清华大学叶钢团队报道了Pi堆叠几何定向超分子二级构建单元形成氢键框架,用于强化NH3吸附。相关研究成果发表在2025年1月15日出版的国际学术期刊《德国应用化学》。
利用超分子二级结构单元(SSBUs)开发多孔晶体材料是一项令人兴奋的突破,它扩展了网状化学的边界。然而,形成由非共价相互作用维持的多核团簇以组装氢键框架仍然是一个关键挑战。
该研究提出了一种新的策略,通过调整共轭构建块的π堆叠几何形状来稳定SSBUs,促进创建具有定制架构的氢键框架,以满足苛刻的气体分离要求。具体来说,带有芳香杂环的羧基的平行位移π-π堆叠促进了由铵阳离子[NH4+]8[COO-]8(SSBU-4)桥接的SSBUs的形成,从而能够组装具有永久孔隙,和受溶剂效应影响的结构多样性的氢键框架。相比之下,非杂环建筑单元表现出几何或能量上不利的π堆叠,导致脆弱的框架在移除无序的客体后倒塌。
值得注意的是,杂环共轭框架在孔通道内含有丰富的开放布朗斯特酸N-H位点,与报道的多孔分子晶体相比,在各种工业气体中表现出显著的NH3吸附能力,具有高容量(275.7 mL/g,273 K,100 kPa)。
附:英文原文
Title: Pi-Stacking Geometry Directed Supramolecular Secondary Building Units Shaping Hydrogen-Bonded Frameworks for Intensive NH3 Adsorption
Author: Xiaojun Ding, Qiang Gao, Yi Su, Jing Chen, Gang Ye
Issue&Volume: 2025-01-15
Abstract: Exploiting supramolecular secondary building units (SSBUs) for developing porous crystalline materials represents an exciting breakthrough that extends the boundaries of reticular chemistry. However, shaping polynuclear clusters sustained by non-covalent interactions for the assembly of hydrogen-bonded frameworks remains a critical challenge. This study presents a novel strategy to stabilize SSBUs by tuning the π-stacking geometry of conjugated building blocks, facilitating the creation of hydrogen-bonded frameworks with tailored architectures for demanding gas separation. Specifically, parallel-displaced π-π stackings of aromatic heterocycles bearing carboxyls promote the formation of SSBUs bridged by ammonium cations [NH4+]8[COO-]8 (SSBU-4), enabling the assembly of hydrogen-bonded frameworks with permanent porosity and structural diversity influenced by the solvent effect. Comparatively, the non-heterocyclic building units exhibit geometrically- or energetically-unfavorable π stackings, resulting in fragile frameworks that collapse after removing disordered guests. Significantly, the heterocycle conjugated frameworks contain abundant open Brnsted acid N-H sites within pore channels, demonstrating remarkable NH3 adsorption ability among diverse industrial gases with a high capacity (275.7 mL/g, at 273 K, 100 kPa) as compared to reported porous molecular crystals.
DOI: 10.1002/anie.202500268
Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202500268
Angewandte Chemie:《德国应用化学》,创刊于1887年。隶属于德国化学会,最新IF:16.823
官方网址:https://onlinelibrary.wiley.com/journal/15213773
投稿链接:https://www.editorialmanager.com/anie/default.aspx