Synthesis and Properties of Benzo-Fused Indeno[2,1-c]fluorenes.

A set of fully-conjugated indenofluorenes has been synthesized and confirmed by solid-state structure analysis. The indeno[2,1-c]fluorenes and their benzo-fused analogues all contain the antiaromatic as-indacene core. The molecules possess high electron affinities and show a broad absorption that reaches into the near-IR region of the electromagnetic spectrum.

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing.

We report a new synthetic route to 5,11-disubstituted indeno[1,2-b]fluorene-6,12-diones that is amenable to larger scale reactions, allowing for the preparation of gram amounts of material. With this new methodology, we explored the effects on crystal packing morphology for the indeno[1,2-b]fluorene-6,12-diones by varying the substituents on the silylethynyl groups.

Indeno[2,1-c]fluorene: a new electron-accepting scaffold for organic electronics.

A new class of fully conjugated indenofluorenes has been synthesized and confirmed by solid-state structure analysis. These indeno[2,1-c]fluorene molecules, containing an antiaromatic as-indacene core (in red), possess high electron affinities and show a broad absorption that reaches into the near-IR region of the electromagnetic spectrum. All of the featured compounds reversibly accept up to two electrons.

Indenofluorenes and derivatives: syntheses and emerging materials applications.

The growing demand for flexible electronic devices and hydrogen storage materials has spurred a resurgence of interest in polyaryl hydrocarbons including graphene, acenes, fullerenes, polythiophenes, etc. Indenofluorenes are another polyaryl molecular scaffold that has shown utility in the organic and hybrid materials arena, with polymers incorporating the indeno[1,2-b]fluorene moiety being common in organic light emitting diodes. This review examines the syntheses and properties of the five distinct indenofluorene regioisomers, with a focus on small molecule applications in organic electronics of this intriguing and somewhat underexplored family of polyaryl hydrocarbons.

6,12-Diarylindeno[1,2-b]fluorenes: syntheses, photophysics, and ambipolar OFETs.

Herein we report the synthesis and characterization of a series of 6,12-diarylindeno[1,2-b]fluorenes (IFs). Functionalization with electron donor and acceptor groups influences the ability of the IF scaffold to undergo two-electron oxidation and reduction to yield the corresponding 18- and 22-π-electron species, respectively. A single crystal of the pentafluorophenyl-substituted IF can serve as an active layer in an organic field-effect transistor (OFET).

Synthesis and photophysical properties of expanded dehydrobenzoannulenoannulene trefoils.

A sequential Sonogashira cross-coupling/Pd-mediated oxidative homocoupling strategy affords two-dimensional dehydrobenzoannulene trefoils containing different sizes of the central annulenic ring system. Use of these conditions instead of Cu-mediated homocoupling conditions yields a structural isomer possessing a triphenylene ([6]annulene) core. Noticeable differences in the absorption and emission spectra are observed depending upon the core unit.

Emission from regioisomeric bis(phenylethynyl)benzenes during pulse radiolysis.

Emission from charge recombination between radical cations and anions of a series of regioisomeric 1,4-, 1,3-, and 1,2-bis(phenylethynyl)benzenes (bPEBs) substituted by various electron donor and/or acceptor groups was measured during pulse radiolysis in benzene (Bz). The formation of bPEB in the excited singlet state ((1)bPEB*) can be attributed to the charge recombination between bPEB(*+) and bPEB(*-), which are initially generated from the radiolytic reaction. This mechanism is reasonably explained by the relationship between the annihilation enthalpy change (-DeltaH(o)) for the charge recombination of bPEB(*+) and bPEB(*-) and excitation energy of (1)bPEB*.