| Pure organic room-temperature phosphorescence(RTP)has the advantages of easy structural functionalization,rich species,good biocompatibility,etc.And because of this,RTP materials often enables unique material characteristics and fabrication of state-of-the-art optoelectronic devices that cannot be realized using conventional fluorescent ones.Therefore,this kind of materials has promising potential applications in sensing,bioimaging,and information storage and anti-counterfeiting.But pure organic RTP materials due to the weak spin–orbit coupling,highly active triplet excitons,and ultrafast deactivation of the external environment,such as vulnerable to oxygen and quenching,the luminescence phenomenon of pure organic RTP materials are generally only observed in low temperature or inert gas environments.As a result,access to organic RTP emission in either liquid or solution phase,especially in the aqueous phase,is still very limited.Therefore,how to construct organic RTP materials in aqueous solution has attracted the attention of researchers.In recent years,macrocyclic compounds have become a research hotspot for realizing RTP in aqueous solution due to their ability to generate a rigid environment to inhibit the non-radiative decay of phosphors and to protect the triplet excited state of the phosphors.In supramolecular systems,the cucurbit[n]urils(Q[n])are particularly important macrocyclic host molecules,due to the hydrophobic interaction of its internal cavity and the ion–dipole interaction between positively charged atoms on the guest molecules and carbonyl oxygens at the portal of Q[n],so that the Q[n] container can encapsulate hydrophobic moieties of various positively charged guest molecules.The assembly of macrocyclic hosts and guests can bring the following advantages to purely organic RTP: the host molecules can provide a rigid environment for the guest molecules to restrain the vibrations of the guest molecules,suppressing the non-radiative relaxation of the triplet state,and the hydrophobic cavity can shielding the guest from the quenching effect of oxygen and other solvent molecules.This method will efficiently reduce synthetic efforts compared with traditional phosphorescent materials,while imparting at the same time the dynamic features typical of supramolecular systems.In this paper,the research progress of RTP system induced by cucurbit[n]urils-based supramolecular assembly was firstly reviewed,and the research objectives were established based on the summary.The main contents of this paper are as follows:(1)A 4-bromophenylpyridine derivative(N1)containing heavy atomic bromine was designed and synthesized,and its structure was characterized by 1H NMR,ESI Mass Spectrometry and FT-IR.The N1@Q[8] system was successfully induced to produce yellow-green RTP emission by self-assembly with Q[8] in aqueous solution.The optical properties and mechanism of N1@Q[8] system were studied by means of 1H NMR,fluorescence(phosphorescent)spectrum and X-ray.In addition,N1@Q[8] system was used for the detection of phenolic compounds and targeted cell imaging,providing a new supramolecular self-assembly method for the water system application of phosphorescence.(2)The N1@Q[8] assembly realizes recognition of different metal cations by exploiting the affinity of Q[n] for different metal ions.The results show that N1@Q[8] system has good selectivity and low detection limit for Cu2+ and Hg2+ ions,and the two metal ions can be easily detected by the interaction time.The mechanism of interaction between metal ions and N1@Q[8] system is also studied.(3)α-bromonaphthalene derivative(B1)containing heavy atomic bromine was designed and synthesized.By self-assembly with Q[7],B1 was induced to produce yellow RTP emission under deoxygenation condition.The RTP emission conditions,optical properties and action mechanism of B1@2Q[7] system in aqueous solution were studied.In addition,the B1@2Q[7] system showed photochromic properties. |
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