Chirality Control of Quadruple Helixes of Metal Strings by Peripheral Chiral Ligands

Chirality control of helixes with the Delta (P) or L (M) form is interesting in various fields such as extended metal atom chains (EMACs), in which the metal backbones are helically wrapped by four ligands. Herein, we report two EMACs, Delta-[Ni-5((-) camnpda)(4)] and Lambda-[Ni-5((+) camnpda)(4)], whose chiralities are controlled by chiral ligands with naphthyridine and camphorsulfonyl groups. There is a large energy difference (108 kcalmol(-1)) between the two helical structures with one chiral ligand. Furthermore, the electron communication between [Ni-2](3+) units is more pronounced than in [Ni-5(bna)(4)Cl-2](2+) (bna = binaphthyridylamido). The results demonstrate control of small-scale helical structure and set the stage for future development of chiral controlled base and nanoelectronic devices.