Reduction in Fluorescence Intensity and Lifetime Of  Coumarin Derivative MFBMC With An Increase in Temperature in Non–Polar and Polar Solvents

Dr. Basavaraj G. Evale

Volume : IV, Issue : IV, April - 2014

Reduction in Fluorescence Intensity and Lifetime Of Coumarin Derivative MFBMC With An Increase in Temperature in Non–Polar and Polar Solvents

Dr. Basavaraj G. Evale

Abstract :

 The influence of temperature (293–333 K) on the fluorescence emission of 4–[5–methyl–3–furan–2–yl–benzofuran–2–yl]–7–methyl–chromem–2–one (MFBMC) is recorded in non–polar (1, 4–dioxane, toluene), and polar (butanol, acetonitril) solvents. It is found that there is no shift in the position of fluorescence maxima, but the intensity decreases with increase in temperature, which depends on the polarity of the solvent. A mechanism of fluorescence quenching with rise in temperature is discussed in terms of the relative location of lowest and  states, and the energy difference between them. The change in temperature ings about a change in the probabilities of radiative and non–radiative transition. The radiationless deactivation of excited–state in the absence of quencher is temperature–dependent and its thermal activation energy has been determined