Employment and resurrection of surfactants in bipyridine promoted oxidation of butanal using bivalent copper at NTP

Research on Chemical Intermediates - A recent “Renaissance” has various fields of chemistry exploring processes that are more Earth-friendly One focus is to make kinetic experiments...     

Synthesis,X-Ray Crystal Structure and Spectroscopic Properties of 1,2,3,4-Tetrahydro-2-(thenyl)-3-(<Emphasis Type="Italic">N</Emphasis>-thenylidine)-4-oxoquinazoline

Abstract  

The Schiff base formed between anthraniloyl hydrazide and thiophen-2-aldehyde is synthesized. Reaction of this Schiff base with VOSO₄ in methanol at room temperature does not yield the expected vanadium complex; instead, the Schiff base is transformed to 1,2,3,4-tetrahydro-2-(thenyl)-3-(N-thenylidine)-4-oxoquinazoline, which has been characterized by elemental analyses and by LC–MS, i.r., n.m.r. and electronic spectroscopies. The X-ray crystal structure of the quinazoline product is reported. The compound crystallizes with monoclinic (P2₁/n) space group, and the cell parameters are: a = 5.9442(7) ?, b = 13.6357(15) ?, c = 19.455(2) ?, β = 90.499(2)°. The oxo-quinazoline product is found to be luminescent when excited at its lowest energy transition.     

Fluorometric sensing of Cu ion with smart fluorescence light-up probe, triazolylpyrene (Py)

We report the detection of Cu²⁺ ion with fluorescence light-up probe, triazolylpyrene (^TNDMBPy). Thus, the probe showed a remarkable fluorescence enhancement of both of the monomer and excimer emissions and a 2:1 probe-Cu²⁺ complexation with high selectivity, high stability constant and low detection limit. Formation of the excimer was also rationalized on the basis of DFT calculation. Our probe is also capable of sensing SDS micelle-encapsulated-Cu²⁺ ion in aqueous media with high association constant, thus, showing its practical utility. Thus, our probe could be used as an efficient Cu²⁺ ion selective fluorescence light-up probe, and may find applications in chemical and biological systems.     

Studies on collective behaviour of gap junction channels

Gap junction provides low resistance pathways for cell-to-cell passive diffusion of ions, metabolites, second messengers etc. and thus, controls development, differentiation in embryonic tissues, and communication in adult tissues. It has been pointed out in our previous work that these passive diffusion channels behave cooperatively which in turn depends on the structural parameters and also membrane potentials. In the present paper, we have analyzed the multichannel bilayer electrophysiological data of rat liver gap junction Connexin 32 (Cx32) hemichannels. Through the measurements of relaxation time it has been demonstrated that one of the relaxation time constants follows a decay pattern with the number of channels open at various potentials applied across the bilayer membrane. This leads to the conclusion that the collective behaviour of rat liver gap junction hemichannels is cooperative in multichannel ensembles.     

Breathing of voltage dependent anion channel as revealed by the fractal property of its gating

The gating of voltage dependent anion channel (VDAC) depends on the movement of voltage sensors in the transmembrane region, but the actual mechanism is still not well understood. With a view to understand the phenomenon we have analyzed the current recordings of VDAC in lipid bilayer membrane (BLM) and found that the data show self-similarity and fractal characteristics. We look for the microscopic and molecular basis of fractal behavior of gating of VDAC. A model describing the oscillatory dynamics of voltage sensors of VDAC in the transmembrane region under applied potential has been proposed which gives rise to the aforesaid fractal behavior.     

An easy access to diversely fused dioxa-2-aza-tricyclo[n.3.1.0]tetra/pentadecanes under solvent-free condition

Efficient syntheses of phenyl/N-heterocycle fused 6,13-dioxa-2-aza-tricyclo[8.3.1.0^2,8]tetradecanes have been accomplished from 8-hydroxy quinoline derivatives under solvent-free condition, using basic alumina as the solid support. The methodology was successfully extended for the synthesis of corresponding pentadecane derivatives under similar reaction conditions. In terms of its general applicability, product yield, reaction time and effortless separation techniques, the methodology is more valuable compared to the solution phase protocols.     

Relative periodic orbits in plane Poiseuille flow

A branch of relative periodic orbits is found in plane Poiseuille flow in a periodic domain at Reynolds numbers ranging from Re=3000$\mathit{Re}=3000$ to Re=5000$\mathit{Re}=5000$. These solutions consist in sinuous quasi-streamwise streaks periodically forced by quasi-streamwise vortices in a self-sustained process. The streaks and the vortices are located in the bulk of the flow. Only the amplitude, but not the shape, of the averaged velocity components does change as the Reynolds number is increased from 3000 to 5000. We conjecture that these solutions could therefore be related to large- and very large-scale structures observed in the bulk of fully developed turbulent channel flows.     

Formation of stable ionized complexes between coinage metal containing superhalogens and moderately reactive molecules: a DFT approach

Structural Chemistry - The possibility of ionization of six moderately reactive molecules (Y), namely silicon dioxide (SiO2), ammonia (NH3), water (H2O), carbon dioxide (CO2), chloroform (CHCl3)...