Bhattacharjee Rameswar, McCormack Megan E, Zhou Zheng, Wei Zheng, Petrukhina Marina A, Kertesz Miklos
Department of Chemistry and Institute of Soft Matter, Georgetown University 37th and O Streets, NW Washington DC 20057-1227 USA
Department of Chemistry, University at Albany, State University of New York 1400 Washington Avenue Albany NY 12222 USA
Chem Sci. 2024 Aug 27;15(37):15221-31. doi: 10.1039/d4sc03774j.
A new and unique π-stacking triphenylene trimer cation radical unit appears in the crystal structure of a newly synthesized salt with an oligomeric gallium(iii) chloride, [(CH)]˙(GaCl), which is the first triphenylene aggregate observed. The structure is attributed to a shared electron distributed over the trimer displaying π-stacking pancake bonding. Computational modeling rationalizes the appearance of a "chain-shaped" rather than a "star-shaped" gallium chloride anion as well as the reasons why the trimer, rather than a radical cation aggregate of different size, is preferred in this system. Moreover, the calculations allowed evaluation of larger cationic triphenylene radical π-stacked aggregates. Additional stabilization due to the shared single unpaired electron is calculated to remain significant at 5-7 kcal mol for aggregates as large as 5-6 units.
一种新的独特的π-堆积三亚苯基三聚体阳离子自由基单元出现在一种新合成的与低聚氯化镓(iii)形成的盐[(CH)]˙(GaCl)的晶体结构中，这是观察到的首个三亚苯基聚集体。该结构归因于分布在三聚体上的共享电子，展现出π-堆积的煎饼状键合。计算模型解释了“链状”而非“星状”氯化镓阴离子的出现，以及在该体系中为何三聚体而非不同大小的自由基阳离子聚集体更受青睐的原因。此外，这些计算使得对更大的阳离子三亚苯基自由基π-堆积聚集体进行评估成为可能。对于多达5 - 6个单元的聚集体，由于共享单未配对电子导致的额外稳定性经计算在5 - 7千卡/摩尔时仍很显著。
