@article { ISI:000239884300028, title = {Theoretical study of N2O reduction by CO in Fe-BEA zeolite}, journal = {Chemphyschem}, volume = {7}, number = {8}, year = {2006}, month = {AUG}, pages = {1795-1801}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

Quantum mechanical (QM) and QM/molecular mechanics (MM) studies of the full catalytic cycle of N2O reduction by CO in Fe-BEA zeolite, that is, oxidation of BEA-Fe by NO and reduction of BEA-Fe-alpha O by CO, is presented. A large QM cluster, representing half of the channel of the BEA zeolite, is used. The contribution of the MM embedding to the calculated activation energies is found to be negligible. The minimum-energy paths for N2O decomposition and reduction with CO are calculated using the nudged elastic bond (NEB) method. Calculated band experimental activation energies ore in good agreement The two possible orientations for the gaseous molecules adsorbing on the Fe site that ore found lead to different activation energies.

}, keywords = {Density functional calculations, iron, nitrogen oxides, reaction mechanisms, zeolites}, issn = {1439-4235}, doi = {10.1002/cphc.200600228}, author = {Fischer, Gerd and Goursot, Annick and Coq, Bernard and Delahay, Gerard and Pal, Sourav} } @article { ISI:000340525300012, title = {Synthesis of alpha,beta-unsaturated delta-lactones by vinyl acetate mediated asymmetric cross-aldol reaction of acetaldehyde: mechanistic insights}, journal = {European Journal of Organic Chemistry}, number = {24}, year = {2014}, month = {AUG}, pages = {5247-5255}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A tandem asymmetric cross-aldol reaction involving the in situ generation of acetaldehyde from vinyl acetate has been developed that may resolve the challenges associated with the handling of acetaldehyde. The simple protocol, mild reaction conditions and unique harmony of an organocatalyst with a biocatalyst make this method a valuable tool for the synthesis of asymmetric beta-hydroxy aldehydes. By using this methodology we have accessed alpha,beta-unstaurated delta-lactones as well as isochromenones with high enantioselectivities from both asymmetric beta-hydroxy aldehydes and ketones. Systemic density functional theory (DFT) studies were also performed to gain mechanistic insights into the role of hydrogen bonding in the asymmetric cross-aldol reaction of acetaldehyde and in the key cis/trans isomerisation step in the synthesis of d-lactones.

}, keywords = {Aldol reactions, asymmetric catalysis, lactones, reaction mechanisms}, issn = {1434-193X}, doi = {10.1002/ejoc.201402551}, author = {Kumar, Manjeet and Kumar, Arvind and Rizvi, Masood and Mane, Manoj and Vanka, Kumar and Taneja, Subhash C. and Shah, Bhahwal Ali} } @article { ISI:000352508300032, title = {Reactivity and operational stability of N-Tailed TAMLs through kinetic studies of the catalyzed oxidation of orange II by H2O2: synthesis and x-ray structure of an N-Phenyl TAML}, journal = {Chemistry A-European Journal}, volume = {21}, number = {16}, year = {2015}, month = {APR}, pages = {6226-6233}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

{The catalytic activity of the N-tailed (biuret) TAML (tetraamido macrocyclic ligand) activators [Fe{4-XC6H3-1,2-(NCOCMe2NCO)(2)NR}Cl](2-) (3; N atoms in boldface are coordinated to the central iron atom; the same nomenclature is used in for compounds 1 and 2 below), [X

}, keywords = {Hydrogen peroxide, iron, kinetics, Oxidation, reaction mechanisms}, issn = {0947-6539}, doi = {10.1002/chem.201406061}, author = {Warner, Genoa R. and Mills, Matthew R. and Enslin, Clarissa and Pattanayak, Shantanu and Panda, Chakadola and Panda, Tamas Kumar and Sen Gupta, Sayam and Ryabov, Alexander D. and Collins, Terrence J.} } @article {47129, title = {Review on selective production of acetophenone from oxidation of ethylbenzene over heterogeneous catalysts in a decade}, journal = {Catalysis Letters}, year = {2021}, month = {JAN}, type = {Article; Early Access 2021}, abstract = {

The consumption of acetophenone (AP) is increasing worldwide because of its applications in products such as alcohol, aldehydes, resins, esters, fragrances, and pharmaceuticals. AP is manufactured via several methods like decomposition of cumene hydroperoxide, Hock process, and Friedel-Crafts acylation reaction using homogeneous catalysts with solvent and oxidant. However, it causes several environmental problems that deteriorate the production of AP with these methods. Oxidation of ethylbenzene (EB) is one of the promising methods to synthesize AP in liquid and vapor phases reaction using heterogeneous catalysts, which plays a vital role for selective production of AP. In this review, numerous heterogeneous catalysts are discussed including transition metal nanoparticles, transition metal complexes, and metal free catalysts (carbon nanotubes) used in last 10 years for oxidation of EB. Additionally, catalyst activity along with reaction parameters and its effect, mechanisms, and kinetics study are summarized in this article. The future scope of this reaction is also highlighted. Moreover, this work identifies best catalysts for bulk production of AP with high yield to satisfy global requirement.

}, keywords = {acetophenone, ethylbenzene, Heterogeneous catalysts, Oxidation reaction, reaction mechanisms}, issn = {1011-372X}, doi = {10.1007/s10562-020-03474-8, Early Access Date = JAN 2021}, author = {Nandanwar, Sachin U. and Rathod, Simmy and Bansal, Videsha and Bokade, Vijay V.} } @article {48714, title = {"Weak" C-H{\textbullet}{\textbullet}{\textbullet}S interaction drives enantioselectivity in cinchona alkaloid complex catalyzed thiocyanation}, journal = {Chemistry-An Asian Journal}, volume = {18}, year = {2023}, month = {JUL}, pages = {e202300321}, type = {Article}, abstract = {

The great success of asymmetric organocatalysis has made it one of the most important advancements made in chemistry in the past two decades. A significant achievement in this context is the asymmetric organocatalysis of the thiocyanation reaction. In the current study, computational studies with density functional theory have been done in order to understand an interesting experimental finding: the reversal of enantioselectivity from R to S when the electrophile is changed from beta-keto ester to oxindole for the thiocyanation reaction with the cinchona alkaloid complex catalyst. The calculations reveal an unusual fact - the principal reason for the reversal is the presence of the C-H center dot center dot center dot S noncovalent interaction, which is present only in the major transition states in each of the two nucleophile cases. Only recently has it been realized that the supposedly weak C-H center dot center dot center dot S noncovalent interaction has the properties of a hydrogen bond, and the fact that this interaction is the cause of enantioselectivity has relevance, because of the large number of asymmetric transformations involving the sulphur heteroatom.

}, keywords = {Density functional calculations, Enantioselectivity, noncovalent interactions, organocatalysis, reaction mechanisms}, issn = {1861-4728}, doi = {10.1002/asia.202300321}, author = {Banerjee, Subhrashis and Vanka, Kumar} }