AUTHOR=Schneider Matthew L. , Markwell-Heys Adrian W. , Linder-Patton Oliver M. , Bloch Witold M. 

TITLE=Assembly and Covalent Cross-Linking of an Amine-Functionalised Metal-Organic Cage

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.696081

DOI=10.3389/fchem.2021.696081

ISSN=2296-2646

ABSTRACT=<p>The incorporation of reactive functional groups onto the exterior of metal-organic cages (MOCs) opens up new opportunities to link their well-defined scaffolds into functional porous solids. Amine moieties offer access to a rich catalogue of covalent chemistry; however, they also tend to coordinate undesirably and interfere with MOC formation, particular in the case of Cu<sub>2</sub> paddlewheel-based MOCs. We demonstrate that tuning the basicity of an aniline-functionalized ligand enables the self-assembly of a soluble, amine-functionalized Cu<sub>4</sub>L<sub>4</sub> lantern cage (<bold>1</bold>). Importantly, we show control over the coordinative propensity of the exterior amine of the ligand, which enables us to isolate a crystalline, two-dimensional metal-organic framework composed entirely of MOC units (<bold>2</bold>). Furthermore, we show that the nucleophilicity of the exterior amine of <bold>1</bold> can be accessed in solution to generate a cross-linked cage polymer (<bold>3</bold>) via imine condensation.</p>