Poletto Daniele, Marongiu Mauro, Hernández-Castillo David, Ferreira Rúben R, Crosta Martina, Mondal Pradip Kumar, González Leticia, Bonifazi Davide
Institute of Organic Chemistry, University of Vienna, Vienna, 1090, Austria.
Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Straße 42, Vienna, 1090, Austria.
Angew Chem Int Ed Engl. 2025 Sep 16:e202517114. doi: 10.1002/anie.202517114.
The rational design of polycyclic aromatic hydrocarbons that combine chemical and physical robustness with finely tuned optoelectronic properties remains a key challenge in materials science. As an initial step toward this goal, we report the synthesis and comprehensive characterization of a new class of boron-, nitrogen-, and oxygen-doped peri-acenoacenes, termed (2,5,4)-trapeziumene congeners. Analysis of these systems provides chemical descriptors that could guide the rational tailoring of their properties through peripheral doping. The target trapeziumene congeners were obtained via a sequence of Suzuki-Miyaura and Buchwald-Hartwig couplings, followed by directed borylation, giving both phenylborane and borinic derivatives with diverse peripheral doping sequences. Single-crystal X-ray diffraction revealed planar to slightly twisted backbones, with peripheral heteroatomic motifs that modulate π-conjugation and intermolecular packing. Photophysical studies showed bright fluorescence (Φ up to 0.99), narrow Stokes shifts, and structured phosphorescence at 77 K. Electrochemical analysis demonstrated p-type behavior and a progressive HOMO-LUMO gap widening upon N→O substitution. Theoretical investigations revealed that N→O substitution asymmetrically affects the excited states, blue-shifting fluorescence while red-shifting phosphorescence, through an asymmetric charge stabilization in the S and T excited states. This is accompanied by a progressive widening of the T-T energy gap.
设计出兼具化学和物理稳定性以及精细调控的光电特性的多环芳烃，仍然是材料科学中的一项关键挑战。作为朝着这一目标迈出的第一步，我们报道了一类新型的硼、氮和氧掺杂的并苯并苊烯（称为(2,5,4)-梯形烯同系物）的合成及全面表征。对这些体系的分析提供了化学描述符，可用于指导通过外围掺杂对其性质进行合理定制。目标梯形烯同系物是通过一系列铃木-宫浦（Suzuki-Miyaura）和布赫瓦尔德-哈特维希（Buchwald-Hartwig）偶联反应，随后进行定向硼化反应得到的，得到了具有不同外围掺杂序列的苯基硼烷和亚硼酸酯衍生物。单晶X射线衍射显示主链呈平面到轻微扭曲的状态，外围杂原子基序调节了π共轭和分子间堆积。光物理研究表明，该化合物具有明亮的荧光（Φ高达0.99）、窄斯托克斯位移以及在77 K下的结构化磷光。电化学分析表明其具有p型行为，并且在N→O取代时HOMO-LUMO能隙逐渐变宽。理论研究表明，N→O取代通过S和T激发态中的不对称电荷稳定作用，不对称地影响激发态，使荧光蓝移而磷光红移。这伴随着T-T能隙的逐渐变宽。
