The Design of Dual-Emissive Composite Material [Zn₂(HL)₃]⁺@MOF-5 as Self-Calibrating Luminescent Sensors of Al³⁺ Ions and Monoethanolamine

Abstract

Introducing another chromophore into a luminescent MOF is a potential way to assembling novel dual-emissive luminescent materials. Putting the chromophore, for which luminescence can be enhanced by Zn²⁺ ion, into MOF-5 by the "bottle around ship" strategy is a simple but efficient synthesis method to realize such dual-emissive materials. According to this strategy, a novel dual-emissive luminescent composite material [Zn₂(HL)₃]⁺@MOF-5 was constructed by loading the [La₃(HL)₂L₂(NO₃)₃H₂O] (1) (H₂L = 7,7'-(ethane-1,1'-diyl)8-hydro-quinoline) into MOF-5, in which the [Zn₂(HL)₃]⁺ anions were transformed from 1 with the existence of Zn²⁺. The dual-emissive composite materials show excellent luminescence with two emissions of MOF-5 at 410 nm and [Zn₂(HL)₃]⁺ at 524 nm. Furthermore, by combining characteristics of MOF-5 and the guest chromophore, the composite material is highly selectively sensitive toward Al³⁺ and monoethanolamine, which makes [Zn₂(HL)₃]⁺@MOF-5 a potential self-calibrated fluorescence sensor.