Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Chemistry

Single molecule detection using graphene can be brought by tuning the interactions via specific dopants. Electrostatic interaction between the most electronegative element fluorine (F) and hydrogen (H) is one of the strong interactions in hydrogen bonding, and here we report the selective binding of ammonia/ammonium with F in fluorographene (FG) resulting to a change in the impedance of the system. Very low limit of detection value of ~0.44 pM with linearity over wide range of concentrations (1 pM–0.1 μM) is achieved using the FG based impedance sensor, andthisscreen printed FG sensor works in both ionized (ammonium) and un-ionized ammonia sensing platforms. The interaction energies of FG and NH3/NH4 + are evaluated using density functional theory calculations and the interactions are mapped. Here FGs with two different amounts of fluorinecontents −~5 atomic% (C39H16F2) and ~24 atomic% (C39H16F12) - are theoretically and experimentally studied for selective, high sensitive and ultra-low level detection of ammonia. Fast responding, high sensitive, large area patternable FG based sensor platform demonstrated here can open new avenues for the development of point-of-care devices and clinical sensors. © 2016, The Author(s).

School of Advanced Sciences

Chennai Campus

World University root node

Fulltext

Scientific Reports

Fluorographene based Ultrasensitive Ammonia Sensor

VIT Unitversity

Department of Chemistry

Vellore Campus

Sustainable Agriculture Reviews Nanoscience in Food and Agriculture 3

Selective Removal of Nitrate and Phosphate from Wastewater Using Nanoscale Materials

A series of eight new copper (II) complexes of types [Cu(HL1)(B)] (4a-4d) and [Cu(HL2)(B)] (4e-4h), where HL1 is N-(2-hydroxy-1-naphthalidene)-2-aminophenol, HL2 is N-(2-hydroxy-1-naphthylidene)-2-mercaptoaniline and B is N, N donor ligands viz bipyridyl (bpy), 1,10-phenanthroline (phen), dipyridoquinoxaline (dpq) and dipyridophenazine (dppz) have been synthesized and characterized by elemental analysis as well as by spectroscopic techniques (IR, UV, ESI mass and EPR spectra). The DNA-binding properties of these copper complexes (4a-4h) have been investigated by electronic absorption, viscosity measurements and docking analyses. The results obtained indicated that the complexes get bonded with DNA via an intercalation binding mode with an intrinsic binding constant, Kb (1.116 ± 0.21 to 7.227 ± 0.21) × 104 M-1. The antimicrobial activity assays with the Schiff's bases and their heteroleptic copper (II) complexes of 4a and 4b exhibited profound activity against gram positive bacteria, gram negative bacteria and fungi. Further, complexes 4d and 4h displayed significant cytotoxicity when examined in vitro on a panel of cancerous cell line - human liver cancer cell line - HepG-2 cells (IC50 = 40.82 and 29.74 μg/ml). © 2015 Elsevier Inc. All rights reserved.

Department of Design and Automation

School of Mechanical Engineering

Department of Integrative Biology

School of Bio Sciences and Technology

Inorganica Chimica Acta

Synthesis, spectroscopic characterization and in vitro studies of new heteroleptic copper (II) complexes derived from 2-hydroxy napthaldehyde Schiff’s bases and N, N donor ligands: Antimicrobial, DNA binding and cytotoxic investigations

In present investigation extracellular synthesis of silver nanoparticles were synthesized using cell free supernatant of Pseudomonas veronii AS41G isolated from Annona squamosa L. The bacterium significantly reduced silver nitrate to generate silver nanoparticles which was characterized with hyphenated techniques. Synthesis of silver nanoparticles preliminary confirmed by UV-Visible spectrophotometry with the intense peak at 410nm, Further FTIR analysis revealed the possible role of biomolecules in the supernatant responsible for mediating the nanoparticles formation. The XRD spectra exhibited the characteristic Bragg peaks of 100, 111, 200, and 220 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. TEM microgram showed polydispersity of nanoparticles with size ranging from 5 to 50nm. Synthesized silver nanoparticles showed antibacterial activity against human and environmental pathogens including MRSA. The study enlightens the role of biosynthesized silver nanoparticles as an emerging alternative for drug resistant microorganisms. The obtained results are promising enough to pave the environmentally benign nanoparticle synthesis processes without use of any toxic chemicals and also envision the emerging role of endophytes towards synthesis of nanoparticles. With scanty reports available on P.veronii species, a new role has been reported in this study which will be very valuable for future researchers working on it.

