Masanobu Aragaki

Facile preparation of TTP series donors by using cyanoethyl groups

Abstract TTP (tctralhiapcntalcnc) scries donors have been prepared by two steps of phosphite-mediated cross-couplings. By using cyanoethyl groups instead of acctoxybenzyl as a protecting group, we have succeeded in improving the yields. The applicability of this method will be discussed.

Crystal structure and physical properties of (TTM-TTP)AuI2

Crystal structure analysis of new organic conductors (TTM-TTP)AuI2 and (TTM-TTP)AuBr2 , where TTM-TTP is 2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene, has been carried out. The donor to anion ratio is 1:1 and the donors form highly one-dimensional columns. These materials, however, show dimerization of the donor molecules along the stacking direction. Therefore the energy gap appears at the Fermi level, and these salts become band insulators. The observed temperature dependence of the conductivity is semiconducting, but the room-temperature conductivity is comparatively high, 10–40 S cm–1 .

ESR Investigation of Organic Conductors (DTM-TTP)(TCNQ)(TCE) and (TMET-TTP) 2(TCNQ)

Magnetic properties of the title compounds are investigated by ESR measurements, and from the temperature dependence of the g -values, the spin susceptibility is separated into donor and TCNQ contr...

Metallic 1:1-composition organic conductors and the estimated U and V

Properties of metallic TTM-TTP (2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) salts with 1:1 composition, in particular magnetic properties of (TTM-TTP)[C(CN) 3 ], are reported. The results are discussed on the basis of molecular orbital calculations of on-site and off-site Coulomb integrals, U and V.

Universal Phase Diagram of θ-Type TMET-TTP Salts

A new θ-type TMET-TTP (2-[4,5-bis(thiomethyl)-1,3-dithiol-2-ylidene]-5-(4,5- ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) salt (TMET-TTP) 2 HSO 4 , which has smaller dihedral angle (116°), and has 2:1 composition, is prepared. This salt undergoes a M-I transition at around 100 K. The ESR measurement indicates that the low-temperature insulating state of this complex is paramagnetic. Thanks to this exceptional salt, a universal phase diagram of θ-type TTP salts can be discussed similarly to θ-type ET salts. In the θ-type ET salts, the universal phase diagram holds in the uniform quarter-filled band. However, our works in the θ-type TMET-TTP salts prove that the universal phase diagram is not largely influenced by the band-filling and the position of E F .

Preparation and properties of cyclohexylenedithio substituted TTP donors

Abstract We have synthesized several TTP (tetralhiapentalene) derivatives with a cyclohexane ring. Some of their salts show metallic conductivity, and have uniform stacks in spite of the bulky cyclohexane group. Among them (ChTM-TTP) 2 Au(CN) 2 exhibits a metal-insulator transition at 120 K, followed by a spin-Pcicrls or antiferromagnetic transition at 40 K. In addition thermoelectric power is consistent with semiconducting behavior and shows that the carriers arc holes on the donors.

Tetrathiapentalene-based organic conductors with magnetic counter anions

An organic donor TTM-TTP (TTM-TTP=2,5-bis[4,5-bis (methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) forms 1:1 composition salts with metal halides. The salts of pure anions, (TTM-TTP)MX 4 (PhCl) 0.5 (M=Fe, Ga; X=Cl, Br) are dimerized insulators, whereas when the halogenes (Cl/Br) orthemetals (Fe/Ga) are alloyed, metallic salts with uniform columns are obtained.

Metallic organic conductor with 1:1 composition including magnetic anion

Organic donor TTM-TTP forms 1:1 composition salts with MX 4 (M = Fe, Ga; X = Cl, Br), which have dimerized one-dimensional columns and are insulators even at room temperature. On the Contrary, (TTM-TTP)FeBr 2 Cl 2 shows high electrical conductivity of about 1000 Scm -1 at room temperature and metallic behaviour down to 160 K. This salt has uniform one-dimensional donor columns. This is the first 1:1 composition organic metal with magnetic anion. The FeX 4 - salts exhibit weak magnetic interactions between the anions; the Weiss temperatures are less than 2.6 K.