Supramolecular Logic Gates Based on the Conjugates of Calixarenes and Carbohydrates.

In the era of application-oriented research, laboratory to real life translation is highly regarded and in great demand. This could mean that molecular science developed for sensing and detecting a variety of chemical species awaits conversion to devices. In that, the molecular logic gates are the most promising ones where the information storage and/or data processing can be easily carried out in terms of molecular inputs and electrical response outputs. This would facilitate the simultaneous execution of a diverse array of molecular sensing functions. The recent progress in molecular logic gates based on supramolecular optical receptors, in particular, fluorescent ones, such as calixarene derivatives and carbohydrate conjugates will have a transformative impact on molecular devices and will encourage this science to yield technology. Therefore, this review provides a critical evaluation of recent publications on molecular logic gates based on the derivatives of calixarenes and glyco-conjugates, including several from our own research group, with the view that the corresponding applications are a beneficiary in laboratory-to-device translation. In addition, this review is also expected to assist young researchers in planning their research focus in the broad area of supramolecular-based logic gates targeting some specific applications.

Recent progress in the development of small-molecule fluorescent probes for detection and imaging of selenocysteine and application in thyroid disease diagnosis.

Selenocysteine (SeCys) is the 21st genetically encoded amino acid present in proteins and is involved in various biological functions. Inappropriate levels of SeCys can be considered as a sign of various diseases. Therefore, small molecular fluorescent probes for the detection and imaging of SeCys in vivo in biological systems are considered to be of significant interest for understanding the physiological role of SeCys. Thus, this article mainly provides a critical evaluation of recent advances made in SeCys detection along with the biomedical applications based on small molecular fluorescent probes published in the literature during the past half a dozen years. Therefore, the article primarily deals with the rational design of fluorescent probes, wherein these were selective towards SeCys over other biologically abundant molecules, in particular the thiol-based ones. The detection has been monitored by different spectral techniques, such as fluorescence and absorption spectroscopy and in some cases even visual color changes. Further, the detection mechanism and the utility of fluorescent probes for in vitro and in vivo cell imaging applications are addressed. For clarity, the main features have been conveniently divided into four categories based on the chemical reactions of the probe, viz., in terms of the cleavage of the responsive group by the SeCys nucleophile: (i) 2,4-dinitrobene sulphonamide group, (ii) 2,4-dinitrobenesulfonate ester group, (iii) 2,4-dinitrobenzeneoxy group and (iv) miscellaneous types. Overall this article deals with the analysis of more than two dozen fluorescent probes demonstrated for selective detection of SeCys along with their applications towards disease diagnosis.

Fluorescent benzofurazan derivatized triazole linked mono and di-glucopyranosyl conjugates: Selective sensing of fluoride ion and coordination features by DFT computation.

Novel benzofurazan derivatized triazole linked mono and di-glucopyranosyl conjugates (L1, and L2) have been synthesized by Cu+1 catalyzed alkyne-azide 1,3 dipolar cycloaddition reaction. All the precursors and the molecules (L1, and L2) were isolated and characterized by 1H & 13C NMR, and ESI-MS. The glycoconjugates have been studied with fourteen different anions for their selective recognition in solution. Among the anions studied L1 exhibited selective fluorescent sensing properties upon binding with F- by showing a 151 ± 8 fold decrease in the emission intensity at 518 nm. The minimum detection limit for F- in acetonitrile was found to be 124 ± 5 ppb. A hypsochromic shift (∼60 nm) of the 450 nm band of L1 was observed upon the interaction with F- through the formation of hydrogen bonding of -NH moiety. The coordination features of [L1+F-] complex were established by Density Functional Theory (DFT) computational studies. The outcome of the study of new glycoconjugates based recognition promotes the emerging of new biological sensor diagnostic tools in the future.