Separation and identification of Taxifolin 3-O-glucoside isomers from Chamaecyparis obtusa (Cupressaceae)

Taxifolin 3-O-glucoside isomers, [(2R, 3R)-, (2R, 3S)-, (2S, 3R)- and (2S, 3S)-] were isolated from leaves of Chamaecyparis obtuse (Cupressaceae). Their structures were elucidated on the basis of UV, MS, CD, 1H- and 13C-NMR spectral data, including 2D shift correlation. It was found that the compounds could be distinguished by the use of 1H- and 13C-NMR spectral data.     

Effective PET and ICT switching of boradiazaindacene emission: a unimolecular, emission-mode, molecular half-subtractor with reconfigurable logic gates

[reaction, structure: see text] We report a unimolecular system functioning as a combinatorial logic circuit for half-subtractor. The emission characteristics can be modulated by chemical inputs, and when followed at two different wavelengths, two functionally integrated logic gates XOR and INHIBIT are obtained. Both logic gates function in the emission mode, and with very large differences in the signal intensity allowing unequivocal assignment of logic-0 and logic-1.     

Ion sensing coupled to resonance energy transfer: a highly selective and sensitive ratiometric fluorescent chemosensor for Ag(I) by a modular approach

We report a novel dimeric boradiazaindacene dye which can be converted in one step to an efficient resonance energy transfer (RET) dyad. In addition, if this modification is done with appropriate ligands, RET can be coupled to ion sensing. The utility of this approach is demonstrated in a highly selective, emission ratiometric chemosensor for Ag(I).     

New Copper（Ⅱ） and Nickel（Ⅱ） Complexes of 4-Morpholinoacetophenone Thiosemicarbazone： Structural, Electrochemical and Antimicrobial Studies

4-Morpholinoacetophenone thiosemicarbazone, MAPT, and its nickel（Ⅱ） and copper（Ⅱ） complexes have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral methods （FT-IR, ^1H NMR） and cyclic voltammetry. Electrochemical behaviors of the complexes have been studied by cyclic voltammetry in DMF media showing metal centered reduction processes for both of them. The redox properties, nature of the electrode processes and the stability of the complexes were discussed. [Cu（MAPT）2]Cl2 complex shows Cu（Ⅱ）/Cu（Ⅰ） couple and quasi-reversible wave associated with the Cu（Ⅲ）/Cu（Ⅱ） process. The reduction/oxidation potential values depend on the structures of complexes. Also, the antimicrobial activities of these complexes were determined against S. aureus, E. coli and B. subtilis.     

Anodic voltammetric behavior of ascorbic acid and its selective determination in pharmaceutical dosage forms and some Rosa species of Turkey

Ascorbic acid is the most common electroactive biological compound found in some plant species (e.g., Citrus species, Rosa species). The electrochemical oxidation of ascorbic acid was investigated by cyclic, linear sweep, differential pulse (DPV), and square wave (SWV) voltammetry. For analytical purposes, a very well-resolved diffusion-controlled voltammetric peak was obtained in acetate buffer at pH 3.50 for DPV and SWV. The linear response was obtained in the range of 3.52–176.1 μg/mL with a detection limit of 0.88 μg/mL for DPV and 0.52 μg/mL for SWV. Based on this study, simple, rapid, selective, and sensitive voltammetric methods were developed for the determination of ascorbic acid in pharmaceutical dosage forms and Rosa species (R. dumalis ssp. boissieri var. boissieri, R. canina, R. pulverulenta, R. heckeliana ssp. vanheurckiana, and R. montana subsp. woronowii). The results obtained are compared with the HPLC data. The developed methods enable the extracts to be analyzed without the necessity of any time-consuming separation. The text was submitted by the authors in English.     

Five new nortropane alkaloids and six new amino acids from the fruit of Morus alba LINNE growing in Turkey

Investigation of the constituents of the fruits of Morus alba LINNE (Moraceae) afforded five new nortropane alkaloids (1-5) along with nor-psi-tropine (6) and six new amino acids, morusimic acids A-F (7-12). The structures of the new compounds were determined to be 2alpha,3beta-dihydroxynortropane (1), 2beta,3beta-dihydroxynortropane (2), 2alpha,3beta,6exo-trihydroxynortropane (3), 2alpha,3beta,4alpha-rihydroxynortropane (4), 3beta,6exo-dihydroxynortropane (5), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (7), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid (8), (3R)-3-hydroxy-12-1(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (9), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid (10), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-hydroxymethyl-piperidin-1-yl]-dodecanoic acid-3-O-beta-D-glucopyranoside (11), and (3R)-3-hydroxy-12-[(1R,4S,5S)-4-hydroxy-5-methyl-piperidin-1-yl]-dodecanoic acid (12) on the basis of spectral and chemical data.     

The Prospect of Dimensionality in Porous Semiconductors

With the advent of silicon-based semiconductors, a plethora of previously unknown technologies became possible. The development of lightweight low-dimensional organic semiconductors followed soon after. However, the efficient charge/electron transfers enabled by the non-porous 3D structure of silicon is rather challenging to be realized by their (metal-)organic counterparts. Nevertheless, the demand for lighter, more efficient semiconductors is steadily increasing resulting in a growing interest in (metal-)organic semiconductors. These novel materials are faced with a variety of challenges originating from their chemical design, their packing and crystallinity. Although the effect of molecular design is quite well understood, the influence of dimensionality and the associated change in properties (porosity, packing, conjugation) is still an uncharted area in (metal-)organic semiconductors, yet highly important for their practical utilization. In this Minireview, an overview on the design and synthesis of porous semiconductors, with a particular emphasis on organic semiconductors, is presented and the influence of dimensionality is discussed.     

Thermal computations of temperature distribution and bulb heat transfer in an automobile headlamp

In this study, experimental and numerical analysis was performed to define thermal deformation inside the head lamp because of usage plastic materials and thermal loads. Buoyancy, radiation and conjugate effects were considered. Velocity and temperature distributions were obtained and possible hot points and condense regions can be determined. Nusselt number distribution on cylindrical bulb were computed and compared with literature. Relatively important heat transfer increase in natural convection was found.