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Shiv Nadar University

(SoNS) School of Natural Sciences

Diabetes a non-communicable disease occurs either due to the lack of insulin or the inability of the human body to recognize it. The recent data indicated an increase in the trend of people diagnosed with type 2 diabetes mainly due to unhealthy life style. Here in we report a new class of oxindole derivatives 6a-k via scaffold hopping of known α-glucosidase inhibitors 1–4. When molecular docking was performed against a homology model of α-glucosidase the resulting compound 6d revealed binding interactions comparable to 1–4. The compounds were accessed through a unique condensation-ring opening protocol of pyridofuranone building blocks. Overall the compounds exhibited decent binding to the yeast α-glucosidase, where the most potent compound 6h, inhibited the enzyme with IC 50 of 0.6 µM. This was nearly threefold improvement from the original known compounds 1–4, selected to design the newer analogs. The reaction kinetics of 6h indicated competitive inhibition. © 2018 Elsevier Ltd

World University root node

Chemistry

Bioorganic and Medicinal Chemistry

Design, synthesis and in vitro study of densely functionalized oxindoles as potent α-glucosidase inhibitors

In this review article, an insight of the physics that explains the phenomenon of torques induced by currents in systems comprising ferromagnetic (FM)-non-magnetic (NM) materials has been provided with particular emphasis on experiments that concern the observation of such torques. An important requirement of systems that enables observation of such relativistic torques is that the material needs to possess large spin-orbit coupling (SOC). In addition, the FM/NM interface should be of high quality so that spin angular momentum can be transferred across the interface. Under such conditions, the magnetization of a magnetic material experiences a torque, and can be reversed, thanks to the phenomenon of the spin Hall effect in the NM layer with large SOC. A reciprocal process also occurs, in which a changing magnetization orientation can produce spin current, i.e. current that supports spin angular momentum. It is important to know how these processes occur which often tells us about the close connection between magnetization and spin transport. This paves the way to transform technologies that process information via magnetization direction, namely in magnetic recording industry. This field of physics being relatively young much remains to be understood and explored. Through this review we have attempted to provide a glimpse of existing understanding of current induced torques in ferromagnetic thin film heterostructures along with some future challenges and opportunities of this evolving area of spintronics. Specifically, we have discussed the state-of-the art demonstrations of current-induced torque devices that show great promise for enhancing the functionality of magnetic memory devices. © The Royal Society of Chemistry.

Physics

Fulltext

RSC Advances

Relativistic torques induced by currents in magnetic materials: physics and experiments

Formulae for the static electronic polarizability and hyperpolarizability are derived in terms of moments of the ground-state electron density matrix by applying the Unsöld approximation and a generalization of the Fermi-Amaldi approximation. The latter formula for the hyperpolarizability appears to be new. The formulae manifestly transform correctly under rotations, and they are observed to be essentially cumulant expressions. Consequently, they are additive over different regions. The properties of the formula are discussed in relation to others that have been proposed in order to clarify inconsistencies. The formulae are then tested against coupled-perturbed Hartree-Fock results for a set of 40 donor-π-acceptor systems. For the polarizability, the correlation is reasonable; therefore, electron density matrix moments from theory or experiment may be used to predict polarizabilities. By constrast, the results for the hyperpolarizabilities are poor, not even within one or two orders of magnitude. The formula for the two- and three-particle density matrices obtained as a side result in this work may be interesting for density functional theories. © 2018 CSIRO.

Australian Journal of Chemistry

Is it Reasonable to Obtain Information on the Polarizability and Hyperpolarizability only from the Electron Density?

Purely organic biluminescent materials are of great interest due to the involvement of both singlet and long-lived triplet emissions, which have been rarely reported in bioimaging and organic light-emitting diodes. We show two molecules 3,4,5,6-tetraphenyloxy-phthalonitrile (POP) and 3,4,5,6-tetrakis-p-tolyloxy-phthalonitrile (TOP), in which POP was found to exhibit fluorescence and persistent room-temperature green phosphorescence (pRTGP) in the amorphous powder and crystal states. Both POP and TOP show aggregation-induced emission in a tetrahydrofuran-water mixture. We found in single-crystal X-ray analysis that intra- and intermolecular lp(O)···π interactions along with π(C = C)···π(C≡N), hydrogen bond (H-B), and C-H···π interactions induce a head-to-tail slipped-stack arrangement in POP. In addition, the X-ray structure of TOP with a slipped-stack arrangement induced by only π(C=C)···π(C≡N) and H-B interactions shows dim afterglow only in crystals. These indicate that more noncovalent interactions found in POP may reinforce relatively efficient intersystem crossing that leads to pRTGP. Given the unique green afterglow feature in amorphous powder of POP, document security protection application is achievable. Copyright © 2018 American Chemical Society.

