A variety of supramolecular fluorescent materials developed by China ECNU can be used in anti-counterfeiting and other fields

Professor xu Lin’s research group from the school of chemistry and molecular engineering of east China normal university focused on the research in the field of supramolecular fluorescent materials chemistry, and carried out systematic research on supramolecular coordination assembly mechanism, stability strengthening of assembly materials and development of new assembly strategies. Recently, this research group obtained innovative results in the regulation of supramolecular fluorescence, and the related research paper was published in nature communications.

In recent years, chemists have constructed a large number of supramolecular fluorescent assemblies with high efficiency through coordination bond guided self-assembly. Based on its applications in sensing, catalysis, information storage, light capture, disease diagnosis and treatment, supramolecular fluorescent assembly has attracted extensive research interest. However, due to the fluorescence quenchability of coordination heavy metals and the dynamic reversibility of coordination bonds, the construction of supramolecular fluorescent assemblies with high fluorescence quantum efficiency and fine regulation of fluorescence emission wavelength has been a difficult and challenging task in this field.

Through rational molecular design, xu Lin’s group synthesized photoinduced electron transfer (PET) and intramolecular charge transfer (ICT) supramolecular fluorescent elements that can be precisely regulated. During the coordination process between the fluorescent unit and the heavy metal Pt (II), the PET effect of pyridine lone pair electrons in the fluorescent unit was inhibited, leading to the improvement of fluorescence quantum efficiency after assembly. In addition, the coordination between Pt (II) and pyridine will also enhance the pull-electron effect of pyridine, leading to the intensification of ICT effect, which will lead to the amplification of the wavelength shift of the assembled body after assembly and the realization of the fluorescence wide-range emission of the supramolecular fluorescent assembly.

At the same time, the luminescence mechanism and control mechanism of supramolecular fluorescent assembly were verified by comparative control experiments, radiative and non-radiative transition distribution experiments, time-dependent single-photon counting method and time-dependent density functional theory.

Based on the excellent fluorescence performance of this series of supramolecular fluorescent metal assemblies, researchers prepared a variety of supramolecular fluorescent materials, such as fluorescent films that can be processed, fluorescent inks with anti-counterfeiting printing properties. For example, under naked eye observation, the prepared material is white in background and does not show any pattern, while under the irradiation of a simple portable fluorescence meter, the prepared material immediately presents Chinese knot patterns with different colors and strong fluorescence.

Xu said the series of supramolecular fluorescent materials are expected to realize applications in intelligent response, information storage and optical information anti-counterfeiting.
Source: China science news