A Combined Experimental and Computational Exploration of Heteroleptic cis‐Pd2L2L’2 Coordination Cages through Geometric Complementarity

Heteroleptic (mixed‐ligand) coordination cages are of interest as host systems with more structurally and functionally complex cavities than homoleptic architectures. The design of heteroleptic cages, however, is far from trivial. In this work, we experimentally probed the self‐assembly of Pd(II) ions with binary ligand combinations in a combinatorial fashion to search for new cis‐Pd2L2L’2 heteroleptic cages. A hierarchy of computational analyses was then applied to these systems with the aim of elucidating key factors for rationalising self‐assembly outcomes. Simple and inexpensive geometric analyses were shown to be effective in identifying complementary ligand pairs. Preliminary results demonstrated the viability of relatively rapid semi‐empirical calculations for predicting the topology of thermodynamically favoured assemblies with rigid ligands, whilst more flexible systems proved challenging. Stemming from this, key challenges were identified for future work developing effective computational forecasting tools for self‐assembled metallo‐supramolecular systems. Calculations based on ligand geometries and computed energies of coordination assemblies were compared against experimental results working towards rationalising the self‐assembly of heteroleptic Pd2L2L’2‐type coordination cages. Valuable insights into the use and limitations of the approaches examined were gained in the continued development of high‐throughput methods to aid molecular design.