Self-organized honeycomb-patterned microporous polystyrene thin films fabricated by calix[4]arene derivatives.

Calix[4]arene derivatives bearing carboxyl groups at the upper rim and alkyl groups at the lower rim were synthesized. Micrometer-size porous honeycomb-patterned thin films were prepared by evaporating chloroform solution of polystyrene containing the calixarene derivatives under high humidity. These films were coated on gold electrodes of QCM, and the high-frequency changes were observed to detect volatile organic compounds such as dichlorobenzene.

Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.

Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.

A novel molecular assembly mode of ferulic acid derivatives.

Ferulic acid derivative assembles with three kinds of non-covalent interactions, i.e., metal coordination, hydrogen bonding and CH-pi interaction: X-ray crystallographic study illustrated the molecular assembly mode.

Effects on Metal Binding of Circular NH- - -O=C Intramolecular Hydrogen Bonding in Hydrophilic Pseudocavities of p-tert-Butylcalix[4]arenes Carrying Amino Acid Moieties.

Calix[4]arenes bearing amino acid moieties were prepared by the reaction of carboxyl-protected amino acids with the acid chlorides of O-carboxymethylcalix[4]arenes. The binding ability toward metal ions was estimated by solvent extraction. These calixarenes showed selective extraction capability toward Na(+) and Ag(+) ions, which increased in the order 2a < 2b < 2d < 2c. The complexing ability was also affected by the nature of the solvents and was higher in ethyl acetate than dichloromethane. (1)H NMR studies showed that the complexation of 2c with Na(+) ion induces a change of the orientation of the amide groups from a network-like pattern with circular N-H- - -O=C intramolecular hydrogen bonding of 2c to a pattern in which carbonyl groups converge on the Na(+) ion. This change was also supported by a measurement of CD spectra.