01520nas a2200277 4500008004100000022001400041245013900055210006900194260000900263300001400272490000900286520054500295653002900840653002500869653000900894653004000903653001900943653003200962100002400994700001801018700001801036700001901054700001701073700002001090856013201110 2020 eng d a1434-193X00aVinylogous michael addition of 3-alkylidene-2-oxindoles to beta,gamma-unsaturated alpha-keto esters by bifunctional cinchona alkaloids0 aVinylogous michael addition of 3alkylidene2oxindoles to betagamm cSEP  a5690-56940 v20203 a

A highly enantioselective vinylogous Michael addition of 3-alkylidene-2-oxindoles with beta,gamma-unsaturated alpha-keto esters using a bifunctional tertiary-amine thiourea catalyst is demontsrated. The challenging Michael reaction with the beta,gamma-unsaturated alpha-keto esters has been accomplished due to the synchronized H-bond guided dual activation of vinylogous nucleophile and electrophile by catalyst. The reaction afforded product in high yield while resulting in excellent stereocontrol (> 19:1E/Zand upto 99 %ee).

10a3-Alkylidene-2-oxindoles10aAsymmetric synthesis10abeta10agamma-Unsaturated alpha-keto esters10aMichael adduct10aVinylogous Michael addition1 aJaiswal, Manish, K.1 aKumar, Rajesh1 aSingh, Sanjay1 aJain, Shailija1 aVanka, Kumar1 aSingh, Ravi, P. uhttps://library.ncl.res.in/content/vinylogous-michael-addition-3-alkylidene-2-oxindoles-betagamma-unsaturated-alpha-keto-esters02882nas a2200265 4500008004100000022001400041245008500055210006900140260000900209300001600218490000700234520201500241100002302256700002302279700001802302700002002320700001802340700003202358700002302390700001802413700002102431700002702452700002302479856011402502 2021 eng d a0020-166900aIonic conductivity of Na3Al2P3O12 glass electrolytes role of charge compensators0 aIonic conductivity of Na3Al2P3O12 glass electrolytes role of cha cSEP  a12893-129050 v603 aIn glasses, a sodium ion (Na+) is a significant mobile cation that takes up a dual role, that is, as a charge compensator and also as a network modifier. As a network modifier, Na+ cations modify the structural distributions and create nonbridging oxygens. As a charge compensator, Na+ cations provide imbalanced charge for oxygen that is linked between two network-forming tetrahedra. However, the factors controlling the mobility of Na+ ions in glasses, which in turn affects the ionic conductivity, remain unclear. In the current work, using high-fidelity experiments and atomistic simulations, we demonstrate that the ionic conductivity of the Na3Al2P3O12 (Si0) glass material is dependent not only on the concentration of Na+ charge carriers but also on the number of charge-compensated oxygens within its first coordination sphere. To investigate, we chose a series of glasses formulated by the substitution of Si for P in Si0 glass based on the hypothesis that Si substitution in the presence of Na+ cations increases the number of SiOAl bonds, which enhances the role of Na as a charge compensator. The structural and conductivity properties of bulk glass materials are evaluated by molecular dynamics (MD) simulations, magic angle spinning-nuclear magnetic resonance, Raman spectroscopy, and impedance spectroscopy. We observe that the increasing number of charge-imbalanced bridging oxygens (BOs) with the substitution of Si for P in Si0 glass enhances the ionic conductivity by an order of magnitudefrom 3.7 x 10(-8) S.cm(-1) to 3.3 x 10(7) S.cm(-1) at 100 degrees C. By rigorously quantifying the channel regions in the glass structure, using MD simulations, we demonstrate that the enhanced ionic conductivity can be attributed to the increased connectivity of Na-rich channels because of the increased charge-compensated BOs around the Na atoms. Overall, this study provides new insights for designing next-generation glass-based electrolytes with superior ionic conductivity for Na-ion batteries1 aKeshri, Shweta, R.1 aGanisetti, Sudheer1 aKumar, Rajesh1 aGaddam, Anuraag1 aIllath, Kavya1 aAjithkumar, Thalasseril, G.1 aBalaji, Sathravada1 aAnnapurna, K.1 aNasani, Narendar1 aKrishnan, N., M. Anoop1 aAllu, Amarnath, R. uhttps://library.ncl.res.in/content/ionic-conductivity-na3al2p3o12-glass-electrolytes-role-charge-compensators03045nas a2200325 4500008004100000022001400041245015900055210006900214260000900283300001100292490000800303520193300311653001402244653001702258653002302275653001902298653002402317100002302341700002202364700002302386700002502409700001802434700002002452700001902472700003202491700002502523700002702548700002302575856012102598 2022 eng d a1359-645400aElucidating the influence of structure and Ag+ -Na+ ion-exchange on crack-resistance and ionic conductivity of Na3Al1.8Si1.65 P-1.8 O-12 glass electrolyte0 aElucidating the influence of structure and Ag Na ionexchange on  cAPR  a1177450 v2273 a

