Two unusual (4,6)- and 8-connected metal-organic frameworks constructed from flexible 1,4-benzenebis(thioacetic acid) and pyridine-based ligands

Two unusual metal-organic frameworks (MOFs) [CoL(4,4'-bipy)](n) (1) and [Ni2L2(bpp)(2)(H2O)](n) (2) (H2L = 1,4-benzenebis(thioacetic acid), bipy = 4,4'-bipy, bpp = 1,3-di(4-pyridyl)propane), have been synthesized and characterized by single-crystal X-ray diffraction. MOF 1 can be considered as constructed by 2D layers, which consist of left-and right-handed helical chains and is further linked by L2- ligands into a 3D (4,6)-connected network with a Schlafli symbol of (4(2).5(2).6(2))(4(2).5(6).6(4).7(3)). MOF 2 is an unique 3D 8-connected self-penetrating network with a Schlafli symbol of (4(24).6(4)), in which the dinuclear {Ni-2} subunits are linked by L2- ligands to form 2D layers along the ac plane and further expanded to a 3D network by bpp ligands. The experimental magnetic susceptibility of MOFs are interpreted with the uniform 1D chain character for 1 and the dimeric nickel law for 2, yielding the exchange integral (J) values of -1.32(2) cm(-1) and 1.32(2) cm(-1), respectively. The exchange integrals indicate weak antiferromagnetic interactions in 1, and weak ferromagnetic interactions in 2.