Fast ionic conduction in cubic hafnium garnet Li<Subscript>7</Subscript>La<Subscript>3</Subscript>Hf<Subscript>2</Subscript>O<Subscript>12</Subscript>

A new member of the family of garnets with fast lithium ion conduction has been found with the composition Li₇La₃Hf₂O₁₂. The anion arrangement corresponds to the oxygen framework in garnets, e.g., in Ca₃Fe₂Si₃O₁₂. Hafnium is coordinated octahedrally while the lanthanum environment can be described as a distorted cube. Lithium occupies a large number of positions with tetrahedral, trigonal planar, and metaprismatic coordination. Li₇La₃Hf₂O₁₂ shows a lithium bulk ion conductivity of 2.4 × 10⁻⁴ Ω⁻¹ cm⁻¹ at room temperature with an activation energy of 0.29 eV.     

Hybrid density functional theory/molecular mechanics calculations of two-photon absorption of dimethylamino nitro stilbene in solution

The dimethylamino nitro stilbene (DANS) molecule is studied for exploring solvent effects on two-photon absorption using the quantum mechanical/molecular mechanical (QM/MM) response theory approach, where the quantum part is represented by density functional theory. We have explored the role of geometrical change of the chromophore in solution, the importance of taking a dynamical average over the sampled structures and the role of a granular representation of the polarization and electrostatic interactions with the classically described medium. The line shape function was simulated by the QM/MM technique thereby allowing for non-empirical prediction of the absolute two-photon cross section. We report a maximum in the TPA cross section for a medium of intermediate solvent polarity (i.e. in chloroform) and provide the grounds for an explanation of this effect which recently has been experimentally observed for a series of charge transfer species in solvents of different polarity. The calculations of absorption energies reproduce well the positive solvatochromic behavior of DANS and are in good agreement with experimental spectra available for the chloroform and DMSO solvents. In line with recent development of the QM/MM response technique for color modeling, we find this methodology to offer a versatile tool to predict and analyze two-photon absorption phenomena taking place within a medium.     

4,7-Diaryl indole-based fluorescent chemosensor for iodide ions

Simple and selective indole based fluorescent sensors for iodide anions are reported. A series of 4,7-diaryl indole derivatives (DAIs) are designed and synthesized using Suzuki coupling. These DAIs shows significant changes in UV-vis and fluorescent intensity only with addition of iodides and not with other anions. The ability of these DAIs to function as selective iodide chemosensor is reported.     

Phytochemical variations among four distinct varieties of Indian cardamom Elettaria cardamomum (L.) Maton

Abstract

Elettaria cardamomum (L.) Maton prestigiously called as Indian cardamom and is mostly cultivated in south India at higher altitudes ranging from 900 to 1400 msl. The chemical composition of dry capsules essential oil of the four distinct varieties was chemo-profiled by gas chromatography-mass spectrometry (GC-MS). Results revealed a higher concentration of major monoterpene 1, 8-Cineole ranging between 28.94% and 34.91% in PV 1 and PV 2 varieties respectively. Other monoterpenes like α-Pinene, Sabinene, Linalool, α-Terpineol and Nerol were present considerable quantities in all of the four cardamom varieties. Two sesquiterpenic constituents namely, ç-Elemene and 1,6,10-dodecatrien-3-ol (Nerolidol) were identified in all varieties. Three ester constituents were also obtained in PV 1 in which α-Terpinyl acetate (26.68%) exhibited as a major ester constituent followed by Ocimenyl acetate (0.80%) and E5-Dodecenyl acetate (0.30%). This is the first published report on the phytochemical concentration of recent varieties of Indian cardamom.