Photophysics of indole-2-carboxylic acid (I2C) and indole-5-carboxylic acid (I5C): Heavy atom effect

- Photophysical parameters of carboxylic indole derivatives have been determined.
- Phosphorescence lifetime of I2C and I5C in water was 912 and 56 μs, respectively.
- The triplet quantum yields of aqueous I2C and I5C were similar to that of indole.
- Temperature dependence of I2C and I5C triplet state quenching by KI was determined.
- The ATR-FTIR spectra of I2C and I5C in the solid state have been recorded.