Synthesis and properties of poly(amic acid)s and polyimides based on 2,2′,6,6′‐biphenyltetracarboxylic dianhydride

Poly(amic acid)s (PAAs) having the high solution stability and transmittance at 365 nm for photosensitive polyimides have been developed. PAAs with a twisted conformation in the main chains were prepared from 2,2′,6,6′‐biphenyltetracarboxylic dianhydride (2,2′,6,6′‐BPDA) and aromatic diamines. Imidization of PAAs was achieved by chemical treatment using trifluoroacetic anhydride. Among them, the PAA derived from 2,2′,6,6′‐BPDA and 4,4′‐(1,3‐phenylenedioxy)dianiline was converted to the polyimide by thermal treatment. The heating at 300 °C under nitrogen did not complete thermal imidization of PAAs having glass‐transition temperatures (T_g)s higher than 300 °C to the corresponding PIs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6385–6393, 2006     

High-speed counter-current chromatography of apple procyanidins

Apple procyanidins were separated by high-speed counter-current chromatography using a type-J multilayer coil planet centrifuge. Several two-phase solvent systems with a wide range of hydrophobicities from a non-polar hexane system to polar n-butanol systems were evaluated their performance in terms of the partition coefficient and the retention of the phase. The best separation of procyanidins B and C was achieved with a two-phase solvent system composed of n-butanol-methyl tert.-butyl ether-acetonitrile-0.1% trifluoroacetic acid (2:4:3:8) using the lower phase as a mobile at a flow-rate of 1.0 ml/min.     

Single molecular multianalyte sensor: jewel pendant ligand

[structure: see text] The jewel pendant ligand has multiple chromogenic units combined in a single molecule with the dyes linked to a semiselective binding site by three heteroatoms (O, N, S) having different HSAB characteristics, to indicate diverse response to individual transition metal ions. Using a single-molecular multianalyte sensor, multiple analytes could be determined with a minimal sensing system.     

Enantioselective Morita-Baylis-Hillman (MBH) reaction promoted by a heterobimetallic complex with a Lewis base

A new double-activation catalysis is presented for the Morita-Baylis-Hillman (MBH) reaction of an α,β-unsaturated ketone and an aldehyde by the combined use of a heterobimetallic asymmetric complex and tributylphosphine ((n-Bu)₃P) to afford the α-methylene-β-hydroxy ketone with up to 99% ee.     

Ruthenium-catalyzed carbonylative cycloaddition of alpha-keto lactones with alkenes or alkynes: the participation of an ester-carbonyl group in cycloaddition reactions as the two-atom assembling unit

The reaction of benzofuran-2,3-dione derivatives 1 with CO and alkenes (or alkynes) results in a carbonylative [2+2+1] cycloaddition in which the ester-carbonyl group is incorporated into a two-atom assembling unit to give spirolactone derivatives 2. This reaction provides the first example of an ester-carbonyl group participating in a carbonylative cycloaddition reaction.     

Solubilization and applications of single-walled carbon nanotubes into aqueous and organic media by the use of nanometer size-controlled fluoroalkyl end-capped oligomeric aggregates

We have studied on the solubilization of single-walled carbon nanotubes (SW-CNTs) into aqueous and organic media by the use of a variety of nanometer size-controlled fluorinated self-assemblies, which were formed by the aggregations of end-capped fluoroalkyl segments in fluoroalkyl end-capped acrylic acid oligomers [R_F-(ACA)_n-R_F], N,N-dimethylacrylamide oligomers [R_F-(DMAA)_n-R_F], acryloylmorpholine oligomers [R_F-(ACMO)_n-R_F], and N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [R_F-(DOBAA)_n-R_F]. Fluorinated self assemblies formed in organic media (colorless solutions) could solubilize SW-CNTs into organic media to afford the transparent pale yellow solutions. The dynamic light scattering measurements showed that the size of fluorinated self-assemblies increased after the solubilization of SW-CNTs into organic media. It was suggested that the solubilization of SW-CNTs into organic media is due to the encapsulation of SW-CNTs into fluorinated assemblies. Fluorinated assemblies were also able to solubilize SW-CNTs into water to give the transparent gray solutions. Among a variety of fluorinated assemblies, fluorinated assemblies formed by R_F-(ACMO)_n-R_F [R_F = CF(CF₃)OC₆F₁₃] oligomer was more effective for the solubilization of SW-CNTs into both aqueous and organic media. Contact angle measurements of dodecane and the fluorescence spectra for poly(methyl methacrylate) cast film modified by fluorinated self-assemblies—SW-CNTs complexes showed that SW-CNTs are dispersed above the PMMA surface.     

INVESTIGATIONS ON THE MECHANISM OF CHLORPROMAZINE PHOTOTOXICITY: EFFECTS ON LYSOSOMES OF CULTURED HUMAN FIBROBLASTS

Abstract The effect of chlorpromazine (CPZ) and UVA on lysosomes of cultured normal human fibroblasts has been investigated. Acid phosphatase (ACPase) activity in 12 000 g pellet of cells treated with CPZ (10 μg/m l ) and UVA (6 × 10⁴ J/m²) was found to be decreased as compared with non-treated, CPZ or UVA treated control cells. This decrease, however, was not accompanied by a concomitant increase in ACPase activity in the 12 000 g supernatant. The addition of Triton X-100 to cells pretreated with CPZ + UVA resulted in only a moderate increase in ACPase activity of the 12 000 g supernatant. ACPase activity of the cells incubated in media containing preirradiated CPZ was also found to he decreased. These results indicate that CPZ + UVA directly inactivate lysosomal enzymes, possibly without affecting the membrane.     

Force in scf theories

A new force approach is reported in which we improve the wavefunction so that the Hellmann-Feynman theorem is satisfied. A sufficient condition for the Hellmann-Feynman theorem to be satisfied is that the basis set includes AO derivatives ?x_r/?x_rfor any basis x_r. Here we test a procedure in which only the first derivative AOs are added to the “parent” AOs. The results are very encouraging.