Solvent and temperature effects on the phosphorescence of 9,10-phenanthrenequinone in fluid solution

摘要: Abstract The phosphorescence of 9,10-phenanthrenequinone (PQ) was observed and studied in carbon tetrachloride (CCl4) acetonitrile (MeCN) using steady-state time-resolved emission spectroscopy. From the estimated quantum yields measured triplet lifetimes at room temperature natural radiative lifetime PQ calculated to be 10±4 ms CCl4 39±8 ms MeCN. showed vibrational fine structure both solvents a hypsochromic shift when going more polar solvent. Both are typical n,π∗ state. Examination effect on intensity initial experiments indicated an activation energy 2.38±0.39 kcal/mol MeCN, negative −0.25±0.04 kcal/mol CCl4. It concluded that emissive state is nature thermal equilibrium with nearby non-emissive π,π∗ these solvents. In lowest 49.1 kcal/mol, second excited almost isoenergetic only 0.25 kcal/mol higher. MeCN there inversion states, 47.6 kcal/mol, higher 50.0 kcal/mol. This first time it has been possible show states due changes solvent measure energies states.