Koji Chiba

Intercalation of colored organic anions into insulator host lattices of layered double hydroxides

Abstract Colored organic anions such as tetra (4-carboxyphenyl)porphyrin (TPP-C), tetra(4-sulfonatophenyl)porphyrin (TPP-S), tetracarboxyphthalocyaninato cobalt (TPC-C) and others were intercalated into the Mg Al and Zn Al layered double hydroxides (LDHs). After the intercalation of organic anions, interlayer spacing of the LDHs increased to 7.8–30.7 A depending on the amounts of intercalated anions and the sizes of these anions. The amounts of intercalated organic anions reached 48–100% of the exchange capacity of the Zn Al LDH. Absorption maxima of TPP-C and TPP-S intercalates were from 439 to 445 nm and longer than 414 to 420 nm, respectively, of TPP-C and TPP-S alone in solvents.

Synthesis of an amylose–polymer inclusion complex by enzymatic polymerization of glucose 1-phosphate catalyzed by phosphorylase enzyme in the presence of polyTHF: a new method for synthesis of polymer–polymer inclusion complexes

The enzymatic polymerization of α-D-glucose 1-phosphate (Glc-1-P) with phosphorylase in the presence of polytetrahydrofuran (polyTHF) leads to an amylose–polyTHF (polymer–polymer) inclusion complex; the present reaction system provides a new method for the preparation of polymer–polymer inclusion complexes.

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 2.3×105 and 7.6×105 . The degree of branching determined by 1 H NMR spectroscopy after reaction with [iPr2 Si(Cl)]2 O is close to the ideal value. Ts=MeC6 H4 SO2 , CSA=10-camphorsulfonic acid.

Intercalation of organic compounds in the layered host lattice MoO3

Organic compounds such as alkylpyridines, methyl viologen and azo compounds have been intercalated into MoO3layers by ion exchange in which MoO3x–(Na+)x reacted with the organic compounds. Indolinespirobenzopyran (SP) was intercalated by a multi-step method in which amine was intercalated in the first step, and by the co-intercalation of amine and SP the MoO3 layer expanded to 24–28 A depending upon the kind of amine used in the first step. In the layers, SP existed as its isomerized coloured species, merocyanine (MC). Reduction of Mo by chemical reduction and intercalation of amines and SP was confirmed by X-ray photoelectron spectroscopy.

Photochromism of spiropyran dye in LiAl layered double hydroxide

Sulfonated spiropyran dye (SP) intercalated into the interlayers of a LiAl layered double hydroxide (LDH) showed reversible photochromism even in the absence of co-intercalated organic acid. Photochromic intercalation compounds containing SP and p-toluenesulfonate (PTS) in a LiAl LDH revealed peak sharpening and peak separation in the absorption spectrum. Fluorescence intensity of SP intercalate increased in the presence of PTS indicating that the interaction between SP molecules is weak.

Preparation and photochromism of sulfonated spiropyran-silica nanocomposites

Reversible and stable photochromic properties of sulfonated spiropyran (SP-SO3−) were achieved by trapping SP-SO3− in a silica matrix by the sol-gel route. The presence of organic anions was essential for the photochromic properties, indicating the importance of the coexistence of polar and non-polar regions. The half-life time (t1/2) of the photoinduced merocyanine (MC) trapped in the silica matrix in the presence of dodecylbenzenesulfonic acid (DBS) was larger than 30 days (k<2.7 × 10−7 s−1). The reversibility of SP-SO3− was improved by the addition of triplet quenchers such as benzophenone, naphthalene and anthracene.

Photoisomerization of indolinespirobenzopyran in layered double hydroxides

Sulfonated Indolinespirobenzopyran (SP-SO3–) and toluene-p-sulfonic acid were co-intercalated into a layered double hydroxide. The new intercalate exhibited photochromic properties; reversible photoisomerization between SP-SO3– and photoinduced merocyanine was attained and photoinduced merocyanine was thermally very stable.

Preparation of new organic-inorganic nanocomposite by intercalation of organic compounds into MoO3 by ultrasound

Abstract 4-Substituted pyridines were reacted with the layered host lattice MoO 3 using ultrasonic wave irradiation. XRD patterns and TG spectra showed the formation of new organic-inorganic nanocomposites. XPS spectra showed that no reduction of Mo metal occurred through the reaction. These results and IR spectra indicated that pyridimium ion interacted with oxygen of MoO 3 by hydrogen bonding.

Synthesis of new aminopolysaccharides by polymerization of 6-amino-6-deoxy-D-glucose and 2,6-diamino-2,6-dideoxy-D-glucose

Abstract This paper describes the spontaneous polymerization of 6-amino-6-deoxy- D -glucose (1b) and 2,6-diamino-2,6-dideoxy- D -glucose (5b) to give new aminopolysaccharides 2 and 6, respectively. The polymerization of 1b took place in the presence of acetic acid via Amadori rearrangement to give 2 having an aminoketose structure. On the other hand, the spontaneous polymerization of 5b proceeded through the selective condensation of a hydroxy group at position 1 with an amino group at position 6 to produce 6 with a glycosylamine structure. The molecular weights were determined by gel permeation chromatographic analyses after acetylation of the product polysaccharides.

Preparation method for organic-inorganic layered compounds including fibrous materials by the reaction of Zn(OH)2 with organic compounds

A preparation method of surface modified inorganic layered compounds including fibrous materials was established by the reaction of amorphous Zn(OH) 2 with organic oxychlorides. The resultant layer structures were similar to those of the layered double hydroxides (LDHs). Although the LDH layers have positive charges the layers of the reaction products obtained here are uncharged. IR spectra indicate that hydroxyl groups reacted with the organic oxychlorides, and new peaks assigned to RCO 2 -Zn bonds appeared around 1400 and 1550 cm –1 and 40-98% of hydroxyl groups were reacted. Interlayer spacings of the reaction products of Zn(OH) 2 with dioxychlorides were 0.71-1.48 nm, and those of Zn(OH) 2 with monooxychlorides were 1.19-2.67 nm and depended on the length of organic compounds. SEM images showed that the reaction products of Zn(OH) 2 with organic oxychlorides had plate-like morphology similar to LDHs. However, the reaction product of Zn(OH) 2 with benzoyl chloride was fibrous.