Lokesh Kumar Kumawat

Bio: Lokesh Kumar Kumawat is an academic researcher from Maynooth University. The author has contributed to research in topics: Bulb & Naked eye. The author has an hindex of 14, co-authored 24 publications receiving 1744 citations. Previous affiliations of Lokesh Kumar Kumawat include University of Johannesburg & Indian Institute of Technology Roorkee.

Thiazole Schiff base turn-on fluorescent chemosensor for Al3+ ion

Abstract: Thiazole Schiff bases 2-(4-phenyl-1,3-thiazol-2-yliminomethyl)phenol (L 1 ) and 1-(4-phenyl-1,3-thiazol-2-yliminomethyl)naphthalen-2-ol (L 2 ) have synthesized and characterized. The interaction of Schiff bases with different metal ions has been studied over UV–vis absorption spectra and photofluorescent spectra. The results are indicated that Schiff base L 1 and L 2 exhibited turn-on fluorescent behavior with Al 3+ ions in methanol, which could be directly detected by the naked-eye under the UV-lamp. The limits of detection were calculated for L 1 and L 2 since 1.0 × 10 −6 and 7.5 × 10 −7 by the titration method. Both sensors exhibited excellent fluorescent behavior in 5.0–13.5 pH range. The fluorescent behavior of legends-aluminum complex solution goes to turn-off in the presence of Ni 2+ and EDTA.

Selective naked-eye detection of Magnesium (II) ions using a coumarin-derived fluorescent probe

Abstract: A simple 4-Methyl-7-hydroxy-8-formyl Coumarin (CS) serves as a selective chemosensor for Mg 2+ in the presence of alkali and alkaline earth metal ions. It showed a significant fluorescence enhancement towards Mg 2+ . The receptor CS exhibited a good binding constant and lowest detection limit for Mg 2+ . The variation of emission signal exists via of reversible chelation enhanced fluorescence (CHEF) with this inherent quenching metal ion.

A new multifunctional rhodamine-derived probe for colorimetric sensing of Cu(II) and Al(III) and fluorometric sensing of Fe(III) in aqueous media

Abstract: A new rhodamine-derived Schiff base RH was synthesized and its sensing behavior toward various metal ions was investigated by UV–vis and fluorescence spectroscopic techniques The sensor exhibited highly selective and sensitive colorimetric response to Cu2+ and Al3+, and “off–on” fluorescence response toward Fe3+ in semi-aqueous media The spectral changes obtained are large enough in the visible region of the spectrum and thus enable naked-eye detection Experimentally proved that the formation of RH–Al3+ complex is fully reversible and can sense to AcO−/F− via break the complex The results revealed that the sensor offers the sequential detection of Al3+ and AcO−/F−

A highly selective colorimetric and turn-on fluorescent chemosensor based on 1-(2-pyridylazo)-2-naphthol for the detection of aluminium(III) ions

Abstract: A new azo compound, 1-(2-pyridylazo)-2-naphthol, has been prepared and characterized. The synthesized compound shows a very high affinity for aluminium. The complexation reaction of aluminium has been explored by Colorimetry, FT-IR, 1 H NMR, HRMS and fluorescence spectroscopy. The detection limit has been found to be 1.81 × 10 −8 M estimated by the titration method. The turn-on fluorescence behaviour of aluminium interaction with ligand has been found to be so fast (

Coumarin-Based Small-Molecule Fluorescent Chemosensors.

Abstract: Coumarins are a very large family of compounds containing the unique 2H-chromen-2-one motif, as it is known according to IUPAC nomenclature. Coumarin derivatives are widely found in nature, especially in plants and are constituents of several essential oils. Up to now, thousands of coumarin derivatives have been isolated from nature or produced by chemists. More recently, the coumarin platform has been widely adopted in the design of small-molecule fluorescent chemosensors because of its excellent biocompatibility, strong and stable fluorescence emission, and good structural flexibility. This scaffold has found wide applications in the development of fluorescent chemosensors in the fields of molecular recognition, molecular imaging, bioorganic chemistry, analytical chemistry, materials chemistry, as well as in the biology and medical science communities. This review focuses on the important progress of coumarin-based small-molecule fluorescent chemosensors during the period of 2012-2018. This comprehensive and critical review may facilitate the development of more powerful fluorescent chemosensors for broad and exciting applications in the future.

Thiazole Schiff base turn-on fluorescent chemosensor for Al3+ ion

Abstract: Thiazole Schiff bases 2-(4-phenyl-1,3-thiazol-2-yliminomethyl)phenol (L 1 ) and 1-(4-phenyl-1,3-thiazol-2-yliminomethyl)naphthalen-2-ol (L 2 ) have synthesized and characterized. The interaction of Schiff bases with different metal ions has been studied over UV–vis absorption spectra and photofluorescent spectra. The results are indicated that Schiff base L 1 and L 2 exhibited turn-on fluorescent behavior with Al 3+ ions in methanol, which could be directly detected by the naked-eye under the UV-lamp. The limits of detection were calculated for L 1 and L 2 since 1.0 × 10 −6 and 7.5 × 10 −7 by the titration method. Both sensors exhibited excellent fluorescent behavior in 5.0–13.5 pH range. The fluorescent behavior of legends-aluminum complex solution goes to turn-off in the presence of Ni 2+ and EDTA.