Yoshio Aso

New electron acceptors for organic metals: extensively conjugated homologues of thiophene–7,7,8,8-tetracyanoquinodimethane (TCNQ)

Two conjugated homologues of thiophene–7,7,8,8-tetracyanoquinodimethane (TCNQ) have been prepared, which form highly conductive complexes with typical electron donors such as 2,2′,5,5′- tetrathiafulvalene (TTF) or 5,6,11,12-tetrathiatetracene (TTT); these complexes have extensive conjugation.

2,3,6,7-tetramethyl and 2,3:6,7-bis(trimethylene) derivatives of 1,4,5,8-tetrachalcogenonaphthalenes: A study on their charge-transfer complexes and radical cation salts

Abstract In order to improve the donor character of 1,4,5,8-tetrachalcogenonaphthalene as the simplest example of TTT homologues, we have studied the syntheses and properties of the title compounds. They were successfully prepared via 1,4,5,8-tetrachloro derivatives of the corresponding alkyl naphthalenes. The alkyl groups serve to enhance not only their donor strength but also solubilities, facilitating their complexation. A variety of their charge-transfer complexes and radical cation salts were thus prepared by means of a mixing method or an electrocrystallization method. Some of them are electrically highly conductive.

Pyridine and pyrazine analogues of TCNQ dianion salts

Abstract Since the heteroquinonoid analogues of 7, 7, 8, 8-tetracyano-1, 4-benzoquinodimethane (TCNQ) are very interesting as potential electron acceptors, we have undertaken the syntheses of pyridine-TCNQ and dimethyl pyrazine-TCNQ. They were not isolated in the neural states but as the dianion salts. The cyclic voltammetry of the dianion salts indicates that pyridine-TCNQ is a much stronger electron acceptor than TCNQ and dimethyl pyrazine-TCNQ is a further stronger one than the former. The TTF complexes of pyridine-TCNQ and dimethyl pyrazine-TCNQ were prepared using the dianion salts and electrically highly conductive.

Selenium analogues of 2-(thiopyran-4-ylidene)-1,3-dithiole as novel unsymmetrical electron donors

The selenium analogues of 2-(thiopyran-4-ylidene)-1,3-dithiole and its 4,5-bis(methylthio) and 4,5-(ethylenedithio) derivatives have been prepared as a new series of unsymmetrical electron donors; some of their complexes with 7,7,8,8-tetracyanoquinodimethane are electrically highly conductive.