title: Ni3versus Ni30: A Truncated Octahedron Metal-Organic Cage Constructed with [Ni5(CN)4]6+Squares and Tripodal Tris-tacn Ligands That are Large and Flexible.
abstract: Reactions of trinickel complex of tripodal tris-tacn ligand N(CH2-m-C6H4-CH2tacn)3(L, tacn=1,4,7-triazacyclononane) in acetonitrile-methanol solution with and without phosphate led to two complexes of distinct nuclearities, [(NiIICl)3(CH3OH)3(HPO4)L](PF6) (Ni3, 1) and [(NiII5(CN)4(H2O)8Cl)6L8]Cl30(Ni30, 2). Ligand L takes upward and downward conformation in the structure of 1 and 2, respectively. It is proposed that phosphate directs the upward conformation of Ni3L to form 1. In the absence of phosphate, Ni3L assembles with cyanide ions, which are formed by Ni-catalyzed C-CN bond cleavage of acetonitrile, to give a nano-sized Ni30cage. Complex 2 represents a discrete truncated octahedron cage assembled with [Ni5(CN)4]6+squares and large and flexible triangular ligands, which is scarcely observed for self-assembled metal-organic cages. The magnetic properties of 1 and 2 were examined, showing intriguing magnetic properties.
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Zongyao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Kunyi
authors.initials: K
authors.lastname: Zheng
authors.affiliation: Department of Physics, Renmin University of China, Beijing, 100872, China.
authors.forename: Tianlong
authors.initials: T
authors.lastname: Xia
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Lijin
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.|School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
keywords: coordination cage; flexible; nickel; self-assembly; tripodal ligand