Herein, the fluorescent carbon dots (CDs) with blue emission were prepared by hydrothermal treatment using pineapple peel as a source of carbon. The as-prepared CDs exhibited turn-Off fluorescence behavior toward Hg2+ and subsequent turn-On behavior for l-cysteine along with enhanced biocompatibility and negligible cytotoxicity for cell imaging. The practical applicability of carbon dots was used for the quantification of Hg2+ in water. On the basis of the spectral characteristic changes, we have designed individual elementary logic operations such as NOT and IMP gates, by utilizing CD as probe and Hg2+ and l-Cys as chemical inputs. We have also demonstrated the utility of this system in electronic security devices and as memory element, with the idea of the switching.

We have developed a “turn‐on” fluorescent probe ARP‐1 as a colorimetric and fluorescent chemosensor for adenosine‐5’‐triphosphate (ATP) through hydrogen bond interactions. The probe exhibits “turn‐on” fluorescence response to ATP with a 15‐fold fluorescence intensity enhancement under 10 equiv. of ATP added. The experimental results show that the response behavior of ARP‐1 toward ATP is pH independent (pH 4.0‐8.0). The novel chemosensor has high specificity towards ATP from other nucleoside polyphosphates such as ADP and AMP. The favorable interaction between a triphosphate unit of ATP and N atoms of probe ARP‐1 is attributed to H‐bonding. Consequently, the enhanced emission and naked‐eye changes are attributed to spirolactam ring‐opening. It is evident from our findings that the role of the chain length as well as the NH, OH groups and the phosphate group(s) contribute to interaction between the probe and the nucleotide. Cell permeability and selectivity towards ATP was demonstrated in HeLa Cells. Colocalization experiments were carried out with MitoTracker green and ARP‐1 showing that the mitochondrion selective imaging ability of ARP‐1. The live cell imaging experiments in HeLa cells exhibited high selectivity of probe ARP‐1 with fluorescence turn‐On response. ARP‐1 could also be explored for understanding the cellular functions.

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The synthesis of boranil dye fluorescent probes for the detection of hydrogen peroxide has been described. The probes have been successfully applied for imaging of H2O2 in HeLa cells under physiological conditions.

The copper(II)‐catalyzed C–S cross coupling of thiazolidine‐2‐thiones with organoboronic acids towards the synthesis of azole sulfides was investigated. This mild and base‐free protocol has the advantages of short reaction times and excellent yields with no need for an ancillary ligand.