Synthesis and spectroscopic characterization of multifunctional D-π-A benzimidazole derivatives as potential pH sensors

Beč, Anja; Vianello, Robert; Hranjec, Marijana (2023) Synthesis and spectroscopic characterization of multifunctional D-π-A benzimidazole derivatives as potential pH sensors. Journal of Molecular Liquids, 386 . ISSN 0167-7322

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Abstract

We report multifunctional D-π-A molecular systems having the N,N-diethylamino group as a pH sensitive donor unit connected to the electron accepting substituents such as the cyano moiety and the pH responsive benzimidazole fragment. For that purpose we have synthesized three types of derivatives, namely acrylonitrile, Schiff base and iminocoumarin derived benzimidazoles, whose photophysical characterization has been carried out in several polar and non-polar organic solvents as well as aqueous solution buffers with different pH. Computationally supported determination of species involved in prototrophic equilibria, including their respective pKa values, has been performed to aid in understanding structural and substituent effects on their UV–Vis and fluorescence spectral properties and pH sensing potentials. Both sets of results jointly indicate that all molecules are predominantly unionized under neutral conditions, while their transition towards monocationic forms, responsible for spectroscopic response changes, occurs at pH ≈ 1–4 for acrylonitriles 4–5, pH ≈ 4–5 for Schiff bases 11–12, and pH ≈ 4.5–6.5 for iminocoumarins 7–8, thus increasing their practical attractiveness for a broad range of applications in the same order.

Item Type:	Article
Uncontrolled Keywords:	Acrylonitriles; Benzimidazoles; DFT computational analysis; Iminocoumarins; pH sensors; Schiff bases; Spectroscopic characterization
Subjects:	NATURAL SCIENCES > Chemistry NATURAL SCIENCES > Chemistry > Theoretical Chemistry NATURAL SCIENCES > Chemistry > Analytic Chemistry NATURAL SCIENCES > Chemistry > Organic Chemistry
Divisions:	Division of Organic Chemistry and Biochemistry
Projects:	Project title Project leader Project code Project type Dizajn, sinteza i računalna analiza novih optičkih kemijskih pH osjetilnih derivata benzazola-BenzpHSens Robert Vianello IP-2020-02-8090 HRZZ Istraživanje antioksidativnog djelovanja benzazolskog skeleta u dizajnu novih antitumorskih agensa-AntioxPot Marijana Hranjec IP-2018-01-4379 HRZZ
Depositing User:	Robert Vianello
Date Deposited:	20 Jan 2025 09:43
URI:	http://fulir.irb.hr/id/eprint/9485
DOI:	10.1016/j.molliq.2023.122493

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