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This article features the first synthesis of coumarin based triazole linked organosilatranes (3–5) derived from terminal alkyne (1) via click methodology. The coumarin tethered organosilatranyl moiety was anchored on magnetic silica surface and was well characterized by numerous spectroscopic and analytical techniques. The resultant hybrid nanoparticles have been characterized in detail by FTIR, UV–vis spectroscopy, Photoluminiscence (P.L), SEM, TEM, XRD, EDX and TGA. The silatranes (3–5) were then assessed for their metal ion binding properties using absorption and emission spectra. It was observed that the synthesized compounds showed significant selectivity for Hg (II). In addition, the interacting ability of coumarin based derivatives was investigated at different pH values and the pH 9 was considered to be the most favorable pH for fluorometric analysis. Importantly, the hybrid nanoparticles possessed enhanced sensorial ability towards Hg 2+ ion and these findings were affirmed using stern volmer equation. In addition, the complexation mode of silatrane (3) with Hg 2+ ion was also elucidated by computational analysis using DFT study. [ABSTRACT FROM AUTHOR]

In general medicinal plants grown under water limiting conditions show much higher concentrations of secondary metabolites in comparison to control plants. In the present study, Withania somnifera plants were subjected to water stress and data related to drought tolerance phenomenon was collected and a putative mechanistic concept considering growth responses, physiological behaviour, and metabolite content and gene expression aspects is presented. Drought induced metabolic and physiological responses as well as drastic decrease in CO 2 uptake due to stomatal limitations. As a result, the consumption of reduction equivalents (NADPH 2+ ) for CO 2 assimilation via the calvin cycle declines significantly resulting in the generation of a large oxidative stress and an oversupply of antioxidant enzymes. Drought also results in the shifting of metabolic processes towards biosynthetic activities that consume reduction equivalents. Thus, biosynthesis of reduced compounds (isoprenoids, phenols and alkaloids) is enhanced. The dynamics of various metabolites have been discussed in the light of gene expression analysis of control and drought treated leaves. Gene encoding enzymes of pathways leading to glucose, fructose and fructan production, conversion of triose phosphates to hexoses and hexose phosphorylation were up-regulated in the drought stressed leaves. The down-regulated Calvin cycle genes were co-ordinately regulated with the down-regulation of chloroplast triosephosphate/phosphate translocator, cytoplasmic fructose-1,6-bisphosphate aldolase and fructose bisphosphatase. Expression of gene encoding Squalene Synthase (SQS) was highly upregulated under drought stress which is responsible for the diversion of carbon flux towards withanolides biosynthesis from isoprenoid pathway. [ABSTRACT FROM AUTHOR]

This work reports the synthesis and structural characterization of a new adenine based organosilicon nucleobase using an efficient and biocompatible Click approach. Synthetic procedure included the preparation of a new N -acetylinic linked propyl silatrane 3 whose structure was confirmed through Single crystal X-ray crystallography. The designed silatrane L is found to be highly selective and sensitive for detection of Cu 2+ with a color change from colourless to yellowish orange. The stoichiometry ratio of L + Cu 2+ was obtained 1:1 by Job’s Plot. The binding of copper ions to the chemosensor was studied over wide pH range and the results demonstrated that the sensor worked well in the physiological range 6–9. Furthermore, the sensing of Cu 2+ was found to be reversible upon addition of EDTA. These results widen the scope of adenine based derivatives in the field of colorimetric probes. The newly synthesized silatrane 3 and the receptor L were successfully characterized by various spectroscopic techniques [IR, NMR ( 1 H, 13 C) and Mass] and elemental analysis. [ABSTRACT FROM AUTHOR]

A triazole tethered chemo sensor molecules with the capability of sensing cations have been synthesized by coupling two sensor based alkynyl indole schiff base unit to azide. The hybrid networks were able to donate electron via azomethine linkage, traizole ring and indole motif to bind copper and nickel effectively. Such indole based hybrids would have potential applications in biological systems. Indole traizoles (In-Tz) were synthesized under microwave irradiation with auto generated pressure (at 60 °C) and characterized by 1H NMR, 13C NMR, Mass and FTIR spectroscopy, thin-layer chromatography (TLC) and elemental analyses. The fabricated sensor exhibited higher sensitivity, large-dynamic concentration ranges and long term stability towards In-Tz conjugated copper and nickel complex for selective Cu 2+ and Ni 2+ sensor. The calibration plot is linear (r 2 : 0.9895, r 2 : 0.9808) over the large Cu 2+ ions and Ni 2+ concentration ranges (1.0 µM). This novel effort has initiated a well-organize way of efficient cationic sensor improvement with triazole for heavy metallic pollutants in environmental and health-care fields in large scales. [ABSTRACT FROM AUTHOR]