) -C(6) -C(18) -C(19) -172.05(9) C(6) -C(5) -C(30) -C(29)
C(15) -C(18) -C(19) -C(20) 21.9(1) C(17) -C(5) -C(30) -C(29) -174.6(1)
C(6) -C(18) -C(19) -C(20) -151.6(1)
S13