Browsing by Author "Tony D. James"

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A quick and selective rhodamine based “smart probe” for “signal-on” optical detection of Cu2+ and Al3+ in water, cell imaging, computational studies and solid state analysis
(Elsevier B.V., 2018) Abhishek Rai; Alok Kumar Singh; Kamini Tripathi; Avinash Kumar Sonkar; Brijesh Singh Chauhan; S. Srikrishna; Tony D. James; Lallan Mishra
A novel rhodamine hydrazone 1 has been synthesized by the condensation of rhodamine B hydrazide with allylsalicylaldehyde and has been fully characterized using various physicochemical techniques including single crystal XRD. Probe 1 can detect Cu2+ and Al3+ ions in aqueous media and displays a turn-on response in absorbance with a high degree of selectivity amongst other common interfering analytes. Al3+ ions lead to fluorescence enhancementby the opening of the spirolactum ring resulting in chelation enhanced fluorescence. DFT and TDDFT calculations support the experimental results. The 1-Al3+ ensemble acts as secondary sensor for pyrophosphate anion due to metal ion induced decomplexation resulting in a low detection limit. Probe 1 can be utilized for bio imaging and displays morphological transformations from crystalline to amorphous state with associated color changes due to mechanical switching. In the solid state, probe 1 displays distinct color changes with emission at different wavelengths in particular Al3+ and Hg2+result in a red shift of the CIE-diagram. While the band gap of probe 1can be tuned from 2.08 eV to 1.60 eV Probe 1 meets many real-world-challenges in that it is prepared using simple synthetic methods, produces fast and distinct response towards multiple-ions, observed by the “naked eye” in solution and on a TLC plate, and can be exploited for binary data storage. © 2018 Elsevier B.V.
Selective Cu2+ Ion Sensing by Nanoaggregates of Pyridyl-2,6-bis(3-allylsalicylaldehyde)hydrazone
(Wiley-Blackwell, 2018) Abhishek Rai; Kamini Tripathi; Avinash Kumar Sonkar; Tony D. James; Saurabh Yashaswee; Surendra Kumar Trigun; Lallan Mishra
Pyridyl-2,6-bis(3-allylsalicylaldehyde) hydrazone (PYAL) forms nanoaggregates (nPYAL) in THF:water (10:90,v/v) with enhanced emission. The nanoagregates display selective and reversible detection of Cu2+ ions with concomitant changes in their morphology and sizes. The detection of Cu2+ ions in human melanoma MDA MB 435 s cell lines using nPYAL has been demonstrated. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim