Intramolecular Energy Transfer Study of Naphthalene-Anthracene-end Labelled Polymethylene

The fluorescence spectra of N-Mn,-A were investigated in various organic solvents selectively, excitation of the naphthalene group at λex = 280nm resulted in two emission peaks with λem = 370nm, λem =450nm. The former is the fluorescence of the naphthalene group and the later is the fluorescence of the anthracene group. It is proved by experiments that naphthalene only has absorption peak with its λmax at 280nm and anthracene shows no absorption at this region. So the energy is transferred from the excited naphthalene to the ground anthracene. The fluorescence spectra of the substrates (n =6,10) with various concentration were investigated in different organic solvents. It is found that the ratio of the intensities of the two fluorescence peaks is independent of the concentration, suggesting that the energy transfer occurs intramolecularly.