Self-assembly and peripheral guest-binding of [Zn 3 L 2 (H 2 O) 6 ] 6+ triangular double helicate

A novel [Zn3L2(H2O)6]6+ triangular double helicate has been self-assembled by subcomponent C3-symmetric triamine, zinc(II) and 2-formylpyridine. The helicate structure was confirmed by 1H NMR, ESI-Mass and single-crystal X-ray diffraction. The results reveal that this sandwich-like helicate contains only limited central cavity but relatively open peripheral apertures. The latter are subject to bind suitable guest molecules by complementary arrangement. During the host-guest study, it's found the most up field shifts (Δδ=−0.06~−0.20ppm) of 1H signals occurred at the ligand protons near the apertures, where the aromatic rings of guests could fit the grooves of the ligands and offer the electronic perturbation to most nearby hydrogens of the host.