Department of Digital Communications

School of Information Technology and Engineering

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Extracellular synthesis of silver nanoparticles by novel Pseudomonas veronii AS41G inhabiting Annona squamosa L. and their bactericidal activity

A new set of ester functionalised Re(i)-based oxamidato bridged neutral dinuclear metallacycles were synthesised by self-assembly of four components from three building blocks in a facile one-pot reaction via an orthogonal bonding approach. Oxidative addition of oxamide ligands (H2L = N,N′-diphenyloxamide, and N,N′-dibenzyloxamide) to rhenium carbonyl (Re2(CO)10) in the presence of semi-rigid and flexible ditopic pyridyl ligands (L′ = o-phenylene diisonicotinate (pdi), ethane diyl di-4-pyridine carboxylate (etdp) and 1,4-butane diyl di-4-pyridine carboxylate (budp)) having ester functionality afforded neutral dirhenium metallacycles of the general formula [(CO)3Re(μ-L)(μ-L′)Re(CO)3] (1-5) under solvothermal reaction conditions. The metallacyclic compounds were characterised using elemental analyses, IR, UV-vis and NMR spectroscopic techniques. Structural analyses of 2-5 by single crystal X-ray diffraction methods revealed a stirrup like molecular framework in which two fac-Re(CO)3 units are bridged together by dissymmetrical NO∩ON bis-chelation of oxamide ligands (as a pedestal of stirrups) and further connected by a flexible ditopic tecton (as an arched anchor of stirrups) in an orthogonal fashion. The cytotoxicity activities of dirhenium metallacycles 1-5 were studied in vitro against three different cancer cell lines and normal cells. © The Royal Society of Chemistry 2015.

Dalton Transactions

Self-assembly of oxamidato bridged ester functionalised dirhenium metallastirrups: Synthesis, characterisation and cytotoxicity studies

Al-doped ZnO thin films were synthesized from oxygen reactive co-sputtering of Al and Zn targets. Explicit doping of Al in the highly c-axis oriented crystalline films of ZnO was manifested in terms of structural optical and electrical properties. Electrical conduction with different extent of Al doping into the crystal lattice of ZnO (AZnO) were characterized by frequency dependent (40 Hz-50 MHz) resistance. From the frequency dependent resistance, the ac conduction of them, and correlations of localized charge particles in the crystalline films were studied. The dc conduction at the low frequency region was found to increase from 8.623 A to 1.14 mA for the samples AZnO1 (1 wt% Al) and AZnO2 (2 wt% Al), respectively. For the sample AZnO10 (10 wt% Al) low frequency dc conduction was not found due to the electrode polarization effect. The measure of the correlation length by inverse of threshold frequency (ω0) showed that on application of a dc electric field such length decreases and the decrease in correlation parameter(s) indicates that the correlation between potentials wells of charge particles decreases for the unidirectional nature of dc bias. The comparison between the correlation length and the extent of correlation in the doped ZnO could not be made due to the observation of several threshold frequencies at the extent of higher doping. Such threshold frequencies were explained by the population possibility of correlated charge carriers that responded at different frequencies. For AZnO2 (2% Al), the temperature dependent (from 4.5 to 288 K) resistance study showed that the variable range hopping mechanism was the most dominating conduction mechanism at higher temperature whereas at low temperature region it was influenced by the small polaronic hopping conduction mechanism. There was no significant influence found in these mechanisms on applications of 1, 2 and 3 V as biases. © 2015 IOP Publishing Ltd.

