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Shiv Nadar University

(SoNS) School of Natural Sciences

C(sp)–C(sp2) bond formation via Sonogashira cross-coupling reactions on 6-halo-2-cyclopropyl-3-(pyridyl-3-ylmethyl)quinazolin-4(3H)-ones with appropriate alkynes was explored. Optimization of reaction conditions with various catalysts, ligands, bases, and solvents was conducted. The combination of PdCl2(MeCN)2 with X-Phos proved to be the best metal–ligand system for this conversion in the presence of triethylamine (Et3N) in tetrahydrofuran at room temperature for iodosubstrates, at 80°C for the bromosubstrates in 8 h, and also for the chlorosubstrates in 16 h. We also demonstrated synthesis of a successful diversity-oriented synthesis library of highly functionalized quinazolinones via Cu-free Sonogashira coupling of diverse aryl halides and azido-alkyne (“click”) ligation reactions with substituted azides. The library exhibited significant antimicrobial activity when screened against several microorganisms. © 2017 Wiley Periodicals, Inc.

World University root node

Chemistry

Journal of Heterocyclic Chemistry

Cu-free Sonogashira Type Cross-Coupling of 6-Halo-2-cyclopropyl-3-(pyridyl-3-ylmethyl) Quinazolin-4(3H)-ones as Potential Antimicrobial Agents

It is proved the equivalence of the compatibility condition of Ramos (2011, 2012) with a condition found in Yadav et al. (2015). The link of Shape Invariance with the existence of a Potential Algebra is reinforced for the rationally extended Shape Invariant potentials. Some examples on X1 and Xℓ Jacobi and Laguerre cases are given. © 2017 Elsevier Inc.

Physics

Fulltext

Annals of Physics

A short note on “Group theoretic approach to rationally extended shape invariant potentials” [Ann. Phys. 359 (2015) 46–54]

Furosemide (FS), a loop diuretic drug, exhibits polymorphism not only in pure entity, but also in cocrystal/salt forms. In continuation of our previous report of color cocrystals polymorphism of FS and 4,4′-bipyridine (4BPY), FS was further screened for color cocrystals by cocrystallization with other pyridines using a slow evaporative solution crystallization method. Interestingly, 2:1 molecular salt of FS and 1,2-bis(4-pyridyl)ethylene (4BPE) displayed color polymorphism in isopropanol yielding an orange (form 1I, plates) and the yellow (form 1II, blocks) crystals concomitantly. The yield of orange crystals, which appeared within 10-15 h, has always been more compared to the later formed yellow crystals, thus signifying the preference for orange crystals. The cocrystallization experiment once also yielded a yellow-colored 2:3 molecular salt (form 1III); however these crystals could not be reproduced later. Further, cocrystallization of FS and 4BPE from THF, dioxane, and their mixture produced comparatively unstable solvates, form 1IV, form 1V, and form 1VI crystals, respectively. Cocrystallization of FS with other pyridines like 1,2 bis(4-pyridyl)ethane (4BPA), 1,2 bis(4-pyridyl)propane (4BPP), 1,2 bis(2-pyridyl)ethylene (2BPE), and 1,10-phenanthroline (Phen) also gave colorless molecular salts 2, 4 and cocrystals 3 and 5 respectively. The single crystal structure analysis revealed the formation of a common sandwich motif between FS and pyridines through varying geometry π-stacking interactions in all the crystals. The significant color difference between the polymorphs could be attributed to the different levels of conjugation generated by dissimilar π-stacking patterns between the two components. Investigation on the origin of the color difference using density functional theory calculations revealed the decrease in the highest occupied molecular orbital-lowest unoccupied molecular orbital gap for orange crystals compared to yellow crystals. © 2017 American Chemical Society.

