Unusual Behavior of Donor-Acceptor Stenhouse Adducts in Confined Space of a Water-Soluble PdII8 Molecular Vessel

Article abstract of DOI:10.1021/jacs.9b03924

Donor-acceptor Stenhouse adducts (DASA) are new-generation photochromic compounds discovered recently. DASA exist normally in open form (blue/violet) and readily convert to cyclic (light yellow/colorless) zwitterionic form reversibly in the presence of green light in toluene/dioxane. In aqueous medium, the open form is not stable and converts to the cyclic zwitterionic form irreversibly. We report here a new self-assembled Pd₈ molecular vessel (MV) that can stabilize and store the open form of DASA even in aqueous medium. Reaction of the 90° acceptor cis-(tmeda)Pd(NO₃)₂ (M) [tmeda = N,N,N′,N′-tetramethylethane-1,2-diamine] with a symmetric tetraimidazole donor (L, 3,3′,5,5′-tetra(1H-imidazol-1-yl)-1,1′-biphenyl) in a 2:1 molar ratio yielded a water-soluble [8+4] self-assembled M₈L₄ molecular barrel (MV). This barrel (MV) is found to be a potential molecular vessel to store and stabilize the open forms of DASA in aqueous medium over the more stable zwitterionic cyclic form, while in the absence of the barrel the same DASA exist in cyclic zwitterionic form in aqueous medium. The hydrophobic interaction between the cavity and the open form of DASA molecules benefits reaching an out-of-equilibrium or reverse equilibrium state in aqueous medium. The presence of excess MV could even drive the conversion of the stable cyclic form to the open form in aqueous medium. The host-guest complex is stable upon irradiating with green light. To the best of our knowledge, this is the first successful attempt to stabilize the open form of DASA molecules in aqueous medium and the first report on the fate of DASA in a confined space discrete molecular architecture. Furthermore, the molecular vessel has been utilized for catalytic Michael addition reactions of a series of nitrostyrene derivatives with 1,3-indandione in aqueous medium.

Full text of DOI:10.1021/jacs.9b03924

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Article
Unusual Behaviour of Donor-Acceptor Stenhouse Adducts (DASA)
in Confined Space of a Water Soluble PdII8 Molecular Vessel
Rupak Saha, Anthonisamy Devaraj, Soumalya Bhattacharyya,
Soumik Das, Ennio Zangrando, and Partha Sarathi Mukherjee
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.9b03924 • Publication Date (Web): 03 May 2019
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Unusual Behaviour of Donor-Acceptor Stenhouse Adducts (DASA) in
Confined Space of a Water Soluble PdII8 Molecular Vessel
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Rupak Saha1, Anthonisamy Devaraj1§, Soumalya Bhattacharyya1§, Soumik Das1, Ennio Zangrando2 and
Partha Sarathi Mukherjee1*
1Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
2Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste 34127, Italy
ABSTRACT: Donor-Acceptor Stenhouse Adducts (DASA) are new generation photochromic compounds discovered in recent
past. DASA exist normally in open form (blue/violet) and readily convert to cyclic (light yellow/colourless) zwitterionic form
reversibly in presence of green light in toluene/dioxane. In aqueous medium, the open form is not stable and converts to the cyclic
zwitterionic form irreversibly. We report here a new self-assembled Pd8 molecular vessel (MV) that can stabilize and store the open
form of DASA even in aqueous medium. Reaction of 90° acceptor cis-(tmeda)Pd(NO3)2 (M) [tmeda = N,N,N′,N′-
tetramethylethane-1,2-diamine] with a symmetric tetraimidazole donor (L, 3,3',5,5'-tetra(1H-imidazol-1-yl)-1,1'-biphenyl) in 2:1
molar ratio yielded a water soluble [8+4] self-assembled M8L4 molecular barrel (MV). This barrel (MV) is found to be a potential
molecular vessel to store and stabilize the open forms of DASA in aqueous medium over the more stable zwitterionic cyclic form,
while in absence of the barrel the same DASA exist in cyclic zwitterionic form in aqueous medium. The hydrophobic interaction
between the cavity and the open-form of DASA molecules benefits to reach an out of equilibrium or reverse equilibrium state in
aqueous medium. Presence of excess molecular vessel (MV) could even drive the conversion of stable cyclic form to open form in
aqueous medium. The host-guest complex is stable upon irradiating with green light. To the best of our knowledge, this is the first
successful attempt to stabilize the open form of DASA molecules in aqueous medium and the first report on the fate of DASA in
confined space discrete molecular architecture. Furthermore, the molecular vessel has been utilized for catalytic Michael addition
reactions of a series of nitrostyrene derivatives with 1,3-indandione in aqueous medium.
Introduction
Scheme 1. General photo-switching behaviour of DASA
molecules. DASA1 and DASA2 are the two molecules
which are investigated in this study.
Light-driven photo-switching molecules have been of great
interest in current research due to their wide applications in
light-mediated catalysis, photo-responsive materials, selective
drug delivery in biological systems, molecular electronics and
so on.1 Azobenzenes, spiropyrans, dithienylethenes and few
others2 are the major contributors in the field of light-driven
photoisomerization related applications. The easy conversion
between the two photo-switching forms of these molecules in
presence of UV light makes them easy to handle and selective
in nature for various applications. However, in order to exhibit
photochromism in low energy visible light compared to the
potentially harmful UV light,3 a new class of photochromic
molecules was reported in 2014, called donor-acceptor
Stenhouse adducts (DASA).4 These molecules photoisomerize
from coloured neutral open forms to colourless zwitterionic
cyclic forms with irradiation of visible light (Scheme 1) in
organic solvents like toluene and dioxane in a reversible
manner. Higher molar absorptivity, reversible and effective
photo-switching under visible light, a high degree of fatigue
resistance, and the simple synthetic procedure make the
DASA more attractive to chemists than many other
competitive photo-switching materials. In this short period, the
DASA molecules found an intriguing place in the field of
polymer science such as temperature localization for bullet
impacts in explosives, targeted drug release by light-triggered
micelle collapse and controlling wettability.5
Till date, the reversible photo-switching nature of DASA has
been restricted to polymer matrices or in solvents such as
toluene and dioxane. In dichloromethane and other
halogenated solvents thermal cyclic to linear equilibrium was
observed to be dominant along with very limited linear to
cyclic photoisomerization making the open DASA form more
stable in these solvents. On the contrary, irreversible linear to
cyclic switching has been observed in protic solvents like
methanol and water where the ring closed (cyclic zwitterionic)
form is stabilized under heating/or in the dark. Thus reversible
photo-switching of these DASA molecules is restricted in very
limited solvents.4,6 However, the presence of molecular
containers may shift the irreversible cycle in the reverse
direction by stabilizing the unstable components.7
Molecular containers such as crown ethers, cavitands, and
self-assembled molecular architectures8 have shown much
versatility and altered the conditions of bringing stability of
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many unstable or reactive species and changed the reaction
Page 2 of 9
yield. The solid was dissolved in D2O and 1H NMR was
recorded to obtain a clear NMR spectrum containing a single
set of the tetraimidazole peaks. The aromatic proton peaks
were assigned with the support of 1H 1H COSY NMR
spectroscopy (Figures S1-S2). Furthermore, diffusion ordered
spectroscopy (DOSY) also confirmed the formation of a single
self-assembled molecular species MV (Figure S3). The
composition of MV was specifically determined by the
electrospray ionisation mass spectroscopy (ESI-MS). The PF6
analogue of the self-assembled MV was prepared by mixing
an aqueous solution of MV with excess KPF6. The PF6
analogue was solubilized in acetonitrile and ESI-MS was
recorded. The appearance of prominent peaks and the isotopic
distribution patterns of the fragments for the PF6 analogue at
m/z = 1779.4772 for [MV-3PF6]3+, 1298.3660 for [MV-
4PF6]4+; 1009.3091 for [MV-5PF6]5+ and 817.2660 for [MV-
6PF6]6+ confirmed the formation of a M8L4 species (Figure
S4). The NMR and ESI-MS studies hinted the formation of a
molecular barrel, however the exact geometry of MV was
required to understand the nature and dimensions of the cavity.
