forward. Traditional crown ether, containing repeating oligo-ethylene oxide units in
a cyclic array, has high ability to bind alkali metal ions, alkaline-earth metals ions,
ammoniums, and primary alkylammonium salts. Previously, researchers focused
their attention on the molecular recognition based on crown ether. Since Stoddart
first reported the complexation of bismetaphenylene-32-crown-10 derivative with
paraquat and diquat in 1987 [2], the multifunctionalized supramolecular assemblies
based on crown ether and organic guests have been fabricated. Nowadays, various
synthetic novel crown ethers, which possess multi-cavity structures and multicomplexation modes, have been successively designed and synthesized to enrich
their functions and applications through several decades of development, such as
supramolecular polymers [3], artificial molecular machines [4], and drug delivery
systems [5].
Photoluminescence is among the most fascinating characteristics of functional
materials. Luminescent materials are applied for a wide variety of applications, such
as chemical sensor [6], bio-imaging [7], drug delivery [8], phototherapy [9], and cell
labeling [10]. Therefore, the integration of fluorophores into crown ether moieties is
advantageous to construct specific responses or develop multistimuli-responsive
photoluminescent crown ether assembly. Crown ether often reversibly binds guest
molecules with high selectivity and could be fine-tuned chemically. So, the assemblies, based on crown ether, are sensitive to environmental changes and external
stimuli like temperature, pH, light, or competitive guests. These features were
successfully utilized to produce more sophisticated functions. In this chapter, we
aim to illustrate the general concepts and structure-function-application relationships
of photoluminescent crown ether assembly. First, we discuss some general luminescence system based on crown ether and organic dyes. Pseudorotaxanes and pseudopolyrotaxanes based on lanthanide luminescence are presented in the second part. In
the last section, we highlight recent developments of supramolecular polymers based
on crown ether with photoluminescence behavior. We hope to shed some light on the
future work based on crown ether and inspire continuous endeavors in this emerging
and exciting research area.
5.2
Luminescent Assemblies Based on Organic Dyes
The idea of introducing fluorophore into crown ether to construct fluorescent
supramolecular materials has attracted tremendous attention in the past few decades
because of their wide applications in sensors, fluorescence probes, organic lightemitting diodes, and solid-state lighting. In the following section, typical examples
are used for briefly discussion and introduction of the construction of the luminescent assemblies based on crown ether and organic dyes.
Mechanically interlocked molecules have been investigated extensively due to
their switchable ability in response to various external stimuli. In recent years,
crown ether has always been used to construct the mechanically interlocked
systems due to its easy modification [11, 12]. In 2012, Qu and coworker [13]
designed and synthesized a bistable [2]rotaxane with high-contrast fluorescence
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Y. Zhou et al.
a cyclic array, has high ability to bind alkali metal ions, alkaline-earth metals ions,
ammoniums, and primary alkylammonium salts. Previously, researchers focused
their attention on the molecular recognition based on crown ether. Since Stoddart
first reported the complexation of bismetaphenylene-32-crown-10 derivative with
paraquat and diquat in 1987 [2], the multifunctionalized supramolecular assemblies
based on crown ether and organic guests have been fabricated. Nowadays, various
synthetic novel crown ethers, which possess multi-cavity structures and multicomplexation modes, have been successively designed and synthesized to enrich
their functions and applications through several decades of development, such as
supramolecular polymers [3], artificial molecular machines [4], and drug delivery
systems [5].
Photoluminescence is among the most fascinating characteristics of functional
materials. Luminescent materials are applied for a wide variety of applications, such
as chemical sensor [6], bio-imaging [7], drug delivery [8], phototherapy [9], and cell
labeling [10]. Therefore, the integration of fluorophores into crown ether moieties is
advantageous to construct specific responses or develop multistimuli-responsive
photoluminescent crown ether assembly. Crown ether often reversibly binds guest
molecules with high selectivity and could be fine-tuned chemically. So, the assemblies, based on crown ether, are sensitive to environmental changes and external
stimuli like temperature, pH, light, or competitive guests. These features were
successfully utilized to produce more sophisticated functions. In this chapter, we
aim to illustrate the general concepts and structure-function-application relationships
of photoluminescent crown ether assembly. First, we discuss some general luminescence system based on crown ether and organic dyes. Pseudorotaxanes and pseudopolyrotaxanes based on lanthanide luminescence are presented in the second part. In
the last section, we highlight recent developments of supramolecular polymers based
on crown ether with photoluminescence behavior. We hope to shed some light on the
future work based on crown ether and inspire continuous endeavors in this emerging
and exciting research area.
5.2
Luminescent Assemblies Based on Organic Dyes
The idea of introducing fluorophore into crown ether to construct fluorescent
supramolecular materials has attracted tremendous attention in the past few decades
because of their wide applications in sensors, fluorescence probes, organic lightemitting diodes, and solid-state lighting. In the following section, typical examples
are used for briefly discussion and introduction of the construction of the luminescent assemblies based on crown ether and organic dyes.
Mechanically interlocked molecules have been investigated extensively due to
their switchable ability in response to various external stimuli. In recent years,
crown ether has always been used to construct the mechanically interlocked
systems due to its easy modification [11, 12]. In 2012, Qu and coworker [13]
designed and synthesized a bistable [2]rotaxane with high-contrast fluorescence
108
Y. Zhou et al.