Crystalline porous frameworks based on double extension of metal-organic and covalent organic linkages

Reticular chemistry is a powerful strategy to design materials with fine-tuned chemical functionality and porosity, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). MOFs typically show high crystallinity due to their reversible coordinative bonds, and the organic backbone of COFs provides chemical stability. Here we synthesize metal-organic-covalent-organic frameworks (MOCOFs) that combine both crystallinity and stability in a single framework by the double extension of metal-organic and covalent organic linkages. Several MOCOFs are obtained by reaction between a cobalt aminoporphyrin and dialdehydes, which are interconnected by cobalt-amine coordination and imine condensation to form three-dimensional networks. The MOCOFs exhibit chiral topological nets, large surface areas, high crystallinities and high chemical stabilities due to the two types of extended linkages. Thus, MOCOFs present a reticular design strategy that further diversifies the chemical and structural space of porous solids.