Prof. C N Sundaresan, Professor (Hon.), Chemistry, SSSIHL (original) (raw)

Papers by Prof. C N Sundaresan, Professor (Hon.), Chemistry, SSSIHL

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016

The subject of the study is the structure and conformation of 1″,4″-Dispiro-cyclohexane-6,6&a... more The subject of the study is the structure and conformation of 1″,4″-Dispiro-cyclohexane-6,6&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-bis(benzothiazoline), a dispiro compound that has a cyclohexyl ring flanked by two benzothiazoline rings on either side. Using single crystal X-ray diffraction measurements, Infra-red absorption, and Raman spectroscopy techniques, it is found that the central cyclohexyl ring assumes the chair conformation and the sulfur, nitrogen atoms in both the benzothiazole rings are in the trans configurations. The experimental findings are further corroborated by geometry optimization and frequency calculations at B3LYP/6-311++G** level of theory using Gaussian 09 suite of program.

It is no wonder that many eminent chemists were attracted to these materials to elucidate the und... more It is no wonder that many eminent chemists were attracted to these materials to elucidate the underlying chemistry. Willstatter, Baeyer, Richard Kuhn, Karrer, Robinson and others made pioneering studies and isolated several new compounds which were included in the curriculum of earlier days. Another pioneer, A G Perkin, second son of Sir W H Perkin, was, according to his elder brother, W H Perkin, Jr, a dabhand with natural dyes. He and A E Everest wrote a book The Natural Organic Colouring Matters, first published in 1918, which was like a Bible to natural product chemists of yesteryears. (You can now read it on line!).

Journal of Molecular Liquids, 2020

Corrosion Inhibition potential of three 2-thioureidobenzheteroazoles, namely, 2-thioureidobenzoxa... more Corrosion Inhibition potential of three 2-thioureidobenzheteroazoles, namely, 2-thioureidobenzoxazole (BOT), 2-thioureidobenzimidazole (BIT), 2-thioureidobenzothiazole (BTT) compounds were predicted theoretically using quantum chemical calculations on type CS 1084 carbon steel in 2 M HCl at 25°C. DFT calculations indicated that BTT showed better inhibition compared to BIT and BOT compounds. Theoretical conclusions were subsequently validated by experiments carried out using Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP) and Scanning Electron Microscopy (SEM). Adsorption of 2-thioureidobenzheteroazoles on the steel surface obeyed the Langmuir adsorption model. Thermodynamic parameters indicated that, the adsorption process is energetically spontaneous, while the calculated kinetic parameters corroborated the adsorption phenomenon at the metal/solution interface. Furthermore, PDP results showed that, the inhibitors behaved as mixed type inhibitors with cathodic dominance. The maximum corrosion inhibition efficiency obtained was 96.1% for BTT at 2 mM concentration. The surface morphology investigations using SEM technique showed lower corrosion inhibition in presence of these inhibitors. Sulphur and nitrogen heteroatoms served as reactive centres for the adsorption of inhibitors, based on the quantum chemical calculations.

Journal of Molecular Liquids, 2018

chemical characterization of drug-bio-surfactant micellar system: A road for developing better ph... more chemical characterization of drug-bio-surfactant micellar system: A road for developing better pharmaceutical formulations. Molliq (2018),

Zeitschrift für Physikalische Chemie, 2019

In this study, quantum chemical calculations and molecular dynamics simulations studies of a seri... more In this study, quantum chemical calculations and molecular dynamics simulations studies of a series of five nonionic surfactants namely: dimethyl alkyl phosphine oxide surfactants (C10-18PO) containing decyl, dodecyl-, tetradecyl-, hexadecyl-, and octadecyl alkyl chains were implemented using the density functional theory (DFT) method to interpret the correlation between the inhibition efficiency and the molecular structure of the different inhibitors in formation water. The global quantities including: highest occupied molecular orbital energy (HOMO), lowest unoccupied molecular orbital energy (LUMO), energy gap (ΔE), dipole moment (μ), total energy (TE), ionization potential (I), electron affinity (A), electronegativity (χ), chemical potential (π), global hardness (η), global softness (σ), global electrophilicity (ω), polarizabilities <α> and fraction of electrons transferred (ΔN) were calculated for the different inhibitors in formation water. The dependence of surface acti...

