Metal-organic frameworks containing (alkynyl)gold functionalities: A comparative evaluation of solvent-assisted linker exchange, de novo synthesis, and post-synthesis modification

A series of metal-organic framework (MOF) materials containing Au^I-carbon covalent bonds was prepared by solvent-assisted linker exchange (SALE) between (alkynyl)gold(phosphine)-functionalized bipyridine linkers and the bipyridyl naphthalene tetracarboxydiimide struts in Zn pillared-paddlewheel MOFs. These new materials could not be obtained by the authors through de novo synthesis or post-synthesis modification, both of which lead to the decomposition of the organometallic complex. In contrast, the SALE process occurs readily under mild conditions that preserve the integrity of both the pillared-paddlewheel structure and the organometallic complex. For bipyridine linkers with similar basicities, the rate of the SALE exhibits a strong inverse dependence on the size of the phosphine ligand in the incoming (alkynyl)gold(phosphine)-functionalized linker, with smaller ligands reacting faster.