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).