Influence of anion on the solid-state assembly of dimeric tweezer complexes

Chiral and racemic forms of a urea–thiazole-based ligand ( R -L and rac -L) form anion-dependent solid-state structures when reacted with a range of silver(I) salts. A combination of hydrogen bonds from the urea groups of the ligands and metal-anion interactions drive these assemblies, alongside argentophilic and π-π interactions. A systematic investigation using a range of counter anions (benzoate, nitrate, sulfate, triflate, tetrafluoroborate, trifluoroacetate) produced a family of crystalline materials, including monomeric and dimeric tweezer-like complexes and one-dimensional coordination polymers with a clear dependence on the nature of the anion. Comparison of racemic and enantiopure systems highlights the influence of chirality on supramolecular packing and intermolecular hydrogen bonding. The influence of the anion, in terms of geometry and coordinating ability, shows a preference for dimeric assemblies with carboxylate and nitrate and only mononuclear complexes with traditionally “weaker” anions. • Chiral and racemic forms of a thiazolyl ligand containing a urea group have been synthesized • Combination of ligands with silver(I) salts gave a variety of dimeric, monomeric, and polymeric complexes. • Carboxylate guests template a discrete dimeric complex as does, to a lesser extent, nitrate, whilst other anions do not. • Both anions and the enantiopurity of the ligand influence the nature of the silver(I) complexes.