Department of Chemistry

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Arylated cyclobutanes were accessed by a versatile palladium-catalyzed secondary C(sp3)−H activation, exploiting chelation assistance by modular triazoles. The C−H arylation led to cyclobutane natural product derivatives in a highly regioselective fashion, setting the stage for the easy access to novel fluorogenic boron-dipyrrin (BODIPY)-labeled probes for live-cell imaging. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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Chemistry - A European Journal

BODIPY-Labeled Cyclobutanes by Secondary C(sp3)−H Arylations for Live-Cell Imaging

Nanomaterial biosensors have revolutionized the entire scientific, technology, biomedical, materials science, and engineering fields. Among all nanomaterials, magnetic nanoparticles, microparticles, and beads are unique in offering facile conjugation of biorecognition probes for selective capturing of any desired analytes from complex real sample matrices (e.g., biofluids such as whole blood, serum, urine and saliva, tissues, food, and environmental samples). In addition, rapid separation of the particle-captured analytes by the simple use of a magnet for subsequent detection on a sensor unit makes the magnetic particle sensor approach very attractive. The easy magnetic isolation feature of target analytes is not possible with other inorganic particles, both metallic (e.g., gold) and non-metallic (e.g., silica), which require difficult centrifugation and separation steps. Magnetic particle biosensors have thus enabled ultra-low detection with ultra-high sensitivity that has traditionally been achieved only by radioactive assays and other tedious optical sources. Moreover, when traditional approaches failed to selectively detect low-concentration analytes in complex matrices (e.g., colorimetric, electrochemistry, and optical methods), magnetic particle-incorporated sensing strategies enabled sample concentration into a defined microvolume of large surface area particles for a straightforward detection. The objective of this article is to highlight the ever-growing applications of magnetic materials for the detection of analytes present in various real sample matrices. The central idea of this paper was to show the versatility and advantages of using magnetic particles for a variety of sample matrices and analyte types and the adaptability of different transducers with the magnetic particle approaches. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.

Magnetochemistry

Magnetic particle bioconjugates: A versatile sensor approach

This study details syntheses of unsymmetrical magnesium(I)-adduct complexes, [(ArNacnac)(D)Mg-Mg(ArNacnac)] (ArNacnac = [(ArNCMe)2CH]-), Ar = xylyl (Xyl), mesityl (Mes), 2,6-diethylphenyl (Dep), or 2,6-diisopropylphenyl (Dip); D = N-heterocyclic carbene or 4-dimethylaminopyridine, DMAP), which X-ray crystallographic studies show to have markedly elongated Mg-Mg bonds. Two of these highly reactive species are shown to reductively trimerize CO to yield rare crystallographically characterized examples of the planar, aromatic deltate dianion, incorporated in the complexes [{(DipNacnac)(D)Mg(μ-C3O3)Mg(DipNacnac)}2] (D = DMAP or:C{N(Me)C(Me)}2). DFT calculations suggest that these complexes form via stepwise two-electron reductions of three CO molecules, resulting in the formation of three C-C bonds within the cyclic deltate unit. This work highlights the utility of activated magnesium(I) adduct complexes as soluble organometallic models for the study of reductive C-C bond-forming events in, for example, the heterogeneously catalyzed Fischer-Tropsch process. © 2019 American Chemical Society.

Journal of the American Chemical Society

Reductive trimerization of CO to the deltate dianion using activated magnesium (I) compounds

Herein we report the synthesis of fluorescent, glycosylated 4-amino-1,8-naphthalimide (Nap) 1, and the related 1,8-naphthalimides Tröger's bases (TBNap) 2 and 3, from 1,8-naphthalic anhydride precursors, the α-mannosides being introduced through the use of CuAAC mediated ‘click' chemistry. We investigate the photophysical properties of these probes in buffered solution and demonstrate their ability to function as fluorescent probes for Concanavalin A (Con A) lectin. We show that both the Nap and TBNap structures self-assemble in solution. The formation of the resulting supramolecular structures is driven by head-to-tail π-π stacking and extended hydrogen bonding interactions of the Nap and the triazole moieties. These interactions give rise to spherical nano-structures (ca. 260 nm and 100 nm, for 1 and 3, respectively), which interact with the Con-A protein, the interaction being probed by using both luminescent and Scanning Electron Microscopy imaging as well as dynamic light scattering measurements. Finally, we show that these supramolecular assembles can be used as luminescent imaging agents, through confocal fluorescence imaging of HeLa cells of the per-acetylated version 2. © The Royal Society of Chemistry.

Organic and Biomolecular Chemistry

Glycosylated naphthalimides and naphthalimide Tröger's bases as fluorescent aggregation probes for Con A

The authors regret that there were errors in the structure of compounds 2/3 in Scheme 1. The correct scheme is shown below. [Formula Presented]. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. © The Royal Society of Chemistry.

