Current–Voltage Characteristics of the Aziridine-Based Nano-Molecular Wires: a Light-Driven Molecular Switch

Using nonequilibrium Green's function formalism combined first-principles density functional theory, we analyze the transport properties of a 4,4-dimethyl-6-(4-nitrophenyl)-2-phenyl-3,5-diaza-bicyclo[3.1.0]hex-2-ene molecular optical switch. The title molecule can convert between closed and open forms by visible or ultraviolet irradiation. The I-V characteristics, differential conductance, on-off ratio, electronic transmission coefficients, spatial distribution of molecular projected self-consistent Hamiltonian orbitals, HOMO-LUMO gaps, effect of electrode materials Y(111)(Y =Au, Ag and Pt) on electronic transport and different molecular geometries corresponding to the closed and open forms through the molecular device are discussed in detail. Based on the results, as soon as possible the open form translates to the closed form, and there is a switch from the ON state to the OFF state(low resistance switches to high resistance). Theoretical results show that the donor/acceptor substituent plays an important role in the electronic transport of molecular devices. The switching performance can be improved to some extent through suitable donor and acceptor substituents.     

Loop quantum gravity modification of the Compton effect

Modified dispersion relations (MDRs) as a manifestation of Lorentz invariance violation, have been appeared in alternative approaches to quantum gravity problem. Loop quantum gravity is one of these approaches which evidently contains modification of dispersion relations. These MDRs will affect the usual formulation of the Compton effect. The purpose of this paper is to incorporate the effects of loop quantum gravity MDRs on the formulation of Compton scattering. Using limitations imposed on MDRs parameters from ultra high energy cosmic rays (UHECR), we estimate the quantum gravity-induced wavelength shift of scattered photons in a typical Compton process. Possible experimental detection of this wavelength shift will provide strong support for underlying quantum gravity proposal.     

Development of 68Ga ethyl cysteinate dimer for PET studies

In this work development of ⁶⁸Ga-ethyl cysteinate dimer (⁶⁸Ga-ECD) a ⁶⁸Ga tracer for possible cerebral blood flow based on ^99mTc ECD homolog is reported. ⁶⁸Ga-ECD was prepared using generator-based ⁶⁸GaCl₃ and ECD at optimized conditions. Quality control, stability, partition co-efficient and the biodistribution of the tracer (by tissue counting and PET/CT in rats) was studied. Significant metabolism of the lipophilic tracer into water soluble metabolite(s) led to urinary excretion of the tracer, un-comparable to that of homologous ^99mTc-compound. Cardiac uptake of the complex suggests formation of a possible lipophil cationic complex and/or metabolite.     

The use of Nafion-H®/NaNO2 as an efficient procedure for the chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions

A combination of Nafion-H® and sodium nitrite in the presence of wet SiO₂ was used as an effective agent for the N-nitrosation of secondary amines under mild and heterogeneous conditions in good to excellent yields.     

Tricholoroisocyanuric Acid as a Useful Reagent in Microwave‐assisted Aromatization of 1,3,5‐Trisubstituted 2‐Pyrazolines

An efficient aromatization of 1,3,5‐trisubstituted 2‐pyrazolines to their corresponding pyrazoles has been performed by tricholoroisocyanuric acid [TCCA] under microwave irradiation in excellent yields. It has been observed that the reactions occur more rapidly under microwave irradiation conditions, and the amount of the reagent TCCA consumed is considerably reduced to afford better yields when compared with conventional thermal conditions at the same temperature.     

Mild Oxidation of 1,3,5‐Trisubstituted Pyrazolines with N‐Bromo‐sulphonamides

1,3,5‐Trisubstituted pyrazolines to pyrazoles are carried out efficiently in the presence of new reagents N,N,N′, N′‐tetrabromo‐benzene‐1,3‐disulfonylamine [TBBDA] and N,N′‐dibromo‐N,N′‐1,2‐ethanediylbis‐(p‐toluenesulphonamide) [BNBTS] in solvent‐free conditions with catalytic amounts of SiO₂ under microwave irradiation in high yields.     

An alkylzinc bromide and a lithium alkyldibromozincate containing tris(organosilyl)methyl groups

The lithium reagent (3) reacts with a molar equivalent of anhydrous zinc bromide to give the dimeric compound (2a), in which zinc is four-coordinate. The product from a similar reaction with Li{C(SiMe₃)₂(SiMe₂NPhMe)} is the lithium zincate [Li(THF)₂(μ-Br)₂Zn{C(SiMe₃)₂(SiMe₂NPhMe)}] (4), in which the zinc is only three-coordinate. The crystal structures of 2a and 4 have been determined.