A pyridyl-benzimidazole based molecular luminescent turnstile

Article abstract of DOI:10.1039/c8nj00890f

A molecular turnstile T1 based on a luminescent pyridyl-benzimidazole stator and a rotor containing a pyridyl coordinating site is designed and its multi-step synthesis is described. The turnstile T1 undergoes free rotation of the rotor around the stator.

Full text of DOI:10.1039/c8nj00890f

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ISSN 1144-0546
PAPER
Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
diarylethene-based metal–organic frameworks
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xsReceived
00th
A pyridyl-benzimidazole based molecular luminescent turnstile
January 20xx,
Bérangère Godde, Dialia Ritaine, Abdelaziz Jouaiti,*, Matteo Mauro, and Mir Wais
Hosseini*
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
A
molecular turnstile T1 based on a luminescent pyridyl- freely rotate around the stator. However, for those bearing
benzimidazole stator and a rotor containing a pyridyl coordinating simultaneously interactions units on both rotor and stator, the
site is designed and its multi-step synthesis described. The rotational movement may be blocked using an external (Fig. 1).
turnstile T1 undergoes free rotation of the rotor around the
Here we report on the design and synthesis of a novel turnstile
stator. In the presence of Ag+ cation as an effector, the rotational
composed of a rotor bearing a pyridyl moiety and a stator based on
movement is locked through simultaneous binding of the cation
a benzimidazole unit bearing also a pyridyl group as coordinating
by both pyridyl coordinating sites. The dynamic reversible
sites. In solution, the switching between the open T1 and closed T1-
Ag+ states of the turnstile was monitored by NMR (1- and 2D) and
behaviour of the turnstile in solution was investigated by 1- and
2D-NMR spectroscopy and by absorption and emission
by absorption and emission spectroscopies.
spectroscopies.
Experimental
Experimental details dealing with synthetic procedures,
characterization, NMR and photophysical investigations are
reported in the Electronic Supplementary Information (ESI).
Introduction
The design and synthesis of dynamic of molecular architectures and
the control of their intramolecular movement is a topic of current
interest. Since the pioneering investigations by Sauvage et al,1
Stoddart et al,2 Feringa et al3 and Balzani et al,4 a variety of
molecular motors, rotors and machines subject to rotational or
translational movement has been reported.5-13 Molecular
turnstiles14-21 constitute a particular class of dynamic systems
undergoing rotational movement. These molecules are based on
two interconnected parts, i.e. a stator and a rotor. The designation
of the two parts, i.e. rotor and stator, is relative since they both
undergo a rotational movement (Fig. 1).
Results and discussion
Design of turnstiles
The design of the turnstile T1 (Scheme 1) is based on a stator and a
rotor connected to the stator by covalent bonds. As for the latter, a
benzimidazole hydroquinone unit has been chosen owing to its
photophysical properties. The benzimidazole based stator is
equipped with a pyridyl unit as a coordinating site. The rotor is
composed of
a
pyridyl moiety as the coordinating site,
and by two
symmetrically substituted at positions
2
6
tetraethyleneglycol spacers linking the rotor to the stator. The
junction between the rotor and the stator is ensured by two other
groups using positions 1 and 4 of the substituted benzimidazole
moiety.
Figure 1. Schematic representations of a turnstile in its open and closed states. In the
absence of the effector (yellow sphere) the rotor spins freely around the stator
whereas in the presence of the effector the rotational movement is blocked.
For turnstiles not equipped with specific interactions sites, the rotor
Scheme 1. Chemical structures of molecular turnstiles in its open T1 and closed T1-Ag+
states and assignment of H-atoms.
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The turnstile is designed to undergo a switching process between
its open T1 and closed T1-Ag+ states (Fig. 1) using Ag(I) cation as the
first mono deprotonated using NaH in dry THF and then condensed
with 2,6-difluropyridine 8. The reaction afforded the compound 9 in
external effector (Scheme 1). The locking of the rotational 87% yield. The latter was activated as its dimesylate derivative 10
movement of the turnstile T1 in the presence of Ag+ as effector
upon treatment with mesyl chloride (MsCl) in presence of Et3N in
anhydrous THF. Finally, the cyclization, leading to the turnstile T1 in
33% yield, was achieved upon condensation of the compound 10
with the hydroquinone derivative 7 in DMF using Cs2CO3 as base.
results from simultaneous binding of the metal cation by both
coordinating sites located on the stator and on the rotor. The
choice of Ag+ cation was based on its affinity to interact with pyridyl
units in a reversible manner and its propensity to adopt a linear
coordination geometry. Furthermore, taking advantage of the poor
solubility of silver halide salts, the locking process may be reversed
leading to the open state of the turnstile upon addition of a salt
such as Et4NBr for example.
