An unprecedented twelve-connected 3D metal-organic framework based on heptanuclear cobalt cluster building blocks

Solvothermal reaction of flexible tetrapodal linker tetrakis[4-(carboxyphenyl) oxamethyl]methane acid (H4L) with cobalt salt yields a new metal-organic framework [Co-7(L)(3)(mu(3)-O)(3)(DMF)(3)]center dot(DMF)(13)(H2O)(25). X-ray crystallography reveals that the structure exhibits a unique 2-nodal (4,12)-connected topology with the Schlafli symbol of (4(33).6(30).8(3))(4(6))(3), constructed from heptanuclear cobalt clusters as 12-connected nodes and tetrahedral ligands as 4-connected nodes. Temperature-dependent magnetic susceptibility measurements reveal that the heptanuclear cobalt clusters exhibit antiferromagnetic property. (C) 2015 Elsevier B.V. All rights reserved.