Simple One-Pot Preparation of a Rapid Response AIE Fluorescent Metal–Organic Framework

Luminogenic
materials, particularly those that have turn-on response
by sensing the analytes, are highly regarded as optical instruments,
sensing material, fluorescent probes, etc. However, most of these
materials are only usable in dilute form and often show the self-quenching
effect at high concentrations. The use of light-emitting AIE-based
materials (aggregation-induced emission) is the solution of this problem.
The rigid structure of these active fluorescence ligands, which contains
several aromatic rings attached to each other, does not lose its fluorescence
properties by increasing the concentration. Unlike other AIE ligands,
which have a complex or multistep synthetic route, here, we present
a simple one-pot method for in situ synthesis of the AIE ligand and
the metal–organic framework (MOF) contained therein. Presence
of metal nodes having varied outer-shell electron configurations affects
the fluorescence intensity of these materials and, thus, both high
and low emissive “turn on” MOFs were readily acquired.
Based on the possible interactions between the free nitrogens on the
ligand and the phenolic compounds, the MOFs enable highly selective
and sensitive detection of phenol derivatives in several seconds with
low detection limits (less than 65 nM for 4-aminophenol and 120 nM
for phenol) through turn-on emission fluorescence.