Efficient encapsulation of chloroform with cryptophane-M and the formation of exciplex studied by fluorescence spectroscopy

Article abstract of DOI:10.1007/s10895-010-0739-5

Efficient encapsulation of small molecules with supermolecules is one of significantly important subjects due to strong application potentials. This article presents the interaction between cryptophane-M and chloroform by fluorescence spectroscopy. The so

Full text of DOI:10.1007/s10895-010-0739-5

J Fluoresc (2011) 21:531–538
DOI 10.1007/s10895-010-0739-5
ORIGINAL PAPER
Efficient Encapsulation of Chloroform with Cryptophane-M
and the Formation of Exciplex Studied
by Fluorescence Spectroscopy
Yanqi Shi & Xueming Li & Jianchun Yang & Fang Gao &
Chuanyi Tao
Received: 27 July 2010 /Accepted: 28 September 2010 /Published online: 15 October 2010
#
Springer Science+Business Media, LLC 2010
Abstract Efficient encapsulation of small molecules with
supermolecules is one of significantly important subjects due
to strong application potentials. This article presents the
interaction between cryptophane-M and chloroform by
fluorescence spectroscopy. The sonicated cryptophane-M
solution exhibits light green color in chloroform, and the
solid obtained from the evaporation of chloroform also has
different color from that of cryptophane-M. In contrast, the
sonicated cryptophane-M solutions in other solvents are
colorless, and the solid obtained from the evaporation of
these solvents has the same color as that of cryptophane-M.
Furthermore, the freshly prepared cryptophane-M solution in
different solvents is almost colorless, and the solid obtained
from the evaporation of these solvents displays the same
color as that of cryptophane-M. Although the sonicated
cryptophane-M solutions in different solvents have very
similar absorption spectra, they exhibit quite different
emission spectra in chloroform. In contrast, the freshly-
prepared cryptophane-M solutions show similar absorption
and emission spectroscopy in various solvents. The variation
of the fluorescence spectroscopy in binary solvents with the
increasing chloroform ratio suggests that cryptophane-M and
chloroform form a 1:1 exciplex, and the binding constant is
estimated to be 292.95 M . Although all solvents are able to
enter into the cavity of cryptophane-M, only chloroform can
stay in the cavity of cryptophane-M for a while, which is
mostly due to the strong intermolecular interaction between
cryptophane-M and chloroform, and this results in the
formation of the exciplex between them.
−1
.
.
.
Keywords Supramolecule Cryptophane-M Exciplex
.
Encapsulation Chloroform
Introduction
The inclusion complexes of the neutral or charged
species in the inner cavity of organic hosts have been
received considerable attention [1, 2]. Such complexes are
generally characterized by weak but specific non-covalent
interaction between the host and the guest [3], which have
been found in a wide range of applications, including
molecular recognition [4], drug delivery [5], separation
and storage [6], biosensing [7] and catalysis (chemical
reaction occurs inside the confined space of a molecular
nanoreactor) [8]. Hence, an excellent selectivity between
the host and the guest could guarantee application
potentials, which means a long-staying of the guest inside
the host. However, it is hard to predict the interaction
between the hosts and the guests. Therefore, the develop-
ment of organic receptors, which can encapsulate the
guests with specific selectivity, is a huge challenge for
chemists. As supramolecules, the cryptophanes (Fig. 1)
Electronic supplementary material The online version of this article
(
doi:10.1007/s10895-010-0739-5) contains supplementary material,
which is available to authorized users.
:
:
Y. Shi X. Li (*) F. Gao
College of Chemistry and Chemical Engineering,
Chongqing University,
Chongqing 400044, China
e-mail: xuemingli@cqu.edu.cn
:
J. Yang C. Tao
Key Laboratory for Optoelectronic Technology & Systems of the
Ministry of Education, College of Optoelectronic Engineering,
Chongqing University,
Chongqing 400044, China

5
32
J Fluoresc (2011) 21:531–538
other cryptophanes so thus it could encapsulate various
guests easily, and it could have more broaden application
potentials. On the other hand, the guest could leave easily
if the interaction between the cryptophane-M and the
guest is not strong enough since the inner exit of
cryptophane-M is large. To our limited knowledge, there
are few reports on the interaction of cryptophane-M with
various solvents. This inspires us to investigate the
interaction between cryptophane-M and the solvents
because the results could provide useful suggestions on
the development of new hosts. In this article, we report
our recent endeavors to clarify if cryptophane-M could
encapsulate various guests with high selectivity with
fluorescence spectroscopy.
