Dirhodium-Based Supramolecular Framework Catalyst for Visible-Light-Driven Hydrogen Evolution.

The direct conversion of solar energy to clean fuels as alternatives to fossil fuels is an important approach for addressing the global energy shortage and environmental problems. Here, we introduce a new dirhodium-complex-based framework assembly as a heterogeneous molecule-based photocatalyst for hydrogen evolution using visible light. Two dirhodium complexes bearing visible-light-harvesting BODIPY (boron dipyrromethene, BDP) moieties were newly designed and synthesized. The obtained complexes were self-assembled to framework structures (supramolecular framework catalysts), which are stabilized intermolecular noncovalent interactions. These frameworks retained excellent visible-light-harvesting properties of BDP moieties. Investigation of the catalytic performance of the supramolecular framework catalysts revealed that the supramolecular framework catalyst with heavy atoms at BDP moieties exhibited excellent performance in the formation of hydrogen with a reaction rate of 275.8 µmol g-1 h-1 under irradiation of visible light, whereas the supramolecular framework catalyst without heavy atoms at BDP moieties was inactive. Moreover, the system has the additional benefits of high durability (up to 96 h), reusability, and facile removal from the reaction mixture. We also disclosed the effect of heavy atoms at BDP moieties on the catalytic activity and proposed a reaction mechanism.

Semiconductive Nature of Lead-Based Metal-Organic Frameworks with Three-Dimensionally Extended Sulfur Secondary Building Units.

Recently, metal-organic frameworks (MOFs) composed of sulfur secondary building units (sulfur-SBUs) have attracted significant attention as unique electronic materials with high conductivities and photo- and electrocatalytic properties. Herein we report the crystal structure of KGF-1, an example of a Pb-MOF composed of three-dimensionally extended sulfur-SBUs that displays molecular sieving behavior, visible-light absorption, and a semiconductor band structure and is a hydrogen-evolution photocatalyst.

Development of a framework catalyst for photocatalytic hydrogen evolution.

The controlled self-assembly of a catalyst module composed of a Rh(ii) paddle-wheel dimer bearing 1,8-naphthalimide-based moieties afforded a novel heterogeneous framework catalyst (FC-1). The framework catalyst exhibited long-lived activity for photocatalytic hydrogen production from water and was easily reused without considerable loss of catalytic activity.