Cycloaddition profile of pentafulvenes with 3-oxidopyrylium betaine: experimental and theoretical investigations

A detailed investigation on the effect of solvent polarity, temperature, and microwave irradiation on periselectivity in cycloaddition reactions of pentafulvenes with 3-oxidopyrylium betaine is described. The base catalyzed generation of 3-oxidopyrylium betaine in CHCl₃ resulted in the exclusive formation of [6+3] adducts. With increase in solvent polarity and temperature, mixtures of [6+3] and [3+2] adducts were formed, where as under microwave irradiation, [3+2] adducts were formed exclusively. The experimental results have been rationalized on the basis of theoretical calculations.     

Transition metal catalyzed carboannulation of diazabicyclic alkenes with ambiphilic bifunctional reagents: a facile route towards functionalized indanones and indanols

Functionalized indanones are readily prepared in good to excellent yields by the Pd/Rh catalyzed carboannulation of bicyclic and tricyclic hydrazines with 2-iodobenzonitrile, 2-cyanophenylboronic acid and 2-formylphenylboronic acid. The reaction with 2-formylphenylboronic acid afforded 3,4-disubstituted cyclopentenes as minor product along with indanones under Rh catalyzed conditions, whereas indanols were obtained as the major product under Pd catalyzed conditions. The products obtained can be synthetically manipulated easily to pharmaceutically important molecules.     

Dynamic singularity in multicomponent glass-forming metallic liquids

In the liquid state, glass-forming Ni59.5Nb40.5 and Ni60Nb34.8Sn5.2 alloys exhibit an extraordinarily high packing fraction. The self-correlation functions measured using quasielastic neutron scattering clearly show the slowing down of microscopic dynamics with an increase in packing fraction. The self-diffusivity in liquid Ni60Nb34.8Sn5.2 decreases by about 2 orders of magnitude within a temperature range of 360 K. For these highly fragile systems, the critical packing fraction obtained form the analysis of incoherent data is in excellent agreement with the prediction made by mode-coupling theory. Our results provide the first experimentally observed value for the critical packing fraction in glass-forming metallic liquids.     

Visible-Light-Mediated Self-Sensitized Oxidative and Regioselective C(sp2)−H Selenylation and Sulfenylation of Substituted 2-Amino-1,4-Naphthoquinones

A photochemical method based on visible-light (white LEDs/sunlight) irradiation has been developed for the regioselective and oxidative C(sp²)−H selenylation and sulfenylation of substituted 2-amino-1,4-naphthoquinones under oxygen atmosphere. The photochemical process does not require any external photoredox catalysts. The other notable advantages of this protocol are metal-free synthesis, visible light/sunlight as energy sources, good substrate scope, and moderate to good yields (41–91 %) with high regioselectivity.     

Ab initio lifetimes in the interatomic Coulombic decay of neon clusters computed with propagators

Interatomic Coulombic decay (ICD) is a radiationless decay mechanism occurring via electron emission in an inner-valence ionized weakly bound cluster. The ICD has been studied for the neon clusters Nen (n=2,...,5). The decay widths of the neon clusters are calculated using ab initio Green's function method. The non-Dyson version of Green's function is employed. This propagator is analytically continued into the complex energy plane with the aid of a complex absorbing potential, and the decaying states are found as resonance states in this plane.     

Unusual concentration-dependent microscopic dynamics of dendrimers in aqueous solution

Dendrimers are novel three-dimensional, hyperbranched globular nanopolymeric macromolecules. The nanoscopic size, narrow polydispersity index, excellent control over molecular structure, availability of multiple functional groups at the periphery, and cavities in the interior made them very attractive candidate for drug delivery. In this communication, we have studied the microscopic dynamics of tetra-acid and pentaerythritol glycidyl ether dendrimers dissolved in aqueous solution with different concentrations. The effects of concentration and temperature to their long-range diffusion process are investigated by dynamic light scattering. Experimental results show a huge variation in the translational diffusion coefficient for the two dendrimers samples. Besides, the dependence of diffusion coefficients on concentration is unusually different in these dendrimer samples. Although the diffusion process follows Arrhenius relation with the temperature in both systems, the activation energy for the diffusion process has a distinct concentration dependence.     

Synthesis and biological evaluation of carbohydrate appended hydrazinocyclopentenes with potent glycation and α-glucosidase inhibition activities

Synthesis and biological evaluation of novel alkylidenecyclopentene glycohybrids via palladium and click chemistry are described. Out of the six molecules synthesized, four molecules were screened against α-glucosidase, α-amylase, and glycation reactions. The results showed that the compound 7f with a galactose appendage is a good α-glucosidase inhibitor and a potent anti-glycation agent under in vitro conditions with an IC₅₀ value of 0.075 μM and 0.022 μM, respectively. The toxicity of the compounds against normal cell lines was checked by MTT assay.     

Synthesis of novel zerumbone derivatives via regioselective palladium catalyzed decarboxylative coupling reaction: a new class of α-glucosidase inhibitors

A new strategy for the synthesis of novel zerumbone derivatives via a regioselective palladium catalyzed decarboxylative coupling reaction using arene carboxylic acids is described. The current methodology involves the repositioning of endocyclic double bond to exocyclic double bond of zerumbone. Preliminary in vitro analysis revealed that most of the newly synthesized derivatives are potent α-glucosidase enzyme inhibitors.     

Fock space multireference coupled cluster theory: Study of shape resonance

The complex absorbing potential along with correlated independent particle potential (CIP) Fock space multireference coupled cluster method is used for the study of resonances. We have studied shape resonance of e^?‐ F₂, e^?‐ N₂O and e^?‐CO molecules. In particular, we have studied e^?‐ F₂ scattering at different bond lengths to know whether is bound at the equilibrium bond length of F₂. © 2013 Wiley Periodicals, Inc.     

Quantum Secure Direct Communication with Mutual Authentication using a Single Basis

In this paper, we propose a new theoretical scheme for quantum secure direct communication (QSDC) with user authentication. Different from the previous QSDC protocols, the present protocol uses only one orthogonal basis of single-qubit states to encode the secret message. Moreover, this is a one-time and one-way communication protocol, which uses qubits prepared in a randomly chosen arbitrary basis, to transmit the secret message. We discuss the security of the proposed protocol against some common attacks and show that no eavesdropper can get any information from the quantum and classical channels. We have also studied the performance of this protocol under realistic device noise. We have executed the protocol in IBMQ Armonk device and proposed a repetition code based protection scheme that requires minimal overhead.