We were successful to grow single crystals of the PF6
analogue of MV by diffusing acetone in to its DMSO solution.
The single crystal structure analysis revealed the formation of
a tetragonal barrel, which crystallizes in tetragonal system,
space group P42/n. The solid-state structure revealed that in
the molecular barrel the tetraimidazole donor is slightly
twisted being roughly of 43° the dihedral angle between the
biphenyl rings. This feature induces two opposite corners of
the molecular vessel of the acceptor units to be upward
(compared to the other two at opposite corners) in the open
faces. The distances between the two opposite corners are
roughly 20.5 and 13.8 Å for Pd(1)-Pd(1'') and Pd(2)-Pd(2''),
respectively, whereas adjacent Pd(1)-Pd(2) atoms are 8.1 Å
apart, (Figure 1).
rates.9 Particularly, the evolution of metal-ligand coordination
bonding has become an advance tool for the synthesis of
numerous self-assembled supramolecular architectures. The
mild reaction conditions and the predesigning aspects of the
final assembly make the coordination driven self-assembly
superior over the other self-assembly methods. In recent time,
coordination driven self-assembly has been used to design
molecular vessels for stabilization of unstable conformers,
catalysis, separation and host-guest chemistry.10 The main
foundations for these versatile applications of the self-
assembled molecular vessels originates due to their easy
handling and easy tunabilities by simply changing the donor or
acceptor lengths to control the rigidity of the final
architectures.
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Herein, we report the synthesis and characterization of a new
water-soluble tetrafacial molecular vessel (MV) obtained via
metal-ligand self-assembly of
a
90° acceptor cis-
(tmeda)Pd(NO3)2 (M) [tmeda = N,N,N′,N′-tetramethylethane-
1,2-diamine] with a symmetric tetraimidazole donor L (L =
3,3',5,5'-tetra(1H-imidazol-1-yl)-1,1'-biphenyl) (Scheme 2).
The molecular vessel was characterized by NMR, ESI-MS and
single crystal X-ray diffraction studies.
Scheme 2. Self-assembly of the molecular vessel MV and
the unusual stabilization of open form of DASA molecules
in aqueous medium.
The confined nanospace of the barrel stabilized the DASA in
open form in aqueous medium. While the open form of DASA
readily converts irreversibly to cyclic form in aqueous
medium, stabilization of open form in aqueous medium in
presence of the molecular vessel is unique. The open form
remains stable in presence of molecular vessel even upon
irradiation with visible or green light, a feature which is again
a reverse observation of what we see in toluene/dioxane.
While the conversion of open form to cyclic form in aqueous
medium is irreversible in absence of the molecular barrel, we
could convert cyclic form to open form of DASA even in
aqueous medium in presence of the molecular vessel MV
(though the process was very slow). Apart from unusual
stabilization of the open forms of DASA molecules in aqueous
medium, MV was found to encapsulate other water insoluble
compounds like nitrostyrene derivatives, which gave us the
eagerness to perform Michael addition reactions in relatively
good yields using MV in catalytic amount in aqueous medium.
Figure 1. SCXRD structure of the molecular vessel MV: (a) Side
view (stick model) showing two Pd atoms located upward in the
open face; (b) view down crystallographic 42 axis; (c) space-filled
model [Colour codes: C (green), N (blue), Pd (orange)]. Hydrogen
atoms, counter anions and solvent molecules were omitted for the
sake of clarity).
The crystal structure showed the presence of two open
windows having a barrel-shaped hydrophobic cavity, which
marks MV as a perfect choice for encapsulation of water
insoluble guest molecules of various sizes and shapes. DASA
molecules have gained a lot of interest since their recent
discovery in 2014 due to their photochromic behaviour in low
energy visible light. Both the DASA1 and DASA2 are soluble
in common organic solvents and show reversible
photochromic behaviour in toluene and dioxane. The open
forms of DASA are generally blue or violet in colour which
upon irradiation with green light slowly becomes pale yellow
via converting to the cyclic form. The cyclic form readily
reverts back to the open form by keeping the solution in dark
Results and Discussion
The tetraimidazole donor, 3,3′,5,5′-tetra(1H-imidazol-1-yl)-
1,1'-biphenyl (L) was synthesized following the previously
reported procedure by treating 3,3′,5,5′-tetrabromo-1,1′-
biphenyl, imidazole, K2CO3, and anhydrous CuSO4 at 180
°C.11 A clear solution of L in DMSO was treated with a
DMSO solution of M in 1:2 molar ratios and was heated for
12 h at 60 °C. The clear pale-yellow solution upon treating
with excess ethyl acetate resulted an off-white solid in good
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or upon heating. On the contrary, their stability in water or
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methanol as the open form diminishes with time and the
zwitterionic cyclic form gains solidity extensively (Figure
S20). Therefore, to check the stability of the open form of the
DASA in presence of the molecular vessel as host, we treated
the pale-yellow aqueous solution of MV with the excess
DASA compounds in water for 2 days and UV-vis spectra
were recorded on the resulted red solutions. Generally, the
open form of the DASA shows an absorption peak at around
540 nm and the zwitterionic cyclic form gives an absorption
band at around 264 nm. Surprisingly, the UV-vis spectra of the
host-guest solution mixture showed broad band near 509 nm
and 512 nm confirming the presence of the open forms of the
DASA1 and DASA2 molecule respectively, which was not
observed when similar conditions were maintained in absence
of the molecular vessel (Figure 2). This observation hints that
the molecular vessel MV can provide significant stability to
arrest the open form in aqueous medium.
