Coordination‐Driven Selective Formation of D2 Symmetric Octanuclear Organometallic Cages

Here we describe the coordination-driven self-assembly of organometallic half-sandwich iridium(III)- and rhodium(III)-based building blocks with asymmetric ambidentate pyridyl-carboxylate ligands. Despite the potential for obtaining a statistical mixture of multiple products, D 2 symmetric octanuclear cages were formed selectively by taking advantage of the electronic effects emanating from the two types of chelating sites - ( O , O' ) and ( N , N' ) - on the tetranuclear building blocks. The metal sources and the lengths of bridging ligands show influence on the selectivity of the self-assembly. Experimental observations, supported by computational studies, suggest that the D 2 symmetric cages are the thermodynamically favoured products. Overall, the results underline the importance of electronic effects on the selectivity of coordination-driven self-assembly, and demonstrate that asymmetric ambidentate ligands can be used to control the design of discrete supramolecular coordination complexes.