Organometallic Borromean Rings and [2]Catenanes Featuring Di‐NHC Ligands
Ye Lu, Patrick D. Dutschke, Jenny Kinas, Alexander Hepp, Guo‐Xin Jin, F. Ekkehardt Hahn
Abstract
Abstract We report herein a series of organometallic Borromean rings (BRs) and [2]catenanes prepared from benzobiscarbene ligands. The reaction of dinickel complexes of the benzobiscarbenes 1 a – 1 c with a thiazolothiazole bridged bipyridyl ligand L 2 led by self‐assembly to a series of organometallic BRs. Solvophobic effects played a crucial role in the formation and stability of the interlocked species. The stability of BRs is related to the N ‐alkyl substituents at the precursors 1 a – 1 c , where longer alkyl substitutes improve stability and inter‐ring interactions. Solvophobic effects are also important for the stability of [2]catenanes prepared from 1 a – 1 c and a flexible bipyridyl ligand L 3 . In solution, an equilibrium between the [2]catenanes and their macrocyclic building blocks was observed. High proportions of [2]catenanes were obtained in concentrated solutions or polar solvents. The proportion of [2]catenanes in solution could be further enhanced by lengthening of the N ‐alkyl substitutes.