Vapor-phase synthesis of low-valent metal-organic frameworks from metal carbonyl synthons

Incorporating low-valent metals as nodes in metal-organic frameworks (MOFs) is orthogonal to the commonly accepted strategy to robust and porous structures. The electronic structures of low-valent metals are chemically unique and have driven the successes of organometallic chemistry. The translation of these properties into MOFs is largely impeded by the lack of generalizable synthetic approaches. Metal carbonyls are bona fide low-valent and volatile synthons, which, by partial chemical substitution may tether ditopic ligands into MOF architectures. We herein demonstrate the formation of CO₂ adsorbing MOFs from the direct vapor-phase substitution of CO by ditopic 4,4′-bipyridine at Mo(0) and W(0) centers, which allows facile coating of low-valent MOFs onto substrates such as indium tin oxide. We envisage this strategy could be generalized to a multitude of mono- and polynuclear metal carbonyls, paralleling the diversity of conventional MOFs.