Liquid-Phase Epitaxially Grown Metal-Organic Framework Thin Films for Efficient Tandem Catalysis Through Site-Isolation of Catalytic Centers

A functional metal-organic framework (MOF) composed of robust porphyrinic material (RPM) based on the pillared-paddlewheel topology is prepared with large 3D channels, and is used to perform a tandem epoxidation/CO2 insertion reaction. The designated system benefits from two metalloporphyrins: 1) a Mn-porphyrin, which catalyzes the epoxidation of an olefin substrate, and 2) a Zn-porphyrin, which catalyzes the epoxide opening. By using an automated liquid-phase epitaxial growth system, the RPM-MOF is also prepared in layer-by-layer fashion as an ultrathin film on a self-assembled-monolayer-coated silicon platform. Deployed as a tandem catalyst, the film version yields a substantially higher catalytic turnover number for tandem methoxy-styrene epoxidation followed by CO2 insertion than the bulk crystalline MOF samples.