Conghuan group, Institute of physics and chemistry, Chinese Academy of Sciences

As the basic unit of building supramolecular system with various properties and functions, macrocyclic compounds are very important for the development of supramolecular chemistry In recent years, with the application of supramolecular chemistry in intelligent materials, the design and synthesis of new stimulus responsive macrocyclic compounds has become a challenging research hotspot in the field of supramolecular chemistry and macrocyclic chemistry Recently, Conghuan research group of Institute of physical and chemical technology of Chinese Academy of Sciences has made new progress in the synthesis of new stimulus response supramolecular fluorescent macrocycles (angel Chem Int ed., 2020, DOI: 10.1002/anie.201913340) Cong Huan, about researcher Cong Huan, graduated from Peking University in 2006 (Tutor: academician Xi Zhenfeng), received his Ph.D from Boston University in 2011 (Tutor: Professor John A Porco), and engaged in post doctoral research at MIT and Caltech from 2011 to 2015 (Tutor: Gregory C Professor Fu), who was selected into the 11th batch of "youth thousand talents plan" of the central organization department in 2015, was incorporated into the Institute of physical and chemical technology of the Chinese Academy of Sciences to carry out independent research The research direction is the precise synthesis of conjugated macrocyclic molecules, which has won academic honors such as "Thieme Chemistry Journals Award" (2017) of Germany and "excellent youth fund" (2019) of the Foundation Committee In recent years, because of its unique structural characteristics and excellent host guest properties, pillararene has attracted extensive attention of scholars at home and abroad At present, as a new generation of supramolecular host compounds, aromatics have been widely used in fields such as fluorescence sensing However, due to the lack of fluorescence groups in their skeletons, most of the construction of fluorescent aromatics at present is mainly realized by introducing fluorescence groups at their edges A new type of supramolecular macrocyclic compound, bowtie arene, was designed by introducing tetrastyrene (TPE), a typical aggregation induced light source (aiegen), into the framework of aromatics The results show that the compound has stimulated response fluorescence (Fig 1) Fig 1 Structural design and switchable fluorescence characteristics of the bow tie aromatics (source: angelw Chem Int ed.) the author first used a new class of monophosphonic ligands, dianthphos (org Lett 2019, 21, 8158) catalyzes the Suzuki coupling reaction between TPE derivatives and the side chain unit of aryl bromide The coupling product obtained in a single step yield of 60% can be directly obtained through Lewis acid catalyzed condensation reaction to obtain the target bicyclic compound - bow tie aromatic hydrocarbon (Fig 2) The single crystal structure of the bicyclic compound shows that its geometry is similar to the bow tie, with two symmetrical cylindrical cavities, and each cavity has almost the same shape and size as the column [5] arene In addition, the stacking mode diagram of the single crystal structure shows that there are multiple noncovalent interactions including π π and C-H π in the crystal of the tie aromatics (Fig 3) Fig 2 Synthesis route of tie aromatics (source: angelw Chem Int ed.) Fig 3 Single crystal structure analysis of tie aromatics (source: angelw Chem Int ed.) have yellow and blue fluorescence in solution and single crystal state respectively; in addition, in different proportions of THF / H 2O mixed solvent, The fluorescence properties of the aromatics also changed significantly with the different molecular stacking states According to the results of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), it is preliminarily confirmed that the fluorescence properties of the molecule are closely related to the molecular stacking state (Fig 4) Fig 4 Fluorescence properties of the aromatic compounds in different states (source: angelw Chem Int ed.) Later, the author found that the disordered state of the ordered aromatic crystals after mechanical grinding can be further induced by p-xylene vapor to make them orderly stacked again (Fig 5) On this basis, the filter paper loaded with bow tie aromatic molecules can achieve multiple reversible erasures of fine fluorescent images and texts under different mechanical forces and exogenous stimulation of xylene vapor (Fig 6) Fig 5 Mechanochemical and vapor induced fluorescence properties of the aromatic compounds in the bow tie (source: angelw Chem Int ed.) Fig 6 Reversible stimulus response fluorescence of the aromatic compounds in the bow tie (source: angelw Chem Int ed.) Finally, the theoretical calculation results show that: the fluorescence of the aromatic compounds in the bow tie in the ordered arrangement state The larger distortion of TPE leads to a significant blue shift of its luminescence, which is consistent with the results of photophysical tests Figure 7 Theoretical calculation results of fluorescence properties of tie aromatics (source: angelw Chem Int ed.) the research results were recently published in angelwandte Chemie International Edition (DOI: 10.1002 / anie 201913340) and selected as VIP articles Lei Shengnan, Ph.D student of the Institute of physics and chemistry, is the first author of this paper Researcher Zeng Yi and associate researcher Xiao Hongyan of the Institute of physics and chemistry gave great assistance in the field of photophysical test and theoretical luminescence calculation, respectively Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information website, chembeangoapp, chembeango official micro blog, CBG information wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the representative research groups in China, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.