Switching of turnstiles
As schematically shown in figure 1, the turnstile T1 is designed to
undergo a switching between its open T1 state subject to a free
rotational movement and its closed T1-Ag+ state for which the
movement is blocked by simultaneous binding of Ag+ cation by both
pyridyl coordinating sites located on the stator and on the rotor
(Scheme 1). The close state of the turnstile T1-Ag+ was
quantitatively prepared as a yellow solid upon treatment at room
temperature and in the dark of T1 with AgCF3SO3 in CH3CN.
Synthesis of turnstiles
The strategy adopted for the synthesis of T1 is based on the
functionalization of 1,4-dimethoxybenzene as the precursor of the
stator and a cyclization step using 2,6-difluoropyridine 8 (Scheme
2).
Solution dynamic behaviour of the turnstiles T1
The dynamic behaviour of T1 and T1-Ag+ was investigated in
solution by both 1D and 2D NMR spectroscopies. For the open (T1)
and closed states (T1-Ag+) of the turnstile, all H-atoms signals were
assigned (Scheme 1) by means of 1H- and 13C-NMR spectroscopy
(see ESI).
1
For T1, the 1D H-NMR (Fig.2, trace 1) spectrum recorded at room
temperature in CD3CN displays highly symmetric resonance
patterns. In the aromatic region, two doublets at 8.71 ppm and 7.73
ppm are assigned to Hm and Hn of the pyridyl unit. Signals
corresponding to Hk and Hl, two doublets characterized by a roof
effect appear at 6.57 and 6.67 ppm. Signals corresponding to H
atoms of the pyridyl moiety appear as a doublet (Hb and Hb’ ) and a
triplet (Ha) at 6.20 ppm and 7.45 ppm respectively.
For the closed state T1-Ag+, signals corresponding to the pyridyl
moiety of the stator (Hm and Hn) and Hk and Hl are downfield
shifted by 0.05 ppm and 0.18 ppm respectively (Fig2, trace 2). For
the pyridyl unit of the rotor, Ha, Hb and Hb’ are upfield shifted by
0. 07, 0.04 ppm respectively (Fig2, trace 2).
Scheme 2. Schematic general synthetic strategy for the preparation of the turnstile T1.
Reaction conditions: i) HNO3, O °C during 1 hour, room temperature, 1 hour then 100
°C, 1 hour; ii) H2, Pd/C, dry THF, room temperature, 24 hours; iii) H2, Pd/C, dry THF,
room temperature, 24 hours; iv) pyridine-4-carboxaldehyde, Na2S2O5, Ethanol, 70 °C,
15 hours; v) CH3I, CuI, Cs2CO3, 1,10-phenantroline, DMF, 90 °C, 20 hours; vi) BBr3, dry
CH2Cl2, -78°C → room temperature, 20 hours, vii) tetraethyleneglycol, NaH, THF,
reflux, 4 days; viii) mesityl chloride, Et3N, THF, room temperature, 12 hours; ix) 7,
Cs2CO3, DMF, 90°C, 48 hours.
The synthesis of the stator 7 is achieved in six steps. Starting with
1,4-dimethoxybenzene 1, compound 2 was prepared as a mixture of
ortho/para dinitro isomers using a reported procedure.22 Reduction
of the mixture by H2 (3 bars) in dry THF afforded the compound 322
after purification by column chromatography. The latter was further
quantitatively hydrogenated into the desired compound 4.23 The
condensation in ethanol of 4 with the commercially available 4-
24
pyridinecarboxaldehyde in the presence of Na2S2O5 afforded the
compound 5 in 70%. To prevent the deprotonation of 5 during the
cyclisation step, the –NH group of the benzimidazole moiety was
methylated by iodomethane affording the compound 6. This step
was achieved using copper iodide, 1,10-phenantroline and cesium
carbonate. Finally, the compound 7 was obtained in 82% yield by
deprotection in dry dichloromethane of compound 6 using BBr3. On
the other hand, the commercially available tetraethyleneglycol was
Figure 2. A portion of the aromatic region of the 1H-NMR (CD3CN, 400 MHz, 298K)
spectrum of T1 (trace 1), T1-Ag+ (trace 2) and T1 after the addition of 1 eq. of Et4NBr
(trace 3).
