Aqueous Dispersion and Temperature Induced Reversible Fluorescence Properties of 1-Pyrenecarboxaldehyde

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. UVVis 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 influence by heating.