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Figure 3: 1H NMR of (a) DASA1⊂MV, (b) MV recorded in D2O
and (c) linear/open form of DASA1 recorded in CDCl3 at 298 K.
Similar observations were also noted for the DASA2
molecule. Moreover, we prepared another solution of the host-
guest complex DASA2⊂MV by taking excess of guest
molecules. The proton spectra gave a similar complicated
NMR with two sharp doublets at 7.85 and 6.66 ppm
confirming the presence of the cyclic form of the DASA2
molecule (Figure 4) along with DASA2⊂MV. The DOSY
spectra showed the presence of two distinguishable bands: one
corresponding to the host-guest complex DASA2⊂MV and
the other representing the free cyclic form of the DASA2
(Figures S14-S15). Here also the proton NMR spectra
Figure 2: Comparison of UV-visible spectra of the open form of
DASA molecules in presence of MV, and in absence of MV in
aqueous medium.
confirmed the formation of
a 1:2 host-guest complex
DASA2⊂MV. While the cyclic form of DASA is stable in
aqueous medium and doesn’t go back to open form in absence
of barrel, addition of excess molecular vessel MV converted
the cyclic form of DASA to open form by forming host-guest
(Figures S18-S19) complex. To the best of our knowledge, the
present observation represents the first example of cyclic-form
to open-form transformation of DASA in aqueous medium
(Scheme 3).
Additionally, the host-guest complexation was confirmed by
1
performing H, DOSY and NOESY NMR in D2O at room
temperature (Figures S9-S13). The 1H NMR spectra confirmed
the formation of the host-guest complex (DASA⊂MV)
revealing a complex spectrum compared to the simple 1H
NMR of the host MV. The aromatic region appeared broad
due to the lack of symmetry in the host-guest complex and
made it difficult to interpret the results. However, the peak at
9.04 ppm, assigned to the imidazole, shifts downfield to 9.11
ppm inferring the formation of DASA1⊂MV complex.
Additionally, the peak at 2.99 ppm due to the presence of the
N methyl protons shifted upfield compared to its proton NMR
spectrum recorded in CDCl3 (Figure 3). The proton shifts are
affected by the interactions between the host and guest
molecules within the DASA1⊂MV complex. The stability of
the host and also the guest molecule was checked by
extracting the deuterated aqueous solution of the host-guest
complex DASA1⊂MV with CDCl3, which transformed the
red aqueous solution back into a pale-yellow solution.
Furthermore, the proton NMR of both the layers was checked
and confirmed that the D2O layer contained the molecular
vessel MV and the CDCl3 layer showed the presence of
Scheme 3. Encapsulation of DASA molecules into the
cavity of MV to give a red solution
To our surprise the host-guest complex solutions
(DASA⊂MV) did not have any effect upon exposure to
visible light and remained unchanged for several months, as
confirmed by NMR analysis (Figures S16-S17).
1
DASA1. The H DOSY spectrum confirmed the formation of
a single host-guest complex DASA1⊂MV. The ratio of the
host-guest complex was determined by calculating the proton
integral values of the imidazole peak of the host molecule and
the N methyl protons peak of the guest molecule revealing
that each MV host molecule can encapsulate two DASA1
molecules.
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Figure 6. Comparison of experimental and theoretical (TD-DFT)
UV/vis spectra (left) and the energy-optimized geometry (right) of
DASA1⊂MV. Colour codes: Hydrogen (sky blue), Carbon
(green), Nitrogen (blue), Palladium (Orange).
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Additionally, to explore the hydrophobic cavity of the
molecular vessel as reaction chamber, nitrostyrene derivatives
(1a-1g) were treated with the deuterated aqueous solution of
1
MV. After centrifuging H NMR for the host-guest (guest =
1
Figure 4: H NMR of (a) MV, (b) DASA2⊂MV in presence of
1d) complex was recorded with the clear solution. The proton
NMR spectrum revealed that the peak corresponding to the
imidazole peak at 9.04 ppm shifted downfield to 9.18 ppm
similar like the DASA molecules. In addition, new peaks
appeared between 6.55-5.78 ppm resulting from the upfield
shift of the aromatic protons of the nitrostyrene 1d. The
DOSY NMR showed a single diffusion band concluding the
presence of a single host-guest complex (1d⊂MV). The
proton NMR integral calculations revealed that the host-guest
complex (1d⊂MV) constitutes of two nitrostyrene guest
molecules inside MV which is similar to the DASA molecules
(Figures S22-S27). This is very appropriate as the nitrostyrene
molecules hold a similar backbone like the DASA molecules
only difference being a shorter tail attached to the hexagon
moiety. Michael addition reactions of 1,3-indandione as a
nucleophile have been utilized to prepare many of its
derivatives which have vast applications in the biological
field.12 Nitrostyrene derivatives being good Michael acceptors,
can provide us a wide range of various functionalized Michael
adducts with 1,3-indandione. However, most reported methods
use acid catalysts in organic solvents which also form
unwanted byproducts due to plausible formation of condensed
products.13 Thus continuous efforts for new and effective
methods are being given for the synthesis of Michael adducts
with 1,3-indandione and nitrostyrenes. After the confirmation
of the encapsulation of different nitrostyrenes inside the
molecular vessel, we carried out supramolecular catalysis in
aqueous medium maintaining a calalytic amount of MV.
Nitrostyrene 1a was treated with 1,3-indandione in presence of
5 mol% MV in 1 mL aqueous medium and the mixture was
stirred for 30 min at room temperature. The reaction mixture
comprising of Michael adduct (2a) was extracted with CDCl3
and the 1H NMR spectral analysis of the crude mixture
revealed the formation of 89% of product 2a. The product 2a
was obtained with high purity by column chromatography
(20% ethyl acetate in hexane) and was thoroughly
characterized by NMR and HRMS spectroscopy. When the
reaction was performed in absence of the cage under identical
reaction conditions, 2a was formed in 25% yield. The product
enhancement from 25 to 89% in presence of MV highlighted
the catalytic involvement of its confined cavity. Furthermore,
several reactions were carried out with various derivatives of
nitrostyrene and treating with 1,3-indandione in aqueous
solution at room temperature (Table 1).
excess guest, (c) cyclic DASA2 recorded in D2O at 298 K.