Journal of Molecular Liquids, 2016

The speed of sound (u)in conjunction with density (ρ) and viscosity (η) for amino acids L-glutami... more The speed of sound (u)in conjunction with density (ρ) and viscosity (η) for amino acids L-glutamine and L-histidine in aqueous solutions of metformin hydrochloride (an anti-diabetic drug) (0.01, 0.07, and 0.13 mol•kg −1) have been measured in the concentration range (0.02-0.20 mol•kg −1) at (293.15, 298.15, 303.15, 308.15, and 313.15) K. In order to account for the consequences of drug-amino acid interactions, various acoustical parameters such as intermolecular free length (L f), relative association (RA), specific acoustic impedance (Z), and molar sound number ([U]) have been evaluated from density and speed of sound data. Combined with viscosity values, the speed of sound data have been used to estimate parameters like relaxation time (τ), internal pressure (π i), molar cohesive energy (MCE)and free volume (V f). The results of acoustical studies are substantiated with UV-Vis studies for ternary system (water + drug + amino acid). The different kinds of intermolecular interactions existing between different components of the mixture are found to be responsible for the varying trends in aforesaid different acoustic parameters.

The paper studies sustainable supply chain management from the perspective of protein biosynthesi... more The paper studies sustainable supply chain management from the perspective of protein biosynthesis, which is one of the most fundamental supply chains present in every organism. After providing a review of literature, the study explains the protein biosynthesis process. The paper then analyzes sustainable supply chains using a biomimetic perspective of protein biosynthesis. Finally, lessons of excellence for supply chain sustainability based on unique characteristics present in the protein biosynthesis process have been delineated.

AIP Conference Proceedings, 2013

ABSTRACT We have undertaken an ab initio computational study of 2-thioureidobenzoxazole based on ... more ABSTRACT We have undertaken an ab initio computational study of 2-thioureidobenzoxazole based on the method of numeric localized atomic orbitals, pseudopotentials and DFT using SIESTA code. Electron Density of States, HOMOLUMO gap, formation energy, bond lengths and bond angles have been calculated. The bond lengths and bond angles are in close agreement with the experimental results reported earlier. It is also observed that the molecule is non magnetic and may behave as semiconductor as the HOMO-LUMO gap is 2.75827 eV.

Resonance, 2013

Indigo and Tyrian purple are two dyes which have captured the imagination of the common man as we... more Indigo and Tyrian purple are two dyes which have captured the imagination of the common man as well as the gentry from the very beginning of human civilization. Their story is like a multicoloured yarn, with strands from chemistry, history, culture and politics. Their popularity is reflected by the fact that their stories are very well documented not only in scientific journals but also in books and even on the celluloid! Recent studies show that indigo may be utilized even as a semi-conducting material.

$Research paper thumbnail of A supramolecular assembly dominated by N–H⋯S hydrogen bonds: Structure of 2-thioureidobenzoxazole by single crystal X-ray diffraction$

Journal of Molecular Structure, 2004

2-Thioureidobenzoxazole (1) was synthesized using 5-amino-3H-1,2,4-dithiazole-3-thione and 2-amin... more 2-Thioureidobenzoxazole (1) was synthesized using 5-amino-3H-1,2,4-dithiazole-3-thione and 2-aminophenol and characterized by X-ray crystallography. The molecule of 1 is essentially planar due to p conjugation and an intramolecular N-H• • •N hydrogen bond also contributes towards its planarity. The crystal lattice is built up of stacks of dimers of 1 generated by N-H• • •S hydrogen bonds. The supramolecular assembly is dictated by weaker N-H• • •S interactions to the exclusion of more stronger N-H• • •X (X ¼ O, N) hydrogen bonds which are normally expected.

