Ligand Architecture Control Geometry, Self-Sorting, and Postsynthetic Modification in Anthracene-Based Organometallic Assemblies

Although various skeletons of organic ligands have been applied to achieve the structural diversity of metallasupramolecular assemblies, limited approaches are available for organometallic cluster-based assemblies. Herein, we present how the architecture of anthracene-based ligands dictated the structure and properties of organometallic cluster-based assemblies. The combination of Pt₃-cluster node [(Tr₂Pt₃)(CH₃CN)₃][BF₄]₂ (Tr = cycloheptatrienyl ring) with disubstituted-anthracene ligands (L1-L3) selectively synthesize the first (Tr₂Pt₃)₈L₁₂-type cubic assembly 1 and cylindric assembly 2 by altering coordination parameters of ligands and noncovalent interactions (π-π stacking and C-H···π interactions). Lengthening L3 with functional linkers gives rise to an unprecedented (Tr₂Pt₃)₂L₃-type self-penetrated assembly 3 with the assistance of π···π stacking interactions between three consecutive stacked anthracene skeletons. Interestingly, synergistically weakening such π···π stacking among anthracene skeletons but increasing it between Pt₃-cluster nodes produces a triple helicate assembly 4. The ligand architecture also affects the postsynthetic modification (PSM) reactivity of these Pt₃-cluster node-based supramolecular assemblies. While triple helicate 5 underwent PSM smoothly upon irradiation without photosensitizers, other assemblies remained photochemically inert under similar conditions. Systematic self-sorting investigations show how marginal differences in ligands can selectively lead to narcissistic and social behaviors in complex systems. The results offer valuable design principles and emphasize the critical role that ligand architecture plays in constructing novel organometallic cluster-based assemblies.