Furthermore, to accomplish the encapsulation of the DASA
molecules, we carried out a control experiment using three
equivalents and one equivalent of the DASA molecules with
respect to one equivalent of MV by stirring at room
temperature for 7 days. Afterwards, the UV-vis spectra of the
centrifuged clear solutions were recorded and compared with
the UV-vis spectra of MV and the cyclic form of DASA in
aqueous medium (Figure 5). The appearance of a shoulder
near 262 nm confirmed the presence of the cyclic form of
DASA molecules when we used three equivalents DASA
molecules, such observations were absent when one equivalent
of DASA molecule was used. The shoulder appeared near 262
nm due to the presence of excess DASA molecules which got
converted to its cyclic form with time. Thus, indicating that
MV acts as a suitable molecular container to stabilize the open
form of the DASA molecules.
Figure 5. Comparative UV-visible spectra of the DASA cyclic
form (guest only), (1:1) DASA:MV (less guest) and (3:1)
DASA:MV (excess guest) showing the formation of host-guest
complexes.
Several attempts to grow single crystals of DASA1⊂MV by
slow evaporation and vapour diffusion technique from the
aqueous solution of the host-guest complex were unsuccessful.
However, the geometry of the complex DASA1⊂MV was
optimized by DFT method by placing two DASA molecules in
head to tail fashion inside the cavity of the molecular vessel
MV (Figure 6). Lastly, to comprehend the optical property,
time-dependent DFT calculation was carried out on the
energy-optimized structure to give an UV/vis spectrum having
a λmax at 548 nm, which is fairly close to the experimental one.
Similarly, for the case of DASA2 the energy-optimized
structure showed an UV/vis spectrum having λmax at 564 nm
(Figure S21).
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Table 1. Michael addition of 1a–1f with 1,3-indandione
supported by MV
DASA readily converts to cyclic form upon irradiation with
green light, after encapsulation the open form was stable even
upon prolong irradiation with green light. Thus, the molecular
vessel represents a safe container for the open form of DASA
even in aqueous medium. While the conversion of open to
cyclic form of DASA in aqueous medium is known to be
irreversible, presence of excess MV could successfully
convert the cyclic form to open form in aqueous form (though
the process was very slow). These results represent an unusual
behaviour of new generation photochromic DASA molecules
in molecular vessel in aqueous medium. Furthermore, the
hydrophobic cavity of the vessel MV is found to be suitable
for catalytic Michael addition reactions of a series of
nitrostyrene derivatives with 1,3-indandione in good yields.
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Entry
Substrate
(Ar)
Conversi Conversi Time
on (%),
on (%),
(h)
without
MV*
with
MV*
Experimental Section
Materials and Methods
a
b
c
d
phenyl
25
25
18
19
89
91
51
54
0.5
2
The reagents and solvents were purchased from reputed
commercial suppliers and were handled without any further
purification. Bruker 400 MHz spectrometer was used to
perform NMR spectra and the described chemical shifts (δ) are
in parts per million (ppm) relative to (CH3)4Si as an internal
standard (0.0 ppm) or proton resonance due to incomplete
deuteration of D2O at 4.79 ppm, (CD3)2SO at 2.50 ppm and
CDCl3 at 7.26 ppm. ESI-MS spectra were carried out on an
Agilent 6538 Ultra-High Definition (UHD) Accurate Mass Q-
TOF spectrometer. UV-Vis spectra were recorded using
Perkin Elmer Lambda-750 spectrophotometer. Tetraimidazole
donor (L)11, DASA14a and DASA24b were synthesized
following the reported procedures.
2-chlorophenyl
4-chlorophenyl
6
2,4-
24
dichlorophenyl
e
f
4-
27
20
72
68
24
24
methylphenyl
4-
methoxypheny
l
Synthesis of Molecular Vessel (MV): The tetraimidazole
donor L (20 mg, 0.048 mmol) was added to a 5 mL DMSO
solution of 33.2 mg cis-Pd(tmeda)(NO3)2 (M) [tmeda =
N,N,N′,N′-tetramethylethane-1,2-diamine] (0.096 mmol) and
heated for 12 h at 60 °C. Product was isolated as solid upon
g
α-napthyl
5
47
24
1
*conversion percentage is based on the H NMR of the crude
sample.
1
addition of ethyl acetate. Isolated yield: 49.6 mg (93 %). H
NMR (400 MHz, D2O at 298 K):  = 9.04 (s, 16H), 7.88 (s,
16H), 7.71 (s, 16H), 7.65 (s, 24H), 3.13 (s, 32H), 2.79 (s,
96H). ESI-MS (m/z): Calcd m/z = 1779.4973 for [MV-
3PF6]3+; 1298.3819 for [MV-4 PF6]4+; 1009.3127 for [MV-5
PF6]5+; 817.2666 for [MV-6 PF6]6+. Found: 1779.4772,
1298.3660, 1009.3091 and 817.2660, respectively.
The reaction time and efficiency of the reaction were both
varied by the substituent attached on the β-nitrostyrene
molecules. The Michael adducts 2a–2g were commenced via
the nucleophilic addition of electron rich 1,3-indandione to β-
nitrostyrene derivatives. The host-guest complex presumably
gets stabilized through π–π interactions within the aromatic
walls of MV and the guest molecules which can be related
Encapsulation of DASA molecules and other Nitrostyrene
Derivatives: 8.9 mg (0.002 mmol) of MV was dissolved in
0.5 mL D2O and the solution was added to 0.006 mmol of the
guest molecules separately. The suspension was stirred for 24
h at room temperature and later the solution was centrifuged to
obtain the clear solution.
1
from the H-1H NOESY spectra. After the product formation
the bulkyness was increased significantly and therefore the
molecular barrel was unable to host the product, as a result
they were easily released and exchanged with another
substrate molecule to carry on the catalytic cycle.
Conclusions
UV-vis Study for DASA molecules: For UV-vis study of
DASA molecules, two solutions containing DASA molecules
were prepared. In the first one 0.002 mmol MV was dissolved
in 1 mL water and 0.002 mmol of DASA molecules were
added (less guest). Secondly, in a similar manner 0.002 mmol
MV was dissolved in 1 mL water and 0.006 mmol of DASA
molecules was added (excess guest). In a separate vial 0.006
mmol of DASA molecules (blank reaction) was also stirred in
1 mL water at room temperature. The three solutions were
then kept under stirring for 7 days. The solutions were diluted
in a similar extent and UV-vis spectra were recorded.
