Herein, we report the reaction between four 1,2-dibromoxylenes and two tetra-3-pyridylporphyrins for the formation of a cofacial porphyrin core spanned by dipyridinium xylene moieties. The metal-free organic nanocage (oNC) was synthesized in one twenty-four h step at a gram-scale with a 91.5% yield. The free base oNC was subsequently metalated with cobalt(II) (Co-oNC), copper(II) (Cu-oNC), and nickel(II) (Ni-oNC) ions to furnish dinuclear complexes that were characterized by mix of mass spectrometry, NMR, EPR, electronic absorption spectroscopy, and for Co-oNC, single-crystal X-ray diffraction. Cofacial cobalt porphyrins are often active as catalysts for the Oxygen Reduction Reaction. Under heterogeneous conditions in water, Co-oNC was 83% selective for the electrocatalytic 4 e^–/4 H⁺ reduction of O₂ to H₂O, matching homogeneous experiments which revealed consistent selectivity for H₂O (88%). This oNC core offers significant advantages over prisms formed by coordination-driven self-assembly: the dipyridnium-xylene coupling can furnish over 1 g of material in a single synthesis and the tethering motif is robust, maintaining a cofacial architecture in acidic and basic solutions. We envision this approach may be generalized to other bis-bromobenzyl building blocks, providing a means to tune metal–metal separation and other structural and electronic properties.

中文翻译：

---

由邻二甲苯桥接的共面卟啉的克级、一锅法合成作为双核结构的支架


在此，我们报道了四个 1,2-二溴氧基和两个四-3-吡啶基卟啉之间的反应，以形成由二嘧啶二甲苯部分跨越的共面卟啉核心。无金属有机纳米笼 （oNC） 以 24 h 的步长以克级合成，产率为 91.5%。随后用钴 （II） （Co-oNC）、铜 （II） （Cu-oNC） 和镍 （II） （Ni-oNC） 离子金属化游离碱 oNC，以提供双核配合物，这些配合物通过质谱、NMR、EPR、电子吸收光谱和 Co-oNC 的混合表征单晶 X 射线衍射。Cofacial 钴卟啉通常作为氧还原反应的催化剂具有活性。在水中的非均相条件下，Co-oNC 对电催化 O₂ 到 H₂O 的 4 e^–/4 H⁺ 还原具有 83% 的选择性，与均相实验相匹配，该实验揭示了对 H₂O 的一致选择性 （88%）。与通过配位驱动的自组装形成的棱镜相比，这种 oNC 核心具有显着优势：二吡啶-二甲苯偶联可以在一次合成中提供超过 1 g 的材料，并且栓系基序很坚固，在酸性和碱性溶液中保持共界面结构。我们设想这种方法可以推广到其他双溴苄基构建单元，提供一种调整金属-金属分离和其他结构和电子特性的方法。