title: Molecular Barrel by a Hooping Strategy: Synthesis, Structure, and Selective CO2Adsorption Facilitated by Lone Pair-π Interactions.
abstract: A sophisticated molecular barrel 5 was efficiently constructed by hooping a 63-membered loop around a D3h-symmetric, shape-persistent bis(tetraoxacalix[2]arene[2]triazine) core. The hooping strategy involved 3-fold ring-closing metathesis (RCM) reactions of six branched olefin arms which were preanchored on the inner core. Through hooping, the loop tightens the cage structure and significantly enhances its stability toward nucleophilic decomposition. The X-ray crystal structure showed the molecular barrel bears three enclosed fan-shaped cavities as divided by the triazine rings and each of the cavities can hold a solvent CHCl3or CH2Cl2molecule. With the intrinsic porosity, the amorphous solids of 5 exhibit considerable CO2uptake with an exceptionally large isosteric enthalpy. Lone pair (lp)-π interactions between the electron-deficient triazine rings and CO2could contribute to the strong adsorption as supported by IR studies and DFT modeling.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Qi-Qiang
authors.identifier: 0000-0001-5988-1293
authors.initials: QQ
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Na
authors.initials: N
authors.lastname: Luo
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Yu-Fei
authors.initials: YF
authors.lastname: Ao
authors.affiliation: School of Materials Science and Engineering, Sun Yat-sen University , Guangzhou 510275, China.
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Chen
authors.affiliation: School of Materials Science and Engineering, Sun Yat-sen University , Guangzhou 510275, China.
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, Sun Yat-sen University , Guangzhou 510275, China.
authors.forename: Cheng-Yong
authors.identifier: 0000-0003-3604-7858
authors.initials: CY
authors.lastname: Su
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: De-Xian
authors.initials: DX
authors.lastname: Wang
authors.affiliation: Key Laboratory of Bioorganic Phosphorous and Chemical Biology (Ministry of Education), Tsinghua University , Beijing 100184, China.
authors.forename: Mei-Xiang
authors.initials: MX
authors.lastname: Wang