Fig. 1 The structure of cryptophanes
are globularly shaped and contain two cone-shaped
cyclotriveratrylene (CTV) units attached to one another
via three O-Z-O bridges, and hence they feature a
preorganized, there-dimensional enforce cavity suitable
for accommodating organic substrates [9–14], represent-
ing an important class of supramolecular hosts that can
form stable inclusion complexes with neutral and cationic
molecules [15–17]. For instance, cryptophanes-A and -E
act as encapsulating host with neutral molecules such as
chloroform, dichloromethane, or methane [18], and chiral
cryptophane-C is able to discriminate the two enantiomers
of CHFClBr [19], and water-soluble cryptophane-O
encapsulates easily choline and acetylcholine [20]. More
recently, the discovery of the binding of xenon in organic
or aqueous solution by cryptophanes opens a new and
fascinating supramolecular field [21].
Mass spectrometry (MS) and NMR spectroscopy are
reliable techniques for the characterization of crypto-
phane molecules, and for the investigation of their
remarkable host-guest properties [22, 23]. X-ray crystal
structure determination confirms the usual ball shape for
the cryptophanes [24]. Raman microspectrometry provides
exceptional spatial resolution and extreme sensitivity that
allow researchers to study micrometer scale solid samples
such as single crystals of cryptophane complexes [25].
Dong and co-workers surveyed the interactions of
cryptophane-A and cryptophane-E with neutral molecules
Experimental
Materials
Organic solvents were obtained from Chongqing Medical
and Chemical Corporation. Other chemicals and reagents
were purchased from Aldrich unless otherwise specified.
The organic solvents were dried using standard laboratory
techniques [28]. The starting materials were purified further
with redistillation or recrystallization before use.
Cryptophane-M was synthesized according to a well-
known method with modified procedures [29], and the
route was presented in Scheme 1.
Experimental Details and Apparatus
All experiments on the preparation and the spectroscopic
determination of the sample solutions were carried out in dark.
We performed contrast experiments for the detection of
encapsulation of the solvents by cryptophane-M. To guarantee
efficient and full encapsulation, the solution was sonicated for
2 h, and was kept for a week. The sonicated solution was
employed for the spectral detection. For comparison, the
CH Cl
(n=0, 1, 2) with the absorption and emission
4-n
n
spectroscopy [26, 27]. Cryptophane-M has larger size than
Scheme 1 Synthesis of
cryptophane-M

J Fluoresc (2011) 21:531–538
533
absorption and emission spectroscopy of the freshly-prepared
cryptophane-M solution was determined.
mixture was stirred for 15 h. After the filtration, the solid
was washed with a methanol/water mixture (100 ml) and
The UV/visible absorption spectra were recorded with a
Cintra spectrophotometer. The emission spectra were
checked with Shimadzu RF-531PC spectrofluorophoton-
meter. Quinine sulfate in 0.5 M H SO (Φ=0.546,
methanol (50 ml) to give 17.01 g of compound 2 as a
1
white powder (yield, 94%). H-NMR (DMSO-d , δ, ppm),
6
6.90 (m, 6H, Ar), 5.06 (t, 2H, OH), 4.41 (d, 4H, CH OH),
2
3.99 (s, 4H, OCH ), 3.74 (s, 6H, OCH ), 1.85 (m, 2H,
2
4
2
3
−
6
−5
1
×10 −×10 mol/L [30]) was used as a reference to
CH2).
