Highly sensitive and selective fluorescence turn-on detection of lead ion in water using fluorene-based compound and polymer

Abstract

A fluorene-based sensory compound and polymers were designed and synthesized for the fluorescence turn-on detection of lead ions in aqueous media. The fluorene unit is used as a fluorophore and also as the building block for making a conjugated fluorene-based polymer. A dicarboxylate pseudo crown was selected as a receptor, which is highly selective towards the lead ion and imparts a good water-solubility to sensory compounds and polymers. The water-soluble sensory compound and fluorene-based polymer show high sensitivity and selectivity towards lead ions in aqueous media. Sensory compound 7a and polymer P2 are highly selective and sensitive for the fluorescence turn-on detection of lead ions in water with a concentration of 4 μM. Fibre-optic sensing for lead ions in water using sensory compound 7a has also been demonstrated.