アンチアロマティック・ディシクロペンタ[b,g]/[a,f]ナフタレン・アイソマーは,調節可能なダイラディカル特性を持つオープンシェル・シングレット基底状態を示している
Tingting Xu1, Yi Han1, Zhongjin Shen1
1Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore, Singapore.
Journal of the American Chemical Society
|November 29, 2021
まとめ
研究者らは,安定した核拡張インダセンの同位体であるディサイクロペンタ[b,g]-ナフタレンとディサイクロペンタ[a,f]ナフタレンを合成した. 両方の分子は,グローバルな反芳香性と,オープンシェルのシングレット基底状態を示し,一つの同位体はより強い反芳香性を示している.
科学分野:
- 有機化学
- 材料科学
- アロマティック性研究
背景:
- コア拡張されたs-およびas-インダセンは1986年以来,著しい関心を集めている.
- この高度に反応する分子の合成は 30年以上に渡って 課題として残っています
研究 の 目的:
- 2つの新しい,比較的安定した,核拡張インダセンの合成を報告する.
- これらの新しい化合物の構造的,電子的,磁性特性を特徴づける.
主な方法:
- ディサイクロペンタ[b,g]ナフタレンとディサイクロペンタ[a,f]ナフタレンの合成
- X線結晶分析について
- 変数温度1H NMRと電子スピン共鳴 (ESR) 測定
- 電子吸収スペクトル
- 理論的な計算だ
主要な成果:
- 2つの安定した核拡張インダセンの同位体,ディサイクロペンタ[b,g]-ナフタレン (5) とディサイクロペンタ[a,f]ナフタレン (6) が成功して合成された.
- X線結晶学では 固有の骨格構造が判明しました 結合が5位と結合が6位に分かれています
- 両化合物は,オープンシェルシングレット基底状態で全般的に反芳香性であることが確認された.
- 分子6は,分子5 (y0 = 30%, ΔEST = -6.88 kcal mol−1) に比べて,より強い反芳香性,より高いダイラジカル特性 (y0 = 48%) と,より小さなシングレット-トリプレットエネルギーギャップ (ΔEST = -0.99 kcal mol−1) を示した.
結論:
- この成功した合成により,高度に反応性のある核拡張インダセンの製造という長年の課題が解決されました.
- アイソメアの独特の構造および電子特性は,それらの異なる抗芳香性およびダイラジカル性との相関関係にある.
- これらの発見は,多循環性芳香炭化水素における反芳香性およびオープンシェルシステムの根本的な性質に関する貴重な洞察を提供します.
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