83 research outputs found

    Carbon(sp2)-carbon(sp3) Bond-forming Cross-coupling Reactions Using Sulfur-Modified Au-Supported Nickel Nanoparticle Catalyst

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    We report a carbon(sp2)-carbon(sp3) bond-forming cross-coupling reactions by employing a nano-size nickel catalyst supported on sulfur-modified gold (SANi). This transformation demonstrates an efficient synthesis of functionalized aryl compounds, including heterocycles. Notably, the reactions proceeded in good yields with significantly low leaching of nickel from SANi. Moreover, SANi could be recycled several times without significant loss of catalytic activity.This is the peer reviewed version of the following article: Ohta R., Shio Y., Akiyama T., et al. Carbon(sp2)-carbon(sp3) Bond-forming Cross-coupling Reactions Using Sulfur-Modified Au-Supported Nickel Nanoparticle Catalyst. Asian Journal of Organic Chemistry, which has been published in final form at https://doi.org/10.1002/ajoc.202200229. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited

    Video Observations of Tiny Near-Earth Objects with Tomo-e Gozen

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    We report the results of video observations of tiny (diameter less than 100 m) near-Earth objects (NEOs) with Tomo-e Gozen on the Kiso 105 cm Schmidt telescope. A rotational period of a tiny asteroid reflects its dynamical history and physical properties since smaller objects are sensitive to the YORP effect. We carried out video observations of 60 tiny NEOs at 2 fps from 2018 to 2021 and successfully derived the rotational periods and axial ratios of 32 NEOs including 13 fast rotators with rotational periods less than 60 s. The fastest rotator found during our survey is 2020 HS7 with a rotational period of 2.99 s. We statistically confirmed that there is a certain number of tiny fast rotators in the NEO population, which have been missed with any previous surveys. We have discovered that the distribution of the tiny NEOs in a diameter and rotational period (D-P) diagram is truncated around a period of 10 s. The truncation with a flat-top shape is not explained well either by a realistic tensile strength of NEOs or suppression of YORP by meteoroid impacts. We propose that the dependence of the tangential YORP effect on the rotational period potentially explains the observed pattern in the D-P diagram.Comment: This article is published in PASJ as open access, published by OUP (https://doi.org/10.1093/pasj/psac043). 27 pages, 16 figure