Novel NBN-Embedded Polymers and Their Application as Fluorescent Probes in Fe3+ and Cr3+ Detection

Abstract

The isosteric replacement of C═C by B–N units in conjugated organic systems has recently attracted tremendous interest due to its desirable optical, electronic and sensory properties. Compared with BN-, NBN- and BNB-doped polycyclic aromatic hydrocarbons, NBN-embedded polymers are poised to expand the diversity and functionality of olefin polymers, but this new class of materials remain underexplored. Herein, a series of polymers with BNB-doped π-system as a pendant group were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization from NBN-containing vinyl monomers, which was prepared via intermolecular dehydration reaction between boronic acid and diamine moieties in one pot. Poly{2-(4-Vinylphenyl)-2,3-dihydro-1H-naphtho[1,8-de][1,3,2]diazaborinine} (P1), poly{N-(4-(1H-naphtho[1,8-de][1,3,2]diazaborinin-2(3H)-yl)phenyl)acrylamide} (P2) and poly{N-(4-(1H-benzo[d][1,3,2]diazaborol-2(3H)-yl)phenyl)acrylamide} (P3) were successfully synthesized. Their structure, photophysical properties and application in metal ion detection were investigated. Three polymers exhibit obvious solvatochromic fluorescence. As fluorescent sensors for the detection of Fe3+ and Cr3+, P1 and P2 show excellent selectivity and sensitivity. The limit of detection (LOD) achieved by Fe3+ is 7.30 nM, and the LOD achieved by Cr3+ is 14.69 nM, which indicates the great potential of these NBN-embedded polymers as metal fluorescence sensors.

Tuning the fluorescence sensing for Fe3+ ions by using different dipyridyl linkers in pillar-layered metal–organic frameworks

“…9 Thus, developing other approaches for detecting Fe 3+ ions is extremely urgent. To date, a plethora of fluorescent sensors for detecting Fe 3+ , such as organic fluorescent sensors (rhodamine 10 and napthalamide 11 ), polymer-based sensors (NBN-embedded polymers), 12 and nanocomposite-based fluorescent sensors (carbon quantum dots and g-C 3 N 4 nanosheets), 13 have been reported because of their high sensitivity, efficiency, and convenient manipulation. 14 However, their practical applications have been limited due to low water solubility, instability, high toxicity, difficult separation, and slow response towards Fe 3+ ions.…”