Molecular Combing of Various Poly(-Alkyl Acrylate) Chains on Mica by the Dipping Method.

If polymer chains could be deposited on a substrate as a fully extended chain, a procedure known as "molecular combing," the chain structure could be characterized by atomic force microscopy in more detail than has been possible with the measurements available today. We show here, for the first time, that flexible polymers can be molecularly combed to fully extended chains by the dipping method. We studied the molecular combing of a series of poly(-alkyl acrylate)s on mica from a chloroform solution by the dipping method and found that poly(-alkyl acrylate)s with an alkyl group longer than -octyl can be molecularly combed into straight chains under optimized conditions.

Maltotriose-Chlorin e6 Conjugate Linked Tetraethyleneglycol as an Advanced Photosensitizer for Photodynamic Therapy. Synthesis and Antitumor Activities against Canine and Mouse Mammary Carcinoma Cells.

Glycoconjugated chlorins represent a promising class of compounds that meet the requirements for the third-generation photosensitizer (PS) for photodynamic therapy (PDT). We have focused on the use of glucose (Glc) to improve the performance of the PS based on the Warburg effect-a phenomenon where tumors consume higher Glc levels than normal cells. However, as a matter of fact, Glc-conjugation has a poor efficacy in hydrophilic modification; thus, the resultant PS is not suitable for intravenous injection.

Microwave-Assisted Heating Reactions of -Acetylglucosamine (GlcNAc) in Sulfolane as a Method Generating 1,6-Anhydrosugars Consisting of Amino Monosaccharide Backbones.

The microwave-assisted heating reaction of -acetyl glucosamine (GlcNAc) in sulfolane is described. The reaction produces two major products that are assignable to 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucopyranose (AGPNAc) and 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucofuranose (AGFNAc). In order to reveal a general feature of the system, the 3, 5, and 10 min reactions were performed at 140, 160, 180, 200, and 220 °C to clarify the time course changes in the conversion of GlcNAc and the yields of the two produced 1,6-anhydrosugars.

Evaluation of Ring Expansion-Controlled Radical Polymerization System by AFM Observation.

We here present a direct link between the reaction mechanisms for the ring-expansion "vinyl" polymerization system and atomic force microscopy (AFM) observations. The brush-modification clearly discriminates the desired cyclic species with the contour lengths () of 28-132 nm and molar masses () of 60.2-283 kg mol from the other linear ones.

Ring-Expansion/Contraction Radical Crossover Reactions of Cyclic Alkoxyamines: A Mechanism for Ring Expansion-Controlled Radical Polymerization.

Macrocyclic polymers present an important class of macromolecules, displaying the reduced radius of gyration or impossibility to entangle. A rare approach for their synthesis is the ring expansion-controlled radical "vinyl" polymerization, starting from a cyclic alkoxyamine. We here describe ring-expansion radical crossover reactions of cyclic alkoxyamines which run in parallel to chain-propagation reactions in the polymerization system.

Surface Modifier-Free Organic-Inorganic Hybridization To Produce Optically Transparent and Highly Refractive Bulk Materials Composed of Epoxy Resins and ZrO Nanoparticles.

Surface modifier-free hybridization of ZrO nanoparticles (NPs) with epoxy-based polymers is demonstrated for the first time to afford highly transparent and refractive bulk materials. This is achieved by a unique and versatile hybridization via the one-pot direct phase transfer of ZrO NPs from water to epoxy monomers without any aggregation followed by curing with anhydride. Three types of representative epoxy monomers, bisphenol A diglycidyl ether (BADGE), 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (CEL), and 1,3,5-tris(3-(oxiran-2-yl)propyl)-1,3,5-triazinane-2,4,6-trione (TEPIC), are used to produce transparent viscous dispersions.

Maltotriose-conjugation to a fluorinated chlorin derivative generating a PDT photosensitizer with improved water-solubility.

Photoactive molecules with the frameworks of chlorin and/or porphyrin possessing four perfluorinated aromatic rings were conjugated with maltotriose (Mal3) via the nucleophilic aromatic substitution reaction and subsequent deprotection reaction of the oligosaccharide moieties. The resulting oligosaccharide-conjugated molecules are ultimately improved as compared to the previously reported monosaccharide-counterparts in terms of water-solubility. In particular, a water-soluble chlorin derivative surrounded by four Mal3 molecules showed an excellent biocompatibility, strong photoabsorption in the longer wavelength regions, and a very high photocytotoxicity.

Maltopentaose-conjugated CTA for RAFT polymerization generating nanostructured bioresource-block copolymer.

We now describe the synthesis of a new family of oligosaccharide-conjugated functional molecules, which act as chain transfer agents (CTAs) for the reversible addition-fragmentation chain transfer (RAFT) polymerization. The synthesis was started from the catalyst-free direct N-glycosyl reaction of 5-azidopentylamine onto maltopentaose (Mal5) in dry methanol at room temperature and subsequent N-protected reaction with acetic anhydride, producing a stable oligosaccharide-building block, such as Mal5 with an azidopentyl group (Mal5-N3). The azido group was hydrogenated using platinum dioxide (PtO2) as a catalyst to give Mal5 with aminopentyl group (Mal5-NH2), which was then reacted with CTA molecules bearing activated ester moieties.