The reversibility of the locking/unlocking process was also studied
by 1D-1H NMR spectroscopy. The addition of one equivalent of
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Et4NBr in CH3CN to a CH3CN solution of T1-Ag+ caused the
precipitation of AgBr. After evaporation of the solvent and
dissolution of the reaction product in CD3CN, the 1H-NMR spectrum
confirmed that the open states of T1 is restored (Fig. 2, trace 3).
Photophysical investigations
The absorption and emission properties of the turnstile in its open
T1 and closed T1-Ag+ were studied in dilute CH3CN solution at room
temperature (Table 1).
1
The locking of the turnstile T1 was investigated by 2D H-1H NOESY
techniques Correlation maps are displayed on Fig. 3 for T1 and T1-
Ag+ complex. For the turnstile T1 (open state), the bidimensional
1H-1H correlation map (Fig. 3 top) shows only the expected short
range cross-correlations between Hm and Ho, Hl and Hj’ as well as
between Hk and Hj of the imidazole moiety. For the rotor part, as
expected, Hb and Hb’ atoms correlate with Hc and Hc’.
Table 1. Photophysical data recorded for T1, T1-Ag+ in CH3CN at
1.0×10-5 M concentration at room temperature.
Absorbance (ε)
λ
em[nm]
τ[ns]
PLQY (%)
[nm, (103 M-1cm-1)]
T1
257(22.5), 283 (15.5),
303sh (10.3)
521
521
8.3
8.5
10
Owing to the fast rotation of the rotor around the stator at room
temperature with respect to the NMR time scale, no through-space
correlations between Hm and Hn and hydrogen atoms of the
tetraethyleneglycol spacers are observed.
T1-Ag+
257 (21.4), 283(14.8),
303sh (9.6)
8.5(air)
sh denotes a shoulder; a λexc = 350 nm
For the turnstile T1, the UV visible absorption spectrum is
composed of three bands (Fig. 4). At shorter wavelength, a narrow (
λabs,max = 257 nm) and intense (ε = 2.2 ×104 M-1 cm-1) absorption
band which can be ascribed to a transition with spin-allowed
singlet-manifold ligand centred (1LC) character is observed. At
longer wavelengths, two others absorption bands at 283 and 303
nm with lower intensity (ε
=
1.5×104 and 1×104 M-1 cm-1
respectively) are observed. These bands can also be ascribed to a
1LC on the basis of the lack of neat solvatochromic effect upon
changing the solvent polarity while using identical concentrations
(Fig. S5).
However, at lower energy, the presence of an overlapping band
with partial intraligand charge transfer (1ILCT) character involving
the π-conjugated pyridyl-benzimidazole chromophore, cannot be
completely ruled out at the present stage owing to the very small
bathochromic shift observed at lower energy going from toluene to
CH2CH2, CH3CN and finally DMF.
Figure 3. Portion of the 2D ROESY correlations (1H-1H NMR, 400 MHz) for T1 in CD3CN
(top) and for T1-Ag+ in CD3CN (bottom) at 298 K.
The locking of the rotational movement leading to the closed state
of the turnstile T1-Ag+ upon addition of Ag+ was also studied by 2D
NMR experiments at room temperature (Fig. 3 bottom). Upon
binding of Ag+ cation by both pyridyl units belonging to the rotor
and to the stator, a novel set of correlations was observed. Indeed,
through-space correlations between Hn, Hm and the hydrogen
atoms of the polyethylene glycol chains demonstrated the
proximity of the pyridyl unit of the stator with the hydrogen of the
rotor and the location of the stator within the cavity of the
Figure 4. UV-visible absorption spectra of turnstiles T1 (red trace) and T1-Ag+ (blue
trace) in CH3CN (1.0×10-5 M) at room temperature.
