@article {46834, title = {Highly efficient chemoselective N-tert butoxycarbonylation of aliphatic/aromatic/heterocyclic amines using diphenylglycoluril as organocatalyst}, journal = {Tetrahedron}, volume = {76}, year = {2020}, month = {JUN }, pages = {131223}, type = {Article}, abstract = {

An efficient approach for the Chemoselective N-tert-butoxycarbonylation of a variety of amines using diphenylglycoluril as organocatalyst has been described. For the first time, a plausible mechanism for the N-tert-butoxycarbonylation has been proposed using density functional theory (DFT) calculations supported by NMR studies. The reusability of the organocatalyst and observation of the desired N-Boc protected amines being formed without the formation of side products like urea, oxazolidinone, isocyanate, and N, N-di-Boc derivatives makes the present protocol desirable. (C) 2020 Elsevier Ltd. All rights reserved.

}, keywords = {DFT studies, Diphenylglycouril, N-tert butoxycarbonylation, organocatalyst, Proton shuttle mechanism}, issn = {0040-4020}, doi = {10.1016/j.tet.2020.131223}, author = {Awasthi, Amardeep and Mukherjee, Anagh and Singh, Mandeep and Rathee, Garima and Vanka, Kumar and Chandra, Ramesh} } @article {48107, title = {Free base phthalocyanine coating as a superior corrosion inhibitor for copper surfaces: a combined experimental and theoretical study}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {648}, year = {2022}, month = {SEP }, pages = {129138}, type = {Article}, abstract = {

In the quest of novel, eco-benign copper corrosion inhibitors, free base and a set of six metal Phthalocyanine (Pc) coatings (where metal is Zn, Cu, Fe, Co, Ni, Mn) are systematically evaluated for their corrosion inhibition efficiency. The study demonstrates that the free base Phthalocyanine coatings are superior corrosion inhibitors for Cu surface in HCl with a corrosion inhibition efficiency of 88\% as compared to its metal counterparts. A detailed and indepth study involving concerted electrochemical polarisation, impedance measurements at various concentrations of HCl assert the superior corrosion inhibition efficiency of free base Pc coatings as compared to its metal counterparts. Underlying factors/interface chemistry contributing to it is brought out using first principle based studies. First principles based computational studies establish that superior corrosion inhibition ability of free base phthalocyanine molecule is attributed to its innate binding ability with copper surface and its better inter-molecular packing. Thus, the theoretical adsorption trends of various studied phthalocyanine molecules while clearly following the experimental corrosion inhibition efficiency trends undermine the importance of contribution of chelating factors for the formation of a stable and efficient corrosion inhibition coating on a surface and that the adhesion/adsorption strength of a molecule correlates directly to its corrosion inhibition efficiency. The experimental observations are further substantiated through FE-SEM, EDAX and XPS studies. The corrosion inhibition efficiency of free base phthalocyanine is followed by its zinc based counterpart at 85\%.

}, keywords = {Copper surface, Corrosion inhibitors, DFT studies, Impedance, Phthalocyanine coatings}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2022.129138}, author = {Samal, Pragnya Paramita and Dekshinamoorthy, Amuthan and Arunachalam, Shivakami and Vijayaraghavan, Saranyan and Krishnamurty, Sailaja} } @article {48259, title = {Investigation of the effect of zeolite supports and the role of W-species for one-pot catalytic conversion of cellulose to ethylene glycol: theoretical \& experimental studies.}, journal = {Chemistry-An Asian Journal}, volume = {18}, year = {2023}, month = {FEB }, type = {Article}, abstract = {

Endeavors were made to study the influence of various zeolite (HY, NaY, NaZSM-5 and HZSM-5) supports with (Al)-Ni-W metal combination catalysts for the ethylene glycol (EG) production, selectively from cellulose. From the experimental results ZSM-5 (NaZSM-5/73.3\% \& HZSM-5/67.7\%) support is superior over HY \& NaY support in selective EG production from cellulose. It was understood that W- species with oxygen vacancies (WO3-x, XPS analysis) plays an important role in producing the glycolaldehyde (GA) intermediate (via C-C cleavages), which on hydrogenation over Ni- sites selectively produce EG. Further, the studies based on the Density Functional Theory (DFT) were conducted to substantiate the involvement of the WO3-x species in the reaction. The adsorption energies and structural changes establish that the C-2-C-3 bond of the glucose elongates and thereby activates on adsorbing to WO3-x sites supporting the formation of GA. Activation of GA on Ni- sites is distinguished by an increase of 0.1 angstrom in C=O bond length, which facilitates the hydrogenation of C=O resulting in EG. The reaction pathway is explained through an analysis of CDD and DOS.

}, keywords = {Cellulose hydrogenolysis, DFT studies, ethylene glycol, zeolites}, issn = {1861-4728}, doi = {10.1002/asia.202201202}, author = {Sreekantan, Sreejith and Singh, Chandrodai Pratap and Krishnamurty, Sailaja and Marimuthu, Banu} } @article {49000, title = {Shape-controlled MoO3/MnO x nanocatalyst for the selective synthesis of 2-phenylquinoxaline drug motifs}, journal = {ACS Applied Nano Materials}, volume = {6}, year = {2023}, month = {DEC }, pages = {23442-23453}, type = {Article}, abstract = {

We have developed a highly effective shape-controlled MoO3/MnOx nanocatalyst for the selective synthesis of 2-phenylquinoxaline drug motifs at room temperature without any external oxidant. Electron microscopy images reveal that the MnOx material contains rod-shaped particles (length: 500-1000 nm and width: 150-200 nm) and the MoO3 species are uniformly dispersed in the MoO3/MnOx material. The MoO3/MnOx nanocatalyst calcined at 500 degrees C (MoO3/MnOx-5) contains abundant strong acid sites and an optimum ratio of Mn4+/Mn3+, which are responsible for the C-N cross-coupling reaction between 2-phenylethylamine and o-phenylenediamine, giving higher yields (\>96\%) of 2-phenylquinoxaline at mild conditions. The broad scope of this catalytic strategy at room temperature and without an external oxidant was confirmed by achieving \>90\% yields of functional 2-phenylquinoxalines from C-N cross-coupling of various o-phenylenediamines and 2-phenylethylamines. The outstanding reusability efficiency of the MoO3/MnOx-5 nanocatalyst up to five cycles without the need for a regeneration step as well as the effective scalability highlighted the practicability of the MoO3/MnOx-based catalytic protocol for carbon-heteroatom coupling reactions at room temperature and without an external oxidant. Using computational studies, the possible reasons for the selective synthesis of 2-phenylquinoxaline over the MoO3/MnOx-5 nanocatalyst were elucidated.

}, keywords = {cascade C-N cross-coupling, DFT studies, room temperature andopen air, shape-controlled MoO3/MnOx nanocatalyst, structure-activity correlation}, doi = {10.1021/acsanm.3c04820}, author = {Singh, Nittan and Putla, Suresh Babu and Pratap Singh, Chandrodai and Kalbande, Pavan Narayan and Choudhary, Priyanka and Krishnamurty, Sailaja and Krishnan, Venkata and Bhatte, Kushal and Sudarsanam, Putla} }