Self‐Assembled Architectures with Segregated Donor and Acceptor Units of a Dyad Based on a Monopyrrolo‐Annulated TTF–PTM Radical

Abstract

An electron donor-acceptor dyad based on a polychlorotriphenylmethyl (PTM) radical subunit linked to a tetrathiafulvalene (TTF) unit through a π-conjugated N-phenyl-pyrrole-vinylene bridge has been synthesized and characterized. The intramolecular electron transfer process and magnetic properties of the radical dyad have been evaluated by cyclic voltammetry, UV/Vis spectroscopy, vibrational spectroscopy, and ESR spectroscopy in solution and in the solid state. The self-assembling abilities of the radical dyad and of its protonated non-radical analogue have been investigated by X-ray crystallographic analysis, which revealed that the radical dyad produced a supramolecular architecture with segregated donor and acceptor units in which the TTF subunits were arranged in 1D herringbone-type stacks. Analysis of the X-ray data at different temperatures suggests that the two inequivalent molecules that form the asymmetric unit of the crystal of the radical dyad evolve into an opposite degree of electronic delocalization as the temperature decreases.

Tetrathiafulvalene–Polychlorotriphenylmethyl Dyads: Influence of Bridge and Open‐Shell Characteristics on Linear and Nonlinear Optical Properties

“…Recently, we have reported different D-π-A systems based on a PTM radical electron-acceptor linked to a TTF electron-donor through conjugated vinylene bridges that exhibit a reversible switching between a neutral and a zwitterionic state in solution through the application of external stimuli [29][30][31][32] or conductivity in solid state. [33][34][35] In order to study the optical properties of this kind of radical dyads and evaluate the influence of the open-shell character and the length of the bridge, we have synthesized and characterized a family of TTF-π-PTM radical derivatives (1a-1c) and their non-radical analogues (2a-2c) (Scheme 1). In this article, we present a detailed study of the intramolecular charge-transfer dependence on the open-shell structure and the bridge length of this family of compounds.…”

Photo-physical properties of donor-acceptor-radical triad based on functionalized tetrathiafulvalene and nitronyl nitroxide radical

“…The design and elaboration of such "TTF-radical" dyads are very challenging and to date only few researchers took this synthetic route: Sugawata et al [23]- [26] developed the functionalization of the TTF core with nitrosyl or nitronyl nitroxide spin carriers while Yamaguchi et al [27] and Datta et al [28], [29] studied such donor-radical dyads from a computational point of view. Additionally, Pilkington et al [30], [31] used the verdazyl moiety as stable radical while Veciana et al exploited the perchlorotriphenylmethyl radicals [32]- [36] to design their dyads.…”

Synthesis and Characterization of Ethylenedithio-MPTTF-PTM Radical Dyad as a Potential Neutral Radical Conductor

“…The intense peak at 385 nm corresponds to the radical chromophore of the PTM subunit and the shoulders appearing around 450 and 550 nm are assigned to the electronic conjugation of the unpaired electron into the conjugated π-framework [12]. The lowest energy band, which appears around 800 nm, is ascribed to the intramolecular charge transfer (ICT) occurring between the electron-donor TTF and electron-acceptor PTM units.…”

“…Subsequently, we evaluate the physical properties in solution of the radical dyad 2 that could be a neutral radical conductor in the solid state. In this direction, we have very recently reported the organic donor-acceptor (D-A) dyad 1 based on the non-planar and spin localized radical perchlorotriphenylmethyl (PTM) radical linked to a monopyrrolo-tetrathiafulvalene (MPTTF) unit that exhibited semiconducting behavior with high conductivity upon application of high pressure [12][13][14][15]. The origin of such conducting behavior was attributed to the increased electronic bandwidth W, thanks to short intermolecular interactions between the MPTTF and PTM subunits, and the decreasing of the Coulomb repulsion energy U due to the charge reorganization occurring at high pressure.…”

“…The origin of such conducting behavior was attributed to the increased electronic bandwidth W, thanks to short intermolecular interactions between the MPTTF and PTM subunits, and the decreasing of the Coulomb repulsion energy U due to the charge reorganization occurring at high pressure. The intramolecular charge transfer between the TTF and PTM moieties, as demonstrated by the formation of charge-separated zwitterionic species in solution when using polar solvents [12,13], is an optimal condition for obtaining neutral radical conductors since the Coulomb repulsion energy U can be minimized.…”