Porous and Robust Lanthanide Metal-Organoboron Frameworks as Water Tolerant Lewis Acid Catalysts

Porous and robust 12-connected metal–organic
frameworks
(MOFs) were constructed by linking tetranuclear lanthanide (Ln) carbonate
clusters with organoboron-derived tricarboxylate bridging ligands.
The high-connectivity Ln-MOFs feature remarkable thermal and hydrolytic
stability and a large number of isolated Lewis acid B­(III) and Ln­(III)
sites on the pore surfaces. The Nd-MOF assisted with sodium dodecylsulfate
was found to be highly effective, recyclable, and reusable heterogeneous
catalyst for the carbonyl allylation reaction, the Diels–Alder
reaction, and the Strecker-type reaction in water. The transformations
were cocatalyzed by Nd­(III) and B­(III) Lewis acids, with activities
much higher than those of the individual organoboron and lanthanide
counterparts and their mixture. This work highlights the potential
of generating highly efficient water-tolerant solid catalysts via
heterogenization of different weak and/or mild Lewis acids in confined
spaces of robust MOFs.