Tuning the Size and Geometry of Heteroleptic Coordination Cages by Varying the Ligand Bent Angle
Ru‐Jin Li, Farzaneh Fadaei‐Tirani, Rosario Scopelliti, Kay Severin
Abstract
Abstract Spherical assemblies of the type [Pd n L 2 n ] 2 n + can be obtained from Pd II salts and curved N‐donor ligands, L. It is well established that the bent angle, α , of the ligand is a decisive factor in the self‐assembly process, with larger angles leading to complexes with a higher nuclearity, n . Herein, we report heteroleptic coordination cages of the type [Pd n L n L′ n ] 2 n + , for which a similar correlation between the ligand bent angle and the nuclearity is observed. Tetranuclear cages were obtained by combining [Pd(CH 3 CN) 4 ](BF 4 ) 2 with 1,3‐di(pyridin‐3‐yl)benzene and ligands featuring a bent angle of α =120°. The use of a dipyridyl ligand with α =149° led to the formation of a hexanuclear complex with a trigonal prismatic geometry; for linear ligands, octanuclear assemblies of the type [Pd 8 L 8 L′ 8 ] 16+ were obtained. The predictable formation of heteroleptic Pd II cages from 1,3‐di(pyridin‐3‐yl)benzene and different dipyridyl ligands is evidence that there are entire classes of heteroleptic cage structures that are privileged from a thermodynamic point of view.