Orientational Self-Sorting in Octahedral Palladium Cages: Scope and Limitations of the “cis Rule”

Abstract

Octahedral coordination cages of the general formula [Pd 6 L 12 ](BF 4 ) 12 were obtained by combining [Pd(CH 3 CN) 4 ](BF 4 ) 2 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 cis configuration at the six metal centers should be preferred ("cis rule"). This prediction was corroborated by spectroscopic data and crystallographic analyses. Limitations of the "cis rule" were also encountered, and possible explanations are discussed.

A pair of conjoined trinuclear sub-frameworks in a pentanuclear double-cavity discrete coordination cage

“…Diverging coordination vectors and appropriate bend angles of the ligands are important parameters that decide the nuclearity of the ensuing cages. Preparation of Pd( ii )-based low-symmetry SCDCC has been achieved by either mixing of Pd( ii ) with a designer unsymmetrical ligand 14,16–21 to afford orientational selectivity of ligand components, or mixing of Pd( ii ) with more than one type of ligand 14,22–26 targeting mixed ligated integrative self-sorting.…”