Correction: Glycosylated naphthalimides and naphthalimide Tröger's bases as fluorescent aggregation probes for Con A (Organic and Biomolecular Chemistry (2019) DOI: 10.1039/c8ob02980f)

Sirtuin inhibitors have attracted much interest due to the involvement of sirtuins in various biological processes. Several SIRT2-selective inhibitors have been developed, and some exhibit anticancer activities. To facilitate the choice of inhibitors in future studies and the development of better inhibitors, we directly compared several reported SIRT2-selective inhibitors: AGK2, SirReal2, Tenovin-6, and TM. In vitro, TM is the most potent and selective inhibitor, and only TM could inhibit the demyristoylation activity of SIRT2. SirReal2, Tenovin-6, and TM all showed cytotoxicity in cancer cell lines, with Tenovin-6 being the most potent, but only TM showed cancer-cell-specific toxicity. All four compounds inhibited the anchorage-independent growth of HCT116 cells, but the effect of TM was most significantly affected by SIRT2 overexpression, suggesting that the anticancer effect of TM depends more on SIRT2 inhibition. These results not only provide useful guidance about choosing the right SIRT2 inhibitor in future studies, but also suggest general practices that should be followed for small-molecule inhibitor development activities. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemMedChem

Direct Comparison of SIRT2 Inhibitors: Potency, Specificity, Activity-Dependent Inhibition, and On-Target Anticancer Activities

An efficient protocol was developed to construct functionally dense quaternary carbons with concomitant formation of a new Csp3-Csp3 bond via Pd-catalyzed decarboxylative transformation of vinyl cyclic carbonates. This redox-neutral catalytic system features stereocontrolled formation of multisubstituted allylic scaffolds with an aldehyde functionality generated in situ, and it typically can be performed at room temperature without any additives. DFT calculations provide a rationale toward the selective formation of these compounds and reveal a complex mechanism that with the help of microkinetic models is able to reproduce the nontrivial dependence of the identity of the product on the nature of the substituents in the substrate. © 2018 American Chemical Society.

A Domino Process toward Functionally Dense Quaternary Carbons through Pd-Catalyzed Decarboxylative C(sp3)-C(sp3) Bond Formation

Abstract: Pd nanoparticles-embedded multiwalled carbon nanotubes (Pd–MWCNTs) were synthesized via in situ chemical reduction method, which provided promising results for preparing finely divided and uniform sized Pd nanoparticles supported on MWCNTs. The Pd–MWCNT catalysts were synthesized in three different weight (wt) ratios of Pd and MWCNT (1:5, 2:5 and 3:5). Morphology and crystallinity of the catalysts were studied by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Electrocatalytic activity of these catalysts toward methanol oxidation was analyzed with two different dispersing agents, such as chitosan (CS, 0.1% w/v) and Nafion (Nf, 0.05% w/v), for the preparation of catalytic inks. Dramatic increases in the electrocatalytic activity of Pd–MWCNT–CS catalysts compared to Pd–MWCNT–Nf catalysts toward methanol oxidation were revealed from cyclic voltammetric, chronoamperometric and CO stripping analysis studies. The anodic peak current densities of the Pd–MWCNT (2:5 wt ratio) interface prepared with chitosan and Nafion inks in alkaline 1 M CH3OH were 2541 and 1041Ag-1Pd, respectively. High CO tolerance of the Pd–MWCNT catalysts was ascertained from the ratio of peak currents and coulombic charges of forward and reverse scans (If/Ib and Qf/Qb) of CV studies and from the less positive potentials for CO stripping, as low as − 0.2 V versus Ag|AgCl. The steady-state current density for methanol oxidation at Pd–MWCNT–CS electrode is nearly five times higher than that of Pd–MWCNT–Nf electrode. Graphical Abstract: [Figure not available: see fulltext.]. © 2017, Springer-Verlag GmbH Germany.

Clean Technologies and Environmental Policy

Pd nanoparticles-embedded carbon nanotube interface for electrocatalytic oxidation of methanol toward DMFC applications

In this work, we have developed for the first time a carboxylic group riched graphene oxide based disposable electrochemical immunosensor for cancer biomarker detection using methylene blue (MB). The developed immunosensor is highly sensitive for detection of biomarker Mucin1 (MUC1) in human serum samples. Development of this disposable electrochemical immunosensor was premeditated by applying specific monoclonal antibodies against MUC1. In this method, we explored highly conductive surface of carboxylic group (-COOH-) rich graphene oxide (GO) on screen-printed carbon electrodes (SPCE). This modified GO-COOH-SPCE was employed for the detection of MUC1 protein based on the reaction with methylene blue (MB) redox probe using differential pulse voltammetry (DPV) technique. Developed immunosensor exhibited good detection range for MUC1 with excellent linearity (0.1 U/mL- 2 U/mL), with a limit of detection of 0.04 U/mL. Upon potential application of developed biosensor, good recoveries were recorded in the range of 96–96.67% with % R.S.D 4.2. Analytical performance of the developed immunosensor assures the applicability in clinical diagnostic applications. © 2018 Elsevier Inc.

Analytical Biochemistry

Carboxylic group riched graphene oxide based disposable electrochemical immunosensor for cancer biomarker detection

Nanomaterial-embedded sensors have been developed and applied to monitor various targets. Mycotoxins are fungal secondary metabolites that can exert carcinogenic, mutagenic, teratogenic, immunotoxic, and estrogenic effects on humans and animals. Consequently, the need for the proper ﻿regulation on foodstuff and feed materials has been recognized from times long past. This review provides an overview of recent developments in electrochemical sensors and biosensors employed for the detection of mycotoxins. Basic aspects of the toxicity of mycotoxins and the implications of their detection are comprehensively discussed. Furthermore, the development of different molecular recognition elements and nanomaterials required for the detection of mycotoxins (such as portable biosensing systems for point-of-care analysis) is described. The current capabilities, limitations, and future challenges in mycotoxin detection and analysis are also addressed. © 2018 Elsevier B.V.