Site-Directed Synthesis of Cobalt Oxide Clusters in a Metal–Organic Framework

Direct control over
structure and location of catalytic species
deposited on amorphous supports represents a formidable challenge
in heterogeneous catalysis. In contrast, a structurally well-defined,
crystalline metal–organic framework (MOF) can be rationally
designed using postsynthetic techniques to allow for desired structural
or locational changes of deposited metal ions. Herein, naphthalene
dicarboxylate linkers are incorporated in the MOF, NU-1000, to block
the small cavities where few-atom clusters of cobalt oxide preferentially
grow, inducing catalyst deposition toward hitherto ill-favored grafting
sites orientated toward NU-1000s mesoporous channels. Despite the
different cobalt oxide location, the resulting material is still an
active propane oxidative dehydrogenation catalyst at low temperature,
reaching a turnover frequency of 0.68 ± 0.05 h–1 at 230 °C and confirming the utility of MOFs as crystalline
supports to guide rational design of catalysts.