Preparation And Properties Of Hydroxy-Carbonyl Group Nonconventional Luminescent Materials

Organic luminescent materials have been widely used in fields such as chemical sensing,biological imaging,electroluminescence,solid-state lighting,and displays.Traditional luminescent materials typically contain aromatic groups,which are synthesized through C-C coupling,C-N coupling,and other reactions that often require expensive heavy metal catalysts.Moreover,aromatic compounds are often harmful to the human body and difficult to degrade in the environment,further limiting their practical applications.In recent years,nonconventional organic luminescent materials have received significant attention from researchers.However,most nonconventional organic luminescent materials typically exhibit bright luminescence only in the solid-state or at high concentrations and are currently in the early stages of research,with their luminescence mechanisms yet to be clarified.Based on this,our project mainly focuses on synthesizing nonconventional luminescent polymers（NLPs）that do not contain aromatic groups through polymerization reactions,and utilizing the interaction between hydroxyl and carbonyl groups to restrict nonradiative transitions and achieve efficient luminescence of NLPs in dilute solutions.The main research contents are as follows:（1）Two different molecular weight linear NLPs-M1 and M2 are constructed by reacting ethylene glycol diglycidyl ether and dihydroxyacetone,and their photophysical properties are studied in detail.The results show that M1 and M2exhibit efficient fluorescence emission in dilute solutions.Additionally,the solution spectra indicate that M1 and M2 exhibit cluster-induced emission（CTE）characteristics.Due to the molecular weight distribution of the polymers,M1 and M2exhibit excitation wavelength dependence in both solution and solid-state.Moreover,M2 can be used for Fe³⁺detection and cell imaging.（2）Three kinds of NLPs-Z1,Z2 and Z3 with different molecular weights were prepared by the reaction of hexahydrophthalic acid diglycidyl ether and dihydroxyacetone,and then Z4 was prepared by the reaction of propan-1,3-diol.The photophysical properties of the three kinds of NLPs-Z1,Z2 and Z3 were studied.The results show that Z1,Z2 and Z3 with carbonyl group can emit blue-green fluorescence efficiently in dilute solution,and Z4 without carbonyl group can emit blue fluorescence at high concentration.The interaction between carbonyl and hydroxyl groups presented in this paper is further verified to provide an effective luminescence strategy for atypical organic luminescent materials in dilute solution.Solution spectra show that Z1,Z2,Z3 and Z4 all have CTE characteristics,and they all have excitation wavelength dependence in solid and solution states.Z2 can effectively recognize Mo⁵⁺and can be used for cell imaging.（3）NNC and NNE were prepared by ring-opening polymerization of triglycidyl isocyanurate and dihydroxyacetone with propan-1,3-diol,respectively.The structures of NNC and NNE were characterized by infrared and nuclear magnetic hydrogen spectroscopy,and their photophysical properties were studied carefully.The results show that NNC containing carbon can still emit fluorescence efficiently in dilute solution,while NNE without carbon can only emit fluorescence efficiently in high concentration,which proves that the interaction between carbon and the hydroxyl group formed after epoxy ring-opening limits the movement of molecules,reduces the non-radiative transition,and enhances the emission of fluorescence.Both NNC and NNE have good photobleaching resistance.In the field of application,NNC doped with PMMA can form uniform transparent films,emit fluorescence and act as luminescent probe to detect Fe³⁺.