Hydrophilic [60]fullerene carboxylic acid derivatives retaining the original 60π electronic system

Water-soluble carboxylic acid derivatives of [60]fullerene retaining the original 60π electronic configuration are prepared from a tetra-tert-butyl ester of bis(fulleroid).     

Pyrrolidinium-based ionic liquids as electrolytes for lithium batteries: A Computational Study

Electrochemical windows (ECWs) of the cyclic ammonium based ionic liquids formed by the combination of two common pyrrolidinium cations—N,N-butylmethyl pyrrolidinum(P_yr14) and N,N-hexylmethyl pyrrolidinium(P_yr16) and five anions—dicyanamide, trifluoroacetate, fluoromethane sulfonate, bis((trifluoromethylsulfonyl)imide, and bis(fluorosulfonyl)imide were investigated. The ECW of each ionic liquid was obtained from the oxidation and reduction potentials of these ionic liquids with respect to a Li⁺/Li reference electrode by using thermodynamic cycle method. The work reveals that the ECWs of these ionic liquids are solely decided by the HOMO energy of pairing anions. The ECWs were also computed using HOMO-LUMO method employing Møller-Plesset perturbation theory to the second order and M06L methods with a basis set of 6-31 + G(d, p). The ECW computed using M06L functional with an extended basis set of 6-311++G(d, p) showed better agreement with experimental values suggesting accurate computation of ECW is possible at lower computational cost.     

Study of the potassium ion insertion of the electrodeposited electrochromic tungsten trioxide thin films

Various types of dynamic adjustable optical shutters have been proposed; they are called as “smart windows”. The electrochromic smart window utilizes the phenomenon of electrochromism. Electrochromism is the property of a material such that its color is changed by an electrochemical redox reaction. Numerous inorganic and organic electrochromic materials have been examined. During the color-bleach process, the redox reaction of the host material causes injection or ejection of both cation (or anion) and an electron (or hole). So it behaves as a mixed ion conductor and hence it has recently attracted interest in the field of solid state ionics. At present, several prototypes of electrochromic smart windows have been proposed and some of them are commercially available. The cathodic electrochromic oxides consist of n-type semiconductors such as TiO₂, V₂O₅, WO₃ and MoO₃. Among them, WO₃ has been intensively examined and used for most electrochromic devices. These materials are cathodically colored in blue. The electrochromic reaction is expressed by $$xA^ + + MO_y \left( {transparent} \right) + x e^ - \Leftrightarrow A_x MO_y \left( {blue} \right)\left( {A = H, Li, Na, K \ldots , MO_y = metal oxide} \right)$$ where the cation A⁺ and electron e^? are co-injected into the host oxide MO_y which results in the formation of the nonstiochiometric compound A_xMO_y. Here the electrodeposition method is used to deposite WO₃ films under by galvanostatic conditions. The parameters like deposition time, deposition temperature, electrolyte concentration, pH and bath temperature are optimized. The XRD results show the triclinic structure for the as-deposited film. The film shows the same structure after intercalation but the peak intensity is different. The tungsten trioxide thin films show the colour change during the intercalation and retrace the original colour. The diffusion coefficient for K⁺ ion is calculated by using the Randles-Servick equation. In this paper the electrochromic properties, the optical properties of the as deposited, ion intercalated and deintercalated WO₃ films and the diffusion coefficient values are presented.     

Investigations on multiply charged nuclei of the primary cosmic radiation near the geomagnetic equator using nuclear emulsions

The charge spectrum obtained from measurements made on tracks of 1329 nuclei of the cosmic radiation of Z?6 and E?7·5 GeV/n has been studied in detail using emulsion stacks exposed over Hyderabad, India (cut off rigidity=16·8 GV) at a depth of 6·8 g/cm² of air for 7¼ hrs. This spectrum has been compared with that available for nuclei of E≥1·5 GeV/n. Within the limits of experimental errors, no dependence of the flux values or ratios of intensities with energy are noticed. This result has important implications on the origin and history of the cosmic radiation. Integral energy spectra of M and H-nuclei have been derived making use of the flux values at the two locations; the spectra thus derived have the least errors associated with these.     

Theoretical studies on the conformations of cyclitols in solution

Theσ-charges on various atoms in inositols have been computed by using the MO-LCAO method of Del Re. The potential and free energies of seven inositols in the normal (N) and alternative (A) conformations have also been calculated. Minimization of the energies of these conformations have been studied by suitably tilting the axial hydroxyl groups. Tilts of about 1.5° are predicted for the hydroxyl groups involved in syn-axial interactions, in the minimum energy conformations. As in aldopyranoses, in inositols also conformations which have fewer axial hydroxyl groups are favoured. The present calculations predict the order of preference ofneo-, allo- andmuco-inositols in the equilibrium mixture, in accordance with the experimental results.