A pyrene-based fluorescent
chemosensor APSB [
N
-(pyrene-1-ylmethylene) anthracen-2-amine]
was designed and developed
by a simple condensation reaction between pyrene carboxaldehyde and
2-aminoanthracene. The APSB fluorescent sensor selectively binds Fe
3+
in the presence of other metal ions. Apart from this, APSB
shows high selectivity and sensitivity toward Fe
3+
ion
detection. The detection limit for APSB was 1.95 nM, and the binding
constant (
K
b
) was obtained as 8.20 ×
10
5
M
–1
in DMSO/water (95/5, v/v) medium.
The fluorescence quantum yields for APSB and APSB–Fe
3+
were calculated as 0.035 and 0.573, respectively. The function of
this fluorescent sensor APSB can be explained through the photo-induced
electron transfer mechanism which was further proved by density functional
theory studies. Finally, a live-cell image study of APSB in HeLa cells
was also carried out to investigate the cell permeability of APSB
and its efficiency for selective detection of Fe
3+
in living
cells.
A couple of N‐(4)‐morpholine/pyrrolidine‐substituted thiosemicarbazones (TSCs) of fluorene‐2‐carboxaldehyde (FM and FP), and their corresponding thiadiazoles (TDZs) (CFM and CFP), were synthesized and characterized (elemental analysis, ultraviolet–visible [UV–Visible], Fourier transform infrared [FT‐IR], nuclear magnetic resonance [NMR; 1H & 13C], high‐resolution mass spectrometry [HRMS], and single‐crystal X‐ray diffraction [SCXRD]) for the evaluation of their anticancer potential. The TDZs were obtained unexpectedly and are possibly formed via single‐step metal (copper)‐mediated oxidative cyclizations of the TSCs. The synthesized compounds are fairly stable in phosphate buffer at the biological pH of 7.4. The density functional theory [DFT] studies were performed to predict the optimized structures and physicochemical properties of these compounds. The compounds were further subjected to computational and experimental biomolecular investigations in order to evaluate their anticancer activity in detail. CFM had the most potent activity against human breast adenocarcinoma (MCF‐7) and human urinary bladder (T24) cancer cells, with IC50 values of 12.00 and 24.80 μM, respectively. In contrast, CFM had negligible cytotoxicity (IC50 = 98.70 μM) against kidney epithelial cells extracted from an African green monkey (Vero) normal cells. This outcome was preferable to that of the widely used medicine Cisplatin. Molecular docking studies were performed with the breast cancer protein “cytochrome P450 1A1” (CYP1A1) and bovine serum albumin (BSA) to predict how effectively the compounds bind to the receptor. The ADMET findings suggest that these compounds have considerable drug‐likeness and oral bioavailability. These insights may open the door for additional medical research into the bioactivities of TSCs and TDZs produced from bioactive carbonyl compounds.
Here, we described a cheap and effective chemosensor
(NHPyTSC)
that can distinguish Hg2+ and Zn2+ ions from
other metal ions and evaluated this phenomenon using several spectroscopy
techniques. With the addition of mercury and zinc ions, the proposed
chemosensor in particular showed noticeable changes in color and absorption
spectra. Additionally, by including EDTA in the NHPyTSC-Hg2+ and NHPyTSC-Zn2+ solutions, colorimetry readings can
be reversed. We developed a molecular-scale sequential information
processing circuit and presented the “writing–reading–erasing–reading”
and “multiwrite” behaviors in the form of binary logic
based on the great reversibility of this process. Moreover, by sequentially
adding Hg2+, Zn2+, and EDTA, NHPyTSC imitates
a molecular keypad lock and molecular logic gates. Density functional
theory (DFT) investigations provided more evidence of the Hg2+ and Zn2+ ions′ ability to attach to NHPyTSC. The
most interesting part of this work is that a study on the latent fingerprint
detection of the powder compound revealed that NHPyTSC exhibits good
adherence and finger ridge features without background stains. When
compared to black and white fingerprint powders, it is discovered
that the NHPyTSC powder produces results that are remarkably clear
on the majority of surfaces. This demonstrated their potential for
real-world use, particularly in the area of criminal investigations.
The Schiff base was first synthesized by Hugo Schiff through the condensation reaction of primary amines with carbonyl compounds (aldehyde or ketone) in 1864. Schiff bases exhibit many structural and electrical characteristics that enable their use in a variety of fields, including medical and chemosensing. Schiff bases generate stable complexes when they bind with different metal ions. Schiff bases are employed as fluorescent turn-on/turn-off chemosensors for the detection of various metal cations, such as Hg2+, Cd2+, Cr3+, Pd2+, and As3+ in various materials due to their outstanding coordination ability. This chapter examines a variety of Schiff bases that are employed in chemosensing procedures for various metal ions (such as divalent and trivalent cations) in various biological, agricultural, and environmental settings.
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