Surprisingly, the presence of Ag+ cation leading to the closed-state
T1-Ag+, did not induce spectral changes in the electronic absorption
profile (Fig. 4). This is most likely due to the concentration (10-5 M)
macrocycle. Furthermore, a strong correlation between Ho (methyl used for the investigation. In order to study this hypothesis,
absorption and emission measurements of T1-Ag+ were carried out
at of 1.0×10-4 and 1.0×10-3 M concentration. It can be noticed that
unit on the imidazole) and the hydrogen atoms of the
polyethyleneglycol spacers is observed. The observation of other
the absorption band at ca. 300 nm undergoes a hypsochromic shift
through spaces correlations between Hm and Hc and Hc’ further
upon increase of the concentration of the T1-Ag+ complex (Fig 5
confirms the above mentioned observations.
top). Concomitantly, for the two bands at ca 260 nm and 280 nm, a
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decrease of the molar extinction coefficient is observed (Fig. 5 top).
The expanded portion of the spectra between 340 and 370 nm (Fig.
5 bottom) shows a slight increase of the lowest-lying absorption
band that can be attributed to a charge transfer transition of the
T1-Ag+ species. This observation suggests a lower affinity of T1 for
Ag(I) cation when compared to previously reported turnstiles.18,19
Figure 6. Normalized emission spectra (
λ
exc = 350 nm) of T1 (red trace) and T1-Ag+ (blue
trace) in dilute CH3CN (1.0×10-5 M) at room.
Excited state lifetime measurements showed a mono-exponential
decay kinetics with τ = 8.3 and 8.5 ns for T1 and T1-Ag+, respectively
indicating that, under the concentration used (1.0×10-5 M), the
turnstile is in its open state T1. This is substantiated by the stability
constants K1:1 = 4.0×103 M-1 determined by NMR spectroscopy.
Indeed, considering 1.0x10-3 M concentration of the turnstile T1,
43%, 50% and 7% distribution for the free turnstile T1, T1-Ag+ (1:1
[T1-Ag2]2+ species respectively may be calculated (Fig. S4). At
1.0x10-5 M concentration, for an equimolar mixture of T1 and
CF3SO3Ag, the simulated speciation profile (Fig. S4) shows the
presence of 96.3%, and 3.7% of T1 and T1-Ag+, respectively.
Furthermore, for T1-Ag+ complex in CH3CN, emission spectra were
recorded at different concentrations (Fig. 7). By increasing the
concentration of T1-Ag+ from 1.0x10-4 to 1.0x10-3 M, a small
bathochromic effect with maxima shifting from 525 to 527 nm is
observed. Such minor variation is in agreement with the weak
binding propensity of T1 for silver cation.
Figure 5. UV-visible absorption spectra of turnstiles T1 (1.0×10-5 M) (red trace), T1-Ag+
(1.0×10-5 M) (blue trace), 1.0×10-4 M (green trace, 1.0×10-3 M (black trace) in CH3CN at
room temperature (top) and zoom of the UV-visible spectra of the turnstile T1 at
(1.0×10-5 M) between 340 and 370 nm (bottom)
In order to investigate this assumption, a titration experiment in the
0–25 eq. range of T1 by Ag+ was carried out using 1H-NMR
spectroscopy by observing the shifts of signals corresponding to Hn
and Hi/Hi’ H atoms (see Fig. S1–S3).
Upon fitting the complete titration curves, stability constants K1:1
=
4.0×103 M-1 and K2:1 = 1.6×106 M-1 were calculated. These two
binding constants correspond to the 1:1 and 2:1 Ag+/ T1 complexes
respectively. The K1:1 is in agreement with stability constants
described in the literature for silver complexes by ligands bearing
two pyridines units.18 The formation of the 1:1 and 2:1 Ag+/T1
complexes were further confirmed by electron spray ionization
mass spectrometry (ESI-MS) using
a sample of T1 and 25
Figure 7. Normalized emission (λexc = 350 nm) spectra of T1 (red trace) and T1-Ag+ at
different concentrations: 1.0×10-5 M (blue trace), 1.0×10-4 M (green trace), 1.0×10-3
(dark trace) in dilute CH3CN and at room.
equivalents of CF3SO3Ag. The mass spectra, represented in Fig. S6,
display peaks at 777.21 and 1033.05 which correspond to the 1:1
and 2:1 Ag+/ T1 complexes respectively. For the 2:1 species, it can
be tentatively assigned to the binding of one Ag+ cation by the two
pyridine moieties and a second one by the benzimidazole unit.
