Donor-π-Acceptor Species Derived from Functionalised 1,3-Dithiol-2-ylidene Anthracene Donor Units Exhibiting Photoinduced Electron Transfer Properties: Spectroscopic, Electrochemical, X-Ray Crystallographic and Theoretical Studies
Steric interactions between the anthraquinoid core and the 1,3-dithiole and dicyanomethylene groups play a key role in determining the physical properties of system 1. The intramolecular charge transfer properties of this donor–π-acceptor species have been explored and cyclic voltammetric data, X-ray crystal structures and ab initio calculations are also reported.
Allocation of Ambipolar Charges on an Organic Diradical with a Vinylene-Phenylenediyne Bridge.
Two redox and magnetically active perchlorotriphenylmethyl (• PTM) radical units have been connected as end-capping groups to a bis(phenylene)diyne chain through vinylene linkers. Negative and positive charged species have been generated, and the influence of the bridge on their stabilization is discussed. Partial reduction of the electron-withdrawing • PTM radicals results in a class-II mixed-valence system with the negative charge located on the terminal PTM units, proving the efficiency of the conjugated chain for the electron transport between the two terminal sites. Counterintuitively, the oxidation process does not occur along the electron-rich bridge but on the vinylene units. The • …
Electronic Interactions in a New π-Extended Tetrathiafulvalene Dimer
The first pi-extended tetrathiafulvalene (exTTF) dimer in which the two exTTF units are covalently connected by 1,3-dithiole rings has been obtained in a multistep synthetic procedure involving the Ullmann cross-coupling reaction by using copper(I) thiophene-2-carboxylate (CuTC). The electronic spectrum reveals a significant electronic interaction between the exTTF units. The electrochemical study carried out by cyclic voltammetry in solution and in thin-layer conditions, and the electrochemical simulation and spectroelectrochemical (SEC) measurements confirm the electronic communication and show that the oxidation of dimer 14 occurs as two consecutive 2 e(-) processes D(0)-D(0)-->D(2+)-D(0…
The Interplay of Inverted Redox Potentials and Aromaticity in the Oxidized States of New π-Electron Donors: 9-(1,3-Dithiol-2-ylidene)fluorene and 9-(1,3-Dithiol-2-ylidene)thioxanthene Derivatives
Derivatives of 9-(1,3-dithiol-2-ylidene)fluorene (9) and 9-(1,3-dithiol-2-ylidene)thioxanthene (10) have been synthesised using Horner-Wadsworth-Emmons reactions of (1,3-dithiol-2-yl)phosphonate reagents with fluorenone and thioxanthen-9-one. X-ray crystallography, solution electrochemistry, optical spectroscopy, spectroelectrochemistry and simultaneous electrochemistry and electron paramagnetic resonance (SEEPR), combined with theoretical calculations performed at the B3P86/6-31G** level, elucidate the interplay of the electronic and structural properties in these molecules. These compounds are strong two-electron donors, and the oxidation potentials depend on the electronic structure of t…