The fluorescence intensities for various vibronic fine structures in the 1-pyrenecarboxaldehyde (PyCHO) fluorescence show strong environment dependence. In aqueous solvent, the distribution of dye is highly depended on its concentration labels and varies from excimer to monomeric state. UV-Vis Spectroscopic analysis could not able to detect dye below 10-7M concentration, whereas a new monomeric peak at 342 nm was observed after heating and cooling treatment at above the concentration. At 10-8M concentration, only monomeric distribution of 1-PyCHO reveals a strong temperature (20-50 °C) induced reversible perturbation of the vibronic band intensities. This suggests the operation of some specific solute-solvent dipole-dipole interaction mechanism strongly influenced by heating.
International Letters of Chemistry, Physics and Astronomy (Volume 6)
M. Ashaduzzaman and M. Kunitake, "Aqueous Dispersion and Temperature Induced Reversible Fluorescence Properties of 1-Pyrenecarboxaldehyde", International Letters of Chemistry, Physics and Astronomy, Vol. 6, pp. 55-62, 2013