Dense Alkyne Arrays of a Zr(IV) Metal-Organic Framework Absorb Co₂(CO)₈ for Functionalization

Finely dispersed Co(0) and CoO species were efficiently loaded into a stable metal-organic framework to impart catalytic activities to the porous solid. The metalation of the MOF host is facilitated by the dense arrays of accessible alkyne units that boost the alkyne-Co₂(CO)₈ interaction. The tetrakis(4-carboxylphenylethynyl)pyrene linker, with eight symmetrically backfolded alkyne side arms, features strong fluorescence and a dendritic Sierpinski shape. The resultant Zr(IV)-MOF features NU-901 topology (scu net, with rhombus channels) and breathing properties (e.g., the contracted (porous) phase reverts to the as-made phase upon contact with DMF (dimethylformamide)). The inserted Co₂(CO)₈ guests quickly react with air to form atomically dispersed CoO species (nondiffracting), and subsequent thermal treatment at 600 °C of the CoO-loaded solid generates an electrocatalyst for the oxygen evolution reaction (OER).