determine the fluorescence quantum yields of the samples
in this study. The melting point was detected using a
Beijing Fukai melting point apparatus. Nuclear Magnetic
Resonance (NMR) was carried out at room temperature
with a Bruker 500 MHz apparatus with tetramethylsilane
Cryptophane-M
A solution of 2 (9.05 g) in formic acid (1.72 L) was
◦
stirred at 55 C for 4 h, and then a residue was obtained
(
TMS) as internal standard. Element analysis was detected
after the evaporation under vacuum, in which the desired
cryptophane-M was isolated by column chromatography
on silica gel (CH Cl /acetone 9:1) to give 1.956 g of
by CE440 elemental analysis meter from Exeter Analytical
Inc.. FT-IR spectra were recorded on a Nicolet Magna-IR
5
2
2
−
1
1
50-II in the region of 4000–400 cm using KBr pellets
cryptophane-M as a solid (yield, 8%). H-NMR (CDCl ,
3
spectrophotometer. All the measurements of the absorption
and fluorescence were made against the blank solution
treated in the same way by using 1.0 cm quartz cell and
carried out at room temperature.
δ, ppm), 6.77 (s, 6H, Ar), 6.67 (s, 6H, Ar), 4.54 (d, 6H,
CHa), 3.72–3.98 (m, 12H, OCH ), 3.80 (s, 18H, OCH ),
2
3
The fluorescence quantum yields of the samples in
various solvents were determined based on the following
equation [31, 32]:
R
2
0
n A I ðl Þdl
0
0
f
0
f
f
Φf ¼Φf
R
ð1Þ
n2A I ðl Þdl
f
f
f
0
Wherein n and n are the refractive indices of the solvents, A
0
and A are the absorption at the excited wavelength,
0
Φf and Φf are the quantum yields, and the integrals denote
the area of the fluorescence bands for the reference and
sample, respectively.
Synthesis of Cryptophane-M
(
a)
1
, 4-Bis(4-formyl-2-methoxyphenoxy)butane (Compound 1)
A solid of NaOH (8 g) and 1,4-dibromobutane (11.8 ml)
was added in the solution of vanillin (30 g) dissolved in
DMF (100 ml), respectively. The mixture was stirred for
8
h under reflux. After cooling to room temperature, the
solid compound was obtained by the filtration to give
1
2
8.64 g of 1 as a beige powder (yield, 80%). H-NMR
(
DMSO-d , δ, ppm), 9.84 (s, 2H, CHO), 7.55 (d, 2H, Ar),
6
7
.39 (s, 2H, Ar), 7.18 (d, 2H, Ar), 4.18 (s, 4H, OCH ), 3.83
2
(
s, 6H, OCH ), 1.93 (q, 4H, CH ).
3 2
1
,4-Bis(4-Hydroxymethyl-2-Methoxyphenoxy)Butane
(
Compound 2)
(b)
Fig. 2 Colors of the solutions (a freshly-prepared solution, b sonicated
solution). From left to right: acetone, ethyl acetate, 1,2-dichloroethane,
1,4-dioxane, dichloromethane, acetonitrile, chloroform
To a mixture of 1 (17.9 g) in methanol (200 ml) was
slowly added NaBH4 (5 g, 131.6 mmol) at 0°C. The

5
34
J Fluoresc (2011) 21:531–538
Table 1 Absorption and fluorescence spectral data of cryptophane-M in
various solvents (A: freshly-prepared solution, B: sonicated solution)
Solvent
,4-dioxane
ethyl acetate
,2-dichloroethane
λ
abs(nm)
log ε
λ
em(nm)
Ф
f
(
a)
b)
1
A
B
A
B
A
B
A
B
A
B
A
B
A
B
283
283
284
283
283
282
283
284
284
284
284
283
283
283
4.65
4.66
4.64
4.65
4.64
4.65
4.65
4.64
4.66
4.65
4.65
4.64
4.65
4.64
435
430
435
432
435
434
435
435
433
434
434
434
433
443
0.286
0.248
0.262
0.208
0.270
0.229
0.230
0.206
0.293
0.233
0.296
0.171
0.276
0.050
(
1
Fig. 3 Colors of solids after the evaporation of the solvents in a
freshly-prepared solution, b sonicated solution). From left to right:
acetone, ethyl acetate, 1,2-dichloroethane, 1,4-dioxane, dichlorome-
thane, acetonitrile, chloroform
dichloromethane
acetone
3
2
7
6
.41 (d, 6H, CHe), 2.18 (m, 12H, CH ). IR (KBr) ν:3408,
932, 1608, 1510, 1466, 1400, 1265, 1142, 1087, 854,
41, 621 cm . Anal. Calcd for C H O : C, 73.60; H,
.79; O, 19.61. Found: C, 73.71; H, 6.84; O, 19.52.
