Inter- and Intra-Hydrogen Bonding Strategy to Control the Fluorescence of Acylhydrazone-Based Conjugated Microporous Polymers and Their Application to Nitroaromatics Detection

Abstract

Acylhydrazone-based fluorescent conjugated microporous polymers (CMPs) with inter-and intra-hydrogen bonding-controlled emissive properties were prepared. The synthesized CMPs (BH-CMP and ABH-CMP) were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, solid-state 13C cross polarization/magic angle spinning nuclear magnetic resonance spectroscopy, and photoluminescence spectroscopy. Interestingly, BH-CMP exhibited emission enhancement via adsorption of water molecules, whereas the emission of ABH-CMP, which possesses free amine groups, decreased upon the addition of water molecules. The differences in the emission trends of BH-CMP and ABH-CMP in the presence of water molecules originate from the formation of different hydrogen-bonding networks in each CMP. The acylhydrazone-based CMPs were applied to the detection of nitroaromatic compounds. As a result, ABH-CMP in DMF exhibited high selectivity for 1,3,5-trinitrotoluene (TNT) over other nitroaromatic compounds nitrobenzene, 1-chloro-4-nitrobenzene, 2,3-dichloronitrobenzene, and 2,4-dinitrotoluene.

A ‘Turn-On’ Carbamazepine Sensing Using a Luminescent SiO2/-(CH2)3NH2/-C6H5 + Rh6G System

“…This observation provides evidence of the formation of hydrogen bonds between the fluorophore molecule and silica particles. These hydrogen bonds restrict the intramolecular rotation mechanism of the fluorophore, leading to improved photoluminescence (PL) properties (see (2) in Figure 2) [29,44]. Furthermore, the lower red shift from 545 nm to 549 nm has been noticed on the PL spectrum of SiO 2 /≡Si(CH 2 ) 3 NH 2 /≡SiC 6 H 5 +Rh6G (ads.)…”