• Molecular design strategy reveals near i

    From ScienceDaily@1337:3/111 to All on Sat Oct 17 21:30:34 2020
    Molecular design strategy reveals near infrared-absorbing hydrocarbon


    Date:
    October 17, 2020
    Source:
    Nagoya University
    Summary:
    The lessons learned from a near infrared absorbing, bowl-shaped
    molecule made only from hydrogen and carbon atoms offers insights
    for future organic conductors.



    FULL STORY ========================================================================== Nagoya University researchers have synthesized a unique molecule with a surprising property: it can absorb near infrared light. The molecule is
    made only of hydrogen and carbon atoms and offers insights for making
    organic conductors and batteries. The details were published in the
    journal Nature Communications.


    ========================================================================== Organic chemist Hiroshi Shinokubo and physical organic chemist
    Norihito Fukui of Nagoya University work on designing new, interesting molecules using organic, or carbon-containing, compounds. In the lab,
    they synthesized an aromatic hydrocarbon called methoxy-substituted as-indacenoterrylene. This molecule has a unique structure, as its
    methoxy groups are located internally rather than at its periphery.

    "Initially, we wanted to see if this hydrocarbon demonstrated novel
    phenomena due to its unique structure," says Fukui.

    But during their investigations, the researchers discovered they could
    convert it into a new bowl-shaped hydrocarbon called as-indacenoterrylene.

    "We were surprised to find that this new molecule exhibits near infrared absorption up to 1300 nanometers," Shinokubo explains.

    What's unique about as-indacenoterrylene is not that it
    absorbs near infrared light. Other hydrocarbons can do this as
    well. as-indacenoterrylene is interesting because it does this despite
    being made of only 34 carbon and 14 hydrogen atoms, without containing
    other kinds of stabilizing atoms at its periphery.

    When the scientists conducted electrochemical measurements, theoretical calculations, and other tests, they found that as-indacenoterrylene was intriguingly stable and also had a remarkably narrow gap between its
    highest occupied molecular orbital (HOMO) and its lowest unoccupied
    molecular orbital (LUMO). This means that the molecule has two
    electronically different subunits, one that donates and another that
    withdraws electrons. The narrow HOMO-LUMO gap makes it easier for
    electrons to become excited within the molecule.

    "The study offers an effective guideline for the design of hydrocarbons
    with a narrow HOMO-LUMO gap, which is to fabricate molecules with
    coexisting electron- donating and electron-withdrawing subunits,"
    says Fukui. "These molecules will be useful for the development of next-generation solid-state materials, such as organic conductors
    and organic batteries." The team next plans to synthesize other near infrared-absorbing aromatic hydrocarbons based on the design concepts
    garnered in this current study.


    ========================================================================== Story Source: Materials provided by Nagoya_University. Note: Content
    may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Yuki Tanaka, Norihito Fukui, Hiroshi
    Shinokubo. as-Indaceno[3,2,1,8,7,6-
    ghijklm]terrylene as a near-infrared absorbing C70-fragment. Nature
    Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-17684-6 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2020/10/201017194219.htm

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