title: Chirality control of quadruple helixes of metal strings by peripheral chiral ligands.
abstract: Chirality control of helixes with the Δ (P) or Λ (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, Δ-[Ni5((-)camnpda)4] and Λ-[Ni5((+)camnpda)4], whose chiralities are controlled by chiral ligands with naphthyridine and camphorsulfonyl groups. There is a large energy difference (108 kcal mol(-1)) between the two helical structures with one chiral ligand. Furthermore, the electron communication between [Ni2](3+) units is more pronounced than in [Ni5(bna)4Cl2](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.
authors.affiliation: Department of Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei, 106, Taiwan (ROC), Fax: (+886) 2-8369-3765.
authors.forename: Chung-Han
authors.initials: CH
authors.lastname: Yu
authors.forename: Min-Shiang
authors.initials: MS
authors.lastname: Kuo
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Chuang
authors.forename: Gene-Hsiang
authors.initials: GH
authors.lastname: Lee
authors.forename: Shao-An
authors.initials: SA
authors.lastname: Hua
authors.forename: Bih-Yaw
authors.initials: BY
authors.lastname: Jin
authors.forename: Shie-Ming
authors.initials: SM
authors.lastname: Peng
keywords: chirality; helical structures; metal-metal interactions; mixed-valent compounds; molecular electronics