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Tetrathiafulvalene–Oligo( para ‐phenyleneethynylene) Conjugates: Formation of Multiple Mixed‐Valence Complexes upon Electrochemical Oxidation
Author(s) -
Lipnická Šárka,
Bělohradský Martin,
Kolivoška Viliam,
Pospíšil Lubomír,
Hromadová Magdaléna,
Pohl Radek,
Chocholoušová Jana Vacek,
Vacek Jaroslav,
Fiedler Jan,
Stará Irena G.,
Starý Ivo
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102868
Subject(s) - tetrathiafulvalene , valence (chemistry) , cyclic voltammetry , trimer , electrochemistry , dimer , chemistry , redox , monomer , sonogashira coupling , bulk electrolysis , electrolysis , crystallography , polymer chemistry , inorganic chemistry , polymer , organic chemistry , electrode , molecule , catalysis , palladium , electrolyte
Short monodisperse oligo‐ ( para ‐phenyleneethynylene) ( p OPE) units bearing laterally attached tetrathio‐substituted tetrathiofulvalene (TTF) units have been synthesised from functionalised aromatic building blocks by using the Sonogashira cross‐coupling methodology. The unusual redox properties of these TTF– p OPE conjugates were observed by employing electrochemical methods, such as cyclic voltammetry and exhaustive electrolysis. We found that formally one half of the TTF units in the p OPE monomer 1 , dimer 2 , and trimer 3 (with 2, 4, and 6 TTF units, respectively) are electrochemically silent during the first‐step oxidation at 0.49 V. We propose the formation of persistent mixed‐valence complexes from the TTF and TTF +. units present in an equal ratio. Such mixed‐valence dyads (single or multiple in the partially oxidised 1 – 3 ) exhibit an unusual stability towards oxidation until the potential of the second oxidation at 0.84 V is achieved. This finding suggests that below this potential the oxidation of the respective mix‐valence complexes is extremely slow.