A Stimuli-Responsive Dual-Emitting Covalent Organic Framework Shows Selective Sensing of Highly Corrosive Acidic Media via Fluorescence Turn-On Signal with White Light Emission

Patra, BC and Datta, S and Bhattacharya, S (2024) A Stimuli-Responsive Dual-Emitting Covalent Organic Framework Shows Selective Sensing of Highly Corrosive Acidic Media via Fluorescence Turn-On Signal with White Light Emission. In: ACS Applied Materials and Interfaces, 16 (6). pp. 7650-7659.

PDF acs_app_mat_int_16_6_2024.pdf - Published Version Restricted to Registered users only Download (6MB)

Abstract

Luminescent covalent organic frameworks (LCOFs) have been employed as platforms for sensing analytes. Judicial incorporation of appropriate functional units inside the framework leads to the different electronic states in the presence of external stimuli, e.g., temperature, pH, etc. We report herein a new COF (TPEPy) as a solid-state acid sensor specific for the highly acidic environments that range from pH �0.5 to �3.0. This COF shows a protonation-induced reversible color change from bright yellow to deep red upon decreasing the pH from 3 to 0.5 and vice versa. No visual color change was, however, observed above pH 3.0. Photoluminescence (PL) studies show that the intrinsic emission peak of the TPEPy COF at 530 nm is shifted to 420 nm owing to the N-protonation of the imine nitrogen of COF within this pH range. Extensive studies demonstrate that the protonation behavior of the COF is counterion dependent. This was revealed when different acids, e.g., HCl, HNO3, HBr, and HI, were employed. The intensity of the proton-induced emission peak at 420 nm depends significantly upon the counterions with the order of HCl > HNO3 > HBr > HI. These anions interact with the protonated TPEPy COF by cation-anion and H-bonding interactions. Further, the pristine COF showed near white light emission at a particular pH of 2.5 (CIE coordinates 0.27, 0.32). From the PL spectrophotometric titrations, the deprotonation pKa was experimentally found to be 1.8 ± 0.02 for the TPEPy COF. The sensor reported herein is reversible, reusable, and regenerable and is useful for assessing pH fluctuations within a strongly acidic range via digital signaling. © 2024 American Chemical Society

Item Type:	Journal Article
Publication:	ACS Applied Materials and Interfaces
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the Authors.
Keywords:	Bromine compounds; Chlorine compounds; Color; Colorimetry; Hydrogen bonds; Negative ions; pH; Protonation, AIEE; COF; Color changes; Counterions; Covalent organic frameworks; Dual emissions; Emission peaks; Protonations; Stimuli-responsive; White light emission, pH sensors, anion; cation; counterion; imine; nitrogen; proton, article; color; deprotonation; fluorescence; lamellar ichthyosis; luminescence; pH; photoluminescence; protonation; signal transduction; solid state; spectrophotometry; temperature; titrimetry; white light
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	09 Apr 2024 11:01
Last Modified:	09 Apr 2024 11:01
URI:	https://eprints.iisc.ac.in/id/eprint/84685

Actions (login required)

View Item