Journal of Physics D: Applied Physics

An insight to the low temperature conduction mechanism of c-axis grown Al-doped ZnO, a widely used transparent conducting oxide

Xanthate functionalized PAMAM dendrimer (XFPD) chelating ligand, first of its kind, has been synthesized from hydroxyl terminated poly(amido)amine dendrimer. Studies on performance of XFPD in removal of Cu2+ and Eu3+ metal ions were carried out from aqueous solution. Investigation on quantitative removal of Cu2+ and Eu3+ metal ions at various pH revealed that XFPD effectively precipitates the metal ions at pH > 4 with settling time of about 3 h. In case of Cu-XFPD complex at pH > 6, settling requires the addition of coagulating agent like aluminium sulphate. The loading capacity of XFPD for Cu2+ and Eu3+ metal ions was estimated to be 0.48 and 0.95 g g-1, respectively. The XFPD chelating ligand deployed for treatment of radioactive liquid waste (RLW) showed that percentage removal of radionuclides were in the following order; 95Zr ≈ 154Eu ≈ 60Co (>99.8) > 144Ce (98.8) > 125Sb (83.3) > 106Ru (79.4) > 55Mn (54.3) > 137Cs (24.0). It has been demonstrated that XFPD chelating ligand has potential application in effective removal of various radionuclides from aqueous waste. © 2015 Elsevier Ltd. All rights reserved.

Journal of Environmental Chemical Engineering

Xanthate functionalized PAMAM dendrimer (XFPD) chelating ligand for treatment of radioactive liquid wastes

Voltammetric and amperometric techniques are powerful analytical tools that are widely used in chemical analysis. This article reviews a summary of some important types of modifying agents and their application in voltammetric and amperometric sensors for clinically and biologically important target species reported from the period 2003 to 2013. In this review, different modifiers such as molecularly imprinted polymers (MIPs), polymers, metal complexes, nanomaterials and composite films are discussed. Under the heading of each modifier, method of fabrication, properties, and applications of chemically modified electrodes (CMEs) are given. Tables that give analyte, modified electrode, measurement technique, measuring medium, linear detection range (LDR) and limit of detection (LOD) referenced from original work are also provided. © 2015, Pleiades Publishing, Ltd.

Journal of Analytical Chemistry

Voltammetric techniques at chemically modified electrodes

The self-assembly of M2(CO)10 (M = Mn, Re), oxamide ligands [H2L = N,N′-dibutyloxamide (dbo), N,N′-dibenzyloxamide (dbno)], and flexible bidentate linkers [L′ = 1,2-bis(4-pyridyl)ethane (bpe), 1,3-bis(4-pyridyl)propane (bpp)] afforded MnI- and ReI-based dinuclear metallacycles [(CO)3M(μ-η4-L)(μ-L′)M(CO)3] (1-6). The oxidative addition of oxamide ligands to the equatorial sites and the addition of flexible dipyridyl ligands to the axial sites of facial metal tricarbonyl cores resulted in the formation of dinuclear metallacycles under one-pot reaction conditions. Metallacycles 1-6 were characterized through elemental analysis, IR, UV/Vis, and NMR spectroscopy. The formation of dinuclear compounds 1 and 4 was ascertained by ESI mass spectrometry. The molecular structures of 2, 3, 5, and 6 were elucidated by single-crystal X-ray crystallographic methods, which revealed horse-stirrup-like dinuclear frameworks in which the metal centers are orthogonally connected by a bridging oxamide ligand through ON∩NO bis(chelation) and a flexible bidentate ligand through M-N coordination. The first one-step syntheses of self-assembled neutral MnI-based dinuclear metallastirrups containing bis(chelating) oxamide ligands and their rhenium analogues are reported herein. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

European Journal of Inorganic Chemistry

Self-Assembly of Oxamidato-Chelated ReI- and MnI-Based Flexible Dinuclear Horse-Stirrup-Like Metallacycles

Hydrothermally synthesized MnFe2O4/rGO composite with sodium alginate binder shows a highly stable capacity of 258 mA h g−1versus Na/Na+at 0.1C rate.