Aggregation-induced enhanced emission (AIEE) Active Conjugated Mesoporous Oligomers (CMOs) with Improved Quantum Yield and Low-Cost Trace Nitro Aromatic Explosives Detection.

The article reports a straightforward strategy for the design and synthesis of highly luminescent conjugated mesoporous oligomers (CMOs) with 'Aggregation- induced enhanced emission' (AIEE) feature through Wittig polymerization of the molecular rotor. Typical molecular rotors such as triphenylamine (TPA) and tetraphenylethene (TPE) as B2, A4 & A3 type nodes have been used to construct AIEE active CMOs, namely CMO1 & CMO2. The quick dissipation of the excited photons was successfully controlled by the restriction of rotation of the phenyl units through the formation of the mesoporous network scaffold in solid/thin film, which provides the high quantum yields for the interlocked CMOs system. Both the CMOs are sensitive and selective to the various nitroaromatics based explosives, whereas CMO1 is more sensitive (Ksv = 2.6 × 106 M-1) towards the picric acid. The increased quenching constant for CMO1 is due to its increased quantum yield and high-energy transfer efficiency. The mechanism for sensing has been studied in detail. The larger pore size and pore density in the mesoporous network of CMO1 are found to be responsible for the greater extent of energy transfer from CMO1 to picric acid. Furthermore, CMO1 has been employed for low-cost filter paper-based detection of trace nitroaromatic containing explosive materials.