Indeno[1,2-b]fluorene derivatives with trimethylsilylethynyl substituents at the 6- and 12-positions were found to undergo cyclo-dimerization, cyclo-trimerization, and higher oligomerizations at room temperature. The cyclic dimer features a novel double-decker motif, composed of two face-to-face stacked bis(propadienylide)dihydroindeno[1,2-b]fluorenes with a short centroid-to-centroid distance of 3.50 Å. The existence of a cyclic trimer and higher oligomers was confirmed by mass spectroscopy and gel permeation chromatography. The results clearly demonstrate the diradical feature of the indeno[1,2-b]fluorene moiety.

中文翻译：

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经由双自由基中间体的6,12-二乙炔基茚并[1,2- b ]芴环低聚

发现在6-位和12-位具有三甲基甲硅烷基乙炔基取代基的茚并[1,2- b ]芴衍生物在室温下进行环二聚，环三聚和更高的低聚。环状二聚体的特征是新颖的双层图案，由两个面对面堆叠的双（丙二烯基）二氢茚并[1,2- b ]芴构成，它们的质心间距离短，为3.50Å。质谱和凝胶渗透色谱法证实了环状三聚体和高级低聚物的存在。结果清楚地证明了茚并[1,2- b ]芴部分的双自由基特征。