A new metal organic framework constructed of Co(II) ions six and seven-coordinated: Synthesis, structure and magnetism

Abstract

In this work are presented the synthesis, structure and magnetic measurements for the [Co(mu(2)-biim)(6) 2Co(mu-H2O)(OH)(6)] (biim = 2,2'-biimidazole) metal-organic framework. The compound crystallizes in the cubic system, space group Pa (3) over bar (a = 16.0312(6) angstrom, V = 4120.0(3) angstrom(3) and Z = 4), containing two crystallo-graphically distinct divalent cobalt ions Co(1) and Co(2) six- and seven-coordinated, respectively. The two metal centers are linked by 2,2'-biimidazole bridging ligand through the N(6) nitrogen donor and Co(2) forming a dimer via bridged water molecule with Co-Co distance of 4.313(3) angstrom, originating a 3D structure. Topological analysis of this compound revealed that the structure is an abi-nodal 3,4-connected network with total point symbol {8(3)}{8(6)}. By fitting of susceptibility data to the Curie-Weiss law it was possible to estimate the magnetic parameters theta(p) and p(eff). Magnetic susceptibility results suggest an antiferromagnetic order in the system. (C) 2014 Elsevier Ltd. All rights reserved.