In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called Excited-State Behavior of 2-(4′-Pyridyl)benzimidazole in Aqueous Solution: Proton-Transfer Processes and Dual Fluorescence, published in 1995-10-05, which mentions a compound: 2208-59-5, mainly applied to excited state reaction pyridylbenzimidazole proton transfer; photolysis pyridylbenzimidazole proton transfer, Synthetic Route of C12H9N3.
The excited-state acid-base behavior of 2-(4′-pyridyl)benzimidazole in aqueous solution has been studied over a wide range of acidity by UV absorption and fluorescence spectroscopy. The species detected in the lowest electronically excited singlet state turned out to be identical to those of the ground state: the anion A, the neutral mol. N, the monocation C protonated at the benzimidazole N3, the monocation T protonated at the pyridyl nitrogen, and the dication D. Nevertheless, the strong increase in the basicity of the pyridyl nitrogen atom in the excited state induces different excited-state proton-transfer processes. The dual fluorescence of 4PBI at neutral pH is explained by the protonation of N* to give T*. On the basis of the steady-state data together with the fluorescence decay measurements at several acidities, a mechanism is proposed to explain the acid-base behavior of 4PBI in the first excited singlet state.
There is still a lot of research devoted to this compound(SMILES：C1(C2=CC=NC=C2)=NC3=CC=CC=C3N1)Synthetic Route of C12H9N3, and with the development of science, more effects of this compound(2208-59-5) can be discovered.
Reference:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles