抗芳香的Dicyclopenta[b,g]/[a,f]纳烯异构体显示开单片基态与可调的二基性质
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
概括
研究人员合成了稳定,核心扩展的因达同体,二cyclopenta[b,g]-naphthalene和二cyclopenta[a,f]naphthalene. 这两种分子均表现出全球抗芳香性和开单片基态,其中一种异构体表现出更强的抗芳香性.
科学领域:
- 有机化学
- 材料科学
- 芳香性研究
背景情况:
- 自1986年以来,核心扩展的s-和as-indacenes具有显著的兴趣.
- 这些高反应性分子的合成已经成为30多年来的一个挑战.
研究的目的:
- 报告两种新型,相对稳定的,核心扩展的印加同体的成功合成.
- 描述这些新化合物的结构,电子和磁性特性.
主要方法:
- 二环[b,g] - 纳和二环[a,f] 纳的合成
- 进行X射线晶体分析.
- 可变温度1HNM和电子自旋共振 (ESR) 的测量.
- 电子吸收光谱
- 理论上的计算.
主要成果:
- 两个稳定的核心扩展的印达同体,二cyclopenta[b,g]-naphthalene (5) 和二cyclopenta[a,f]naphthalene (6),已经成功合成.
- 通过X射线结晶学发现了不同的骨干结构: 5的键位移和6的键位移.
- 这两种化合物均被证实具有全球抗芳香性,具有开单片基态.
- 与5分子 (y0 = 30%, ΔEST = -6.88 kcal mol-1) 相比,分子6表现出更强的反芳香性,更高的二基性质 (y0 = 48%) 和更小的单元-三元能量差距 (ΔEST = -0.99 kcal mol-1).
结论:
- 这种成功的合成克服了长期以来制备高度反应的核扩展印加的挑战.
- 异构体的独特结构和电子特性与它们不同程度的抗芳香性和激进性有关.
- 这些发现为多环芳中反芳性和开系统的基本性质提供了宝贵的见解.
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