title: Solvent-Mediated Transformation from Achiral to Chiral Nickel(II) Metal-Organic Frameworks and Reassembly in Solution.
abstract: Reactions of 5-nitroisophthalic acid (NO2 -H2 ip), 1,4-bis(imidazol-1'-yl)butane (bimb), and Ni(NO3 )2 ⋅6 H2 O gave rise to four metal-organic frameworks (MOFs), [Ni2 (NO2 -ip)2 (bimb)1.5 ]n (1), [Ni4 (NO2 -ip)3 (bimb)2 (OH)2 (H2 O)]n ⋅(CH3 CH2 OH)0.5 n (2), [Ni(NO2 -ip)(bimb)1.5 (H2 O)]n ⋅(H2 O)n ⋅(CH3 CH2 OH)0.5 n (3), and [Ni(NO2 -ip) (bimb)(μ-H2 O)]n ⋅(H2 O)n (4). The metal/ligand ratio, pH value, and solvent exerted a subtle but crucial influence on the formation of complexes 1-4, which possess different visual color and crystal structures. Complex 1 exhibits a twofold interpenetrating 3D pillared bilayer framework composed of binuclear and mononuclear Ni(II) units, whereas complex 2 is a 3D chiral network that consists of asymmetric tetranuclear Ni(II) units. Complexes 3 and 4 are 3D layer-pillared frameworks that consist of mononuclear Ni(II) ions and a 3D six-connected network of μ-water-bridged dinuclear Ni(II) units, respectively. Interestingly, achiral 4 can be transformed into chiral 2 by using a solvent-mediated single-crystal-to-single-crystal process without any chiral auxiliary. Magnetic analyses of 2 and 4 show the occurrence of antiferromagnetic interactions. Complex 3 is difficult to obtain directly as a single solid phase, but it can be homogeneously formed by solvent-mediated transformations from 1, 2, and 4.
authors.affiliation: Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007 (P.R. China). xiaojuli@fjnu.edu.cn.|State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (P.R. China). xiaojuli@fjnu.edu.cn.
authors.forename: Xiaoju
authors.initials: X
authors.lastname: Li
authors.affiliation: Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007 (P.R. China).
authors.forename: Zhenjiang
authors.initials: Z
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (P.R. China).
authors.forename: Xinxiong
authors.initials: X
authors.lastname: Li
authors.affiliation: Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007 (P.R. China).|State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002 (P.R. China).
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Guo
keywords: chirality; metal-organic frameworks; nickel; solvent effects; structural transformation