2
acetonitrile
chloroform
−
1
6
0
66 12
(a) 1.0
(
a) 450
1
,4-dioxane
acetone
ethyl acetate
0
0
0
0
0
.8
.6
.4
.2
.0
4
3
3
2
2
1
1
00
50
00
50
00
50
00
50
0
Acetonitrile
Acetone
1
,2-dichloroethane
dichloromethane
acetonitrile
chloroform
1,4-Dioxane
Chloroform
1,2-dichloroethane
Ethyl acetate
Dichloromethane
2
60
280
300
320
340
Wavelength(nm)
4
00
450
500
550
600
Wavelength(nm)
(
b) 1.0
(b) 400
1
,4-dioxane
acetone
ethyl acetate
0
0
0
0
0
.8
.6
.4
.2
.0
350
1
,4-Dioxane
Acetone
Ethyl acetate
1,2-dichloroethane
Dichloromethane
Acetonitrile
1
,2-dichloroethane
3
2
2
1
1
00
50
00
50
00
dichloromethane
acetonitrile
chloroform
Chloroform
5
0
0
2
60
280
300
320
340
400
450
500
550
600
Wavelength(nm)
Wavelength(nm)
Fig. 4 UV-visible absorption spectra of cryptophane-M (2.0×
Fig. 5 Fluorescence emission spectra of cryptophane-M(2.0×
10 mol·L ) in solvents when excited at 376 nm (a freshly-
prepared solution, b sonicated solution)
−
5
−1
−5
−1
1
0
mol·L ) in various solvents (a freshly-prepared solution, b
sonicated solution)

J Fluoresc (2011) 21:531–538
535
solution. The color is much different from that of
cryptophane-M. In contrast, the solids obtained from the
evaporation of other solvents of the sonicated cryptophane-
M solutions display the same color as that of cryptophane-
M, as shown in Fig. 3 (b). While, the solids obtained from
the evaporation of the solvents of various fresh-prepared
cryptophane-M solutions have the same color as that of
cryptophane-M, as shown Fig. 3 (a). The results indicate that
cryptophane-M is able to encapsulate chloroform, and the
strong interaction between them makes chloroform remained
inside the cavity. In other words, an inclusion complex-like of
cryptophane-M and chloroform could be formed. Although
the other solvents could enter into the cavity, they could run
out of the cavity quickly as well if the interaction between
cryptophane-M and the solvents are weak.
(
a)
(
a)
8
6
4
2
00
00
00
00
0
1
2
3
4
5
6
7
8
9
1
(
b)
0
Fig. 6 Emission photographs of solutions (a freshly-prepared
solution, b sonicated solution). From left to right: acetone, ethyl
acetate, 1,2-dichloroethane, 1,4-dioxane, dichloromethane, acetoni-
trile, chloroform
400
450
500
550
600
Wavelength(nm)
(
b)
3
2
2
1
1
00
50
00
50
00
Results and Discussions
Solvents as Guests
1
0
We chose various solvents as guests because they could be
encapsulated by cryptophane-M since they have small
molecular sizes. While, the solvents could leave easily if
intermolceular interaction between cryptophane-M and the
solvents is not strong enough. It is interesting to observe
that the color of the sonicated cryptophane-M solution in
chloroform changes from colorless to light green, while it
does not exhibit any color in other solvents such as 1,4-
dioxane, ethyl acetate, 1,2-dichloroethane, dichlorome-
thane, acetonitrile and acetone, as shown in Fig. 2 (b). In
contrast, the freshly-prepared cryptophane-M solution is
colorless in various solvents, as shown in Fig. 2 (a).
