Indeno[2,1-c]fluorene: A New Electron-Accepting Scaffold for Organic Electronics

Abstract

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. Their electronic properties make this class of compounds attractive for applications in organic electronic devices.

Recent Progress in Quinoidal Singlet Biradical Molecules

“…81 The X-ray determined structure shows strong bond length alternation in the central 5-6-5 core, indicative of small singlet biradical character. The electrochemical HOMOLUMO gaps are relatively large (2.08 eV for 39a, 1.73 eV for 39c).…”

Spirobifluorene Regioisomerism: A Structure–Property Relationship Study

“…[1,2] Similarly, Haley and co-workers have shown the impact of the regioisomerism on the electronic properties of a promising family of antiaromatic indenofluorene derivatives. [3,4] Spiro configured compounds constitute one of the most important class of OSCs. Indeed, since the discovery of the 'spiro concept', the 9,9'-spirobifluorene (SBF) has become a central molecular scaffold in organic electronics.…”

Unusually short excited state lifetimes of indenofluorene and fluorenofluorene derivatives result from a conical intersection

“…Numerous small-molecule systems have been developed toward this goal that employ extended pi-conjugated centers [5][6][7][8][9]. One such molecular class of interest is the p-quinodimethane-containing indenofluorenes and related molecules (e.g., 1-3, Figure 1), which have recently been realized through synthesis [10][11][12][13][14][15][16][17]. Intriguingly, these compounds have been found to be non-emissive and thus we wished to examine their photophysics.…”