Optimal Synergy between Azulenes and Acenes in Azuacenes with 6-7-5 Ring Topology.

Azuacenes, defined as azulene fused with acenes in a 6-7-5 ring topology and spanning lengths from 3 to 6 rings, have been synthesized using a new skeleton editing and [3 + 2] annulation synthesis protocol as a distinction regarding the procedures to obtain the 6-5-7 isomers. Comprehensive studies on ground-state and excited-state spectroscopy, electrochemical properties, chemical stability, and solid-state structure have been conducted to compare these azuacenes with acenes. For the same number of rings, we found that azuacenes improve the chemical stability of acenes (i.

Folded-twisted mechanisms control dynamic redox properties, photophysics and electron transfer of anthanthrene-quinodimethanes.

The synthesis, electrochemical, spectroelectrochemical, photophysical and light induced electron transfer reactions in two new anthanthrene quinodimethanes have been studied and analyzed in the context of dynamic electrochemistry. Their properties are dependent on the interconversion between folded and twisted forms, which are separated by a relatively small energy range, thus allowing to explore their interconversion by variable temperature measurements. The photophysics of these molecules is mediated by a diradical excited state with a twisted structure that habilitates rapid intersystem crossing.

Enhancing the Cumulene Character of One-Dimensional Acetylene-Based Systems by Stimuli-Induced Planarization of Their Two Pro-diradicaloid Cyclopenta[h,i]aceanthrylene Units.

Acetylene/polyynes -(C≡C-) and cumulenes =(C=) are connectors widely used for the realization of one-dimensional (1D) π-conjugates. Although both π-moieties are constituted by sp carbon atoms, their different bond connectivity confers distinct physicochemical properties to the resulting systems. In this context, while many acetylene/polyyne- and cumulene-based derivatives have been prepared and studied, no reports have tackled the possibility to reversibly alter the acetylene/polyyne-cumulene electronic character of these derivatives using mild conditions.

Gated off-site radical injection: Bidirectional conductance modulation in single-molecule junctions.

Uncovering the effects of radical injection into responsive organic molecules is a long-sought goal, and the single-molecule junctions provide a unique way to investigate molecular conductance evolution during the radical injection. We can modulate the main channel conductance by using electronic injection from off-site neutral radicals acting as gating terminals. Two families of cyclopentadienone derivatives were synthesized, featuring the inter-pyridyl main conductance channel and the inter-radical paths that are linear (FCF) or cross conjugated (PCP).