In conclusion, we report here a new Pd(II) molecular vessel
(MV) by self-assembly of a tetraimidazole donor with a 90°
Pd(II) acceptor utilizing metal-ligand coordination self-
assembly. Donor Acceptor Stenhouse Adducts (DASA) are
new generation photochromic compounds to show photo-
switching in visible light. The open form of DASA
irreversibly converts to cyclic zwitterionic form in aqueous
medium. Surprisingly, the newly developed molecular vessel
MV was found to be potential for storing DASA molecules in
their open form in aqueous medium. This was possible due to
the hydrophobic cavity in MV, which makes the open form of
DASA molecules highly stable in aqueous medium. Though in
hydrophobic solvents (toluene/dioxane), the open form of
General Procedure for the Catalytic Michael Addition
Reactions: To solid nitrostyrene 1 (0.08 mmol), 3 mL
aqueous solution of the MV (5 mol %) was added followed by
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Journal of the American Chemical Society
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an addition of 1,3-indandione (0.096 mmol). The mixture was
HRMS calcd for 2g [M + H]+ m/z = 346.1079. Found
346.1024. Elemental Analysis for C21H15N1O4: C 73.04, H
4.38, N 4.06. Found: C 72.82, H 4.19, N 4.26.
1
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stirred at room temperature for the time periods indicated in
Table-1 at room temperature. Then the reaction mixture was
extracted with chloroform and further column chromatography
was done using silica gel, eluting with 20% ethyl acetate in
hexane to afford the pure product 2, which was characterized
by 1H and 13C NMR and mass spectroscopy (HRMS).
X-Ray Crystallographic Studies:
Single crystal X-ray diffraction data of MV were collected at
the X-ray diffraction beamline (XRD1) of the Elettra
Synchrotron of Trieste (Italy), with a Pilatus 2M image plate
detector and a monochromatic wavelength of 0.700 Å.
Complete dataset was collected at 100 K with nitrogen stream
and the structure was solved by direct methods using SHELX-
2007 software package incorporated in WinGX.14 The
structure was solved by direct methods and Fourier analyses.
Then it was refined by the full-matrix least-squares method
based on F2 with all observed reflections using the SHELX-
201315 program incorporated in WinGX. The non-hydrogen
atoms in the main fragment were refined with anisotropic
displacement parameters and hydrogen atoms were fixed at
geometrical position. SQUEEZE option of PLATON was used
at the final cycles of refinement in order to account for the
contribution of disordered solvent molecules to the calculated
structure factors.
1
2a: H NMR (400 MHz, CDCl3): δ = 7.89-7.74 (m, 4H), 7.15
(s, 5H), 5.34 (dd, 1H), 5.10 (dd, 1H), 4.43 (d, 1H), 3.45 (d,
1H). 13C NMR (100 MHz, CDCl3): δ = 199.45, 197.96,
142.75, 142.72, 136.36, 136.33, 135.71, 129.32, 128.87,
128.69, 123.74, 123.66, 76.70, 55.76, 42.48. HRMS calcd for
2a [M + H]+ m/z = 296.0923. Found 296.0894. Elemental
Analysis for C17H13N1O4: C 69.15, H 4.44, N 4.74. Found: C
68.97, H 4.32, N 4.89.
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2b: H NMR (400 MHz, CDCl3): δ = 7.99-7.84 (m, 4H), 7.39
(d, 2H), 7.19 (s, 2H), 5.17 (dd, 1H), 4.97 (s, 1H), 4.83 (dd,
1H), 3.60 (d, 1H). 13C NMR (100 MHz, CDCl3): δ = 198.06,
197.93, 142.31, 136.52, 136.41, 135.07, 134.62, 130.86,
129.87, 129.42, 127.96, 123.97, 123.89, 75.26, 55.21, 37.95.
HRMS calcd for 2b [M + H]+ m/z = 330.0533. Found
330.0594. Elemental Analysis for C17H12N1O4Cl1: C 61.92, H
3.67, N 4.25. Found: C 61.59, H 3.61, N 4.17.
2c: 1H NMR (400 MHz, CDCl3): δ = 7.89-7.79 (m, 4H), 7.13-
6.96 (m, 4H), 5.44-5.25 (m, 1H), 5.19-5.13 (m, 1H), 4.42-4.18
(m, 1H), 3.44 (d, 1H). 13C NMR (100 MHz, CDCl3): δ =
199.21, 197.62, 142.64, 137.48, 137.44, 136.61, 136.56,
130.31, 129.56, 123.89, 123.77, 76.55, 55.70, 41.73. HRMS
calcd for 2c [M + H]+ m/z = 330.0533. Found 330.0612.
Elemental Analysis for C17H12N1O4Cl1: C 61.92, H 3.67, N
4.25. Found: C 61.71, H 3.59, N 4.34.
2d: 1H NMR (100 MHz, CDCl3): δ = 8.00-7.85 (m, 4H), 7.41-
7.35 (m, 2H), 7.18 (dd, 1H), 5.13 (dd, 1H), 4.93 (dd, 1H), 4.84
(dd, 1H), 3.56 (d, 1H). 13C NMR (100 MHz, CDCl3): δ =
197.80, 197.65, 142.27, 136.66, 136.57, 135.48, 135.18,
133.66, 130.67, 130.31, 128.28, 124.03, 124.00, 75.17, 55.07,
37.53. HRMS calcd for 2d [M + H]+ m/z = 364.0143. Found
364.0087. Elemental Analysis for C17H11N1O4Cl2: C 56.07, H
3.04, N 3.85. Found: C 56.21, H 2.94, N 3.62.
2e: 1H NMR (100 MHz, CDCl3): δ = 7.90-7.83 (m, 4H), 7.05-
6.93 (m, 4H), 6.32 (dd, 1H), 5.08 (dd, 1H), 4.39 (d, 1H), 3.43
(d, 1H), 2.16 (s, 3H). 13C NMR (100 MHz, CDCl3): δ =
199.56, 198.00, 142.80, 138.41, 136.29, 136.27, 132.61,
129.99, 128.72, 123.76, 123.65, 76.88, 55.79, 42.16, 21.39.
HRMS calcd for 2e [M + H]+ m/z = 310.1079. Found
310.1056. Elemental Analysis for C18H15N1O4: C 69.89, H
4.89, N 4.53. Found: C 69.63, H 4.67, N 4.29.
ASSOCIATED CONTENT
Supporting Information.
1
1
1H, 13C, H-1H COSY, H-1H NOESY and DOSY NMR spectra,
ESI-MS data, crystallographic data of MV in CIF format (CCDC
No. 1905284), UV-vis spectra of the molecular vessel (MV),
Donor-Acceptor Stenhouse Adducts (DASA) and the catalyzed
products associated with this article are attached.
AUTHOR INFORMATION
Corresponding Author
*psm@iisc.ac.in (P. S. Mukherjee)
Author Contributions
§ Authors contributed equally
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
P.S.M. thanks the SERB (New Delhi) for financial support. A.D.
is grateful to UGC (New Delhi) for Dr. D. S. Kothari postdoctoral
fellowship. S.B. acknowledges the CSIR, New Delhi for the
research fellowship.