Furthermore, the red-brown solid is obtained after the
evaporation of chloroform from sonicated cryptophane-M
9
8
7
6
5
4
3
2
5
0
1
0
450
500
550
600
650
Wavelength(nm)
Fig. 7 Fluorescence spectra of cryptophane-M (4×10− mol·L−1) in
ethyl acetate/chloroform binary solvents (v/v). 1.100:0; 2.90:10;
.80:20; 4.70:30; 5.60:40; 6.50:50; 7.40:60; 8.30:70; 9.20:80;
10.10:90. a excited at 376 nm and b excited at 397 nm
6
3

5
36
J Fluoresc (2011) 21:531–538
0
.5
.0
0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
Y=1.01X+5.68
2
R =0.99703
-8.5
-8.0
-7.5
-7.0
-6.5
-6.0
-5.5
ln[G]
Fig. 9 Simulation of host and guest sizes
Fig. 8 Benesi–Hildebrand plot for inclusion complexes
On the other hand, a large difference is observed for the
emission spectra of the sonicated cryptophane-M solution
in chloroform from that in other solvents, for instance 1,4-
dioxane, ethyl acetate, 1,2-dichloroethane, dichlorome-
thane, acetonitrile and acetone. As shown in Fig. 5 (b), in
chloroform, the maximal emission wavelength of the
sonicated cryptophane-M solution is red-shifted, and its
emission intensity is much reduced. Table 1 shows that the
maximal emission wavelength of the sonicated
cryptophane-M solution exhibits about 10 nm red-shift in
chloroform with respect to that in other solvents, and the
fluorescence quantum yield of the sonicated cryptophane-M
solution in chloroform is much lower than that in other
solvents. In contrast, the emission spectra of the freshly-
prepared cryptophane-M solution display only a little
difference in various solvents (Fig. 5 (a)). We shall point
out the emission intensity of the sonicated cryptophane-M
solution are lower than that of the freshly-prepared
cryptophane-M solution in various solvents at the same
excitation conditions, and as a result, the fluorescence
quantum yields of the freshly-prepared cryptophane-M
solutions are higher than those of the sonicated
cryptophane-M solution in various solvents. However, the
emission of cryptophane-M is much lower and it displays a
larger change in chloroform after sonication (Fig. 6). The
above results demonstrate that chloroform can not only be
encapsulated by cryptophane-M, but stay inside the cavity
for a while. In contrast, although the other solvent
molecules could enter cavity, they can not remain inside
the cavity for a long time.
Fig. 4 (a) shows that no obvious difference is observed
for the absorption spectra of cryptophane-M in various
solvents, such as 1,4-dioxane, ethyl acetate, 1,2-dichloro-
ethane, dichloromethane, chloroform, acetonitrile and ace-
tone. Table 1 presents the spectral data of cryptophane-M in
various solvents. The data suggest that the maximal
absorption wavelength and the molar extinction coefficients
of cryptophane-M are almost the same in various solvents.
The results seem some strange because the color of
cryptophane-M solution in chloroform is different from
that in other solvents (see Fig. 2 (a)). The absorption
spectra indicate that the complex-like of cryptophane-M
and chloroform is not a real molecule at the ground state,
and thus the electron transition nature of cryptophane-M is
not affected by the chloroform. Although the strong non-
covalent interaction between cryptophane-M and chloro-
form could keep chloroform stayed inside the cavity, it is
still not an actual complex. As a consequence, the
absorption spectra of the freshly-prepared cryptophane-M
solutions are almost the same in various solvents, and they
are almost identical to that of the sonicated cryptophane-M
solution (Fig. 4 (b)).
