A broad pore size distribution mesoporous SnO2 as anode for lithium-ion batteries

Journal of Solid State Electrochemistry - We demonstrate here that mesoporous tin dioxide (abbreviated M-SnO2) with a broad pore size distribution can be a prospective anode in lithium-ion...     

Curcumol and its one-step formation from curdione

The absolute stereochemistry of curcumol ( 1 ) is confirmed on the basis of the spectroscopic data. The existence of two conformations in curdione ( 4 ) is revealed by nOe experiments at ambient temperature. One-step conversion of 4 into 1 stereospecifically proceeds via the ene-reaction without epimerization at any asymmetric center in 4 .     

Electron transfer reactions. Reaction of dibenzobarrelenes with potassium

The results of our studies on potassium-induced transformations of several bridgehead-substituted dibenzobarrelenes are presented. The dibenzobarrelenes 1b,c,e,f having methyl, hydroxymethyl, methoxy and phenyl groups, respectively, at the bridgehead position and the bridgehead-dimethyl derivative 1g give, on treatment with potassium in THF, the corresponding anthracenes 8b,c,e-g, dihydrodibenzobarreneses 6b,c,e-g and benzoic acid (5). The dibenzobarrelenes 1b,g give, in addition to 8b,g, 6b,g and 5, the corresponding mono-debenzoylated products 7b,g, whereas the methoxy derivative 1e gives both anthraquinone (9) and an enol derivaiive 11, besides 8e, 6e and 5. In contrast, the reaction of the hydroxy derivative 1d with potassium in THF gives a mixture of 5, anthracene (8a), the anthrone 10 and the anthrol 12. To assess the role of oxygen in these reactions, if any, the reactions of some representative substrates such as 1b,d,e with potassium in THF, saturated with oxygen and with potassium superoxide have been studied. Cyclic voltammetric studies have been carried out to measuee the reduction potentials for both one electron and two electron processes, leading to the generation of the corresponding radical anions and dianion intermediates. The radical anions of 1b-g have also been generated pulse radiolytically in methanol and their spectra show absorption maxima in the regions 310-390 and 400-450 nm.     

Electron spin relaxation rates for nitridochromium(V) tetratolylporphyrin and nitridochromium(V) octaethylporphyrin in Frozen solution

T ₁ andT _m for nitridochromium(V) tetratolylporphyrin and nitridochromium(V) octaethylporphyrin were measured by saturation recovery and electron spin echo EPR, respectively, between 10 and 130 K. The temperature dependence of 1/T ₁ was similar to that observed previously for chromium(V) complexes of hydroxycarboxylic acids. The spin lattice relaxation rate was faster in the perpendicular plane (the porphyrin plane) than normal to this plane. 1/T _m was orientation dependent with the fastest rates observed for orientations intermediate between the principal axes. The orientation dependence of 1/T _m increased with increasing temperature and decreasing rigidity of the matrix, and is attributed to molecular motion.     

Aroylethenesulfonylacetic acid methyl ester: a synthon for novel sulfone linked bis heterocycles

Novel sulfone linked bis heterocycles containing two different heterocyclic rings viz., pyrazoline in combination with thiadiazole, oxadiazole and triazole were synthesized and studied their antimicrobial activity.     

Synthesis of C1–C11 eribulin fragment and its diastereomeric analogues

A practical stereoselective synthesis of the central C1–C10 fragment of eribulin and its two diastereomeric analogues is developed. Our approach relied on the use of l-ascorbic acid as the starting material which allowed accessing a key intermediate with a syn diol moiety (C9 and C10 of eribulin) and a carboxylic ester group. A functionalized six membered lactone having several required hydroxyl groups was then obtained. In a number of steps, the lactone was converted to an intermediate for our key oxa-Michael reaction. A regio- and stereocontrolled intramolecular oxa-Michael reaction completed the synthesis of the C1–11 fragment having a trans-fused tetrahydropyrans with the exact stereochemistry of various hydroxyl groups, as in eribulin.     

Incorporating engineering intuition for parameter estimation in thermal sciences

This paper proposes a new method of incorporating priors based on engineering intuition for solving inverse problems. The thesis of this paper is that if an asymptote can be found to a problem in applied sciences or engineering, estimation of parameters can be first done for this asymptotic variant, which in principle should be simpler, since one or more parameters of the original problem may vanish for the asymptotic variant. Even so, by solving the inverse problem associated with the asymptotic variant, estimates of key parameters of the full problem can be obtained. This information can then be quantitatively incorporated as priors in the estimation of parameters for the full version of the problem which we call as prior generation through asymptotic variant. The goal is to see if this methodology will significantly reduce the uncertainties in the resulting estimates. To demonstrate this methodology, the classic problem of unsteady heat transfer from a one dimensional fin is chosen. The inverse problem is posed as the simultaneous estimation of the temperature dependent transfer coefficient (h _θ ) and the thermal diffusivity (α) of the fin material, given experimentally measured temperature–time histories at various locations along the fin. The asymptotic variant θ _(x,t) is the steady state problem where the influence of thermal diffusivity vanishes. Using surrogate temperature data generated from assumed values of h _θ , first the asymptotic variant of the problem is solved using the Markov Chain Monte Carlo method in a Bayesian framework to generate an estimate of h _θ . The estimate of h _θ is then used as an informative prior for solving the inverse problem of determining h _θ and α from θ _(x,t), and the effect of prior is quantitatively assessed by performing estimation with and without the prior. Finally, for purposes of validation, in-house experiments have been done where θ _(x,t) is generated using liquid crystal thermography and these data are used to estimate h _θ and α. A comparison of experimentally measured temperatures with those that are simulated by using estimated values of (h _θ , α) to solve the governing equation to the problem is also done.     

Adsorption of molecular hydrogen on inorganometallic complexes B<Subscript>2</Subscript>H<Subscript>4</Subscript>M (M=Li,Be, Sc,Ti, V)

Molecular interaction between hydrogen molecules and B₂H₄M (M=Li, Be, Sc, Ti, V) complexes has been studied using the DFT method (M06 functional) and 6-311++G** basis set. The hydrogen uptake capacity of the complexes considered is higher than the target set by the US Department of Energy (5.5 wt% by 2020). The metal atom bound strongly to the B₂H₄ substrate. Adsorption of molecular hydrogen on Be-, Ti-, and V-decorated complexes is thermodynamically possible for all the pressures and temperatures considered whereas it is unfavorable for Li-decorated complexes for all the pressure and temperatures. For the Sc-doped complexes, adsorption of molecular hydrogen is favorable below 330 K and entire pressure range considered. All the H₂ adsorbed complexes are kinetically stable. For all the complexes, the interaction between the inorganometallic complexes and the H₂ molecules adsorbed is attractive whereas that between adsorbed H₂ molecules is repulsive. We have also performed molecular dynamics simulations to confirm the same number of H₂ molecule adsorption from the simulations and DFT calculations.