Dominating Antiaromatic Character of <i>as</i>-Indacene Decides Overall Properties of a Formally Aromatic Dicyclopenta[<i>c</i>]fluorenothiophene
作者:Priyank Kumar Sharma、Dibyendu Mallick、Himanshu Sharma、Soumyajit Das
DOI:10.1021/acs.orglett.3c00261
日期:——
Dicyclopenta[c]fluorenothiophene 5 was synthesized as the isoelectronic polycyclic heteroarene analogue of an as-indacenodifluorene with a (4n + 2)π-electron perimeter. Single-crystal and 1H NMR analyses indicated a quinoidal ground state for 5, which was supported by theoretical calculations while suggesting a degree of antiaromaticity of the as-indacene subunit greater than that for s-indacenodifluorene
Dicyclopenta[ c ]fluorenothiophene 5被合成为具有 (4 n + 2)π 电子周长的as-茚并二芴的等电子多环杂芳烃类似物。单晶和1 H NMR 分析表明5为醌型基态,这得到理论计算的支持,同时表明as -indacene difurene 3的抗芳香性程度大于s -indacenodifluorene 。5的主要反芳香性由到达近红外区域的宽弱强吸收尾、四级氧化还原两性和小的 HOMO-LUMO 能隙证明。