Journal of Physical Chemistry Letters

Biluminescence via Fluorescence and Persistent Phosphorescence in Amorphous Organic Donor(D4)-Acceptor(A) Conjugates and Application in Data Security Protection

We report on the preparation of hexa-functional cardanol (renewable phenolic compound) benzoxazine with a phosphazene core (CPN) for use as a greener eco-friendly halogen-free flame retardant reactive additive for the formation of sustainable polyphosphazene polybenzoxazine networks for flame resistant applications. The structure and purity of the monomer was confirmed by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H-, 13C-, 31P NMR) and gel permeation chromatography studies. The CPN monomer showed good compatibility with benzoxazine monomer (CPN0) as suggested by the cocuring studies. The thermal properties of the copolymer can be directly tuned by altering the composition of the monomer blend. The occurrence of phosphazene-phosphazane thermal rearrangement is also suggested for the thermal behavior (thermogravimetry analysis) at higher loading of CPN in the monomer feed ratio. An improvement in mechanical properties of the copolymer with increase in glass transition temperature was confirmed by enhancement in cross-link density as compared to neat polybenzoxazine. The reactive nature and presence of phosphazene core improved both the smoke density rating, vertical burning rating and led to higher limiting oxygen index. The FTIR and scanning electron microscopy studies of residual char supported the formation of functionalities and morphologies favorable to support the flame resistance behavior of polymer by incorporation of reactive benzoxazine with phosphazene core. Finally, we demonstrate that incorporation of cardanol phosphazene network has good compatibility with the polybenzoxazine phenolic thermosets with improvement in flame retardancy. The higher cardanol (65.7\%) and phosphorus content (3.4\%) and reactive nature of synthesized compound is attractive as a sustainable additive with the scope of their utilization with other polymeric resins. © 2017 American Chemical Society.

ACS Sustainable Chemistry and Engineering

Eco-Friendly Halogen-Free Flame Retardant Cardanol Polyphosphazene Polybenzoxazine Networks

A family of pharmacophore acetylenic indole-3-carboxaldehyde (3) and acetylenic indole schiff bases (5 a-5 i) bearing indole framework were synthesized to afford structurally diverse moieties. Acetylenic indole-3-carboxaldehyde was coupled with various amines to furnish the novel scaffolds 5 a-5 i. These acetylenic indole Schiff bases (AISB) were synthesized in shorter times under microwave irradiation in comparison to classical reaction conditions. AISB were experimentally characterized by using IR, 1H NMR, 13C NMR, X ray crystallographic and mass spectrometric methods. The synthesized compounds showed promising anti-bacterial and anti-fungal properties when tested in vitro against six bacterial and seven fungal strains. Among these, hybrids 5 a, 5 c, 5 e and 5 g were found to be even more potent than the standard drugs and were more influential against the bacterial than the fungal strains. These more potent compounds were then evaluated for their cytotoxicity by MTT assay on Hek293 and HeLa cells. The synergistic effect of bis-acetylenic compound 5 g with kanamycin and amphotericin B has also been scrutinized. Further, the structural and electronic properties of the molecules were investigated theoretically by performing density functional theory (DFT). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemistrySelect

Acetylenic Indole-Encapsulated Schiff Bases: Synthesis, In Silico Studies as Potent Antimicrobial Agents, Cytotoxic Evaluation and Synergistic Effects

Angewandte Chemie

Kovalente organische Netzwerke und K{\"{a}}figverbindungen: Design und Anwendungen von polymeren und diskreten organischen Ger{\"{u}}sten

We study an extension of the minimal supersymmetric standard model (MSSM) with additional right-handed singlet neutrino superfields. While such an extension incorporates a mechanism for the neutrino mass, it also opens up the possibility of having the right-sneutrinos ($\nu$˜ ) as the lightest supersymmetric particle (LSP). In this work, we focus on the viability of rather small (≲500 GeV) higgsino mass parameter ($\mu$), an important ingredient for “naturalness”, in the presence of such a LSP. For simplicity, we assume that the bino and wino mass parameters are much heavier; thus we only consider (almost) pure and compressed higgsino-like states, with small O(10−2) gaugino admixture which nevertheless still affect the decay of the low-lying higgsino-like states, thus significantly affecting the proposed signatures at colliders. Considering only prompt decays of the higgino-like states, especially the lightest chargino, we discuss the importance of leptonic channels consisting of up to two leptons with large missing transverse energy to probe this scenario at the Large Hadron Collider (LHC). In addition we also comment on the dark matter predictions for the studied scenario.

Journal of High Energy Physics

Natural SUSY at LHC with right-sneutrino LSP

Temperature-pressure phase diagram of the Kitaev hyperhoneycomb iridate $\beta$-Li2IrO3 is explored using magnetization, thermal expansion, magnetostriction and muon spin rotation measurements, as well as single-crystal x-ray diffraction under pressure and ab initio calculations. The N{\'{e}}el temperature of $\beta$-Li2IrO3 increases with the slope of 0.9 K/GPa upon initial compression, but the reduction in the polarization field Hc reflects a growing instability of the incommensurate order. At 1.4 GPa, the ordered state breaks down upon a first-order transition, giving way to a new ground state marked by the coexistence of dynamically correlated and frozen spins. This partial freezing in the absence of any conspicuous structural defects may indicate the classical nature of the resulting pressure-induced spin liquid, an observation paralleled to the increase in the nearest-neighbor off-diagonal exchange $\Gamma$ under pressure.