Tokyo University of Science

About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Thin film & Enantioselective synthesis. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.

A novel LIESST iron(II) complex exhibiting a high relaxation temperature.

Abstract: The spin-crossover iron(II) complex [Fe(L)(CN)2]·H2O (1) has been investigated. Complex 1 has a pentagonal bipyramidal structure which is seven-coordinated, containing an N3O2 macrocycle and two CN- ligands. Water molecules bind the complex by means of hydrogen bonding. It was found that the complex 1 exhibited a light-induced excited spin state trapping (LIESST) effect. The relaxation temperature is above 130 K, which is the highest temperature for LIESST compounds reported so far.

Stabilized α-Helix Structure of Poly(l-lysine)-block-poly(ethylene glycol) in Aqueous Medium through Supramolecular Assembly

Abstract: Stabilization of the α-helix structure of the poly(l-lysine) segment in a poly(ethylene glycol)−poly(l-lysine) block copolymer was evidenced in aqueous medium through circular dichroism (CD), 1H-NMR, and static light scattering (SLS) measurements. It was revealed that poly(l-lysine) oligomers (Mw = 2450), which themselves cannot form an α-helix structure due to substantially lower molecular weight, form an α-helix structure under high-pH condition when they are conjugated with poly(ethylene glycol). Moreover, it has been suggested by static light scattering that the block copolymer under high-pH condition exists as a dimer with α-helical poly(l-lysine) segments. The α-helix content in the block copolymer gradually decreased in a linear manner with the addition of urea, which is in sharp contrast to the high molecular weight poly(l-lysine) (Mw = 170 000), showing a steep transition from an α-helix structure to a random coil at a critical urea concentration (1.0 M). To completely shift the conformation of t...

A Gel-Based Approach To Design Hierarchical CuS Decorated Reduced Graphene Oxide Nanosheets for Enhanced Peroxidase-like Activity Leading to Colorimetric Detection of Dopamine

Abstract: Supramolecular colorless copper(I)–thiourea hydrogel (Cu-TU gel) has been made a mechanically strong functional hybrid material in the graphene oxide (GO) framework. Mild heat treatment (85 °C) of the hybrid material fetches black product containing hierarchical copper sulfide decorated reduced graphene oxide nanosheets (CuS-rGO) through an obvious in-house redox transformation reaction between Cu(I) and GO without any additive. The as-synthesized CuS-rGO nanocomposite exhibits impressive peroxidase-like activity where oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue product is observed in solution phase with H2O2. Systematic control experiments suggest that strong covalent interaction between CuS and rGO synergistically enhances the catalytic activity of CuS-rGO in comparison to its individual counterparts. Furthermore, an important biomolecule, dopamine, has been found to selectively inhibit, in succession, the oxidizing action of H2O2 for TMB oxidation reaction. Thus, dopamine-depend...

Design of poly(ethylene glycol)/streptavidin coimmobilized upconversion nanophosphors and their application to fluorescence biolabeling.

Abstract: Infrared-to-visible upconversion phosphors (i.e., rare earth ion-doped Y2O3 nanoparticles (UNPs)) were synthesized by the homogeneous precipitation method. Because the charge on the erbium (Er) ion-doped Y2O3 (Y2O3:Er) NP (UNP1) surface is positive under neutral conditions, the UNP1 surface was electrostatically PEGylated using negatively charged poly(ethylene glycol)-b-poly(acrylic acid) (PEG-b-PAAc). The adsorption of PEG-b-PAAc was confirmed by Fourier transform infrared (FT-IR) measurements and thermal gravimetric analysis (TGA). The surface charge of the PEGylated UNP1s (PEG-UNP1s) was effectively shielded by the PEGylation. The dispersion stability of the UNP1s was also significantly improved by the PEGylation. The PEG-UNP1s were dispersed over 1 week under physiological conditions as a result of the steric repulsion between the PEG chains on the UNP1 surface. The upconversion emission spectrum of PEG-UNP1s was observed under physiological conditions and was confirmed by near-infrared excited fluore...