A Single-Crystal to Single-Crystal Conversion Scheme for a Two-Dimensional Metal-Organic Framework Bearing Linear Cd₃ Secondary Building Units

The single-crystal to single-crystal (SCSC) conversion of metal-organic frameworks (MOFs) represents a facile route to new MOFs with structures and functionalities that are challenging to obtain by direct synthesis. However, conversion products are often structurally limited for a given precursor. We herein report that a two-dimensional (2D) MOF featuring a linear Cd₃ cluster secondary building unit (SBU) converts into one type of three-dimensional (3D) interpenetrated and two types of 3D non-interpenetrated MOFs upon reaction with dipyridyl ligands. One of the interpenetrated 3D MOFs, in turn, undergoes either ligand substitution to give isoreticular interpenetrated MOFs, or ligand addition to give a self-penetrated 3D MOF. This rich SCSC conversion library is made possible by the inclined nature of the Cd₃ SBU with respect to the 2D plane of the starting material to create an anisotropic environment around the SBU.