In silico design and screening of hypothetical MOF-74 analogs and their experimental synthesis

a ligand in MOF-74, and thin black lines abstract connections within a single SBU rod. (a) View of the ab face of etb net. (b) View of the bc face of the etb net. Crystal structure assembly The etb net of MOF-74, visualized in Fig. 4, exhibits special complexities which preclude the use of previously developed methods for in silico crystal design. Three distinct problems arise. Firstly, not all edges in nets that abstract a 1-D rod MOF represent a linker or segment of a linker. As seen in Fig. 4, only some edges (highlighted in red) in the etb net abstract the ligand that connects one SBU rod to another, while others abstract edges that exist within the SBU rod itself (highlighted by thin black lines). Secondly, each node in etb does not abstract a single, discrete SBU in MOF-74 but rather they abstract only the metal atom contained within the SBU rod. For example, all nodes that can be visited without traversing a red edge represent the three metals contained by one rod within a single unit cell. Thirdly, attempting to dene the c-component of the SBU rod's central (a, b, c) coordinates becomes ambiguous since the rod transverses periodic boundary conditions in the c-direction. Thus the process of embedding the SBU rods in three dimensional space can signicantly change depending on the selected linker. Upon exchange of the red edges in Fig. 4b with an alternative linker to DOBDC, the edge may in fact no longer be parallel to the ab face and all the SBU rods will shi relative to each other in the c-direction based on the new ligand's geometry. These three difficulties necessitate a new methodology to quickly assemble crystal structures from the 61 selected ligands. Fig. 3 A sample of the 61 molecules found in the PubChem database that were identified as potential ligands for MOF-74 analogs. The middle linker, olsalazine, is utilized to synthesize a novel MOF-74