SENSING OF ANIONS AND α-AMINO ACIDS USING DINUCLEAR COMPLEXES OF Cu(II) AND Zn(II) WITH TRIPODAL AMINE LIGANDS UNDER INDICATOR DISPLACEMENT ASSAY APPROACH

Abstract

In this research, the dinuclear and mononuclear copper(II) and zinc(II) complexes with anthracene based tripodal amine ligands (Cu2L2, Zn2L2, CuL3 and ZnL3) were synthesized and characterized by standard analytical techniques. The sensing abilities towards anions and α-amino acids were investigated using the indicator displacement assay (IDA) approach. The detection of pyrophosphate anion (PPi) by Zn2L2 with four complexometric indicators was carried out. The results indicated that the [Zn2L2•MTB] ensemble could discriminate the PPi from other phosphate containing anions. 1H and 31P NMR spectroscopy as well as DFT calculations confirmed that PPi bound to Zn2L2 in a 2 : 2 manner. The detection limit of PPi for the reported IDA system was 0.3 µM. The mononuclear complexes with tripodal amine based IDA receptors (ML3), where M = Cu2+ and Zn2+, for anions were investigated for colorimetric histidine (His) sensor under displacement assay using PAR as an indicator. [CuL3·PAR] can detect histidine selectively while [ZnL3·PAR] can be interfered by phosphate containing anions. Furthermore, [CuL3·PAR] can be used to detect His in real urine samples with limit of detection of 0.5 µM.