Table 2 The molecular sizes of solvents (Å)
Solvent
,4-dioxane
Molecular size (length)
1
4.78
4.35
6.61
4.28
2.85
3.16
2.85
acetone
ethyl acetate
1
,2-dichloroethane
Exciplex of Cryptophane-M with Chloroform
dichloromethane
acetonitrile
In order to reveal the deep reason on the large changes of
the emission spectra of the sonicated cryptophane-M
chloroform

J Fluoresc (2011) 21:531–538
537
solution in chloroform, we detected further the emission
spectra of the sonicated cryptophane-M solution in various
chloroform/other solvent binary solvents. Fig. 7 shows the
typical variation of emission spectra of sonicated
cryptophane-M solution in chloroform/ethyl acetate binary
solvents. Seen from Fig. 7 (a), with increasing chloroform
ratio, the fluorescence intensity decreases gradually, and the
emission wavelength is red-shifted gradually. This demon-
strates that chloroform has a stronger interaction with
cryptophane-M than other solvents. It is interesting to
observe that a new emission band with a maximal
emission wavelength of 497 nm is formed with increas-
ing ratio of chloroform in the mixed solvents (Fig. 7),
and an equal emission point (482 nm) appears. This
indicates that an inclusion complex between cryptophane-
M and chloroform could be formed at the excited state.
This explains well why the emission intensity of the
sonicated cryptophane-M solution is much reduced in
chloroform. While in contrast, such variation is not
observed for the freshly-prepared cryptophane-M solution
in various chloroform/other solvent binary solvents, which
demonstrates that the encapsulation is prerequisite for the
formation of cryptophane-M and chloroform exciplex. It is
reasonable to assume that the intermolecular interaction time
between cryptophane-M and chloroform in the excited state
could be very short, thus no guests could not enter into or
leave out of the cavity in such small period. This in turn
indicates that there are so enough chloroform molecules in the
cavity of cryptophane-M as the sample is excited that the
exciplex could be formed. However, due to weak interaction
between cryptophane-M and other solvents, the amount of the
guest molecules in the cavity of cryptophane-M could be too
few to interact with the host.
excellent linearity, which implies that the inclusion
exciplex has a stoichiometry of 1:1. The value of K is
−
1
292.95 M . The sizes of the host and guest are
calculated by HyperChem 8.0 [35], and the data are
shown in Table 2 and Fig. 9. It is obvious that all solvents
could enter into cryptophane-M based on the molecular
size. While, the strong non-covalent interaction (could be
dipole-dipole interaction) could stabilize the association
between cryptophane-M and chloroform. On the other
hand, the red-brown color of the solid obtained from the
sonicated cryptophane-M after the evaporation of chlo-
roform changes to cryptophane-M’s color if the solid is
kept in dark for a very long time, which confirms that the
interaction between cryptophane-M and chloroform is
non-covalent. It demonstrates that there exists a
non-covalent interaction between cryptophane-M and
chloroform.
Conclusions
The present study demonstrates that chloroform could be
encapsulated efficiently by cryptophane-M, and it could
stay inside of the cavity for a while. We show powerful
evidences that a real exciplex is formed between
cryptophane-M and chloroform as it is excited. The binding
−
1
constant of exciplex reaches 292.95 M . The results
suggest that the other solvents could enter into the cavity
of cryptophane-M, while the weak interaction between the
host and the guest could not keep these solvents remained
inside of the cavity. The interaction between chloroform
and cryptophane-M would be an ideal model for the
molecular recognition of cryptophane-M in terms of the
size and shape-fit as well as the recognition model between
the host and the guest molecules.
We further determined the formation constant (K) of the
exciplex of cryptophane-M and chloroform. The complex
formation between a host (H) and a guest (G) can be
described by a chemical reaction as:
Acknowledgements The work was supported by the National
Natural Science Foundation of China (No.60871039), the Science
and Technology Development Project of Chongqing
(No.2009AC6157) and the Fundamental Research Funds for the
Central Universities (No.CDJXS10122217).
