Structural,thermal, and ion dynamics studies of PVA-CS-NaI-based biopolymer electrolyte films

Journal of Solid State Electrochemistry - A series of biopolymer blend electrolytes (BPBEs) based on ((100-x)PVA-xCS)-NaI, viz. BPBE-1 to BPBE-5 (x = 10, 20, 30, 40, 50 in wt%), respectively, were...     

Packing in honeycomb networks

Molecules arranging themselves into predictable patterns on silicon chips could lead to microprocessors with much smaller circuit elements. Mathematically, assembling in predictable patterns is equivalent to packing in graphs. An H-packing of a graph G is a set of vertex disjoint subgraphs of G, each of which is isomorphic to a fixed graph H. If H is the complete graph K ₂, the maximum H-packing problem becomes the familiar maximum matching problem. In this paper we give algorithms to find a perfect packing of HC(n) with P ₆ and K _1,3 when n is even and thus determines their packing numbers. Further we also study the packing of HC(n) with 1, 3-dimethyl cyclohexane.     

Embedding hypercubes into cylinders, snakes and caterpillars for minimizing wirelength

We consider the problem of embedding hypercubes into cylinders to minimize the wirelength. Further, we show that the edge isoperimetric problem solves the wirelength problem of regular graphs and, in particular, hypercubes into triangular snakes and caterpillars.     

Anisochrony of the O-methylene protons of the C-2-ethyl ester function in triethyl meso,cis-1,3-dimethylcyclohexane-1,2,3-tricarboxylate—Atropisomerism of an ester group

The methylene protons of the ethyl ester function at C-2 in triethyl meso, cis-1,3-dimethylcyclohexane-1,2,3-tricarboxylate (A) are anisochronous, despite the apparent symmetry of structure A. The necessary diastereotopy is thought to be engendered by the central ester being stabilized in a rotamerization in which the O:C·O plane is held parallel to the general plane of the 6-membered ring while fast exchanges take place among rotamers about the alkyl–oxygen bond; other rotamers about the ester axis are thought to encounter high order repulsive steric/polar interactions with the flanking ester functions and C-methyl groups. Evidence for the axial orientation of the C-1 and C-2 ester functions in A, based on comparisons of its ¹H NMR spectral characteristics with those of its RS-cis, trans and meso, trans analogues, is presented. The role of ion-pairing in the stereoselectivity of methylation of precursor enolates, leading to the formation of these three systems, is briefly discussed. A comment on the appropriateness, or otherwise, of drawing conformational conclusions from the magnitudes of the anisochrony in comparable systems is included. Triester A is thought to be the first instance where atropisomerism about an sp³? sp² bond involving an ordinary ester function has been detected employing a prochiral sensor group.     

A simple and efficient synthesis of novel N,N′‐bis (1H‐pyrrol‐1‐yl)‐1‐[2‐(2‐aryl‐5‐methyl‐3‐oxo‐2,4‐dihydro‐3H‐1,2,4‐triazol‐4‐yl)ethyl]‐1H‐1,2,3‐triazole‐4,5‐dicarboxamides

One‐pot reaction of 3‐aryl‐5‐methyl‐1,3,4‐oxadiazolin‐2‐ones 1a‐g with ethanolamine yielded the 4‐(2‐hydroxyethyl)‐2‐aryl‐5‐methyl‐2,4‐dihydro‐3H‐1,2,4‐triazolin‐3‐ones 2a‐g which were converted to the azido compounds 6a‐g . These azides on 1,3‐dipolar cycloaddition with DMAD afforded the dimethyl‐1‐[2‐(2‐aryl‐5‐methyl‐3‐oxo‐1,2,4‐triazol‐4‐yl)ethyl]‐1H‐1,2,3‐triazol‐4,5‐dicarboxylates 7a‐g which on conversion to bishydrazides 8a‐g and further cyclisation with 2,5‐hexanedione afforded the title compounds 9a‐g . This new short route for the so far unkown bis‐(triazolinone‐triazole)ethanes involves mild and convergent 1,3‐dipolar cycloaddition reaction yielding overall good yields of the products.     

Continuous maps with the disjoint support property

Periodica Mathematica Hungarica - It is well known that for each $$n\ge 0$$ , there is a continuous map $$ f :S^{n}\rightarrow \partial \bigtriangleup ^{n+1}$$ with the disjoint support property....     

Ag ion irradiated based sensor for the electrochemical determination of epinephrine and 5-hydroxytryptamine in human biological fluids

A promising and highly sensitive voltammetric method has been developed for the first time for the determination of epinephrine (EP) and 5-hydroxytryptamine (5-HT) using 120 MeV Ag ion irradiated multi-walled carbon nano tube (MWCNT) based sensor. The MWCNT were irradiated at various fluences of 1e12, 3e12 and 1e13 ions cm⁻² using palletron accelerator. The simultaneous determination of EP and 5-HT has been carried out in phosphate buffer solution of pH 7.20 using square wave voltammetry and cyclic voltammetry. Experimental results suggested that irradiation of MWCNT by Ag ions enhanced the electrocatalytic activity due to increase in effective surface area and insertion of Ag ions, leading to a remarkable enhancement in peak currents and shift of peak potentials to less positive values as compared to the unirradiated MWCNT (pristine). The developed sensor exhibited a linear relationship between peak current and concentration of EP and 5-HT in the range 0.1–105 μM with detection limit (3σ/b) of 2 nM and 0.75 nM, respectively. The practical utility of irradiation based MWCNT sensor has been demonstrated for the determination of EP and 5-HT in human urine and blood samples.     

A facile synthesis of pyrazolo[3,4‐D]pyridazines Via the 1,3‐dipolar cycloaddition of 3‐arylsydnones. Synthesis and computational studies of 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐D]pyridazine‐3,6‐diones and their 3,6‐dichloro derivatives.

The synthetic utility of 1,3‐dipolar cycloaddition of DMAD to sydnones has been exploited in the preparation of new 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐d]pyridazine‐3,6‐diones 7a‐j and their aromatic 3,6‐dichloro analogues 8a‐j . The lactam‐lactim tautomerism of compound 7a has been studied by the semi emperical (PM3) and ab initio methods.     

Versatile Catalytic Applications of Manganese(II,III) Schiff Base Complexes (Review)

Russian Journal of General Chemistry - Manganese forms a big number of complexes with Schiff bases that are extensively used as catalysts of oxidation, epoxidation, decarboxylation, coupling...