Phosphorescence and ST absorption in vanadyl(IV) tetraphenylporphyrin at room temperature

Abstract Contrary to an early view, vanady(IV) tetraphenylporphyrin (VOTPP) in solution and its vacuum-sublimed film at room temperature are found to be luminescent in the near-infrared. Luminescence lifetimes of VOTPP in chloroform at room temperature and 77 K are evaluated as 60 ns and 2.2 μs, respectively. In addition, a weak light absorption ascribable to a singlet-to-triplet excitation is found at 733 nm with a molar extinction coefficient of 5 M −1 cm −1 .