Haley Lab, University of Oregon

Indenofluorene Scaffolds


Polycyclic hydrocarbons that possess extended π-conjugation are of tremendous interest due to their potential use in optical and Figure 1 electronic device applications. While a majority of studies have focused on acenes and their derivatives (for example, compounds 1-2), these systems are susceptible to degradation due to environmental effects, through oxidative or photolytic pathways; thus, there is a pressing need for alternative, acene-like topologies. Current research in the lab is focused on molecules based on or inspired by the indenofluorene (IF) skeleton, such as compounds 3-5. Over the last few years, we have adapted and/or developed general methods for the assembly of a variety of fully conjugated IF derivatives and initiated exploration of their materials properties. We have shown that IFs can be prepared in gram quantities with good overall yields and excellent purity using methodologies amenable to large-scale production.

 

In addition to being challenging synthetic targets, IFs help to provide answers to fundamental questions about structure, bonding, and reactivity in expanded, conjugated structures. They also have the potential to act as rigid, planar, electron-accepting cores for the formation of advanced materials with novel electronic properties. We are exploiting the materials potential of IFs via a combined experimental and theoretical approach, with an emphasis toward the use of indenofluorenes as organic semiconductors in devices. Importantly, we demonstrated recently that single crystals of an aryl-substituted IF could serve as an active layer in an organic field-effect transistor that exhibits ambipolar behavior.



Selected Publications



Synthesis and Characterization of Two Unsymmetrical Indenofluorene Analogues: Benzo[5,6]-s-indaceno[1,2-b]thiophene and Benzo[5,6]-s-indaceno[2,1-b]thiophene



Marshall. J. L.; O'Neal, N. J.; Zakharov, L. N.; Haley, M. M. J. Org. Chem. 2016, in press.
DOI: 10.1021/10.1021/acs.joc.6b00340




Synthesis of Open-Shell Ladder π-Systems by Catalytic C–H Annulation of Diarylacetylenes



Maekawa, T.; Ueno, H.; Segawa, Y.; Haley, M. M.; Itami, K. Chem. Sci. 2016, 7, 650-654.
DOI: 10.1039/C5SC03391H




Synthesis and properties of fully conjugated indacenediselenophene and diindenoselenophene derivatives



Marshall. J. L.; Rudebusch, G. E.; Vonnegut, C. L.; Zakharov, L. N.; Haley, M. M. Tetrahedron Lett. 2015, 56, 3235-3239.
DOI: 10.1016/j.tetlet.2014.12.096




Synthesis and Optoelectronic Properties of Indeno[1,2-b]fluorene-6,12-dione Donor–Acceptor–Donor Triads



Frederickson, C. K.; Haley, M. M. J. Org. Chem. 2014, 79, 11241-11245.
DOI: 10.1021/jo502009p




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



Rose, B. D.; Shoerb, L. E.; Wasielewski, M. R.; Haley, M. M. Chem. Phys. Lett. 2014, 616-617, 137-141.
DOI: 10.1016/j.cplett.2014.10.031




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



Rose, B. D.; Santa Maria, P. J.; Fix, A.G.; Vonnegut, C. L.; Zakharov, L.; Parkin, S. R.; Haley, M. M. Beilstein J. Org. Chem. 2014, 10, 2122–2130.
DOI: 10.3762/bjoc.10.219




Quinoidal diindenothienoacenes: Synthesis and properties of new functional organic materials



Rudebusch, G. E.; Fix, A. G.; Henthorn, H. A.; Vonnegut, C. L.; Zakharov, L.; Haley, M. M. Chem. Sci. 2014, 5, 3627-3633.
DOI: 10.1039/C4SC01432D




Experimental and Computational Studies of the Neutral and Reduced States of Indeno[1,2-b]fluorene



Rose, B. D.; Sumner, N. J.; Filatov, A. S.; Peters, S. J.; Zakharov, L. N.; Petrukhina, M. A.; Haley, M. M. J. Am. Chem. Soc. 2014, 136, 9181–9189.
DOI: 10.1021/ja503870z




Synthesis and properties of fully-conjugated indacenedithiophenes



Young, B. S.; Chase, D. T.; Marshall, J. L.; Vonnegut, C. L.; Zakharov, L. N.; Haley, M. M. Chem. Sci. 2014, 5, 1008-1014.
DOI: 10.1039/C3SC53181C




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



Fix, A. G.; Deal, P. E.; Vonnegut, C. L.; Rose, B. D.; Zakharov, L. N.; Haley, M. M. Org. Lett. 2013, 15, 1362–1365.
DOI: 10.1021/ol400318z




6,12-Diarylindeno[1,2-b]fluorenes: Syntheses, Photophysics, and Ambipolar OFETs



Chase, D. T.; Fix, A. G.; Kang, S. J.; Rose, B. D.; Weber, C. D.; Zhong, Y.; Zakharov, L. N.; Lonergan, M. C.; Nuckolls, C.; Haley, M. M. J. Am. Chem. Soc. 2012, 134, 10349–10352.
DOI: 10.1021/ja303402p




Fluoreno[4,3-c]fluorene: A Closed-Shell, Fully Conjugated Hydrocarbon



Rose, B. D.; Vonnegut, C. L.; Zakharov, L. N.; Haley, M. M. Org. Lett. 2012, 14, 2426–2429.
DOI: 10.1021/ol300942z




Electron-Accepting 6,12-Diethynylindeno[1,2-b]fluorenes: Synthesis, Crystal Structures, and Photophysical Properties



Chase, D. T.; Fix, A. G.; Rose, B. D.; Weber, C. D.; Nobusue, S.; Stockwell, C. E.; Zakharov, L. N.; Lonergan, M. C.; Haley, M. M. Angew. Chem. Int. Ed. 2011, 50, 11103–11106.
DOI: 10.1002/anie.201104797




Synthesis, Crystal Structures, and Photophysical Properties of Electron-Accepting Diethynylindenofluorenediones



Rose, B. D.; Chase, D. T.; Weber, C. D.; Zakharov, L. N.; Lonergan, M. C.; Haley, M. M. Org. Lett. 2011, 13, 2106–2109.
DOI: 10.1021/ol200525g




Indeno[1,2-b]fluorenes: Fully Conjugated Antiaromatic Analogues of Acenes



Chase, D. T.; Rose, B. D.; McClintock, S. P.; Zakharov, L. N.; Haley, M. M. Angew. Chem. Int. Ed. 2011, 50, 1127–1130.
DOI: 10.1002/anie.201006312