Hydrazine-Selective Fluorescent Turn-On Probe Based on Ortho-Methoxy-Methyl-Ether (o-MOM) Assisted Retro-aza-Henry Type Reaction

Abstract

Hydrazine (N2H4) is one of the most widely used industrial chemicals that can be utilized as a precursor of pesticides, pharmaceutics, and rocket propellant. Due to its biological and environmental toxicity with potential health risks, various sensing tools have been developed. Among them, fluorescence-based molecular sensing systems have been highlighted due to its simple-operation, high selectivity and sensitivity, and biocompatibility. In our recent report, we disclosed a ratiometric type fluorescent probe, called HyP-1, for the detection of hydrazine, which is based on ortho-methoxy-methyl-ether (o-MOM) moiety assisted hydrazone-formation of the donor (D)-acceptor (A) type naphthaldehyde backbone. As our follow-up research, we disclose a turn-on type fluorescent probe, named HyP-2, as the next-generation hydrazine probe. The sensing rational of HyP-2 is based on the o-MOM assisted retro-aza-Henry type reaction. The dicyanovinyl moiety, commonly known as a molecular rotor, causes significant emission quenching of a fluorescent platform in aqueous media, and its cleavage with hydrazone-formation, which induces a significant fluorescence enhancement. The high selectivity and sensitivity of HyP-2 shows practical explicabilities, including real-time paper strip assay, vapor test, soil analysis, and real water assay. We believe its successful demonstrations suggest further applications into a wide variety of fields.

Research progress of auxiliary groups in improving the performance of fluorescent probes

“…12) as the next-generation hydrazine probe. 43 The sensing principle of HyP-2 is based on an o -MOM-assisted retro-aza-Henry reaction. It consists of o -MOM and a dicyanovinyl molecular rotor moiety that can be cleaved by hydrazine.…”

Articulated Structures of D-A Type Dipolar Dye with AIEgen: Synthesis, Photophysical Properties, and Applications

“…First, we chose 6-(dimethylamino)-3-hydroxy-2-naphthaldehyde (compound 3) as a representative D-A type fluorophore, because its hydroxy moiety could be linked with AIEgen material without disturbing the character of dipolar backbone. The synthesis and distinguishable applications of compound 3 have been presented by our research group [22][23][24][25][26][27]. For an AIEgen material, we chose bromomethyl-functionalized TPE because it showed a typical property of AIEgen and has been widely used throughout various research fields [28][29][30].…”

A Dual Spectroscopic Probe Based on Benzothiazole for Detection of Hydrazine

“…Hydrazine (N 2 H 4 ), appearing as a colorless and transparent oily liquid, plays important roles in the fields of chemical industry, pharmaceutical synthesis, biology and pesticide. It is widely used for synthesis of chemical foaming agents, cleaning and refinement of precious metals, processment and treatment of exhaust gas and waste liquid, inlaying plastics and metals, and it is often employed as spacecraft and aircraft propellants as well [1–9] . N 2 H 4 can couple with water to form stable hydrazine hydrate (N 2 H 4 •H 2 O).…”