Synthesis And Characterization Of Rhodamine B Derivatives

A series of alkylrhodamine B esters were designed and synthesized from rhodamine B. The synthetic process was established and optimized. The analytical conditions of the resonance light scattering are optimized and the work line is drawn. When SOCl2 is used as the acylating agent, methyl alcohol to rhodamine B =10:1(mole ratio), reaction temperature is 70℃(methylrhodamine B 60℃) and reaction time is 7h, the yields of products are above 80%.The fluorescence analytical results show that the maximum absorption and emission wavelength of alkylrhodamine B esters, comparing with rhodamine B, generate red shift and the fluorescence intensity tone more than rhodamine B. It is indicated that the carbon-chain of ankylrhodamine B esters have little influence on the fluorescence intensity. To the methylrhodamine B ester, the maximum absorption and emission wavelengths are not affected by the concentration while the fluorescence intensity enhances as the concentration increases; the maximum absorption and emission wavelengths generate red shift with the enhancing of the solvent polarity while the fluorescence intensity weakens; the maximum absorption and emission wavelengths have no changes with increasing of the irradiating time, but the fluorescent intensity reduces apparently. Methylrhodamine B ester can be used to determine DNA concentration.5(6)-nitro, anmio, iodic, bromic, chloro and fluoro rhodamine B were synthesized. The synthetic process was optimized. The 5(6)-aminorhodamine B modified by electron donor amino substituent has stronger fluorescence intensity than rhodamine B, meanwhile the maximum absorption and emission wavelengths generate red shift. To the 5(6)-nitroodamine B synthesized by electron with drawing group, the fluorescence intensity is weaker than rhodamine B, while the maximum absorption and emission wavelengths generate red shift. The fluorescence intensity of 5(6)-halogenated derivatives is stronger than rhodamine B, while the the maximum absorption and emission wavelengths generate red shift, ordered as I