Phospharadialenes—A New Kid in Town

Abstract

A bright future: The realization that a mixture of squaraine derivatives drastically improve quantum efficiency in the visible and near‐IR region of organic solar cells, and the synthesis of the first phospharadialene serve as the focus for a short overview of oxocarbons and related heteroorganic compounds.

Aromatic Versus Heteroradialene Character in Extended Thiophloroglucinol Ligands and their Trinuclear Nickel(II) Complexes

“…[74][75][76][77][78][79] However, during our efforts to synthesize such extended thiophloroglucinol ligands we realized that in the triplesalen ligands and in extended phloroglucinol ligands in general, the central backbone must be described as the N-protonated tautomer rather than the Oprotonated tautomer, with a major contribution of resonance structure IV with exocyclic C=C and C=O bonds (Scheme 1 d). [85,86] Radialenes are alicyclic compounds exhibiting cross-conjugation of the double-bond system, that is, radialenes do not have a delocalized aromatic p system. [85,86] Radialenes are alicyclic compounds exhibiting cross-conjugation of the double-bond system, that is, radialenes do not have a delocalized aromatic p system.…”

“…[38,[80][81][82][83][84] This ketoenamine resonance structure is reminiscent of [6]radialenes and has been termed heteroradialene. [85,86] Radialenes are alicyclic compounds exhibiting cross-conjugation of the double-bond system, that is, radialenes do not have a delocalized aromatic p system. [85,87,88] The loss of the delocalized aromatic p system in the heteroradialene resonance structure is anticipated to be a second major reason for the inefficient spin-polarization in triplesalen complexes despite the low spin-density in the O p z orbitals.…”

“…80–84 This keto‐enamine resonance structure is reminiscent of [6]radialenes and has been termed heteroradialene 85. 86 Radialenes are alicyclic compounds exhibiting cross‐conjugation of the double‐bond system, that is, radialenes do not have a delocalized aromatic π system 85. 87, 88…”

On‐Surface Synthesis of [3]Radialenes via [1+1+1] Cycloaddition

“…Among the family of radialenes, [3]radialene is the smallest and has a special cross-conjugated six-center, six π-electron system, [3] and is regarded as a structural isomer of benzene but with different conjugation patterns, which shed light on the fundamental understanding of the conjugation effect on properties and functions. [2,4] [3]Radialene and its derivatives exhibit unique optical and electrochemical properties, [1,[5][6][7] such as tunable absorption from UV/Vis to NIR, [6] and multiple redox potentials. [7] An ideal and straightforward pathway to generate [3]radialenes is the [1+1+1] cycloaddition of the unsaturated groups of the reactants.…”

Functional small-molecules & polymers containing PC and AsC bonds as hybrid π-conjugated materials

“…Due to the high reactivity of compounds containing unsaturated AsQC bonds, 10 no polymers containing arsaalkenes have been reported to date. The incorporation of arsenic into p-conjugated hybrid systems is thus stimulating; its polarizable nature, lower LUMO levels leading to higher electron affinity, 11 lower oxophilicity in comparison to phosphorus species, diffuse frontier orbital nature that could be exploited in a stimuli responsive fashion, as well as innate atomic properties which could be used in a perturbative manner, are a few hypotheses for its usage.…”