Masa Karasu

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 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.

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.

New preparation method for surface-modified inorganic layered compounds

New surface-modified inorganic layered compounds have been prepared by the reaction of Zn(OH)2 with organic oxychlorides in which 71–98% of the OH groups reacted. Their layered structures are similar to those of the layered double hydroxides (LDHs). Although LDHs have cationic charges, the reaction products are uncharged. The interlayer spacings of the reaction products were 8.3–14.8 A for the products of Zn(OH)2 with dioxychlorides, and 11.9–16.7 A for the reaction products of Zn(OH)2 with monooxychlorides, depending on the lengths of the organic compounds.

PREPARATION OF CONDUCTING FILM COMPOSED OF POLYANILINE AND METAL OXIDE BY SOL-GEL METHOD

Conducting thin films were prepared by entrapping water-suspended polyaniline into a silica matrix by a sol-gel route. Without metal oxide, the conductivity of the film decreased after heat treatment. However, in the presence of metal oxides such as TiO 2 and Al 2 O 3 , the conductivity increased after heat treatment at 85 °C and reached 17 Scm −1 The conductivity of the film depended on the kinds and amounts of metal oxides and the temperature of heat treatment.

Intercalation of Azo Compounds into Layered Aluminium Dihydrogentriphosphate and a Layered Double Hydroxide

The inner surfaces of inorganic layered compounds such as aluminium dihydrogen-triphosphate (ADHP) and layered double hydroxide (LDH) were modified by azo compounds. Upon intercalation of 4-phenylazoaniline and 4,4′-azodianiline into ADHP, the interlayer spacing increased from 6.4 to 21.5 Å and 20.6 Å, respectively. The intensity of IR peaks due to P-–OH of ADHP and amino groups of guests decreased by the thermal treatment of the intercalates. The interlayer spacings also decreased to 16.9 Å and 16.7 Å, respectively, indicating a dehydration reaction between P–-OH and amino groups. The LDH inner surface was modified by the reaction with trans-p-phenylazobenzoylchloride (PAB-Cl). Upon surface modification, the interlayer spacing increased from 7.6 Å to about 27 Å. The absorption of this surface-modified LDH near 410 nm increased upon irradiation with UV light and decreased upon irradation with visible light, indicating the occurrence of trans–cis isomerization of PAB-Cl between the layers.