REFERENCES
1
2f: H NMR (100 MHz, CDCl3): δ = 7.89-7.74 (m, 4H), 7.07
(1)
(a) Jia, C.; Migliore, A.; Xin, N.; Huang, S.; Wang, J.;
(d, 2H), 6.65 (d, 2H), 5.30 (dd, 1H), 5.09 (dd, 1H), 4.39 (d,
1H), 3.65 (s, 3H), 3.41 (d, 1H). 13C NMR (100 MHz, CDCl3):
δ = 199.68, 198.07, 159.67, 142.82, 136.33, 136.29, 130.01,
127.51, 123.74, 123.62, 114.63, 76.99, 55.88, 55.54, 41.87.
HRMS calcd for 2b [M + H]+ m/z = 326.1028. Found
326.1092. Elemental Analysis for C18H15N1O5: C 66.46, H
4.65, N 4.31. Found: C 66.02, H 4.43, N 4.53.
Yang, Q.; Wang, S.; Chen, H.; Wang, D.; Feng, B. Covalently bonded
single-molecule junctions with stable and reversible photoswitched
conductivity. Science 2016, 352, 1443-1445; (b) Andréasson, J.;
Pischel, U. Smart molecules at work—mimicking advanced logic
operations. Chem. Soc. Rev. 2010, 39, 174-188;
(c)
Liu,
D.;
Chen, W.; Sun, K.; Deng, K.; Zhang, W.; Wang, Z.; Jiang, X.
Resettable, multi‐readout logic gates based on controllably reversible
aggregation of gold nanoparticles. Angew. Chem., Int. Ed. 2011, 50,
4103-4107; (d) Andréasson, J.; Pischel, U.; Straight, S. D.; Moore, T.
A.; Moore, A. L.; Gust, D. All-photonic multifunctional molecular
logic device. J. Am. Chem. Soc. 2011, 133, 11641-11648; (e)
Leydecker, T.; Herder, M.; Pavlica, E.; Bratina, G.; Hecht, S.; Orgiu,
E.; Samorì, P. Flexible non-volatile optical memory thin-film
transistor device with over 256 distinct levels based on an organic
1
2g: H NMR (100 MHz, CDCl3): δ = 8.37 (d, 1H), 7.99 (d,
1H), 7.83-7.72 (m, 5H), 7.65 (t, 1H), 7.52 (d, 2H), 7.34 (t,
1H), 5.39 (s, 2H), 4.93 (d, 1H), 3.68 (s, 1H). 13C NMR (100
MHz, CDCl3): δ = 198.95, 198.07, 142.45, 142.39, 136.33,
136.26, 134.52, 133.56, 131.36, 129.48, 129.38, 127.59,
126.63, 125.64, 123.86, 123.82, 123.23, 76.27, 56.20, 35.83.
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bicomponent blend. Nature nanotechnology 2016, 11, 769; (f) Stoll,
temperature-mapping molecular sensor for polyurethane-based
elastomers. Appl. Phys. Lett. 2016, 108, 041906.
R. S.; Hecht, S. Artificial light‐gated catalyst systems. Angew. Chem.,
Int. Ed. 2010, 49, 5054-5075; (g) Zhang, X.; Hou, L.; Samori, P.
Coupling carbon nanomaterials with photochromic molecules for the
generation of optically responsive materials. Nat. Commun. 2016, 7,
11118; (h) Zheng, Z.-g.; Li, Y.; Bisoyi, H. K.; Wang, L.; Bunning, T.
J.; Li, Q. Three-dimensional control of the helical axis of a chiral
nematic liquid crystal by light. Nature 2016, 531, 352; (i) Liu, J.; Bu,
W.; Pan, L.; Shi, J. NIR‐triggered anticancer drug delivery by
upconverting nanoparticles with integrated azobenzene‐modified
mesoporous silica. Angew. Chem. 2013, 125, 4471-4475; (j) Lv, G.;
Cui, B.; Lan, H.; Wen, Y.; Sun, A.; Yi, T. Diarylethene based
fluorescent switchable probes for the detection of amyloid-β
pathology in Alzheimer's disease. Chem. Commun. 2015, 51, 125-
128; (k) Szymański, W.; Beierle, J. M.; Kistemaker, H. A.; Velema,
W. A.; Feringa, B. L. Reversible photocontrol of biological systems
by the incorporation of molecular photoswitches. Chem. Rev. 2013,
113, 6114-6178.
1
2
3
4
5
6
7
8
(6) (a) Mallo, N.; Brown, P. T.; Iranmanesh, H.; MacDonald, T. S.;
Teusner, M. J.; Harper, J. B.; Ball, G. E.; Beves, J. E. Photochromic
switching behaviour of donor–acceptor Stenhouse adducts in organic
solvents. Chem. Commun. 2016, 52, 13576-13579; (b) Mallo, N.;
Foley, E. D.; Iranmanesh, H.; Kennedy, A. D.; Luis, E. T.; Ho, J.;
Harper, J. B.; Beves, J. E. Structure–function relationships of donor–
acceptor Stenhouse adduct photochromic switches. Chem. Sci. 2018,
9, 8242-8252; (c) Lerch, M. M.; Wezenberg, S. J.; Szymanski, W.;
Feringa, B. L. Unraveling the photoswitching mechanism in donor–
acceptor stenhouse adducts. J. Am. Chem. Soc. 2016, 138, 6344-6347.
(7) (a) Mal, P.; Breiner, B.; Rissanen, K.; Nitschke, J. R. White
phosphorus is air-stable within a self-assembled tetrahedral capsule.
Science 2009, 324, 1697-1699; (b) Takezawa, H.; Akiba, S.; Murase,
T.; Fujita, M. Cavity-directed chromism of phthalein dyes. J. Am.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Chem. Soc. 2015, 137, 7043-7046;
(c)
Samanta,
D.;
Galaktionova, D.; Gemen, J.; Shimon, L. J.; Diskin-Posner, Y.;
Avram, L.; Král, P.; Klajn, R. Reversible chromism of spiropyran in
the cavity of a flexible coordination cage Nature communications
2018, 9, 641
(2) (a) Fredrich, S.; Göstl, R.; Herder, M.; Grubert, L.; Hecht, S.
Switching diarylethenes reliably in both directions with visible light.
Angew. Chem., Int. Ed. 2016, 55, 1208-1212;
(b)
Baroncini,
(8)
(a) Seidel, S. R.; Stang, P. J. High-symmetry coordination
M.; d'Agostino, S.; Bergamini, G.; Ceroni, P.; Comotti, A.; Sozzani,
P.; Bassanetti, I.; Grepioni, F.; Hernandez, T. M.; Silvi, S.
