Phenanthridine‐Based Donor/Acceptor Fluorescent Dyes: Synthesis, Photophysical Properties and Fluorometric Sensing of Biogenic Primary Amines

Abstract

Synthesis of two new and straight forward phenanthridine based fluorophores (PA1 and PA2) have been described. The molecular structure of PA1 and PA2 was confirmed by spectroscopic studies (1 H NMR, 13 C NMR and HRMS). The dyes are further characterized by comprehensive photophysical study, and their data are critically analyzed. The fluorescence properties of these DÀ A chromophores are highly influenced by the position of the hydroxyl substitution and the solvent polarity. These probes exhibited an arsenal of advantageous features such as higher Stokes shift values and appreciable photostability. Compounds PA1 and PA2 are found to be indicating fluorescent ratiometric detection towards primary amines (PAs) with high selectivity and sensitivity. With this background, sensing of PAs was extended to biogenic amines as they have primary amine functionality. As expected, these fluorophores have excellent detection ability towards neurotransmitters, such as dopamine (DA) and serotonin (SN) with a low limit of detection (LOD) such as 1.61 nM and 0.31 nM respectively. The sensing mechanism of the probe PA1 with PAs are based on the nucleophilic addition and confirmed through investigation by 1 H NMR titration, mass analysis and theoretical calculations. Moreover, sensor probe PA1 based test paper strip was developed, which could detect DA conveniently when visualized under 365 nm UV lamp.

Aromatic fluorine atom-induced highly amine-sensitive trimethine cyanine dye showing colorimetric and ratiometric fluorescence change

“…The obtained value shows sensitivity as high as that of an activated ester and aldehydes. 8,10,11 Next, absorbance changes in various solvents were followed to examine the sensitivity of dye 2a to n-hexylamine (Fig. S1 †).…”

“…[1][2][3][4] Amines could cause serious damage in public health and the environment owing to their toxic nature, so, simple, fast, lowcost, and accurate amine monitoring systems are becoming highly urgent. 5 The detection of amines using ratiometric uorescence through utilized intramolecular charge transfer (ICT), [6][7][8][9][10][11][12][13][14][15][16][17] twisted ICT, 18 aggregation-induced emission, [19][20][21][22][23] and excited state intramolecular proton transfer 24 has been reported.…”

A benzothiazole-based new fluorogenic chemosensor for the detection of CN− and its real-time application in environmental water samples and living cells

“…The density functional theory at the B3LYP/631 G(d) level was utilized effectively to predict photochromism and reaction-based photochromic molecules with high accuracy. 29,[64][65][66][67][68][69][70] The entire geometry optimizations of the probe BID and its interaction with CN À were performed using the aforementioned technique, and its structure is shown in Fig. S9.…”

Investigation of the Geometric and Spectroscopic Properties of Four Twisted Triphenylpyridinium Donor–Acceptor Dyes

“…Organic donor–acceptor (D–A) dyes are of interest because of their application in molecular electronics such as solar cells, , molecular sensing, organic light-emitting diodes, photodynamic therapy, and hydrogen evolution catalysts . Typically, the architecture of such dyes follows a donor−π–acceptor structure, whereby an electron-donating group is linked to an electron-accepting group via a conjugated π-bridge.…”