Excited State Intramolecular Proton Transfer (ESIPT) to Aromatic C-Atom: Influence of Substitution on o-Phenylphenol.

LEANDRO MENA; LILIANA B. JIMENEZ; MARIA T. BAUMGARTNER

Encuentro; XIII Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2017

substitution of the ring containing the -OH in o-phenylphenol. It is of interest to analyse the effect of the electronic nature of the substituents in the ESIPT global efficiency.The compounds 1-5 were synthetized and purified following previously published procedures. After that, solutions of 1-5 were prepared using an acetonitrile/D2O mixture as solvent and then photolysed under 254 nm light. 1H-NMR spectra were taken before and after irradiation to quantify the D-incorporation as a measure of the efficiency of the ESIPT. It was found a linear correlation between the donor/acceptor character of the substituents and the ESIPT overall yield. ESIPT improves when the donor character increases. For example, compound 2 incorporates a 7% of D-atom in addition respecting to the model compound o-phenylphenol (3). On the contrary, the ESIPT is almost negligible when a strong acceptor substituent, as -CN (5), is attached.