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Supplementary Information- Full Experimental
Preparation and crystallization of -CD inclusion complexes with aryl alkyl ketones
Butyrophenone and valerophenone were purchased from Aldrich and used as is.
In a typical inclusion complex preparation, about 200 l of the liquid guest compound
(either butyrophenone or valerophenone) was suspended on 40 ml of a saturated aqueous
solution of -CD. The mole ratio of guest:-CD was in slight excess of 3:2. This
solution was stirred at room temperature at which point the guest ketone would interact
and complex with the -CD in the aqueous phase. The inclusion complex immediately
precipitated out of solution as a white powder. This solution was then heated to 85-90ºC
to dissolve the inclusion complexes. Slow cooling of this solution to room temperature
over the course of 3-4 days produced crystals of the inclusion complexes.
Crystallographic studies
For the -CD/butyrophenone complex, a crystal of dimensions 0.7 x 0.5 x 0.4
mm was sealed inside a glass capillary for X-ray diffraction data collection. Care was
taken to make sure the capillary was sealed air-tight so as to prevent dehydration of the
crystal, which destroys the crystal. Data were collected at room temperature on an
automated Siemens P4 diffractometer with a Mo target sealed tube source. 8062
reflections (6708 unique- Rint= 0.0306) were collected to 2max=50. Data were collected
using the omega-scans method. The phase problem was solved by molecular
replacement of the -CD coordinates from the isomorphous -CD/coumarin structure1.
Difference electron density maps (Fo-Fc) revealed that the guest molecules were very
disordered. The disorder was interpreted with a model built with the guest
butyrophenone phenyl rings located in the center of the -CD dimer torus with the alkyl
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chains extending to the primary hydroxyl ends (Fig. A1). The guest butyrophenone
molecules were modeled as pairs distributed over 4 sites. The choice of 4 sites was
somewhat arbitrary. Refinement provided the best results with 4 sites. Conformations of
the guest butyrophenones could not be determined from the maps, but their general shape
could be. Due to previous characterization of the -CD dimer environment as being nonconstraining2, gas phase conformations or near gas-phase conformations which fit the
shape of the difference electron density maps were built into the model. The
conformational geometry of the guest sites is summarized in Table A1. These guest
molecules were then refined as rigid bodies with restrained isotropic displacement
parameters. In the end, least-squares refinement on F2 of 923 parameters was carried out
using SHELXL973 and converged to a final R1=0.0668, wR2= 0.1748, and GOF = 1.052
for 5202 reflections with Fo> 4(Fo). All non-hydrogen atoms were treated
anisotropically except those of the guest molecules and low occupancy waters.
Hydrogens on carbon atoms were generated using geometric considerations and were
fixed in a riding model. A final difference electron density map showed no distinct
features with max = 0.31 and min = -0.30 eÅ-3.
Data collection on a crystal of the -CD/valerophenone complex was conducted
similarly to that described above for the -CD/butyrophenone complex. 12065
reflections (11163 unique- Rint= 0.0241) were collected to 2max=60. The crystal was
isomorphous to the -CD/butyrophenone complex, so the phase problem was solved by
molecular replacement of the -CD coordinates from it. Difference electron density
maps (Fo-Fc) revealed that the guest molecules were disordered similar to the -CD
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Figure A1: The disordered butyrophenone molecules fit to the difference electron
density (Fo – Fc) in the -CD dimer. -CD is in gray with the butyrophenone molecules
colored by pairs. Hydrogen atoms are omitted for clarity. The difference electron
density is in light gray at a level of  = 0.25 e/Å3 (ave = 0.00 e/Å3; RMS dev. = 0.08
e/Å3).
O


Table A1 Torsion angles for included butyrophenone molecules
Butyrophenone Site
Torsion
1
2
3
4
170º
180º
180º
180º
1
60º
60º
60º
60º
2
3
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Figure A2: The disordered valerophenone molecules fit to the difference electron
density (Fo – Fc) in the -CD dimer. -CD is in gray with the valerophenone molecules
colored by pairs. Hydrogen atoms are omitted for clarity. The difference electron
density is in light gray at a level of  = 0.30 e/Å3 (ave = 0.00 e/Å3; RMS dev. = 0.09
e/Å3).
O


