Covalent-Frameworked 2D Crown Ether with Chemical Multifunctionality
Jinseok Kim, Sungin Kim, Jinwook Park, Jinwook Park, Sungsu Kang, Dong Joo Seo, Namjun Park, Siyoung Lee, Jae Jun Kim, Won Bo Lee, Jungwon Park, Jungwon Park, Jong‐Chan Lee
Abstract
Here, we present the synthesis and characterization of a novel 2D crystalline framework, named C 2 O, which mainly consists of carbon and oxygen in a 2:1 molar ratio and features crown ether holes in its skeletal structure. The covalent-frameworked 2D crown ether can be synthesized on a gram-scale and exhibits fine chemical stability in various environments, including acid, base, and different organic solvents. The C 2 O efficiently activates KI through the strong coordination of K + with crown ether holes in a rigid framework, which enhances the nucleophilicity of I – and significantly improves its catalytic activity for CO 2 fixation with epoxides. The presence of C 2 O with KI results in remarkable increases in CO 2 conversion from 5.7% to 99.9% and from 2.9% to 74.2% for epichlorohydrin and allyl glycidyl ether, respectively. Moreover, C 2 O possesses both electrophilic and nucleophilic sites at the edge of its framework, allowing for the customization of physicochemical properties by a diverse range of chemical modifications. Specifically, incorporating allyl glycidyl ether (AGE) as an electrophile or ethoxyethylamine (EEA) as a nucleophile into C 2 O enables the synthesis of C 2 O-AGE or C 2 O-EEA, respectively. These modified frameworks exhibit improved conversions of 97.2% and 99.9% for CO 2 fixation with allyl glycidyl ether, outperforming unmodified C 2 O showing a conversion of 74.2%. This newly developed scalable, durable, and customizable covalent framework holds tremendous potential for the design and preparation of outstanding materials with versatile functionalities, rendering them highly attractive for a wide range of applications.