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

C−H hydroxylation of aryl acetamides and alkyl phenylacetyl esters was accomplished via challenging distal weak O-coordination by versatile ruthenium(II/IV) catalysis. The ruthenium(II)-catalyzed C−H oxygenation of aryl acetamides proceeded through C−H activation, ruthenium(II/IV) oxidation and reductive elimination, thus providing step-economical access to valuable phenols. The p-cymene-ruthenium(II/IV) manifold was established by detailed experimental and DFT-computational studies. © 2020 The Authors. Published by Wiley-VCH GmbH

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Chemistry - A European Journal

Insights into Ruthenium(II/IV)-Catalyzed Distal C−H Oxygenation by Weak Coordination

Detailed density functional theory calculations provide valuable insight into reactivity-controlling factors in transition metal-catalyzed C-H activation by carboxylate assistance. The chelation-Assisted activation of a variety of arenes by 3d and 4d transition metal complexes was analyzed by means of bond order analysis through density functional theory (DFT) calculations as well as energy decomposition analysis through DLPNO-CCSD(T) calculations, thereby providing in-depth information on distinct electronic influences on the key C-H activation transition state and demonstrating a preferred activation through a base-Assisted internal electrophilic substitution (BIES) rather than a concerted metalation-deprotonation (CMD) pathway. Copyright © 2020 American Chemical Society.

ACS Catalysis

Reactivity-Controlling Factors in Carboxylate-Assisted C-H Activation under 4d and 3d Transition Metal Catalysis

The folded form of S-Peptide is found to be essential for the activation of RNase-S complex. Herein the folding-unfolding dynamics of S-Peptide and its protonated form in mild acidic conditions are investigated to assess the most favorable folding pathway in physiological conditions. Our results confirm that the pH assisted S-peptide structures could indeed influence on the binding and collapse of the hydrophobic groups, which in turn can modulate the structural stability of S-Peptide α-helix. We affirm that the protonated S-Peptide has its partially and completely folded states which are readily accessible whereas in the case of non-protonated S-Peptide, there exists an energy barrier in attaining the folds. Further, the RNase-S complex formation could be mostly assisted by mild acidic pH and we also confirm that the folding-unfolding pathways of S-Peptide are independent of the pH. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemistrySelect

Folding-Unfolding Dynamics of pH-Assisted Structures of S-Peptide

Mixed Pd–Au bimetallic nanoparticles embedded nitrogen doped graphene composites (PdAu/NG180) are explored for efficient electrocatalytic oxidation of methanol. A simple hydrothermal one-pot polyol method, involving simultaneous reduction of both Pd and Au, is utilized for the synthesis of Pd20-xAux/NG180 (x wt % = 0, 5, 10 and 15). This method is of multiple advantages such as inexpensiveness, reagent-free and environment-friendly being surfactant free. The morphology, crystal structure and chemical composition of NG180, Pd/NG180 and Pd20-xAux/NG180 catalysts are analyzed by XRD, FESEM-EDX, TEM, XPS and Raman spectroscopy methods. Electrocatalytic activities of PdAu/NG180 nanocomposites toward methanol oxidation reaction (MOR) in alkaline media are investigated by cyclic voltammetry, chronoamperometry and CO stripping measurements. Pd20-xAux/NG180 exhibited an increase in the electroactive surface area of Pd to twice by the coexistence of Au. In cyclic voltammetry studies, Pd10Au10/NG180 catalyst exhibits highest peak current density for MOR and is 1.5 times highly efficient compared to Pd20/NG180 with an enhanced shift in the onset potential by 140 mV to lower overpotentials. Besides, Pd10Au10/NG180 catalyst exhibited enhanced electroactive surface area and long-time durability in comparison to Pd20/NG180 catalyst. The steady state current density for MOR observed with Pd10Au10/NG180 at the end of 4000 s (98 mA mg−1Pd) is higher than those observed with all the other catalysts at the end of mere 1000 s alone (97, 61, and 32 mA mg−1Pd). The promising high electrocatalytic activity of Pd10Au10/NG180 is well corroborated from CO stripping experiments that the specific adsorption of CO onto Pd10Au10/NG180 (0.71 C m−2) is merely half to that observed onto Pd20/NG180 (1.49 C m−2). © 2019 Hydrogen Energy Publications LLC

International Journal of Hydrogen Energy

One-pot synthesis of Pd20-xAux nanoparticles embedded in nitrogen doped graphene as high-performance electrocatalyst toward methanol oxidation

Numbers of Visually impaired persons are suffering a lot for communicating their thoughts. Braille literacy is not affordable to all since the printers are expensive which costs roughly one Lakhs. This work aims to develop a braille embosser for the affordable price which embosses the A4 size sheet with braille code. Arduino Uno controller is employed to control the angular position of the stepper motor. The input is given as text format to the serial monitor of the arduino IDE. The input texts are converted into Unicode in order to get the corresponding braille code. With the help of stepper motors code is printed on the paper.

