Acridine-based complex as amino acid anion fluorescent sensor in aqueous solution

• The novel fluorescent sensors based on acridine can selective recognize Cu2 + through ligand-to-metal binding process.
• The reported fluorescent sensors for the selective recognition of amino acid anion using metal complex in aqueous solutions
• The binding constants were calculated.

Novel acridine-based fluorescence sensors containing alaninol ligands, L1 and D1, were designed and synthesized. The structure of the compound was characterized by IR, 1H NMR, 13C NMR, MS spectra. L1 and D1 possess efficient Cu2 + cation ON–OFF selective signaling behavior based on ligand-to-metal binding mechanism at physiological pH condition. Additionally, the L1–Cu(II) and D1–Cu(II) complexes could further serve as reversible OFF–ON signaling sensing ensemble to allow ratiometric response to amino acid anion in aqueous solution.

A pair of new acridine fluoroionophore containing two alaninol ligands, L1 and D1, was designed and synthesized. The structures of these compounds were characterized by IR, MS, 1H NMR, 13C NMR spectra and elemental analysis. Their photophysical properties toward metal ions were studied by absorption and fluorescence spectra. The presence of Cu2 + resulted in significant quenching of the fluorescence emission from sensor, while other metal ions posed little interferences. The fluorescence response was concentration-dependent and induced the formation of a 1:1 ligand/metal complex in buffered aqueous. Additionally, the Cu2 + complex ensemble could further serve as a probe to act as a sensor for amino acid anion via a complex mode.Figure optionsDownload as PowerPoint slide