Crystal Growth and Design

Salts and Cocrystals of Furosemide with Pyridines: Differences in π-Stacking and Color Polymorphism

Hamiltonians that are multivalued functions of momenta are of topical interest since they correspond to the Lagrangians containing higher-degree time derivatives. Incidentally, such classes of branched Hamiltonians lead to certain not too well understood ambiguities in the procedure of the quantization. Within this framework we pick up a model which samples the latter ambiguities and which, simultaneously, turns out to be amenable to a transparent analytic and perturbative treatment. © Published under licence by IOP Publishing Ltd.

Journal of Physics: Conference Series

Branched Hamiltonians for a Class of Velocity Dependent Potentials

Volume expansion and elastic softening of the Sn anode on lithiation result in mechanical degradation and pulverization of Sn, affecting the overall performance of Li-Sn batteries. It can, however, be overcome with the help of void space engineering by using a LixSn phase as the prelithiated anode, where an optimal value for x is desired. Currently, Li4.25Sn is known as the most lithiated Li-Sn compound, but recent studies have shown that at high pressure, several exotic and unusual stoichiometries can be obtained that may even survive decompression from high-to-ambient pressure with improved mechanical properties. With a belief that hydrostatic pressure may help in realizing Li-richer (x &gt; 4.25) Li-Sn compounds as well, we performed extensive calculations using an evolutionary algorithm and density functional theory to explore all stable and low-energy metastable Li-Sn compositions at pressures ranging from 1 atm to 20 GPa. This not only helped us in enriching the chemistry of a Li-Sn system, in general, but also in improving our understanding of the reaction mechanism in Li-Sn batteries, in particular, and guiding a route to improve the performance of Li-ion batteries through synthesis of Li-rich phases. Besides the experimentally known Li-Sn compounds, our study reveals the existence of five unreported stoichiometries (Li8Sn3, Li3Sn1, Li4Sn1, Li5Sn1, and Li7Sn1) and their associated crystal structures at ambient and high pressure. Although Li8Sn3 has been identified as one of the most stable Li-Sn compound in the entire pressure range (1 atm-20 GPa) with R3m symmetry, the Li-rich compounds like Li3Sn1-P2/m, Li4Sn1-R3m, Li5Sn1-C2/m, and Li7Sn1-C2/m are predicted to be metastable at ambient pressure and found to get thermodynamically stable at high pressure. Here, the discovery of Li5Sn1 and Li7Sn1 opens up the possibility to integrate them as a prelithiated anode for efficiently preventing electrochemical pulverization, as compared to the experimentally known highest lithiated compound, Li17Sn4. © 2017 American Chemical Society.

ACS Applied Materials and Interfaces

Understanding the Lithiation of the Sn Anode for High-Performance Li-Ion Batteries with Exploration of Novel Li-Sn Compounds at Ambient and Moderately High Pressure

Perturbation bounds for Mostow's decomposition and the bipolar decomposition of matrices have been computed. To do so, expressions for the derivative of the geometric mean of two positive definite matrices have been derived. © 2017 Elsevier Inc.

Mathematics

Linear Algebra and Its Applications

Perturbation bounds for Mostow's decomposition and the bipolar decomposition

We discuss the effects of the brane-localized mass terms on the fixed points of the toroidal orbifold T2/Z2 under the presence of background magnetic fluxes, where multiple lowest and higher-level Kaluza-Klein (KK) modes are realized before introducing the localized masses in general. Using linear algebra, we find that, in each KK level, one or more of the degenerate KK modes are almost inevitably perturbed, when single or multiple brane-localized mass terms are introduced. When the typical scale of the compactification is far above the electroweak scale or the TeV scale, we apply this mechanism for uplifting unwanted massless or light modes which are prone to appear in models on magnetized orbifolds. © 2017 American Physical Society.