Heteroatom Chemistry, 1994

... 460, (1979); (b) J. Barluenga, M. To-mas, A. Ballesteros, and A. Lopez, Tetrahedron Lett., 30... more ... 460, (1979); (b) J. Barluenga, M. To-mas, A. Ballesteros, and A. Lopez, Tetrahedron Lett., 30 (49), 1989, 6923-6926; (c) G. Sridevi, P. Jayapra-sad Rao, and K. Kondal Reddy, Synth. Cornrn., 19(5-6/, 1989, 965-972; (d) CN Sundaresan: Ph.D. The-sis, Sri Sathya Sai Institute of ...

Acta Crystallographica Section E Structure Reports Online, 2014

In the title compound, C8H9N4S+·Cl−·H2O, the cation is approximately planar, with a dihedral angl... more In the title compound, C8H9N4S+·Cl−·H2O, the cation is approximately planar, with a dihedral angle of 7.71 (8)° between the mean planes of the benzoimidazole ring system and the thiourea unit. In the crystal, cations, anions and water molecules of crystallization are linked by O—H...Cl, N—H...O, N—H...Cl and N—H...S hydrogen bonds into a three-dimensional network. π–π stacking is observed between the benzene and imidazole rings of neighbouring molecules, the centroid–centroid distance being 3.5774 (11) Å.

Acta Crystallographica Section E Structure Reports Online, 2013

In the title compound, C6H6BrNO, the Br atom is displaced from the pyridine ring mean plane by 0.... more In the title compound, C6H6BrNO, the Br atom is displaced from the pyridine ring mean plane by 0.0948 (3) Å, while the hydroxyl O atom and the methyl C atom are displaced by 0.0173 (19) and 0.015 (3) Å, respectively. In the crystal, molecules are linkedviaO—H...N hydrogen bonds, forming chains propagating along thea-axis direction. These chains are linked by C—H...Br hydrogen bonds, forming corrugated two-dimensional networks lying parallel to theacplane.

Journal of Advanced Chemical Sciences, 2015

The ligand, 1-(1 H -benzimidazol-2-yl)guanidine (GBI) gives two absorbance peaks at 245 nm and 29... more The ligand, 1-(1 H -benzimidazol-2-yl)guanidine (GBI) gives two absorbance peaks at 245 nm and 295 nm respectively. GBI complexes with mercury(II) to form a white coloured complex. The analytical parameters such as effect of pH, reagent dosage, reaction time, effect of mercuric ion concentration, effect of interfering ions have been studied. The range of detection was determined to be 0.01 – 1000 μg/mL. The minimum detection limit is 10 ng/mL. The method is fairly sensitive and does not involve any preconcentration procedures. The method was appropriately validated using analytical procedures.

Journal of Molecular Liquids, 2015

This paper investigates the effect of a heterocyclic compound, iso-perthiocyanic acid (IPA) (0.01... more This paper investigates the effect of a heterocyclic compound, iso-perthiocyanic acid (IPA) (0.01, 0.05, and 0.10 mol•kg − 1) on the micellization behavior of sodium dodecylsulphate (SDS) (1-52 mmol•kg − 1) in dimethylsulphoxide (DMSO) by employing three conventional techniques viz. conductivity, density, and speed of sound measurements over a wide temperature range (293.15-313.15 K). From all the techniques, the critical micelle concentration (CMC) values have been determined, and the results have been discussed in terms of SDS-IPA solvophobic and hydrogen bonding interactions in DMSO. The temperature dependence of the CMC values has proved the dominance of disruption of structured DMSO molecules around the alkyl chain of SDS. Further, the X CMC values have been used to calculate the standard thermodynamic parameters of micellization like enthalpy (ΔH m o), free energy (ΔG m o), and entropy (ΔS m o). The density and speed of sound data have been used to evaluate the volumetric and compressibility parameters like apparent molar volume (ϕ v), isentropic compressibility (K s), and apparent molar isentropic compression (ϕ κ) to get more clear insight with regards to solute-solute / solute-solvent interactions existing in the present SDS-IPA-DMSO ternary system. In addition, an attempt has also been made to examine the antifungal activity of IPA in combination with SDS in aqueous medium.