Induced Circular Dichroism of Achiral Cyclic Bisurea via Hydrogen Bonds with Chiral Carboxylates.

Chiral induction properties of achiral bisurea derivatives by binding tetrabutylammonium salts of N-acetylated chiral carboxylates (Ac-AlaO, Ac-ValO, Ac-LeuO, and Ac-PheO) was studied. Ultraviolet-visible titrations showed 1:1 complex formation between the bisureas and the carboxylates. The calculated association constants of cyclic bisurea (1a) were 5-10 times larger than those of the acyclic derivative (2), and 1a showed the highest binding affinity for Ac-LeuO.

Intercalation of naphthoic acid into Zn/Al layered double hydroxide.

Zn/Al Layered Double Hydroxide (Zn/Al LDH) consists of positively charged metal hydroxide sheets with anions located between the layers to compensate charges. By the reaction of carbonate Zn/Al LDH (CO3(2-)) with 2-naphthoic acid, two intercalation compounds were obtained indicating the occurrence of ion exchange reaction. Interlayer spacing increased from 0.

pH sensitive organic-inorganic layered nanomaterials by self-assembly of indigocarmine between the inorganic layers.

New pH sensitive organic-inorganic intercalation compounds having different interlayer spacing were prepared. Zn-Al layered double hydroxide (LDH) is an anion exchangeable inorganic layered compound whose interlayer spacing is 0.76 nm.

Study on the reactivity of diarylmethane derivatives in supercritical alcohols media: reduction of diarylmethanols and diaryl ketones to diarylmethanes using supercritical 2-propanol.

We found that diarylmethanols and diaryl ketones were smoothly reduced to the corresponding diarylalkanes using supercritical 2-propanol in good yields. Furthermore, we determined the specific reaction of fluorene using supercritical methanol at high temperature.

Vine-twining polymerization: amylose twines around polyethers to form amylose-polyether inclusion complexes.

In this paper, we describe a new polymerization manner termed as "vine-twining polymerization" to produce amylose-polymer inclusion complexes. The polymerization was achieved by an enzymatic polymerization of alpha-D-glucose-1-phosphate monomer catalyzed by phosphorylase in the presence of polyTHF as a guest polymer. The structure of the product was determined by X-ray powder diffraction and (1)H NMR measurements to be the inclusion complex.

Synthesis of Hyperbranched Aminopolysaccharides.

Sugar dihydroozaxole monomers with two free hydroxyl groups undergo acid-catalyzed polymerization to hyperbranched aminopolysaccharides [Eq. (a)]. Their molecular weights were determined by the light-scattering method to be between 2.