Development of Low cost 6 Dot Unicode Braille printer for aiding visually impaired persons

Recent advances in wearable sensor technologies offer new opportunities for improving dietary adherence. However, despite their tremendous promise, the potential of wearable chemical sensors for guiding personalized nutrition solutions has not been reported. Herein, we present an epidermal biosensor aimed at following the dynamics of sweat vitamin C after the intake of vitamin C pills and fruit juices. Such skin-worn noninvasive electrochemical detection of sweat vitamin C has been realized by immobilizing the enzyme ascorbate oxidase (AAOx) on flexible printable tattoo electrodes and monitoring changes in the vitamin C level through changes in the reduction current of the oxygen cosubstrate. The flexible vitamin C tattoo patch was fabricated on a polyurethane substrate and combined with a localized iontophoretic sweat stimulation system along with amperometric cathodic detection of the oxygen depletion during the enzymatic reaction. The enzyme biosensor offers a highly selective response compared to the common direct (nonenzymatic) voltammetric measurements, with no effect on electroactive interfering species such as uric acid or acetaminophen. Temporal vitamin C profiles in sweat are demonstrated using different subjects taking varying amounts of commercial vitamin C pills or vitamin C-rich beverages. The dynamic rise and fall of such vitamin C sweat levels is thus demonstrated with no interference from other sweat constituents. Differences in such dynamics among the individual subjects indicate the potential of the epidermal biosensor for personalized nutrition solutions. The flexible tattoo patch displayed mechanical resiliency to multiple stretching and bending deformations. In addition, the AAOx biosensor is shown to be useful as a disposable strip for the rapid in vitro detection of vitamin C in untreated raw saliva and tears following pill or juice intake. These results demonstrate the potential of wearable chemical sensors for noninvasive nutrition status assessments and tracking of nutrient uptake toward detecting and correcting nutritional deficiencies, assessing adherence to vitamin intake, and supporting dietary behavior change. © 2020 American Chemical Society.

ACS Sensors

Epidermal Enzymatic Biosensors for Sweat Vitamin C: Toward Personalized Nutrition

A ruthenium-catalyzed electrochemical dehydrogenative annulation reaction of imidazoles with alkynes has been established, enabling the preparation of various bridgehead N-fused [5,6]-bicyclic heteroarenes through regioselective electrochemical C−H/N−H annulation without chemical metal oxidants. Novel azaruthenabicyclo[3.2.0]heptadienes were fully characterized and identified as key intermediates. Mechanistic studies are suggestive of an oxidatively induced reductive elimination pathway within a ruthenium(II/III) regime. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Angewandte Chemie - International Edition

Azaruthena(II)-bicyclo[3.2.0]heptadiene: Key Intermediate for Ruthenaelectro(II/III/I)-catalyzed Alkyne Annulations

According to the American Society of Anesthesiologists Closed Claims Database, one of three drug-related errors is the result administrating an incorrect dose. Directly measuring drug concentration removes the uncertainty in the dose-concentration relationship and addresses inter- and intra-subject variabilities that affect the pharmacokinetics of anesthetics. Here we describe a dual-analyte microcatheter-based electrochemical sensor capable of simultaneous real-time continuous monitoring of fentanyl (FTN) and propofol (PPF) drugs simultaneously in the operating rooms. Such a dual PPF/FTN catheter sensor relies on embedding two different modified carbon paste (CP)-packed working electrodes along with Ag/AgCl microwire reference electrodes within a mm-wide Teflon tube, and uses a square wave voltammetric (SWV) technique. The composition of each working electrode was judiciously tailored to cover the concentration range of interest for each analyte. A polyvinyl chloride (PVC) organic polymer coating on the surface of CP electrode enabled selective and sensitive PPF measurements in μM range. The detection of nM FTN levels was achieved through a multilayered nanostructure-based surface modification protocol, including a CNT-incorporated CP transducer modified by a hybrid of electrodeposited Au nanoparticles and electrochemically reduced graphene oxide (erGO) and a PVC outer membrane. The long-term monitoring capability of the dual sensor was demonstrated in a protein-rich artificial plasma medium. The promising antibiofouling behavior of the catheter-based multiplexed sensor was also illustrated in whole blood samples. The new integrated dual-sensor microcatheter platform holds considerable promise towards real-time, in-vivo detection of the anesthetic drugs, propofol and fentanyl, during surgical procedures towards significantly improved safe delivery of anesthetic drugs. © 2020 Elsevier B.V.

