engleski

Excited state intramolecular proton transfer from nitrogen to carbon

ESIPT has been in the focus of interest owing to different applications. The most common acidic site is phenolic OH (oxygen photoacid), whereas the basic sites are usually heteroatoms such as carbonyl oxygen or pyridine nitrogen. Moreover, transfer of a proton from oxygen photoacids to a carbon atom of adjacent aromatic ring is already well accepted, as some very efficient reactions have been reported [1, 2], indicating that protonation of carbon is not necessarily slow [3]. Nitrogen photoacids are known, but ESIPT reports are scarce and in principle involve transfer to a very basic pyridine nitrogen. Here we report that the ESIPT to carbon is also a general reaction, involving nitrogen photoacids. The ESIPT has been investigated in a series of aminoaromatic compounds by irradiations in deuterated solvents, where upon D-incorporation denotes the ESIPT pathways. Furthermore, to get insight into the reaction mechanism we conducted fluorescence measurements and laser flash photolysis. The proposed ESIPT mechanism was corroborated by ADC(2)-based electronic structure computations.

ESIPT to carbon ; Nitrogen photoacids

nije evidentirano