NOPR Collection:

Synthesis of quinolines from glycerol over tungstic acid functionalized mesoporous KIT-6 catalyst in aqueous medium

Mon, 01 Aug 2016 00:00:00 GMT

Title: Synthesis of quinolines from glycerol over tungstic acid functionalized mesoporous KIT-6 catalyst in aqueous medium Authors: Udayakumar, V; Pandurangan, A Abstract: Mesoporous tungstic acid functionalized KIT-6 has been synthesized through a condensation of (3-chloropropyl) triethoxysilane and Si-KIT-6 followed by substitution of chloromethylation functionalized KIT-6 by sodium tungstate dihydrate. The synthesized tungstic acid functionalized KIT-6 (W-KIT-6) was characterized by low and wide angle X-ray diffraction analysis (XRD), N₂ adsorption-desorption isotherm, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), NH₃-temperature programmed desorption (NH₃-TPD), ¹³C CP/MAS NMR spectrum and FT-IR analysis. The functionalized KIT-6 posses surface area of 663 m²/g with corresponding pore size 6.3 nm and pore volume 0.65 cm³/g. The catalytic activity of W-KIT-6 nanoparticles evaluated in the Skraup synthesis of quinoline and its derivatives using water as solvent, the results show the target compound was obtained as 89% yield with complete conversion of glycerol (100%) under the reaction conditions of 200 ^oC for 3 h. The catalyst has been recycled for five times without significant loss in catalytic activity. Page(s): 919-928

Ruthenium carbonyl complex bearing thioether containing Schiff base ligand: Structure, electrochemistry and catalytic activity

Mon, 01 Aug 2016 00:00:00 GMT

Title: Ruthenium carbonyl complex bearing thioether containing Schiff base ligand: Structure, electrochemistry and catalytic activity Authors: Biswas, Sujan; Roy, Puspendu; Sarkar, Deblina; Mondal, Tapan Kumar Abstract: New ruthenium(II) carbonyl complex, cis-(CO)-trans-(Cl)-[Ru(CO)₂(L)Cl₂] (1) (L = 2-(methylthio)-N-((pyridine-2-yl)methylene)benzenamine) has been synthesized and characterized by several spectroscopic techniques. The geometry of the complex has been confirmed by single crystal X-ray structure. Cyclic voltammogram of (1) exhibits irreversible Ru(II)/Ru(III) oxidation and ligand based reduction. The electronic structure, redox properties, absorption and emission properties of the complex have been interpreted by DFT and TDDFT calculations. The complex efficiently catalyzes the oxidation of alcohols in presence of N-methylmorpholine-N-oxide. Page(s): 929-937

Structure and reactivity of di-n-butyltin(IV) derivative of chlordiazepoxide based on electronic structure calculations

Mon, 01 Aug 2016 00:00:00 GMT

Title: Structure and reactivity of di-n-butyltin(IV) derivative of chlordiazepoxide based on electronic structure calculations Authors: Pokharia, Sandeep; Joshi, Rachana; Pokharia, Mamta; Yadav, Swatantra Kumar; Mishra, Hirdyesh Abstract: Density functional theory calculations in electronic structure studies of n-Bu₂SnL₂ (where L is the monoanion of chlordiazepoxide (LH), a benzodiazepine derivative with hypnotic action) have been reported using the Gaussian09 software. The molecular geometries of LH and tetrahedral n-Bu₂SnL₂ have been optimized at B3LYP/6-31G(d,p) and B3LYP/6-31G(d,p)/Def2-SVP(Sn) level of theory, respectively. Harmonic vibrational frequencies are computed at the same level of theory to find the true potential energy surface minima. The effect of functional, basis set and computational cost is analyzed. The various geometrical and thermochemical parameters have been obtained in gas phase and in the solvent. The atomic charges at all the atoms are calculated using Mulliken population analysis, Hirshfeld population analysis and natural population analysis. The charge distribution within the studied complex is explained on the basis of molecular electrostatic potential maps, and conceptual-DFT based global reactivity descriptors using the finite difference approximation method. The calculated parameters suggest a distorted tetrahedral geometry around the central Sn atom. The calculated Sn-O bond lengths reveals different degree of interaction of two chlordiazepoxide units with the di-n-butyltin(IV) moiety. Among the atoms coordinated to the central Sn atom, oxygen from one LH unit is nucleophilic, whereas the second oxygen atom from the other LH unit is electrophilic in nature. The results provide an insight into the efficacy of computational methods in understanding the structure and reactivity of organotin(IV) derivatives of hetero donor atoms. Page(s): 938-949

Bifunctional organocatalysts for the synthesis of jasminaldehyde and their derivatives

Mon, 01 Aug 2016 00:00:00 GMT

Title: Bifunctional organocatalysts for the synthesis of jasminaldehyde and their derivatives Authors: Ganga, Venkata Subba Rao; Abdi, Sayed H R; Kureshy, Rukhsana I; Khan, Noor-ul H; Bajaj, Hari C Abstract: L-Proline in the presence of benzoic acid is found to be an effective catalytic system for the cross-aldol condensation of benzaldehyde with 1-heptanal under solvent free condition amongst the several amino acids screened for this reaction. Under the optimized reaction conditions, the desired product (e.g. jasminaldehyde) is formed up to 96% selectivity in one hour using the desired arylaldehyde: 1-alkanaldehyde ratio as low as 2:1 under controlled addition of 1-alkanaldehyde. Page(s): 950-955