Tuning interactions between ligands in self-assembled double-decker phthalocyanine arrays

Lanthanide double-decker (DD) complexes represent an interesting system to engineer intermolecular interactions at different distances from the surface. Such atomic-level understanding and control are crucial for the development of molecular devices with three-dimensional complexity. We herein demonstrate an example of how the surface arrangements of DD molecules are influenced by varying intermolecular interactions. By varying the size of a ligand, we observed significant expansion of the lattice even though the top ligands of DD molecules remain too small to interact directly with each other. We also demonstrate that DD molecules in different local environments adopt significantly different structures. Such structures suggest that subtle interactions exist between the top ligand of one molecule and the bottom ligands of its neighbors.