Photoinduced reversible switching of porosity in molecular crystals
based on star-shaped azobenzene tetramers. Nat. Chem. 2015, 7, 634;
(c) Kumar, K.; Knie, C.; Bléger, D.; Peletier, M. A.;
Friedrich, H.; Hecht, S.; Broer, D. J.; Debije, M. G.; Schenning, A. P.
A chaotic self-oscillating sunlight-driven polymer actuator. Nat.
Commun. 2016, 7, 11975; (d) Klajn, R. Spiropyran-based dynamic
materials. Chem. Soc. Rev. 2014, 43, 148-184; (e) Saad, A.; Oms, O.;
Dolbecq, A.; Menet, C.; Dessapt, R.; Serier-Brault, H.; Allard, E.;
Baczko, K.; Mialane, P. A high fatigue resistant, photoswitchable
fluorescent spiropyran–polyoxometalate–BODIPY single-molecule.
Chem. Commun. 2015, 51, 16088-16091; (f) van Dijken, D. J.;
Kovaříček, P.; Ihrig, S. P.; Hecht, S. Acylhydrazones as widely
tunable photoswitches. J. Am. Chem. Soc. 2015, 137, 14982-14991;
(g) Liu, Z.; Liu, T.; Lin, Q.; Bao, C.; Zhu, L. Sequential
cages via self-assembly. Acc. Chem. Res. 2002, 35, 972-983; (b)
Mishra, A.; Dubey, A.; Min, J. W.; Kim, H.; Stang, P. J.; Chi, K.-W.
Molecular self-assembly of arene-Ru based interlocked catenane
metalla-cages. Chem. Commun. 2014, 50, 7542-7544; (c) Pollock, J.
B.; Cook, T. R.; Stang, P. J. Photophysical and computational
investigations of bis (phosphine) organoplatinum (II) metallacycles. J.
Am. Chem. Soc. 2012, 134, 10607-10620;
(d) Sun, Q. F.;
Murase, T.; Sato, S.; Fujita, M. A Sphere‐in‐Sphere Complex by
Orthogonal Self‐Assembly. Angew. Chem., Int. Ed. 2011, 50, 10318-
10321; (e) Fujita, M.; Tominaga, M.; Hori, A.; Therrien, B.
Coordination assemblies from a Pd (II)-cornered square complex.
Acc. Chem. Res. 2005, 38, 369-378; (f) Wood, C. S.; Ronson, T. K.;
Belenguer, A. M.; Holstein, J. J.; Nitschke, J. R. Two-stage directed
self-assembly of a cyclic [3] catenane. Nat. Chem. 2015, 7, 354; (g)
Hardy, M.; Struch, N.; Topić, F.; Schnakenburg, G.; Rissanen, K.;
Lützen, A. Stepwise Construction of Heterobimetallic Cages by an
Extended Molecular Library Approach. Inorg. Chem. 2017, 57, 3507-
3515; (h) Mittal, N.; Saha, M. L.; Schmittel, M. A seven-component
metallosupramolecular quadrilateral with four different orthogonal
complexation vertices. Chem. Commun. 2015, 51, 15514-15517;
(i) Huang, C.-B.; Xu, L.; Zhu, J.-L.; Wang, Y.-X.; Sun, B.;
Li, X.; Yang, H.-B. Real-time monitoring the dynamics of
coordination-driven self-assembly by fluorescence-resonance energy
transfer. J. Am. Chem. Soc. 2017, 139, 9459-9462; (j) Jiang, B.; Chen,
L.-J.; Xu, L.; Liu, S.-Y.; Yang, H.-B. A series of new star-shaped or
branched platinum–acetylide derivatives: synthesis, characterization,
and their aggregation behavior. Chem. Commun. 2013, 49, 6977-
6979; (k) Yan, X.; Wang, H.; Hauke, C. E.; Cook, T. R.; Wang, M.;
Saha, M. L.; Zhou, Z.; Zhang, M.; Li, X.; Huang, F. A suite of
tetraphenylethylene-based discrete organoplatinum (II) metallacycles:
Controllable structure and stoichiometry, aggregation-induced
emission, and nitroaromatics sensing. J. Am. Chem. Soc. 2015, 137,
control over thiol click chemistry by a reversibly photoactivated thiol
mechanism of spirothiopyran. Angew. Chem. 2015, 127, 176-180;
(h) Mazzier, D.; Crisma, M.; De Poli, M.; Marafon, G.;
Peggion, C.; Clayden, J.; Moretto, A. Helical Foldamers
Incorporating Photoswitchable Residues for Light-Mediated
Modulation of Conformational Preference. J. Am. Chem. Soc. 2016,
138, 8007-8018; (i) Kobayashi, Y.; Katayama, T.; Yamane, T.;
Setoura, K.; Ito, S.; Miyasaka, H.; Abe, J. Stepwise two-photon-
induced fast photoswitching via electron transfer in higher excited
states of photochromic imidazole dimer. J. Am. Chem. Soc. 2016, 138,
5930-5938.
(3)
switches. Angew. Chem., Int. Ed. 2015, 54, 11338-11349.
(4) (a) Helmy, S.; Leibfarth, F. A.; Oh, S.; Poelma, J. E.;
Bleger, D.; Hecht, S. Visible‐light‐activated molecular
Hawker, C. J.; Read de Alaniz, J. Photoswitching using visible light: a
new class of organic photochromic molecules. J. Am. Chem. Soc.
2014, 136, 8169-8172; (b) Helmy, S.; Oh, S.; Leibfarth, F. A.;
Hawker, C. J.; Read de Alaniz, J. Design and synthesis of donor–
acceptor stenhouse adducts: a visible light photoswitch derived from
furfural. J. Org. Chem. 2014, 79, 11316-11329.
15276-15286;
(l) Fan, W. J.; Sun, B.; Ma, J.; Li, X.; Tan, H.;
Xu, L. Coordination‐Driven Self‐Assembly of Carbazole‐Based
Metallodendrimers with Generation‐Dependent Aggregation‐Induced
Emission Behavior. Chem. Eur. J. 2015, 21, 12947-12959; (m) Wei,
P.; Yan, X.; Huang, F. Supramolecular polymers constructed by
orthogonal self-assembly based on host–guest and metal–ligand
interactions. Chem. Soc. Rev. 2015, 44, 815-832; (n) Komine, S.;
Takahashi, S.; Kojima, T.; Sato, H.; Hiraoka, S. Self-assembly
processes of octahedron-shaped Pd6L4 cages. J. Am. Chem. Soc.
2019, 141, 3178–3186; (o) Li, E.; Jie, K.; Zhou, Y.; Zhao, R.; Huang,
F. Post-Synthetic Modification of Nonporous Adaptive Crystals of
Pillar [4] arene [1] quinone by Capturing Vaporized Amines. J. Am.
