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

Rose, Bradley D.; Vonnegut, Chris L.; Zakharov, Lev N.; Haley, Michael M.

doi:10.1021/ol300942z

Cited by 66 publications

(50 citation statements)

References 22 publications

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“…The first system explored using transient absorption spectroscopy in solution was fluoreno[4,3-c]fluorene derivative 1a [10]. The initial absorptive feature that appears at approximately 675-800 nm (Figure 2a) is likely related to the S 2 state, as the calculated S 0 -S 1 transition is forbidden in this system (vide infra).…”

Section: Resultsmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Rose

Shoer

Wasielewski

et al. 2014

Chemical Physics Letters

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a b s t r a c tThe ultrafast excited state decay rates for indenofluorene and fluorenofluorene derivatives as measured by transient absorption spectroscopy are reported. The excited state lifetimes of the molecules were extremely short (ca. 9-12 ps) and are a result of the p-xylylene motif in indenofluorenes and the corresponding expanded 2,6-naphthoquinonedimethide in fluorenofluorene. Quantum chemical calculations indicate that the fast relaxation to the ground state results from a potential energy surface crossing between the S 0 and S 1 states. This process in turn provides an efficient route for excited state deactivation and explains why this class of quinoidal molecules is non-emissive.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Rose

Shoer

Wasielewski

et al. 2014

Chemical Physics Letters

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“…(Scheme ) . Since this first example of reductive dearomatization using SnCl 2 , a wide variety of substituted [1,2‐ b ]IFs and [1,2‐ b ]IF analogues including indeno[2,1‐ c ]fluorene 63 , fluoreno[4,3‐ c ]fluorene 64 , diindeno[1,2‐ b :2′,1′‐ n ]perylene 65 , and heteroatom‐containing derivatives 66 a – d , and 67 a – c have been realized (Figure ) . While early research demonstrated IFs 62 – 65 contained a nonaromatic para ‐xylylene core, the Haley lab has recently shown that substituting or replacing the outer ring of the [1,2‐ b ]IF with thiophene ( 66 a and 67 a ) or benzothiophene ( 66 c , d and 67 b , c ) dramatically increases the antiaromaticity of the s ‐indacene core.…”

Section: Snii‐mediated Reduction Of Diolsmentioning

confidence: 99%

“…(Scheme 23). [110] Since this first example of reductive dearomatization using SnCl 2 ,awide variety of substituted [1,2-b]IFs [111] and [1,2-b]IF analogues including indeno[2,1-c]fluorene 63, [112] fluoreno[4,3-c]fluorene 64, [113] diindeno[1,2-b:2',1'n]perylene 65, [114] andh eteroatom-containing derivatives 66 ad,a nd 67 a-c have been realized ( Figure 8). [115] While early research demonstrated IFs 62-65 contained an onaromatic paraxylylene core, [110,112,114] Scheme23.…”

Section: Acid-free Sn II -Mediated Reductiono Fdiolsmentioning

confidence: 99%

Reductive Aromatization/Dearomatization and Elimination Reactions to Access Conjugated Polycyclic Hydrocarbons, Heteroacenes, and Cumulenes

et al. 2017

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Acenes, heteroacenes, conjugated polycyclic hydrocarbons, and polycyclic aromatic hydrocarbons (collectively referred to in this review as conjugated polycyclic molecules, CPMs) have fascinated chemists since they were first isolated and synthesized in the mid 19th century. Most recently, these compounds have shown significant promise as the active components in organic devices (e.g., solar cells, thin‐film transistors, light‐emitting diodes, etc.), and, since 2001, a plethora of publications detail synthetic strategies to produce CPMs. In this review, we discuss reductive aromatization, reductive dearomatization, and elimination/extrusion reactions used to form CPMs. After a brief discussion on early methods to synthesize CPMs, we detail the use of reagents used for the reductive (de)aromatization of precursors containing 1,4‐diols/diethers, including SnCl2 and iodide (I−). Extension of these methods to carbomers and cumulenes is briefly discussed. We then describe low‐valent metal species used to reduce endoxides to CPMs, and discuss the methods to directly reduce acenediones and acenones to the respective acene. In the final section, we describe methods used to affect aromatization to the desired CPM via extrusion of small, volatile molecules.

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“…[14] We have examined alternative IF geometries such as the [2,1-c] isomer (e.g., 10). [15] We can dearomatize expanded central cores such as naphthalene (e.g., 11) [16] and thienoacenes (e.g., 12). [17] We have studied their redox chemistry [11] and photophysics [8] as well as made forays into materials applications.…”

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confidence: 99%