A solomon link through an interwoven molecular grid

A molecular Solomon link was synthesized through the assembly of an interwoven molecular grid consisting of four bis(benzimidazolepyridyl)benzthiazolo[5,4-d]thiazole ligands and four zinc(II), iron(II), or cobalt(II) cations, followed by ring-closing olefin metathesis. NMR spectroscopy, mass spectrometry, and X-ray crystallography confirmed the doubly interlocked topology, and subsequent demetalation afforded the wholly organic Solomon link. The synthesis, in which each metal ion defines the crossing point of two ligand strands, suggests that interwoven molecular grids should be useful scaffolds for the rational construction of other topologically complex structures. Gridlocked: A molecular Solomon link was obtained in 72 % yield through the self-assembly of a 2×2 interwoven molecular grid consisting of four thiazole ligands and four transition-metal cations, followed by ring-closing olefin metathesis. Interwoven grids should prove to be useful intermediates in the synthesis to higher-order molecular knots and links.