Fabrication of new type field effect transistors using charge transfer complex layers

We fabricated field effect transistors (FETs) using door (TTF, TMTSF) and acceptor (TCNQ) molecules, and we investigated the change of conductivity in the charge transfer (CT) complex layer by applying gate voltages. Several types of FETs having TTF/TCNQ and TMTSF/TCNQ layered structures were examined. The stacked‐layer FET showed a large transconductance compared with a single‐layer FET. The experimental results demonstrate that the CT complex layer formed between donor and acceptor films mainly works as a conduction channel. Furthermore, the change in the degree of charge transfer corresponding to conductivity change was confirmed by infrared absorption spectra. © 2000 Scripta Technica, Electr Eng Jpn, 134(1): 10–16, 2001     

Electrochemical reaction of lithium alanate dissolved in diethyl ether and tetrahydrofuran

We present electrochemical properties of lithium alanate (LiAlH₄) dissolved in aprotic ethers – diethyl ether (Et₂O) and tetrahydrofuran (THF) – under an Ar atmosphere of 1 atm at 298 K. Specific conductivities of both LiAlH₄–THF and LiAlH₄–Et₂O solutions are measured by AC four-terminal method. Cyclic voltammetry is performed with using a beaker-type electrochemical cell consisted of a Ni wire, Ni mesh and Li wire as a working, counter and reference electrode, respectively. In order to clarify the electrochemical behavior, anodic polarization of LiAlH₄–THF solution is measured. The current density of 1.0 M LiAlH₄–THF solution reaches to 1 A cm⁻², which is higher than the LiAlH₄–Et₂O solution. Quantitative analysis of H₂ gas generated on the working electrode during the potentiostatic electrolysis tells that the number of electrons involved in the anodic reaction at the limiting current is one in case of the LiAlH₄–THF solution. We propose conceivable electrochemical reactions of LiAlH₄ in the non-aqueous ethereal solutions.     

Structural analysis of unknown dyes detected in hajikami (ginger pickled in vinegar)

Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.     

Modification of transport properties of ion exchange membranes,XIII. Surface-modified cation exchange membranes prepared from polyamines and a copolymer membrane containing p-stryenesulfonyl chloride

A membrane precursor was prepared by the copolymerization of p-styrenesulfonyl chloride and divinylbenzene in the presence of a poly(vinyl chloride) supported cloth. The surface of the membrane was treated with various amines, and then the sulfonyl chloride groups in the internal part of the membrane were hydrolyzed with an aqueous sodium hydroxide solution in organic methanol or acetone solvent. Hydrolysis conditions were examined for the introduction of the sulfonic acid groups. The membrane modified by ethylenediamine exhibited slightly bipolar properties during the electrodialysis of seawater. Surface-modified membranes using tetraethylenepentamine exhibited excellent monovalent cation permselectivity, low membrane electric resistance, and long performance durability during the electrodialysis of seawater.