Upon photo-excitation with λexc = 350 nm, T1 and T1-Ag+ in CH3CN
display broad and featureless yellow emission at room temperature
with maxima centred at 521 nm with photoluminescence quantum
yield (PLQY) of 10% and 8.5%, respectively (table 1). As shown in
Fig. 6, the emission spectra profile is unaffected by the presence of
1 eq. of Ag+, while PLQY seems to be only slightly affected.
Finally, in order to assess the nature of the emitting excited state, a
solvent effect study was carried out for T1 (Fig. 8) using toluene
(λem = 478 nm), CH2Cl2 (λem = 508 nm) CH3CN (λem = 521 nm) and
DMF (λem = 522 nm) with λexc = 350 nm. The investigation
highlighted the partial charge transfer nature of the radiative
transition. Indeed, the emission spectra recorded at identical
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dilution (1.0×10-5 M) show a bathochromic shift of its maximum
upon increasing solvent polarity.
7 G. S. Kottas, L. I. Clarke, D. Horinek, J. Michl, Chem. Rev. 2005,
105, 1281–1376.
8 Y. Shirai, A. J. Osgood, Y. Zhao, K. F. Kelly, J. M. Tour, Nano Lett.
2005, 5, 2330–2334.
9 E. R. Kay, D. A. Leigh, F. Zerbetto, Angew. Chem. Int. Ed. 2007, 46,
72–191.
10 K. Kinbara, T. Muraoka, T. Aida, Org. Biomol. Chem. 2008, 6,
1871–1876.
11 G. Vives, H.-P. J. de Rouville, A. Carella, J.-P. Launay, G. Rapenne,
Chem. Soc. Rev. 2009, 38, 1551–1561.
12 F. Coutrot, E. Busseron, Chem. Eur. J. 2009, 15, 5186–5190.
13 E. A. Neal, S. M. Goldup, Chem. Sci. 2015, 6, 2398–2404.
14 T. C. Bedard, J. S. Moore, J. Am. Chem. Soc. 1995, 117, 10662–
10671.
15 A. Carella, J. Jaud, G. Rapenne, J.-P. Launay, Chem. Commun.
2003, 2434–2435.
Figure 8. Solvent effect for T1. Normalized emission spectra of turnstiles of T1 (1.0×10-5
M ) in toluene (red wine trace), in CH2Cl2 (black trace), CH3CN (red trace) and DMF
(olive trace).
16 N. Weibel, A. Mishchenko, T. Wandlowski, M. Neuburger, Y.
Leroux, M. Mayor, Eur. J. Org. Chem. 2009, 6140–6150.
17 K. Skopek, M. C. Hershberger, J. A. Gladysz, Coord. Chem. Rev.
2007, 251, 1723–1733.
Conclusions
18 a) A. Guenet, E. Graf, N. Kyritsakas, L. Allouche, M. W. Hosseini,
Chem. Commun. 2007, 2935–2937 ; b) A. Guenet, E. Graf, N.
Kyritsakas, M. W. Hosseini, Inorg. Chem. 2010, 49, 1872–1883 ; c) T.
Lang, A. Guenet, E. Graf, N. Kyritsakas, M. W. Hosseini, Chem.
Commun. 2010, 46, 3508–3510 ; d) A. Guenet, E. Graf, N. Kyritsakas,
M. W. Hosseini, Chem. Eur. J. 2011, 17, 6443–6452 ; e) T. Lang, E.
Graf, N. Kyritsakas, M. W. Hosseini, Dalt. Trans. 2011, 40, 3517–
3523 ; f) T. Lang, E. Graf, N. Kyritsakas, M. W. Hosseini, Dalt. Trans.
2011, 40, 5244–5248 ; g) T. Lang, E. Graf, N. Kyritsakas, M. W.
Hosseini, Chem. Eur. J. 2012, 18, 10419–10426 ; i) T. Lang, E. Graf,
N. Kyritsakas, M. W. Hosseini, New J. Chem. 2013, 37, 112–118.
19 a) N. Zigon, A. Guenet, E. Graf, M. W. Hosseini, Chem. Commun.
