The only exception is SU-111 formed from tetramethylammonium which is not a hydrogen-bond donor. Hydrogen bonds formed with the phenol oxygen 1 or the carbonyl oxygen 4 are both observed in five of the MOFs, while the ether oxygen 3 is less frequently involved in hydrogen bonding, appearing in only four structures. As an example, Fig. and shows the locations of the two unique OSDAs in SU-103 and their interactions with ellagate ligands. The nitrogen atom shown in Fig. is located at the edge of the pore, forming hydrogen bonds with type 2 phenol oxygen atoms from two ligands. A second OSDA (Fig. ) is positioned between two ligands, forming hydrogen bonds with the carbonyl oxygen atoms of two ligands.