Bis(aminoaryl) Carbon‐Bridged Oligo(phenylenevinylene)s Expand the Limits of Electronic Couplings

Abstract

Carbon-bridged bis(aminoaryl) oligo(para-phenylenevinylene)s have been prepared and their optical, electrochemical, and structural properties analyzed. Their radical cations are class III and class II mixed-valence systems, depending on the molecular size, and they show electronic couplings which are among the largest for the self-exchange reaction of purely organic molecules. In their dication states, the antiferromagnetic coupling is progressively tuned with size from quinoidal closed-shell to open-shell biradicals. The data prove that the electronic coupling in the radical cations and the singlet-triplet gap in the dications show similar small attenuation factors, thus allowing charge/spin transfer over rather large distances.

Carbon‐Bridged p‐Phenylenevinylene Polymer for High‐Performance Solution‐Processed Distributed Feedback Lasers

“…Now, while the longer chain oligomers achieved excellent laser performance, COPV1 showed weaker ASE performance, with a rather high threshold of 90 kW cm −2 and a lifetime of only 1.8 × 10 2 pp. The instability problems were attributed to the reactive terminal sites of the photoexcited states . In this work, our hypothesis is that through polymerization, the terminal sites of COPV1 would be protected (in a similar way to the longer COPV homologues which have a smaller distribution of terminal sites and thus higher photostability) so its photostability would improve.…”

Synthesis, Photophysical and Electronic Properties of New Red‐to‐NIR Emitting Donor–Acceptor Pyrene Derivatives

“…[32] In general, delocalized (Robin-Day class-III) derivatives possess an asymmetric and narrow lowest energy band, while in localized (Robin-Day class-II) derivatives the lowest energy band results from an intervalence charge transfer (IV-CT) with a well-defined symmetric Gaussian shape. [64] For that reason, Ito and co-workers concluded that compound III + is a fully delocalized Robin-Day class-III derivative and assumed an electronic coupling V ofṽ IVCT max 2 = 2608 cm À1 . [32] However, our TD-DFT computations on the monocations 7 + and 8 + , with a specially adjusted functional (BLYP with 35 % exact HF exchange [65] ), show that the lowest energy excitation is a result of the promotion of an electron from the b-HOMO to the b-LUMO orbital and these orbitals show the expected phase behavior for localized Robin-Day class-II compounds (Figure 7).…”

Wurster‐Type Nanographenes as Stable Diradical Dications

“…Their interesting properties have fueled their development for potential applications in optoelectronics, [1,2] nonlinearo ptics, [3,4] spintronics [5] and organic photovoltaics. [9][10][11][12][13][14][15][16] Aminiumi ons are isoelectronic to carbon and the highere lectronegativity of the nitrogen atom contributes to their high stability in the biradicalf orm. [9][10][11][12][13][14][15][16] Aminiumi ons are isoelectronic to carbon and the highere lectronegativity of the nitrogen atom contributes to their high stability in the biradicalf orm.…”