Glasses are emerging as promising and efficient solid electrolytes for all-solid-state sodium-ion batteries. However, they still suffer from poor ionic conductivity and crack-resistance, which need to be improved for better battery performance, reliability, and service life. The current study shows a significant enhancement in crack resistance (from 11.3 N to 32.9 N) for Na3Al (1.8) Si-1.65 P1.8O12 glass (Ag-0 glass) upon Na+ -Ag+ ion-exchange (IE) due to compressive stresses generated in the glass surface while the ionic conductivity values (similar to 10(-5) S/cm at 473 K) were retained. In this study, magic angle spinning-nuclear magnetic resonance (MAS-NMR), molecular dynamics (MD) simulations, Vickers micro hardness, and impedance spectroscopic techniques were used to evaluate the intermediate-range structure, atomic structure, crack resistance and conductivity of the glass. MAS-NMR and MD simulations confirm the presence of Si-OAl-O-P groups in the glass, thus enabling formation of Na percolated channel regions. AC-conductivity analysis for Ag-0 and ion-exchanged Ag-0 glass suggests that the mobility of Na+ ion increases with increasing temperature. It is observed that the measured mean square displacement (root < R-2(t(p))>) for sodium cations using AC-conductivity isotherms is nearly constant up to 448 K and then increases with increasing temperature up to 523 K. From the impedance spectra for ion-exchanged Ag-0 glass, it is identified that the increase in root < R-2 (t(nu))> and thereby, the mobility of sodium-ions for Ag-0 glass is due to the structural variations in the Ag-0 glass with increasing the temperature. Overall, the mechanisms presented in this article helps in formulating better glass based electrolyte materials for room temperature or high temperature sodium-ion batteries. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

10aamorphous10aIon-exchange10aIonic-conductivity10aMD simulations10aMechanical property1 aKeshri, Shweta, R.1 aMandal, Indrajeet1 aGanisetti, Sudheer1 aKasimuthumaniyan, S.1 aKumar, Rajesh1 aGaddam, Anuraag1 aShelke, Ankita1 aAjithkumar, Thalasseril, G.1 aGosvami, Nitya, Nand1 aKrishnan, N., M. Anoop1 aAllu, Amarnath, R. uhttps://library.ncl.res.in/content/elucidating-influence-structure-and-ag-na-ion-exchange-crack-resistance-and-ionic02203nas a2200241 4500008004100000245009800041210006900139260000800208300000900216490000700225520141400232100001801646700002101664700002201685700002001707700001701727700001701744700001701761700002301778700001801801700001701819856012501836 2026 eng d00aFast self-healing in a layered molecular crystal mediated by stress-induced symmetry breaking0 aFast selfhealing in a layered molecular crystal mediated by stre cFEB a25250 v173 a

In recent years, symmetry-breaking has emerged as a powerful tool for significantly altering various physical properties in 2D layered materials. However, the breaking of symmetry by means of mechanical stress in organic crystals remains elusive. Here, we demonstrate a simple approach to engineer symmetry-breaking through mechanical stress fields in a layered molecular crystal, resulting in autonomous and fast self-healing under ambient temperature and pressure conditions. Fracture mechanics analysis reveals that the crystal adheres to an elasto-plastic model, with formation of a plastic zone at the crack tip, which prevents further crack propagation, facilitating the self-healing process. Spatially resolved Raman mapping reveals that the crack formation is accompanied by a distinct symmetry-breaking mechanism at the microstructural level. A six-fold increase in non-linear second harmonic (SH) activity, triggered by mechanical perturbation, further validates the local symmetry breaking in an otherwise centrosymmetric crystal. Furthermore, symmetry is restored following successful healing, as evidenced by the disappearance of the SH signal in the healed regions. This study not only broadens the scope of self-healing mechanisms viable in molecular materials but also offers key insights into the role of symmetry breaking and its potential for related technological applications.

1 aGhosh, Ishita1 aBiswas, Rabindra1 aTanwar, Manushree1 aBhunia, Surojit1 aDas, Kaustav1 aTorris, Arun1 aMondal, Amit1 aRaghunathan, Varun1 aKumar, Rajesh1 aReddy, Malla uhttps://library.ncl.res.in/content/fast-self-healing-layered-molecular-crystal-mediated-stress-induced-symmetry-breaking