Angewandte
Communications
Chemie
How to cite: Angew. Chem. Int. Ed. 2021, 60, 7654–7658
International Edition:
German Edition:
Supramolecular Chemistry
Photo-Controllable Catalysis and Chiral Monosaccharide Recognition
Induced by Cyclodextrin Derivatives
Lei Chen, Yong Chen, Yi Zhang, and Yu Liu*
Dedicated to the 100th anniversary of Chemistry at Nankai University
Abstract: A supramolecular catalytic system was constructed
from polycationic a-cyclodextrin (6-Iz-a-CD) and gold nano-
particles (AuNP) using a supramolecular assembly strategy.
The cavity of cyclodextrin is the channel by which the substrate
molecules come into contact with the catalytic center. Intro-
duction of the azobenzene-modified diphenylalanine (Azo-
FF) guest molecule allowed for precise photo-control of the
catalytic activity owing to its sensitive response to irradiation.
Importantly, as a unique glucose oxidase the AuNP@6-Iz-a-
CD realizes unprecedented chiral recognition catalysis for
chiral monosaccharides. In combination with a 3,3’,5,5’-tetra-
methylbenzidine (TMB) color reaction, AuNP@6-Iz-a-CD is
able to recognize the chirality of various monosaccharides.
interactions. The usual method for accomplishing such
regulation is to covalently attach host molecules directly to
the AuNP surface and then add an appropriate guest
molecule that acts as a cross-linking agent to promote
AuNP aggregation.[13] However, light-controlled regulation
of the aggregation state and catalytic activity of AuNP in
supramolecular systems remains relatively unexplored. In
addition, the use of AuNP for selective catalysis has not been
explored. Almost all host molecules have the ability to
distinguish substrates, such as chiral cavities in cyclodextrins
for enantiomers recognition. Thus, to develop AuNP for
selective catalysis, we undertook to incorporate them into
supramolecular assemblies held together by non-covalent
interactions. Herein, we report the development of catalytic
supramolecular assemblies held together by electrostatic
interactions between AuNP and the polycationic cyclodextrin
hexakis-(6-iodo-6-deoxy)-a-cyclodextrin (6-Iz-a-CD).[14] An
optically responsive azobenzene-modified diphenylalanine
(Azo-FF) guest molecule was used to regulate the catalytic
activity of the AuNP@6-Iz-a-CD through triggering a rever-
sible morphological transition upon irradiation (Scheme 1).
Importantly, the recognition of chiral molecules by 6-Iz-a-CD
cavity can realize the selective catalytic oxidation of glucose
with different configurations.[15] Based on the chiral recog-
nition catalysis oxidation ability of the AuNP@6-Iz-a-CD for
chiral monosaccharide, combined with the color reaction of
3,3’,5,5’-tetramethylbenzidine (TMB), provides an unprece-
dented conveniently way for colorimetric recognition of
chiral monosaccharide.
The AuNP were prepared by a sodium citrate reduction
method,[15] and their particle size was verified by transmission
electron microscopy (TEM) (average size = 17 nm; Support-
ing Information, Figure S1a). The surface of the AuNP is
covered with citrate groups and the potential of AuNP is
À64 mV (Figure S1b) and the 6-Iz-a-CD host molecules were
synthesized by previously reported method (Supporting
Information, Scheme S1, Figure S2),[16] To verify that mixing
the AuNP and 6-Iz-a-CD resulted in coverage of the AuNP
by 6-Iz-a-CD, we performed UV-vis spectroscopy and zeta
potential measurements. In AuNP aqueous solution, the
increase of 6-Iz-a-CD concentration results in surface poten-
tial changes from negative potential to positive potential and
accompanied by the blue shift and then red shift of the surface
plasmon resonance (SPR) absorption band (Figure 1a,b)
which indicated the AuNP experienced the process of
dispersion in aqueous solution, aggregation and redispersion
(Figure S3).[17] By monitoring the change of the absorption
value of nanoparticles at 525 nm, it is determined that the
I
ntelligent supramolecular assemblies are a hot topic of re-
search owing to their potential applications for nanomedi-
cine,[1] nanomaterials,[2] catalysis,[3] and chiral molecular
recognition.[4] Considerable effort has been devoted to
preparing intelligent supramolecular materials that respond
to external stimuli such as enzymes,[5] pH,[6] and light.[7]
Among these stimuli, light is unique in that it can be delivered
instantaneously to the responsive unit without hindrance by
steric constraints or solvent viscosity.[8] Many light-responsive
compounds have been reported.[9] Azobenzene derivatives
are considered to be ideal triggers because their affinity for
the cavities of cyclodextrins changes markedly upon irradi-
ation, a property that has prompted research on the use of
light to regulate the functional properties of supramolecular
assemblies.[10] For instance, we recently reported paclitaxel-
modified b-cyclodextrin and arylazopyrazole assemblies that
can be used for photo-control of microtubule aggregation in
cells via a specific interaction between paclitaxel and micro-
tubules and reversible binding between the arylazopyrazoles
and b-cyclodextrin.[11]
Gold nanoparticles (AuNP) are widely recognized as
promising building blocks for intelligent supramolecular
assemblies because their optical and catalytic properties
depend on their aggregation state.[3b,12] One way to dynam-
ically regulate their aggregation state is to use host–guest
[*] L. Chen, Dr. Y. Chen, Y. Zhang, Prof. Dr. Y. Liu
College of Chemistry, State Key Laboratory of Elemento-Organic
Chemistry, Nankai University
Tianjin 300071 (P. R. China)
E-mail: yuliu@nankai.edu.cn
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
7654
ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 7654 –7658