Talanta

An integrated microcatheter-based dual-analyte sensor system for simultaneous, real-time measurement of propofol and fentanyl

A series of neutral, bulky diazabutadienediyl-substituted beryllacycles [Be(DipDAB)(L)] (DipDAB = [(DipNCH)2]2-, Dip = 2,6-diisopropylphenyl; L = OEt2, THF,:C(RNCH)2; R = Me (TMC), Pri(IPriMe)) have been prepared and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The preparation of similar complexes bearing the smaller tert-butyl-substituted diazabutadienediyl ligand ([(ButNCH)2]2-, viz. ButDAB) was attempted but gave rise to complex product mixtures, several components of which were isolated in trace yields. This phase of the study did, however, lead to the preparation of the homoleptic beryllium diradical complex [Be(ButDAB•)2], which was characterized by X-ray crystallography and EPR spectroscopy. In efforts to access BeI-BeI-bonded dianions, [(DipDAB)Be-Be(DipDAB)]2-, reductions of [Be(DipDAB)(L)] were pursued, but these instead afforded largely intractable product mixtures. Treating ethereal solutions of [Be(DipDAB)(OEt2)] with lithium alkyls afforded highly reactive, heterocyclic beryllate salts, [Li(OEt2)2,1][Be(DipDAB)R] (R = Me, Bun). Subsequent treatment of [Li(OEt2)][Be(DipDAB)Bun] with either N,N,N′,N′-tetramethylethylenediamine (tmeda) or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (pmdeta) led to the formation of [Li(tmeda)2][Be(DipDAB)Bun] and [Li(pmdeta)][Be(DipDAB)Bun]. Reactions between two of the heterocyclic beryllate salts and [BeX2(OEt2)2] (X = Br, I) did not lead to clean salt metathesis reactions but gave mixtures of many products, several of which were isolated in very low yields. While the noninnocent nature of the diazabutadienediyl ligands of [Be(DipDAB)(L)] and the [Be(DipDAB)R]-anions, hampered explorations of their further reactivity, these heterocycles hold promise as synthons for beryllium coordination chemistry. © 2020 American Chemical Society. All rights reserved.

Organometallics

Neutral, Anionic and Paramagnetic 1, 3, 2-Diazaberyllacyles Derived from Reduced 1, 4-Diazabutadienes

The functional application of RNA-guided CRISPR-associated Cas9 protein, a bacterial immune system-based protein complex, via which in vivo, highly specific, and well-regulated, gene-editing processes are being monitored at an unprecedented level, has led to remarkable progress in genetic engineering and technology. The complicated in vivo process of genome interrogation followed by gene editing by the Cas9 complex was recently reported by Knight et al. (Science, 2015, 350, 823-826) using an elegant single-particle tracking method, aided by the two-photon fluorescence correlation spectroscopic technique. In contrast to the usually observed fast target-searching and protein-binding events in biophysical systems, an interesting slow genome-interrogation process by the RNA-guided CRISPR-Cas9 system through a crowded chromatin environment of a mammalian cell has been revealed in Knight et al.'s study. Motivated by this experiment, in this paper, we provide a generalized theoretical framework to capture this particular target-searching mechanism of the CRISPR-Cas9 protein complex. We show that an analysis on the basis of 3D subdiffusion under a cylindrical volume, created by several nonspecific off-target interactions from the DNA strands, can capture the essential details of the process. Moreover, on the basis of this model, we quantify the dynamics of this process and estimate the survival probability, first passage time, and the intensity correlation function of the tagged proteins of the experiment. The results from our theoretical predictions are found to be consistent with the experimental observations, and hence, seem to provide a plausible microscopic picture of the process. © 2020 American Chemical Society.