Physical Review D

Brane-localized masses in magnetic compactifications

We analyze the flavor structure of composite vector bosons arising in a model of vectorlike technicolor — often called hypercolor (HC) — with eight flavors that form a one-family content of HC fermions. Dynamics of the composite vector bosons, referred to as HC ρ in this paper, are formulated together with HC pions by the hidden local symmetry (HLS), in a way analogous to QCD vector mesons. Then coupling properties to the standard model (SM) fermions, which respect the HLS gauge symmetry, are described in a way that couplings of the HC ρs to the left-handed SM quarks and leptons are given by a well-defined setup as taking the flavor mixing structures into account. Under the present scenario, we discuss significant bounds on the model from electroweak precision tests, flavor physics, and collider physics. We also try to address B anomalies in processes such as B → K(∗)μ+μ− and B→D(recently reported by LHCb, Belle, (ATLAS, and CMS in part). Then we find that the present model can account for the anomaly in B → K(∗)μ+μ− consistently with the other constraints while it predicts no significant deviations in B→D(∗) ν from the SM, which can be examined in the future Belle II experiment. The former is archived with the form C9 = −C10 of the Wilson coefficients for effective operators of b → sμ+μ−, which has been favored by the recent experimental data. We also investigate current and future experimental limits at the Large Hadron Collider (LHC) and see that possible collider signals come from dijet and ditau, or dimuon resonant searches for the present scenario with TeV mass range. To conclude, the present b → sμ+μ− anomaly is likely to imply discovery of new vector bosons in the ditau or dimuon channel in the context of the HC ρ model. Our model can be considered as a UV completion of conventional U(1)′ models. © 2017, The Author(s).

Journal of High Energy Physics

Phenomenology of flavorful composite vector bosons in light of B anomalies

We classify possible boundary conditions of a 6d Dirac fermion Ψ on a rectangle under the requirement that the 4d Lorentz structure is maintained, and derive the profiles and spectrum of the zero modes and nonzero KK modes under the two specific boundary conditions, (i) 4d-chirality positive components being zero at the boundaries and (ii) internal chirality positive components being zero at the boundaries. In the case of (i), twofold degenerated chiral zero modes appear which are localized towards specific directions of the rectangle pointed by an angle parameter θ. This leads to an implication for a new direction of pursuing the origin of three generations in the matter fields of the standard model, even though triple-degenerated zero modes are not realized in the six dimensions. When such 6d fermions couple with a 6d scalar with a vacuum expectation value, θ contributes to a mass matrix of zero-mode fermions consisting of Yukawa interactions. The emergence of the angle parameter θ originates from a rotational symmetry in the degenerated chiral zero modes on the rectangle extra dimensions since they do not feel the boundaries. In the case of (ii), this rotational symmetry is promoted to the two-dimensional conformal symmetry though no chiral massless zero mode appears. We also discuss the correspondence between our model on a rectangle and orbifold models in some details. © 2017 The Author(s)

Nuclear Physics B

6d Dirac fermion on a rectangle; scrutinizing boundary conditions, mode functions and spectrum

Nonheme iron complexes bearing tetradentate N-atom-donor ligands with cis labile sites show great promise for chemoselective aliphatic C-H hydroxylation. However, several challenges still limit their widespread application. We report a mechanism-guided development of a peroxidase mimicking iron complex based on the bTAML macrocyclic ligand framework (Fe-bTAML: biuret-modified tetraamido macrocyclic ligand) as a catalyst to perform selective oxidation of unactivated 3° bonds with unprecedented regioselectivity (3°:2° of 110:1 for adamantane oxidation), high stereoretention (99\%), and turnover numbers (TONs) up to 300 using mCPBA as the oxidant. Ligand decomposition pathways involving acid-induced demetalation were identified, and this led to the development of more robust and efficient Fe-bTAML complexes that catalyzed chemoselective C-H oxidation. Mechanistic studies, which include correlation of the product formed with the FeV(O) reactive intermediates generated during the reaction, indicate that the major pathway involves the cleavage of C-H bonds by FeV(O). When these oxidations were performed in the presence of air, the yield of the oxidized product doubled, but the stereoretention remained unchanged. On the basis of 18O labeling and other mechanistic studies, we propose a mechanism that involves the dual activation of mCPBA and O2 by Fe-bTAML, leading to formation of the FeV(O) intermediate. This high-valent iron oxo remains the active intermediate for most of the reaction, resulting in high regio- and stereoselectivity during product formation. © 2017 American Chemical Society.