Framework-isomerism: highly augmented copper(II) paddlewheel-based MOF with unusual (3,4)-net topology

The synthesis and structure of a new, highly augmented {Cu2} ‘paddlewheel’-based metal-organic framework (MOF) that is stabilized by tritopic benzoate ligands is reported. The structure adopts an uncommon, less-symmetrical (3,4)- connected net topology and represents a rare framework isomer of the extensively studied {Cu2}-based pto and tbo analogues. The concomitant formation of three isomeric forms using {Cu}2- ‘paddlewheel’ complexes and a single triangular, tri-functional ligand is unique and stems from the rotational flexibility of the benzoate moieties. Computational analyses support the structural studies and underline that this observed net topology can give rise to an exceptionally high surface area (>3500 m2/g), despite the triple-interpenetrated nature of the compound.