Zhao Hui, Su Wei, Luo Yanhua, Ji Yaohui, Li Zengchang, Jiu Hongfang, Liang Hao, Chen Biao, Zhang Qijin
Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, Anhui, People's Republic of China.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Nov;65(3-4):846-51. doi: 10.1016/j.saa.2006.01.018. Epub 2006 Mar 31.
Bathochromic shift in excitation spectrum was observed during emission measurement of Eu(DBM)(3)Phen containing dilute solution in methyl methacrylate (MMA). Detailed analysis shows that the reason of bathochromic shift is not the formation of molecule aggregation. It is caused by the intense absorption of ligands in the complex. Based on this model, a new method has been established to rectify excitation spectra before emission measurement of systems with different concentration. There exists a critical value of the absorption strength, which is 0.87 from calculation. Higher absorption than this value will cause the bathochromic shift of excitation peak. The wavelength whose absorbance is 0.87 will be the position of the strongest excitation peak. With 200 ppm and 500 ppm Eu(DBM)(3)Phen as the standard sample, relations between relative concentration and wavelength of excitation peak in Eu(DBM)(3)Phen system were deduced and plotted. Theoretical curves are in good agreement with experiment data except extra-dilute concentration, for partial decomplexation of the beta-diketonate and phenanthroline ligands.
