Synthesis And Properties Of Novel Carbazole And 1,8-naphthalimide Derivatives And Their Rare Earth Complexes

Rare earth elements have special optical,electrical,and magnetic properties and can be used as substrates and activators for the manufacture of various functional materials.Complexes of rare earth ions and organic ligands have important application value.Rare earth complexes can be used in agricultural greenhouse films,luminescent coatings,fluorescent anti-counterfeiting materials,structural probes,and fluorescent labels,fluorescent probe,fluorescent immunoassays,etc.In this paper,four novel carbazole derivative ligands and four novel 1,8-naphthalimide ligands were designed and synthesized.Their structures were characterized by 1H NMR,MS,UV and IR.The corresponding target rare-earth complexes were successfully prepared.The structure of the target rare earth complexes was characterized by elemental analysis,UV and IR,molar conductance and thermogravimetric analysis,and the luminescent properties of the target rare earth complexes were studied.It's interaction with bovine serum albumin and its electrochemical properties were explored.The research work of this paper is as follows:(1)A series of new carbazole derivatives were synthesized by using carbazole and para-substituting aniline as the main starting materials.First,carbazole and ethyl bromoacetate was reacted to synthesize 9-carbazole ethyl acetate,and then 9-carbazole ethyl acetate hydrolysis given intermediate 9-carbazole acetic acid;the 2-chloro-N-acetyl para substituent aniline was synthesized from para-substituted aniline and chloroacetyl chloride;the intermediate 9-carbazole acetic acid and 2-chloro-N-acetyl para-substituted aniline was used as raw material to obtain a series of novel carbazole derivatives.Finally,the ligand was reacted with the nitrate solution of Eu3+ to obtain the target Eu(?)complex.The luminescence properties of the target Eu(?)complexes were investigated using a fluorescence spectrometer.The experimental results shown that all the target Eu(?)complexes emit characteristic red light of Eu3+ ions and all have high color purity.The different substituents on the ligand in the target Eu(?)complex affected the fluorescence intensity of the target Eu(?)complex.The introduction of an electron-donating group(-OCH3,-CH3)can enhanced the fluorescence intensity of the target Eu(?)complex but introduced electron-withdrawing group(-Cl,-NO2)weaken the fluorescence intensity of the target Eu(?)complex.The fluorescence quantum yield indicated that the lowest triplet excited state energy level of the organic ligand introduced into the electron-donating group(-OCH3,-CH3)with the resonance emission level of the Eu3+ ion matches well than the lowest triplet excited state energy level of the organic ligand of the introduced into electron-withdrawing groups(-Cl,-NO2)with the resonance emission level of the Eu3+ ion,and the energy transfer efficiency between them is better.Using fluorescence spectrometer and UV spectrometer to explored the interaction between the ligand(target Eu(?)complex)with bovine serum albumin.The results showed that the microenvironment surrounding amino acids with fluorescent properties,such as tryptophan,phenylalanine,and tyrosine,in bovine serum albumin(BSA)has been altered and led to quenching of its endogenous fluorescence.UV analysis showed that the endogenous fluorescence quenching of the target ligand and Eu(?)complexes with bovine serum albumin(BSA)was a static fluorescence quenching.(2)A series of novel 1,8-naphthalimide derivatives were synthesized using 4-brom-o-1,8-naphthalic anhydride and para-substituted benzoic acid as the main starting materials.Firstly,4-bromo-1,8-Naphthalic anhydride and 2-aminopyridin reacted to give N-(2-pyrid-yl)-4-bromo-1,8-naphthalimide,then N-(2-pyridyl)-4-br omo-1,8-naphthalimide reacted with diethanolamine to given intermediate N-(2-py ridyl)-4-[bis(2-hydroxyethyl)amino]-1,8-napht-halimide;Finally,intermediate N-(2-pyridinyl)-4-[bis(2-hydroxyethyl)amino]-1,8-naphthalimide and para-substituent ben zoic acid as starting materials to given a series of novel 1,8-naphthalimide deri vatives.Finally,the ligand was reacted with the Tb3+ to obtain the target Tb(?)complex.The luminescence properties of the target Tb(?)complexes were inve stigated using fluorescence spectre.Finally,the electrochemical performanced of the target Tb(?)complex was explored using electrochemical workstation.The experimental results shown that all target Tb(?)complexes emit characteristic green light of Tb3+ions and all have high color purity.The different substituents on the ligand affected the fluorescence intensity of the target Tb(?)complex.The introduction of an electron-donating group(-OCH3,-CH3)can enhanced the fluorescence intensity of the target Tb(?)complex but introduced electron-with drawing group(-Cl,-NO2)weakend the fluorescence intensity of the target Tb(?)complex.The fluorescence quantum yield indicated that the introduction of an electron-donating group(-CH3,-OCH3)in the target Tb(?)complex increased the density of the electron cloud and conjugated ?-bond system in the Tb(?)complex,While introducted electron-withdrawing group(-Cl,-NO2)weakend the conjugation effect and increased the difference between the triplet state of the ligand and the resonance energy level of the Tb(?)ion,energy transfer eff iciency and fluorescence quantum yield declined.Electrochemical analysis shown that the introduction of electron-donating groups(-OCH3,-CH3)in the ligands will increased the HOMO and LOMO levels of the corresponding target Tb(III)complexes,while introduced electron-withdrawing group(-Cl,-NO2)into the lig ands will reduced the HOMO and LOMO levels of the corresponding target Tb(?)complexes.