Orientational Self-Sorting in Octahedral Palladium Cages: Scope and Limitations of the " Rule".

Octahedral coordination cages of the general formula [PdL](BF) were obtained by combining [Pd(CHCN)](BF) with heteroditopic N-donor ligands. Four different ligands were employed. These ligands have 3-pyridyl donor groups at one end and 4-pyridyl, imidazolyl, or triazolyl donor groups at the other end. According to a geometric analysis, cages with a configuration at the six metal centers should be preferred (" rule"). This prediction was corroborated by spectroscopic data and crystallographic analyses. Limitations of the " rule" were also encountered, and possible explanations are discussed.