A Magnesium-Selective Ionophore Containing Four Amide Carbonyl Ligands Derived from L-Tartaric Acid and Axial Furano Oxygen Binding Sites

Octahedrally converging hexadentate macrocyclic receptors 1 and 2, based on L-tartaric acid and furanmoieties, were synthesized andtheir complexation properties studied. In this paper,magnesium ion selectivitiesdetermined by ISE experiments, chiroptical changes observedby circular dichroism(CD) on complexation, and association constants measuredby NMR titration arediscussed.     

Preparation of holographic gratings of liquid crystals dispersed in polyurethane acrylates under controlled reaction conditions.

Transmission gratings of holographic polymer-dispersed liquid crystals (HPDLC) are prepared under controlled reaction conditions by adding various amounts of chain-transfer agent (CTA). The resulting films have a higher gel content with lower cross-link density, less dark reaction, less grating shrinkage with much smoother LC/polymer interfaces, smaller induction period, and fast saturation of diffraction efficiency, which shows a maximum of 95 % with 1 % CTA. An optimum LC content of 35 % is verified on the basis of morphology and reaction kinetics.     

Studies on mass production of transformed Panax ginseng hairy roots in bioreactor

The growth properties of Panax ginseng hairy roots transformed by Agrobacterium rhizogenes were compared between flask and aerated column or stirred bioreactor. In flask cultures, sucrose, initially 30 g/L, was nearly exhausted after 45 d of culture. The pH of the medium dropped from 5.5 to 4.96 after 10 d, but afterward it gradually increased to 6.4. After 45 d, hairy roots grew about 16-folds. The growth rate of hairy roots in air-bubble column or stirred bioreactor cultures was 1.13 (1.11) to 1.23 (1.20) g fresh wt (dry wt)/(g of cells·d), respectively. For both bioreactors, growth was about three times as high as in the flask cultivation.     

Surface-enhanced Raman study of organic sulfides adsorbed on silver

The surface-enhanced Raman scatterings of dimethyl sulfide, diethyl sulfide and dimethyl disulfide have been investigated in silver sol. The dimethyl disulfide molecule decomposes on silver to the corresponding mercaptide implying facile cleavage of its S---S bond. The C---S bond in dialkyl monosulfide appears not to cleave on silver. For diethyl sulfide, the C₂ conformation seems to be favorable on silver than other conformations.     

Preparation of 2,4-diarylquinolines and substituted dihydrobenz-[c]acridines by the condensation of certain c(α),o-dilithiooximes with 2-aminobenzophenones

C(α),O-Dilithiooximes were prepared in an excess of lithium diisopropylamide and condensed with several 2-aminobenzophenones, followed by acid hydrolysis of the oximes to the ketones, which then underwent cyclodehydration and linear dehydration to give substituted quinolines or dihydrobenz[c]acridines.     

Polyarylate–polystyrene block copolymer from macro-azoinitiator: Synthesis and its thermal properties

A macro-azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy-terminated polyarylates having viscosity-average molecular weights of 6200, 8100, and 12 400. These macro-azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate-polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc.