Unprecedented trinodal 4-connected metal-organic frameworks (MOFs) with 2-fold interpenetration

Via hydrothermal synthesis, the self-assembly of Co(SCN)(2) with the mixed rigid and flexible N,N'-bidentate donors, 4,4'-bpy and bimb (4,4'-bpy 4,4'-bipyridine, bimb 1,4-bis(imidazol-1-yl)butane), generated a novel complex: [Co(bimb)(4,4'-bpy)(SCN)(2)] (1), which is the first example of an extended coordination polymer incorporating these mixed neutral N,N'-bidentate ligands. The structure contains (4,4) 2D [Co-4(4,4'-bpy)(2)(bimb)(4)] layers further pillared by 4,4'-bpy ligands to form an unusual 3D framework that can be classified as a 4-connected (6(4).8(2))(6(3).8(3))(2)(6(5).8) net based on three kinds of planar Co nodes. Two of these nets interpenetrate.