Naslov
Spectroscopic properties of differently substituted aroylhydrazones

Autori
Galić, Nives

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
18th International Symposium and Summer School on Bioanalysis, Book of Abstract / Kilar, Ferenc - Komarno : J. Selye University, 2018, 24-24

Skup
18th International Symposium and Summer School on Bioanalysis

Mjesto i datum
Komárno, Slovačka, 25.06.2018. - 30.06.2018

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
aroylhydrazones, spectroscopy, tautomeric and isomeric interconversion

Sažetak
The structural identification of N'-(2, 3- dihydroxyphenylmethylidene)-3-pyridinecarbo- hydrazide (1), N'-(2, 5- dihydroxyphenylmethylidene)-3-pyridinecarbo- hydrazide (2), N'-(3-chloro-2-hydroxy- phenylmethylidene)-3-pyridinecarbohydrazide (3), N'-(2-hydroxy-4-methoxyphenyl- methylidene)-3-pyridinecarbohydrazide (4), and N'-(2-hydroxy-4-nitrophenyl-methylidene)-3- pyridinecarbohydrazide (5) was performed in solvents of different polarities (DMSO, acetone, methanol, ethanol etc.) by different spectroscopic techniques (NMR, UV-Vis, fluorescence, IR, Raman). In all solution, compounds 1-4 were in ketoamino form (form I-E, –CO–NH–N=C–), stabilized by intramolecular H- bond between hydroxyl proton and nitrogen atom of the C=N group. In acetone solution compound 5 also adopted the most stable form I. However, in polar protic solvents (MeOH, EtOH) the equilibria between neutral hydrazone molecule in I-E form and deprotonated molecule in I-Z form was immediately observed, while continuous conversion of I-E to I-Z was recorded during time in DMSO when solution was kept in dark. However, when DMSO solution of 5 was exposed to UV light, an isomerisation to form III-E in equilibrium with III-Z (–CO–NH–NH–C=C–) occurred in all solvents. The tautomeric and isomeric interconversion was most pronounced in DMSO solution, and is consequence of mutual effect of solvent and light. Among hydrazones studied, the chloro- and methoxy-derivatives have shown pH dependent and reversible fluorescence emission connected to deprotonation/protonation of salicylidene part of the molecules.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA