Institute for Organic Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany.
Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Straße 21, 79104 Freiburg, Germany.
J Am Chem Soc. 2021 Aug 11;143(31):12244-12252. doi: 10.1021/jacs.1c05251. Epub 2021 Jul 29.
Conjugated nanohoops provide a platform to study structure-property relationships; they are attractive hosts for supramolecular chemistry as well as promising candidates as new organic materials. We herein present []cyclodibenzopentalenes ([]CDBPs) as antiaromatic analogues of []cycloparaphenylenes. Platinum-mediated macrocyclization of dibenzopentalene boronic esters provided the trimer and tetramer with strain energies of up to 80 kcal mol. In the solid state, the cylindrical [4]CDBP molecules align to form columnar structures. The larger hoop [4]CDBP binds both fullerenes C and C with temperature-dependent exchange behavior, providing higher activation energies for the exchange compared to [10]CPP. The antiaromatic character of the []CDBPs paired with the cyclic conjugation leads to high HOMO energies and lowered LUMO energies with band gaps below 2 eV. This work presents a new class of the antiaromatic and nonalternant curved nanocarbons with intriguing supramolecular and ambipolar optoelectronic properties.
共轭纳米环为研究结构-性能关系提供了一个平台；它们是超分子化学的理想主体，也是有前途的新型有机材料候选物。在此，我们将[]环二苯并对苯撑（[]CDBP）作为[]环对苯撑的反芳香类似物。二苯并对苯撑硼酸酯的铂介导大环化提供了具有高达 80 kcal/mol 的应变能的三聚体和四聚体。在固态中，圆柱形[4]CDBP 分子排列形成柱状结构。较大的环[4]CDBP 与富勒烯 C 和 C 结合，具有温度依赖性的交换行为，与[10]CPP 相比，交换的活化能更高。[]CDBP 的反芳香特性与环状共轭相结合，导致 HOMO 能量较高，LUMO 能量较低，带隙低于 2 eV。这项工作提出了一类新的反芳香和非交替弯曲纳米碳，具有有趣的超分子和双极光电特性。
