Solution Disproportionation Energies of 1,2,3,5-Dithia- and Diselenadiazoles. Direct Comparison of Solution Oxidation Potentials with Ionization Energies in the Gas Phase

Thiazyl radicals: old materials for new molecular devices

“…Gas phase measurements on a number of thiazyl radicals derivatives have shown good correlation with theoretical estimates of both IP and EA. 39 These in turn have been in excellent agreement with solution electrochemical studies of the reduction and oxidation behaviour of the DTDA rings. 38 These electrochemical studies by Boeré 39 and others on phenyl-substituted DTDA radicals have shown that small changes to the redox potential can be achieved in a predictable and systematic manner.…”

“…39 These in turn have been in excellent agreement with solution electrochemical studies of the reduction and oxidation behaviour of the DTDA rings. 38 These electrochemical studies by Boeré 39 and others on phenyl-substituted DTDA radicals have shown that small changes to the redox potential can be achieved in a predictable and systematic manner. In the case of DTDA radicals, the singly occupied molecular orbital (SOMO) is localised on the CN 2 S 2 ring (Fig.…”

The Synthesis and Characterization of Stable Radicals Containing the Thiazyl (SN) Fragment and Their Use as Building Blocks for Advanced Functional Materials

“…The electrochemical method does not provide accurate absolute U eff values, but the correlation between E cell and either calculated or gas phase determined (IE-EA) U eff is very good, as shown by Boeré who investigated the solution electrochemical properties of a large number of dithia-and diselenadiazolyl radicals. 96 These radicals turn out to have quite large E cell values (1.43 ± 0.06 V for dithiadiazolyls and 1.25 ± 0.03 V for diselenadiazolyls) which are not very sensitive to substituent effects (Section 9.3.2). The implications are that, even if the desired uniform radical π stacked structure based on dithia-or diselenadiazolyl radicals could be realized, effective (metallic) charge transport would be unlikely because of the high H disp values inherent to these radicals.…”

“…87,94,95 Radicals with electron donating or withdrawing groups directly attached to the ring show a stronger substituent dependence. 96 For example, radical 35 with R = NMe 2 is oxidized at +0.35 V and reduced at −0.96 V, while the derivative with R = CF 3 has oxidation and reduction potentials of +0.91 and −0.42 V respectively. The gas phase electronic spectrum of one derivative (R = H) has been recorded; the transition centered at 617 nm corresponds to excitation into what is essentially an S-S σ * orbital.…”

Synthesis, Electronic Structures, and Electrochemistry of 3‐Triarylphosphoraniminato‐1,3,5‐trithia‐2,4,6,8‐tetrazocines: Detection of Trithiatetrazocinyl Radical Anions

“…For diamagnetic and formally electron‐rich thiazyl heterocycles of this type, voltammetry can assess (i) the redox stability window, also known as the “cell potential” E cell between the most accessible oxidation and reduction processes and (ii) the degree of redox‐tunability exerted by substituents on the R and ER′ 3 groups. We have previously made use of a series of 3‐ and 4‐substituted aryl R groups as a standard set of substituents for various thiazyl heterocycles to test relative redox‐tunability ,,. Here we report application of this concept to type G compounds by the synthesis and full chemical‐ and structural characterization of a double series of 3‐triarylphosphoraniminato‐7‐aryl‐1,3,5‐trithia‐2,4,6,8‐tetrazocines 4 (with Ar′=Ph) and 5 (with Ar′=4‐CH 3 OC 6 H 4 ).…”