Chem. Soc. 2018, 140, 15070-15079; (p) Shi, B.; Liu, Y.; Zhu, H.;
Vanderlinden, R. T.; Shangguan, L.; Ni, R.; Acharyya, K.; Tang, J.;
Zhou, Z.; Li, X.; Huang, F.; Stang, P. J. Spontaneous Formation of a
Cross-Linked Supramolecular Polymer Both in the Solid State and in
(5)
(a) Balamurugan, A.; Lee, H.-i. A visible light responsive
on–off polymeric photoswitch for the colorimetric detection of nerve
agent mimics in solution and in the vapor phase. Macromolecules
2016, 49, 2568-2574; (b) Singh, S.; Friedel, K.; Himmerlich, M.; Lei,
Y.; Schlingloff, G.; Schober, A. Spatiotemporal photopatterning on
polycarbonate surface through visible light responsive polymer bound
DASA compounds. ACS Macro Lett. 2015, 4, 1273-1277;
(c)
Poelma, S. O.; Oh, S. S.; Helmy, S.; Knight, A. S.; Burnett, G. L.;
Soh, H. T.; Hawker, C. J.; de Alaniz, J. R. Controlled drug release to
cancer cells from modular one-photon visible light-responsive
micellar system. Chem. Commun. 2016, 52, 10525-10528; (d) Mason,
B.; Whittaker, M.; Hemmer, J.; Arora, S.; Harper, A.; Alnemrat, S.;
McEachen, A.; Helmy, S.; Read de Alaniz, J.; Hooper, J. A
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Journal of the American Chemical Society
Page 8 of 9
Solution Driven by Platinum (II) Metallacycle-Based Host–Guest
Interactions J. Am. Chem. Soc. 2019, 141, 6494-6496.
(9) (a) Chakrabarty, R.; Mukherjee, P. S.; Stang, P. J.
Supramolecular coordination: self-assembly of finite two-and three-
dimensional ensembles. Chem. Rev. 2011, 111, 6810-6918; (b)
1
2
3
4
Cook, T. R.; Stang, P. J. Recent developments in the preparation and
chemistry of metallacycles and metallacages via coordination. Chem.
5
6
7
8
Rev. 2015, 115, 7001-7045;
(c) Forgan, R. S.; Sauvage, J.-P.;
Stoddart, J. F. Chemical topology: complex molecular knots, links,
and entanglements. Chem. Rev. 2011, 111, 5434-5464; (d)
McConnell, A. J.; Wood, C. S.; Neelakandan, P. P.; Nitschke, J. R.
Stimuli-responsive metal–ligand assemblies. Chem. Rev. 2015, 115,
7729-7793; (e) Mukherjee, S.; Mukherjee, P. S. Template-free
multicomponent coordination-driven self-assembly of Pd (II)/Pt (II)
molecular cages. Chem. Commun. 2014, 50, 2239-2248.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
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31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(10) (a) Howlader, P.; Mondal, B.; Purba, P. C.; Zangrando, E.;
Mukherjee, P. S. Self-Assembled Pd (II) Barrels as Containers for
Transient Merocyanine Form and Reverse Thermochromism of
Spiropyran. J. Am. Chem. Soc. 2018, 140, 7952-7960;
(b)
Brenner, W.; Ronson, T. K.; Nitschke, J. R. Separation and selective
formation of fullerene adducts within an MII8L6 cage. J. Am. Chem.
Soc. 2016, 139, 75-78; (c) Anhäuser, J.; Puttreddy, R.; Lorenz, Y.;
Schneider, A.; Engeser, M.; Rissanen, K.; Lützen, A. Chiral self-
sorting behaviour of [2.2] paracyclophane-based bis (pyridine)
ligands. Org. Chem. Front., 2019,6, 1226-1235;
(d) Biswas, P.
K.; Saha, S.; Paululat, T.; Schmittel, M. Rotating catalysts are
superior: suppressing product inhibition by anchimeric assistance in
four-component catalytic machinery. J. Am. Chem. Soc. 2018, 140,
9038-9041.
(11) Luo, L.; Wang, P.; Xu, G.-C.; Liu, Q.; Chen, K.; Lu, Y.;
Zhao, Y.; Sun, W.-Y. Zinc (II) and cadmium (II) complexes with
rigid 3, 3′, 5, 5′-tetra (1H-imidazol-1-yl)-1, 1′-biphenyl and varied
carboxylate ligands. Crystal Growth & Design 2012, 12, 2634-2645.
(12) (a) Singh, G. S.; Desta, Z. Y. Isatins as privileged
molecules in design and synthesis of spiro-fused cyclic frameworks.
Chem. Rev. 2012, 112, 6104-6155;
(b) Pizzirani, D.; Roberti,
M.; Grimaudo, S.; Di Cristina, A.; Pipitone, R. M.; Tolomeo, M.;
Recanatini, M. Identification of biphenyl-based hybrid molecules able
to decrease the intracellular level of Bcl-2 protein in Bcl-2
overexpressing leukemia cells. Journal of medicinal chemistry 2009,
52, 6936-6940.
(13) (a) Amireddy, M.; Chen, K. Organocatalytic synthesis of
spirocyclohexane indane-1, 3-diones via
a chiral squaramide-
catalyzed Michael/aldol cascade reaction of γ-nitro ketones and 2-
arylideneindane-1, 3-diones. Tetrahedron 2015, 71, 8003-8008; (b)
Duan, H.; Chen, Z.; Han, L.; Feng, Y.; Zhu, Y.; Yang, S. Palladium-
catalyzed chemoselective synthesis of indane-1, 3-dione derivatives
via tert-butyl isocyanide insertion. Org. Biomol. Chem. 2015, 13,
6782-6788.
(14) (a) Sheldrick, G. SHELXTL-Plus. Program for the Solution
and Refinement of Crystal Structures Bruker Analytical X-Ray
Systems, Madison, Wisconsin, USA 1998; (b) Farrugia, L. WinGX
version 1.64, an integrated system of windows programs for the
solution, refinement and analysis of single-crystal X-ray diffraction
data University of Glasgow, Glasgow 2003; (c) Farrugia, L. J. WinGX
suite for small-molecule single-crystal crystallography J. Appl.
Crystallogr. 1999, 32, 837-838.
(15) Sheldrick, G. M. SHELXT–Integrated space-group and
crystal-structure determination Acta Crystallographica Section A:
Foundations and Advances 2015, 71, 3-8..
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Unusual Behaviour of Donor-Acceptor Stenhouse Adducts (DASA)
in Confined Space of a Water Soluble PdII Molecular Vessel
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Rupak Saha1, Anthonisamy Devaraj1§, Soumalya Bhattacharyya1§, Soumik Das1, Ennio Zangrando2 and Partha Sarathi
Mukherjee1*
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