Torsion
1
2
3

Table A2 Torsion angles for included valerophenone molecules
Valerophenone Site
1
2
3
4
150º
150º
150º
150º
50º
45º
45º
45º
60º
60º
60º
60º
4
5
150º
45º
60º
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butyrophenone complex. Thus, the disorder was handled in a similar manner. The guest
valerophenone molecules were modeled as pairs distributed over 5 sites (Figure A2).
Again, the choice of 5 sites was somewhat arbitrary. Refinement provided the best
results with 5 sites and it also was the best interpretation of the difference electron
density maps. Conformations of the guest valerophenones were determined in a manner
similar to that described above for the butyrophenone complex. Due to slightly larger
size of the guest valerophenones, some torsion angles were forced to deviate from ideal
gas phase angles. The guest conformations are summarized in Table A2. Refinement of
the guest molecules did not produce much improvement in the refinement statistics (over
the non-refined model) and produced worse guest positions, so their positions were not
refined. Guest atom displacement parameters were determined from iterative fixing of
values and structure factor calculations until no improvement was seen. In the end, leastsquares refinement on F2 of 907 parameters was carried out using SHELXL97 and
converged to a final R1=0.0915, wR2= 0.1426, and GOF = 1.020 for 6425 reflections with
Fo> 4(Fo). All non-hydrogen atoms were treated anisotropically except those of the
guest molecules and low occupancy waters. Hydrogens on carbon atoms were generated
using geometric considerations and were fixed in a riding model. A final difference
electron density map showed no distinct features with max = 0.49 and min = -0.58 eÅ-3.
Crystal data and refinement details for the two structures are summarized in Table A3.
Photochemical Studies
To determine that the aryl alkyl ketones underwent Norrish Type II
photoreactions in the -CD complex crystals, photochemical studies were carried out.
Crystals of the -CD/butyrophenone and -CD/valerophenone inclusion complexes
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Table A3 Crystal data and structure refinement statistics for
-CD complexes with aryl alkyl ketones
butyrophenone
valerophenone
(C42H70O35)(C10H12O)(H2O)11.5
(C42H70O35)(C11H14O)(H2O)11
Empirical formula
Formula weight
1490.36
1495.38
Temperature
293(2)K
293(2)K
Wavelength
0.71073 Å
0.71073 Å
Crystal system
Monoclinic C
Monoclinic C
Space group
C2
C2
Unit cell dimensions
a
19.352(2) Å
19.339(2) Å
b
24.599(2) Å
25.581(1) Å
c
15.916(2) Å
16.010(2) Å
109.378(7)
109.080(7)

3
Volume
7147(1) Å
7485(1) Å3
Z
4
4
Density(calc.)
1.385 g/cm3
1.327 g/cm3
Crystal size
0.7 x 0.5 x 0.4 mm
0.6 x 0.4 x 0.4 mm
Resolution
0.84 Å
0.71 Å
Reflections (unique)
8062(6708, Rint=0.0306)
12065(11163, Rint=0.0241)
Data/restraints/param. 6708/55/923
11163/63/907
Goodness-of-fit on F2 1.052
1.020
2
R indices [Fo>4(Fo)] R1=0.0668, wR(F )=0.1748 R1=0.0915, wR(F2)=0.2504
Largest diff. peak and hole
0.313 and –0.298 e•Å –3
0.487 and –0.575 e•Å –3
prepared as described above were put into Pyrex test tubes, which were then sealed and
flushed with N2, and then irradiated with a Hanovia 450W medium pressure Hg arc lamp
for 2 days. Care was taken to make sure the crystals did not dehydrate. The photolyzed
crystals were then dissolved in water, and methylene chloride was used to extract the
photoproduct. The extraction mixture was then analyzed by GC-MS. For the
valerophenone extraction mixture, the gas chromatograph showed three peaks (Figure
A3), two of which were determined to be acetophenone and valerophenone based on
comparison to retention times of prepared standards. The chemical ionization mass
spectrum of the third peak showed it to be the cyclobutanol. Due to the hydroxyl and the
strained four-membered ring, the molecular ion of the cyclobutanol would not be
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Figure A3: GC-MS gas chromatograph for the valerophenone extraction mixture (top)
and mass spectrum of the cyclobutanol (bottom). See text for details.
expected to be very stable and should readily fragment. A small peak occurs at
mass/charge 163, corresponding to M +1 for the cyclobutanol. The major peak occurs at
(M+1) – 18, corresponding to loss of water from the molecular ion. Thin layer
chromotography using an eluent of 75% hexane, 15% acetone, and 10% ethanol verified
that there were three components in the mixture, two of which were acetophenone and
valerophenone, respectively. GC-MS analysis of the extraction mixture from the
butyrophenone complex gave only two peaks, which corresponded to acetophenone and
butyrophenone. It is probable that the cyclobutanol came off the column at the same
time as the butyrophenone. TLC analysis using the same eluent described above showed
that there were three components in the mixture. The third component was assumed to be
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the cyclobutanol. Thus it was confirmed that the E and C processes occur in the -CD
complex crystals.
1
2
3
T. J. Brett, J. M. Alexander, J. L. Clark, I. C. R. Ross, G. S. Harbison, and J. J. Stezowski, Chem.
Commun., 1999, 1275.
T. J. Brett, S. Liu, P. Coppens, and J. J. Stezowski, Chem. Commun., 1999, 551.
G. M. Sheldrick, SHELXL97. Program for the Refinement of Crystal Structures. University of
Göttingen, Germany, 1997.
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