K
H þG !H ꢀG
The formation constant (K) and the ratio of the complex
were calculated from the data [33] using the modified
Benesi–Hildebrand equation [34]:
References
1
. Brotin T, Dutasta JP (2009) Cryptophanes and their complex-
es#present and future. Chem Rev 109(1):88–130
F ꢁF
2. Chaffee KE, Fogarty HA, Brotin T, Goodson BM, Dutasta JP
2009) Encapsulation of small gas molecules by cryptophane-
11 in organic solution. 1. Size- and shape-selective complex-
0
ln
¼ln K þn ln½Gꢂ
ð2Þ
(
1
F
wherein F and F represent the fluorescence intensity of
ation of simple hydrocarbons. J Phys Chem A 113(49):13675–
13684
. Diez NM, de la Pena AM, Garcia MCM, Gil DB, Canada-Canada F
0
cryptophane-M in the presence and absence of chloro-
form, respectively; K and n are the binding constant and
the number of binding sites; K and n are constants. Fig. 8
3
(2007) Fluorimetric determination of sulphaguanidine and sulpha-
methoxazole by host-guest complexation in beta-cyclodextrin and
shows the plot of ln(F /F-1) versus ln[G] exhibits
partial least squares calibration. J Fluoresc 17(3):309–318
0

5
38
J Fluoresc (2011) 21:531–538
4
. Enoch IVMV, Swaminathan M (2006) Fluorimetric study on
molecular recognition of beta-cyclodextrin with 2-amino-9-fluore-
none. J Fluoresc 16(4):501–510
19. Crassous J, Collet A (2000) The bromochlorofluoromethane saga.
Enantiomer 5(5):429–438
20. Garel L, Lozach B, Dutasta JP, Collet A (1993) Remarkable effect
of receptor size in the binding of acetylcholine and related
ammonium-ions to water-soluble cryptophanes. J Am Chem Soc
115(24):11652–11653
5
. Chen Y, Pang Y, Wu JL, Su Y, Liu JY, Wang RB, Zhu BS, Yao YF,
Yan DY, Zhu XY, Chen Q (2010) Controlling the Particle Size of
Interpolymer Complexes through Host-Guest Interaction for Drug
Delivery. Langmuir 26(11):9011–9016
129
21. Taratula O, Dmochowski IJ (2010) Functionalized
Xe contrast
6
7
8
9
. Benounis M, Jaffrezic-Renault N, Dutasta JP, Cherif K, Abdelghani
A (2005) Study of a new evanescent wave optical fibre sensor for
methane detection based on cryptophane molecules. Sens Actuators
B 107(1):32–39
agents for magnetic resonance imaging. Curr Opin Chem Biol 14
(1):97–104
22. Brotin T, Darzac M, Forest D, Becchi M, Dutasta JP (2001)
Formation of cryptophanes from their precursors as viewed by
liquid secondary ion mass spectrometry. J Mass Spectrom 36
(10):1092–1097
23. Huber G, Beguin L, Desvaux H, Brotin T, Fogarty HA, Dutasta
JP, Berthault P (2008) Cryptophane-xenon complexes in organic
solvents observed through NMR spectroscopy. J Phys Chem A
112(45):11363–11372
24. Petrov O, Tosner Z, Csoregh I, Kowalewski J, Sandstrom D
(2005) Dynamics of chloromethanes in cryptophane-E inclusion
complexes: A H-2 solid-state NMR and X-ray diffraction study. J
Phys Chem A 109(20):4442–4451
. Kim BS, Ko YH, Kim Y, Lee HJ, Selvapalam N, Lee HC, Kim K
(
2008) Water soluble cucurbit[6]uril derivative as a potential Xe
carrier for Xe-129 NMR-based biosensors. Chem Commun
4:2756–2758
2
. Marjanska M, Goodson BM, Castiglione F, Pines A (2003)
Inclusion complexes oriented in thermotropic liquid-crystalline
solvents studied with carbon-13 NMR. J Phys Chem B 107
(
46):12558–12561
. Chaffee KE, Marjanska M, Goodson BM (2006) NMR studies of
chloroform@cryptophane-A and chloroform@bis-cryptophane in-
clusion complexes oriented in thermotropic liquid crystals. Solid
State Nucl Mag 29(1–3):104–112
25. Cavagnat D, Brotin T, Bruneel JL, Dutasta JP, Thozet A, Perrin
M, Guillaume F (2004) Raman microspectrometry as a new
approach to the investigation of molecular recognition in solids:
Chloroform-cryptophane complexes. J Phys Chem B 108
(18):5572–5581
1
0. Bouchet A, Brotin T, Cavagnat D, Buffeteau T (2010) Induced
chiroptical changes of a water-soluble cryptophane by encapsula-
tion of guest molecules and counterion effects. Chem Eur J 16
(
15):4507–4518
26. Zhang CH, Shen WL, Wen GM, Chao JB, Qin LP, Shuang SM,
Dong C, Choi MMF (2008) Spectral study on the interaction of
1
1. Martinez A, Robert V, Gornitzka H, Dutasta JP (2010) Controlling
helical chirality in atrane structures: solvent-dependent chirality
sense in hemicryptophane-oxidovanadium(V) complexes. Chem
Eur J 16(2):520–527
2. Tosner Z, Lang J, Sandstrom D, Petrov O, Kowalewski J (2002)
Dynamics of an inclusion complex of dichloromethane and
cryptophane-E. J Phys Chem A 106(38):8870–8875
n
cryptophane-A and neutral molecules CH Cl4-n (n=0, 1, 2).
