Effect of nanointegration on photoinduced hydrogen-generating nanogel systems

The nanointegration mechanism for photoinduced hydrogen nanogenerators using nanogels is described. By spatially integrating poly(N-isopropylacrylamide-co-Ru(bpy)(3)) nanogels as a photosensitizer and Pt nanoparticles as a catalyst, a mechanism using electrostatic interactions and the shrinking behavior of the thermosensitive polymer network is revealed. In addition, to evaluate the sensitivity to exterior energy, light, and heat, the integrated nanospace is controlled by using thermosensitive nanogels, which drastically shrink above the volume phase transition temperature. Such nanospatial control of multiple kinds of functional molecules in a photochemical reaction is important for the realization of artificial photosynthetic systems.     

Selective determination of trace iron in different oxidation states in natural water by flow injection-solid phase spectrometry

A novel method for the selective determination of Fe(II) and Fe(III) in water using 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (PSAP) was developed. QAE-Sephadex anion exchanger packed in a flow-through cell was used as a medium not only for both the concentration and the spectrophotometric measurements of the Fe-PSAP complex, but also for reduction of the Fe(III)-PSAP complex. The PSAP complex of Fe(II) or Fe(III) was strongly adsorbed on the anion exchanger in a weakly acidic to weakly basic region, but the Fe(III) complex was readily and completely reduced to the Fe(II) complex only in a neutral to weakly alkaline region in the solid phase. These properties were utilized to determine the Fe(II) and total Fe concentration without the addition of any reducing agent. The detection limits (3σ) were 0.18 ng for Fe(II) and 0.18 ng for total Fe using a 3.2-cm(3) sample solution. The present method is applicable to the determination of dissolved iron species present at μg dm(-3) levels in natural water samples.     

Maximizing field-effect mobility and solid-state luminescence in organic semiconductors

Conductive and emissive: organic transistors made from a simple styrylanthracene derivative have high charge mobility and high luminescence quantum yields. These properties are attributed to the lack of singlet fission, and challenge the idea that the efficient π interactions required for high mobility always lead to quenching of emission. The transistors emit blue electroluminescence and are stable during operation and storage.     

Synthesis and characterization of 1,8-naphthalimide with [6]helicene skeleton

A 1,8-naphthalimide with [6]helicene derivative scaffold has been designed and synthesized. The (P)- and (M)-enantiomers of the [6]helicene derivative were resolved by HPLC on a chiral column. The single crystal of the [6]helicene derivative exhibits an intermolecular interactions of the 1,8-naphthalimide units.     

LSI-based amperometric sensor for bio-imaging and multi-point biosensing

We have developed an LSI-based amperometric sensor called "Bio-LSI" with 400 measurement points as a platform for electrochemical bio-imaging and multi-point biosensing. The system is comprised of a 10.4 mm × 10.4 mm CMOS sensor chip with 20 × 20 unit cells, an external circuit box, a control unit for data acquisition, and a DC power box. Each unit cell of the chip contains an operational amplifier with a switched-capacitor type I-V converter for in-pixel signal amplification. We successfully realized a wide dynamic range from ±1 pA to ±100 nA with a well-organized circuit design and operating software. In particular, in-pixel signal amplification and an original program to control the signal read-out contribute to the lower detection limit and wide detection range of Bio-LSI. The spacial resolution is 250 μm and the temporal resolution is 18-125 ms/400 points, which depends on the desired current detection range. The coefficient of variance of the current for 400 points is within 5%. We also demonstrated the real-time imaging of a biological molecule using Bio-LSI. The LSI coated with an Os-HRP film was successfully applied to the monitoring of the changes of hydrogen peroxide concentration in a flow. The Os-HRP-coated LSI was spotted with glucose oxidase and used for bioelectrochemical imaging of the glucose oxidase (GOx)-catalyzed oxidation of glucose. Bio-LSI is a promising platform for a wide range of analytical fields, including diagnostics, environmental measurements and basic biochemistry.     

Spontaneous resolution of aromatic sulfonamides: effective screening method and discrimination of absolute structure

An effective screening method combining parallel synthesis and solid-state CD measurements was established to identify achiral aromatic sulfonamides that show spontaneous resolution with rapidity. We found that 4 of the 12 achiral sulfonamides crystallized as chiral crystals through this method. The chirality of each sulfonamide was discriminated by solid-state CD spectra and Flack parameter in an X-ray analysis. Correspondence between the observed Cotton effect and the absolute configuration could be confirmed by time-dependent DFT calculations. [structure: see text]