Synthesis and Structures of Two Novel Three-Dimensional Metal−Organic Frameworks: Comprising an Unprecedented Tetraflexure Helix
journal contributionposted on 04.08.2010, 00:00 by Zhe Dong, Yao-Yu Wang, Rui-Ting Liu, Jian-Qiang Liu, Lin Cui, Qi-Zhen Shi
Two isomorphous three-dimensional metal−organic frameworks, [M(dtb)(4,4′-bipyridine)1.5(H2O)]n (1, M = Ni; 2, M = Co) [dtb = 5,5′-dithiobis(2-nitrobenzoic acid), 4,4′-bipy = 4,4′-bipyridine], have been synthesized by ligating metal ions with V-shaped H2dtb and linear 4,4′-bipy ligands, and they have been characterized structurally by single crystal X-ray diffraction studies and FT-IR and TGA analysis. Complexes 1 and 2 exhibit fascinating interweaved meso-helices and represent the first examples of metal−organic frameworks with four spiral shafts in one helical chain, named a tetraflexural helix. The pitch of the single helical chain is up to 27.741 Å, which is out of the normal scope of helical pitch.