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The fluorescence properties of polymethylene bis-β-naphthoates with various chainlengths (B_n) in poor solvents such as dimethyl sulfoxide-water (DMSO-H_2O) and ethylene glycol-water (EG-H_2O) were measured under stationary and nonstationary conditions at various temperatures.Hydrophobic interactions bring the two chromophores of B_3,B_4,B_5 and B_(10) into sandwich arrangementin ground state,thus promote intramolecular excimer formation upon excitation.The perfect over-lapping structure of B_2 can not be formed in ground state because of the eclipsed conformation of twomethylene groups in such a sandwich arrangement,The favorable conformation of B_2 is the structurein which the two naphthyl rings are in proximity.The activation energy,enthalpy and entropychanges of excimer formation of B_2 were calculated from the fluorescence decay parameters.
The fluorescence properties of polymethylene bis-β-naphthoates with various chainlengths (B_n) in poor solvents such as dimethyl sulfoxide-water (DMSO-H_2O) and ethylene glycol-water (EG-H_2O) were measured under stationary and nonstationary conditions at various temperatures .Hydrophobic interactions bring the two chromophores of B_3, B_4, B_5 and B_ (10) into a sandwich arrangement in ground state, thus promoting intramolecular excimer formation upon excitation. The perfect over-lapping structure of B_2 can not be formed in ground state because of the eclipsed conformation of twomethylene groups in such a sandwich arrangement, The favorable conformation of B_2 is the structure in which the two naphthyl rings are in proximity. The activation energy, enthalpy and entropychanges of excimer formation of B_2 were calculated from the fluorescence decay parameters.