去氧胆酸钠水溶液中4-二甲氨基查尔酮荧光的超常增强

类似于电子给体一受体取代的蔑类化合物,4-二甲基氨基查尔酮的光激发态包含E,A和P态。其中E和A态对应于TICT荧光体的LE和TICT态,而P态系由E态经双键扭转弛豫形成的双自由基态。

ULTRA ORDINARILY HIGH ENHANCEMENT OF THE FLUORESCENCE OF 4-DIMETHYLAMINOCHALCONE IN AQUEOUS SODIUM DEOXYCHOLATE SOLUTION

The fluorescence intensity and maximum wavelength of 4-dimethylaminochalcone(DMAC)in aqueous solution are observed to increase with the concentration of sodium deoxycholate (SDOC), a steroidal surfactant,to their maxima and then decrease,while in thesolution of an aliphatic surfactant sedium laurate(NaL),both the parameters increase withincreasing NaL concentration and level off after micelle formation. Although the fluores-cence maximum wavelength of DMAC is shorter in SDOC system than that in NaL system,the fluorescence intensity is much higher in SDOC system. The ultraordinarily high enhancement of DMAC fluorescence in SDOC system is rationalized as being due to the aggregation of rigid SDOC molecule in aqueous solution. The SDOC aggregate provides DMAC with an also rigid microenvironment where the formation of the photoinduced nonemissivebiradical state P. of DMAC is hindered and thus the emission is much strongly enhanced.Before the formation of micelle,SDOC molecule is shown to exist mainly in dimer which forms a sandwich supramolecular complex with DMAC by an association constant of 9 3.2L/mol.