Talanta 76(2):235–240
27. Zhang CH, Shen WL, Fan RY, Zhang GM, Shuang SM, Dong
C, Choi MMF (2010) Spectral study on the inclusion complex
1
1
3
of cryptophane-E and CHCl . Spectrochim, Acta Part A 75
(1):157–161
3. Lang J, Dechter JJ, Effemey M, Kowalewski J (2001) Dynamics
of an inclusion complex of chloroform and cryptophane-E:
Evidence for a strongly anisotropic van der Waals bond. J Am
Chem Soc 123(32):7852–7858
28. Perrin DD, Armarego WLF, Perrin DR (1966) Purification of
Laboratory Chemicals. Pergamon, New York
29. Canceill J, Collet A (1988) Two-step synthesis of D and C3h
3
cryptophanes. JCS Chem Comm 9:582–584
1
4. Roesky CEO, Weber E, Rambusch T, Stephan H, Gloe K, Czugler
M (2003) A new cryptophane receptor featuring three endo-
carboxylic acid groups: Synthesis, host behavior and structural
study. Chem Eur J 9(5):1104–1112
30. Eaton DF (1988) Reference materials for fluorescence measure-
ment. Pure & Appl Chem 60(7):1107–1114
31. Maus M, Retigg W, Bonafoux D, Lapouyade R (1999) Photoin-
duced intramolecular charge transfer in a series of differently
twisted donor-acceptor biphenyls as revealed by fluorescence. J
Phys Chem A 103(18):3388–3401
1
5. Tosner Z, Petrov O, Dvinskikh SV, Kowalewski J, Sandstrom D
(
2004) A C-13 solid-state NMR study of cryptophane-E: chloro-
methane inclusion complexes. Chem Phys Lett 388(1–3):208–211
6. Garcia C, Humiliere D, Riva N, Collet A, Dutasta JP (2003)
Kinetic and thermodynamic consequences of the substitution of
SMe for OMe substituents of cryptophane hosts on the binding
of neutral and cationic guests. Org Biomol Chem 1(12):2207–
32. Lukeman M, Veal D, Wan P, Ranjit V, Munasinghe N, Corrie JET
(2004) Photogeneration of 1, 5-naphthoquinone methides via
excited-state (formal) intramolecular proton transfer (ESIPT) and
photodehydration of 1-naphthol derivatives in aqueous solution.
Can J Chem 82:240–253
1
2
216
33. The supporting data are available electronically on the supple-
mentary material at http://www.springerlink.com/content/104905/
34. Kandagal PB, Ashoka S, Seetharamappa J, Shaikh SMT,
Jadegoud Y, Ijare OB (2006) Study of the interaction of an
anticancer drug with human and bovine serum albumin: spectro-
scopic approach. J Pharm Biomed Anal 41(2):393–399
35. Hyperchem 8.0 Package, Hyperchem Inc., Gainesville, FL
1
1
7. Brotin T, Cavagnat D, Dutasta JP, Buffeteau T (2006) Vibrational
circular dichroism study of optically pure cryptophane-A. J Am
Chem Soc 128(16):5533–5540
8. Sun P, Jiang YD, Xie GZ, Du XS, Hu J (2009) A room
temperature supramolecular-based quartz crystal microbalance
(
QCM) methane gas sensor. Sens Actuators B 141(1):104–108