<p><a></a><a></a><a></a><a></a><a></a><a></a><a></a><a>The development of
highly-sensitive recognition of </a><a></a><a></a><a></a><a></a><a>hazardous </a>chemicals, such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs), is of
significant importance because of their widespread social concerns related to
environment and human health. Here, we
report a three-dimensional (3D) covalent organic framework (COF, termed
JUC-555) bearing tetraphenylethylene (TPE) side chains as an
aggregation-induced emission (AIE) fluorescence probe for sensitive
molecular recognition.<a></a><a> </a>Due to the rotational restriction of TPE rotors in highly
interpenetrated framework after inclusion of dimethylformamide (DMF), JUC-555 shows impressive AIE-based strong fluorescence. Meanwhile, owing to the large pore size (11.4 Å) and suitable intermolecular distance of aligned TPE
(7.2 Å) in JUC-555, the obtained
material demonstrates an
excellent performance in the molecular recognition of
hazardous chemicals, e.g., nitroaromatic explosives, PAHs, and even thiophene
compounds, via a fluorescent quenching mechanism. The quenching constant (<i>K</i><sub>SV</sub>) is two orders of magnitude better than
those of other fluorescence-based porous materials reported to date. This
research thus opens 3D functionalized COFs as a promising identification tool
for environmentally hazardous substances.</p>
3D Cage COFs: A Dynamic Three-Dimensional Covalent Organic Framework with High-Connectivity Organic Cage Nodes