2,5-Bis(1,3-dithiol-2-ylidene)-2,5-dihydrothiophene and its bis(alkylthio) derivatives: a new synthetic approach to thienoquinonoid-extended tetrathiafulvalenes and their conductive complexes

Synthesis, Stabilities, and Redox Behavior of Mono-, Di-, and Tetracations Composed of Di(1-azulenyl)methylium Units Connected to a Benzene Ring by Phenyl- and 2-Thienylacetylene Spacers. A Concept of a Cyanine−Cyanine Hybrid as a Stabilized Electrochromic System

“…We selected di(1-azulenyl)(phenyl- and 2-thienyl)methylium units ( 2 + and 3 + ) for the construction of the hybrid system as polymethine end groups, due to their high stability and also the existence of strong absorption in the visible region owing to the contribution of their cyanine substructure. The 2-thienyl derivative 3 + might further stabilize the presumed two-electron reduction state by the contribution of the thienoquinoid substructure instead of the quinoidal form of benzene rings. , The tert -butyl substituents were introduced into the azulene ring for the improvement of thermodynamic stabilities and the reversibility of both electrochemical reduction and oxidation upon CV. As the central π-electron system, we chose a benzene ring with acetylene spacers for decreasing steric hindrance between the large cationic centers.…”

Synthesis, Properties, and Redox Behavior of Di(1-azulenyl)(2- and 3-thienyl)methyl Cations and Dications Composed of Two Di(1-azulenyl)methylium Units Connected with 2,5-Thiophenediyl and 2,5-Thienothiophenediyl Spacers

“…4 Thiophene and thienothiophene units have been frequently used in thienoquinoid or condensed forms in the design of new molecular skeletons. 5 Aiming at the construction of multistage redox systems with a stabilized carbocation, we have prepared dications composed of two di (1-azulenyl) with 2-or 3-thiophenecarbaldehydes in acetic acid at room temperature for 24 h in 79%, 82%, 80%, and 86% yields, respectively. Thus, reaction of 12a,b and 13a,b with DDQ in dichloromethane at room temperature followed by an addition of a 60% aqueous HPF 6 solution yielded di(1-azulenyl)(2-and 3-thienyl)methyl cations (7a,b and 8a,b) as hexafluorophosphate in 95%, 100%, 95%, and 100% yields, respectively.…”

Synthesis of materials for molecular electronic applications

“…EDT-BDTT ( 52). 34 BDTT is one of the most powerful donors of the TTF class and alkylthio-substitution as in 52 leads to a slight reduction in its electron-donor ability though TCNQ salts of the latter show significantly higher conductivity (by ca. lo2-lo3), reflecting enhancement of intra-and inter-stack interactions produced by the sulfur atoms at the edges of the donor skeleton.…”