Covalent Crosslinked Metal-organic Frameworks as Well-defined Heterogeneous Catalysts

We propose a versatile synthetic approach to robust crystalline solids combining porous structures and extensive covalent crosslinks, in order to achieve the functionality and stability crucial for heterogeneous catalysis. In particular, we aim for metal-carboxylate frameworks featuring: 1) larger pores to contain a wider variety of organic molecules; 2) extensively decorated with hydroxy (-OH) side chains for crosslinking. The central idea here builds on a stepwise synthetic strategy: namely, we plan to first set up a crystalline host net using the reversible but rather robust metal-carboxylate coordination bonds, and then introduce covalent linkers to strengthen the hydroxyl-decorated host net. The porosity is to arise from the rigid, tritopic aromatic backbone of the ligand, whereas the covalent crosslinks will be realized by reagents reactive towards the hydroxy groups pendant in the pores. We will select crosslinks that not only strengthen the net, but bring along active functionality for catalytic processes.