Synthesis of Pyrazinodithiadiselenafulvalenes. New Unsymmetrical π-Donors

Abstract

Unsymmetrical dithiadiselenafulvalenes, which are annelated on the 1,3-dithiole or 1,3-dise1enole moiety to a 1,4-pyrazine ring, have been prepared by the cross coupling method and characterized as electron-donors for use in conductive charge-transfer salts.

Bis(methylethylenedithio)tetrathiafulvalene

“…The title compound, BMeEDT-TTF, a ~'-donor closely related to BEDT-TrF, has been reported previously (Papavassiliou, Zambounis & Yiannopoulos, 1987); however, no systematic investigations have been carded out. Recently, a modified synthesis and detailed characterization of the title compound have been reported and 1H NMR studies indicate it to be an isomeric mixture.…”

CSe2-free synthesis of [1,3]diselenole-2-thione and its application to syntheses of iodinated tetraselenafulvalenes (TSeFs)

“…Synthesis of the parent TSeF was first reported in 1974 by Engler and Patel 3 and a large number of both symmetrical and unsymmetrical TSeFs have been synthesized within the last three decades. Except for the parent TSeF 4 and a few examples of heterocycle-fused TSeFs, 5,6 the highly toxic and bad smelling reagent CSe 2 was employed as a key material in the syntheses of [1,3]diselenole-2-selone derivatives, which are essential to TSeF synthesis. Some research groups still use CSe 2 for the syntheses of TSeFs, however, the trend is moving away from using such a highly toxic reagent considering the protection of the environment and researchers own safety.…”

Synthesis, Structure and Properties of an Unsymmetrical Tetraselenafulvalene Donor Fused with a Pyrazino-Ring (PEDTTSeF) and its Cation Radical Salt

“…With this in mind, we focused on introducing the TSeF framework to PEDTTTF in order to realize the intermolecular network through the N±S and N±Se contacts and to stabilize the metallic state. In this communication, we report the synthesis, crystal structure and electro-chemical properties of a novel unsymmetrical TSeF donor, pyrazinoethylenedithio-TSeF (PEDTTSeF) 1 (Scheme 1), along with the crystal and band structures, and the electrical and magnetic properties of its cation radical salts.PEDTTSeF was synthesized by a cross-coupling reaction of pyrazino-1,3-diselenol-2-one 2 [7] and 4,5-ethylenedithio-1,3-diselenol-2-one 3 [2b] with trimethylphosphite in refluxing toluene. The reaction mixture was reduced in vacuo and the resultant red oil was purified by column chromatography (silica gel, dichloromethane).…”

“…PEDTTSeF was synthesized by a cross-coupling reaction of pyrazino-1,3-diselenol-2-one 2 [7] and 4,5-ethylenedithio-1,3-diselenol-2-one 3 [2b] with trimethylphosphite in refluxing toluene. The reaction mixture was reduced in vacuo and the resultant red oil was purified by column chromatography (silica gel, dichloromethane).…”