Aldehyde group driven aggregation-induced enhanced emission in naphthalimides and its application for ultradetection of hydrazine on multiple platforms.

Niranjan Meher,Swagatika Panda,Parameswar Krishnan Iyer,Sachin Kumar

doi:10.1039/c8sc00643a

Niranjan Meher, Swagatika Panda + Show 2 more

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https://doi.org/10.1039/c8sc00643a

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Journal: Chemical Science	Publication Date: Jan 1, 2018
Citations: 111	License type: CC BY 3.0

Affiliation: Indian Institute of Technology Guwahati, CeNTech

Abstract

Restriction of intramolecular motion (RIM) of rigid aromatic cores is the most universal mechanism so far that can successfully explain almost all AIE/AIEEgenic systems. By designing two novel naphthalimide derivatives (NIB and NIBD), we experimentally demonstrated the effect of a single formyl group that can efficiently transform an aggregation caused quenching (ACQ) system (NIB) into an AIEEgenic system (NIBD) by strengthening the RIM process. Besides, the newly designed naphthalimide AIEEgen (NIBD) accomplished ultrasensitive detection of hydrazine at the parts per trillion level (LOD/81 ppt) in aqueous media with high selectivity and enormous improvement over the existing state of the art. An exceptional sensitivity is also achieved in the vapor phase (LOD/0.003%) using a Whatman paper strip based portable device for simple and cost-effective on-site detection. The detection mechanism involved a reaction-based spontaneous formation of a non-fluorescent hydrazone Schiff base derivative (NIBDH). The in vitro potentiality of the AIEEgenic probe was also demonstrated in two mammalian cell lines i.e. HeLa (human cervical cancer cell line) and HEK293T (Human embryonic kidney cell line that expresses a mutant version of the SV40 large T antigen). Owing to the highly selective formation of the hydrazone Schiff base complex with hydrazine, NIBD responds to the existence of hydrazine in both these cell lines without any interference from other biologically rich metal ions and amino acids. These outcomes could initiate a much wider use of formyl group induced condensed state emission and a key hypothesis that could generate newer avenues for ACQ to AIEE transformations for several practical applications including hydrazone Schiff base complexation for probing and manipulating hydrazine biology associated with several metabolic activities.

Highlights

Organic molecules with condensed state emission are receiving huge attention due to their versatile real-world applications.1a,b A er the discovery of hexaphenyl silole (HPS) in 2001, a number of aggregation induced emission (AIE) and aggregation induced enhanced emission (AIEE) active cores have been reported by various groups
Synthesis and characterization of naphthalimides with aggregation caused quenching (ACQ) and AIEE properties. Both the naphthalimides were synthesized by alkylation of 4-bromo-1,8-naphthalicanhydride followed by Suzuki coupling with phenylboronic acid/4-formylphenylboronic acid in good yields
The complete synthetic processes and associated spectra have been presented in the Electronic supplementary information (ESI).† The phenyl group was intentionally incorporated onto the naphthalimide ring to implement the restriction in intramolecular rotation (RIR) phenomenon in their condensed state, whereas the formyl group was introduced to provide a speci c recognition site for hydrazine through the favourable hydrazone Schiff base formation at room temperature

Summary

Introduction

Organic molecules with condensed state emission are receiving huge attention due to their versatile real-world applications.1a,b A er the discovery of hexaphenyl silole (HPS) in 2001, a number of aggregation induced emission (AIE) and aggregation induced enhanced emission (AIEE) active cores have been reported by various groups. The formyl group containing the naphthalimide AIEEgen was perceived to react spontaneously with hydrazine to form Schiff base derivatives and has been applied to detect hydrazine in multiple challenging platforms (Fig. 1).

Results

Conclusion