The synthesis of π-conjugated organic materials through C–H activation and functionalization has recently received increasing attention. In this work, four pyrid-2-yl-appended para-phenylene oligomers (1–4) with two to five phenyl repeating units were synthesized via the Ru-catalyzed C–H activation of 2-phenylpyridine, followed by oxidative homocoupling or the arylation with a para-phenylene dibromide substrate. The single-crystal X-ray data and crystal packing of 1 and 3 are presented. In response to acid stimuli, the blue emissions of 1–3 are replaced by red-shifted cyan emissions, which are associated with the charge transfer transition from the phenylene backbone to the protonated pyridinium units. However, the emission of the longest congener 4 is largely quenched upon protonation. This length-dependent emission property is rationalized by DFT and TDDFT calculations.

通过C–H活化和官能化合成π共轭有机材料最近受到越来越多的关注。在这项工作中，四吡啶-2-基-所附对亚苯基低聚物（1 - 4）配有二至五个苯基重复单元通过2-苯基吡啶的钌催化的C-H活化合成，随后通过氧化自偶联或与对-亚苯基二溴化物底物芳基化。给出了1和3的单晶X射线数据和晶体堆积。响应于酸刺激，蓝色排放1 - 3被红移的青色发射物取代，这与从亚苯基主链到质子化吡啶鎓单元的电荷转移过渡有关。然而，最长的同类物4的发射在质子化时被很大程度上猝灭。通过DFT和TDDFT计算可以合理地确定这种取决于长度的发射特性。