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Updated: Mar 7, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
A new fluorogenic sensing platform for salicylic acid derivatives based on π-π and NH-π interactions between
Anup Pandith1, Giridhari Hazra1, Hong-Seok Kim1
1Department of Applied Chemistry, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
Abstract:
A novel simple fluorescent probe was designed for the recognition of electron-rich salicylic acid derivatives (SAs). The imidazole-appended aminomethyl perylene probe 1 selectively differentiated between electron-rich amino-SAs and electron-deficient nitro-SAs in EtOH, exhibiting the highest selectivity and sensitivity toward 5-aminosalicylic acid (5-ASA) and showing strong 1:1 binding (Ka=1.37×107M-1). This high selectivity and sensitivity resulted from the synergistic multiple hydrogen bonding interactions of secondary amine and imidazole units and π-π interactions between electron-rich and electron-deficient rings, along with the unusual NH-π interactions between 5-ASA and the perylene moiety of 1. The limit of detection (LOD) for 5-ASA in EtOH was 0.012ppb.

