N-Sulfur[ n ]arene: Synthesis and Solution-State Double-Threaded Dimerization Assisted by Multiple S···S Interactions

Directional yet weak noncovalent interactions including σ-hole interactions are attractive for formation of discrete supramolecular assemblies but are often suppressed in solution. Here, we demonstrate solution-phase dimerization of a macrocycle driven by cooperative σ-hole interactions. Single-crystal X-ray diffraction analysis revealed a double-threaded dimer stabilized by alkyl-chain penetration and multiple S···S contacts. Concentration-dependent NMR spectroscopy and diffusion-ordered spectroscopy measurements suggested that dimer formation in solution is stabilized by cooperative effects, including S···S interactions and alkyl-chain threading.