2013, 49, 3637–3639 ; b) N. Zigon, A. Guenet, E. Graf, N. Kyritsakas,
M. W. Hosseini, Dalt. Trans. 2013, 42, 9740–9745 ; c) N. Zigon, N.
Kyritsakas, M. W. Hosseini, Dalton. Trans. 2014, 43, 152–157; d) N.
Zigon, M. W. Hosseini, Chem. Commun. 2015, 51, 12486–12489 ; e)
N. Zigon, P. Larpent, A. Jouaiti, N. Kyritsakas, M. W. Hosseini,
Dalton. Trans. 2014, 43, 15779–15784 ; f) N. Zigon, P. Larpent, A.
Jouaiti, N. Kyritsakas, M. W. Hosseini, Chem. Commun. 2014, 50,
5040–5042.
In conclusion, the pyridyl-benzimidazole based molecular turnstile,
T1, was designed and synthesised using a convergent multi-step
procedure. The switching between its open state T1 and closed
state T1-Ag+ was investigated by 1- and 2D-NMR analysis and by
absorption and emission spectroscopy in solution. The locking by
addition of Ag+ cation as effector and un-locking by addition of Br-
anion was shown to be reversible. The turnstile shows a yellow
photoluminescence in CH3CN with PLQY value of ca. 10%. The
bathochromic shift observed for the emission process upon
increasing the solvent polarity indicated that the radiative transition
arises from an excited state with partial charge transfer nature. The
use of other effector such as Pd(II) is currently under investigation.
Acknowledgements
We thank the University of Strasbourg, the C.N.R.S., the
International centre for Frontier Research in Chemistry (icFRC),
the Labex CSC (ANR-10-LABX- 0026 CSC) within the
Investissement d’Avenir program ANR-10-IDEX-0002-02, the
Institut Universitaire de France and the Ministère de
l’Enseignement Supérieur et de la Recherche for financial
support and a scholarship to BG.
20 I. N. Meshkov, V. Bulach, Y. G. Gorbunova, N. Kyritsakas-Gruber,
M. S. Grigoriev, A. Y. Tsivadze, M. W. Hosseini, Inorg. Chem, 2016,
55, 10774 –10782.
21 B. Godde, A. Jouaiti, A. Fluck, N. Kyritsakas, M. Mauro, and M. W.
Hosseini Dalton Trans., 2017, 46, 14897 14906.
22 P. Hammershøj, TK. Reenberg, M. Pittelkow, C. B. Nielsen, O.
Hammerich and J. B. Christensen, Eur. J. Org. Chem., 2006, 12,
2786-2794.
23 C. Morin, T. Besset, J.-C. Moutet, M. Fayolle, M. Brückner, D.
Limosin, K. Becker and E. Davioud-Charvet , Org. & Bio. Chemistry,
2008, 6, 2731-2742
24 a) H. Naeimi and N. Alishahi, Research article, Organic Chemistry
International, 2012; b) C.-K. Ryu, E.-H. Song, J.-Y. Shim, H.-J. You, K.-
U. Choi, I.-H. Choi, E.-Y. Lee and M.-J. Chae, Bioorg. Med. Chem.
Lett., 2003, 13, 17-20.
Notes and references
1 J.-P. Sauvage, Angew. Chem. Int. Ed. 2017, 56, 11080 – 11093.
2 J. F. Stoddart, Angew. Chem. Int. Ed. 2017, 56, 11094 – 11125.
3 B. L. Feringa, Angew. Chem. Int. Ed. 2017, 56, 11060 – 11078.
4 V. Balzani, M. Venturi, M., A. Credi, In Molecular Devices and
Machines: a Journey into the Nanoworld; Wiley-VCH: Weinheim,
2003; pp 1–457.
5 C. A. Schalley, K. Beizai, F. Vögtle, Acc. Chem. Res. 2001, 34, 465–
476.
6 R. Kelly, Topics in Current Chemistry; R. Kelly, Ed.; Springer: Berlin,
Heidelberg, 2005; Vol. 262, pp 1–227.
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A molecular turnstile based on a luminescent pyridyl-benzimidazole stator and a rotor
containing a pyridyl coordinating site may be reversibily switched between its open and
closed states upon binding/unbinding of silver cation.

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