A new fluorogenic sensing platform for salicylic acid derivatives based on π-π and NH-π interactions between electron -deficient and electron-rich aromatics

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 aminoSAs and electron-deficient nitro-SAs in EtOH, exhibiting the highest selectivity and sensitivity toward 5aminosalicylic acid (5-ASA) and showing strong 1:1 binding (Ka =137 x 10(7) M-1). This high selectivity and sensitivity resulted from the synergistic multiple hydrogen bonding interactions of secondary amine and imidazole units and n-n interactions between electron-rich and electron-deficient rings, along with the unusual NH-n interactions between 5-ASA and the perylene moiety of 1. The limit of detection (LOD) for 5-ASA in EtOH was 0.012 ppb. (C) 2017 Elsevier B.V. All rights reserved.