Synthesis, Structure, and Magnetic Properties of the Low-Symmetry Tetranuclear Cubane-like Nickel Complex [Ni4(pypentO)(pym)(μ3-OH)2(μ-Oac)2(NCS)2(OH2)]

The tetranuclear [Ni4(pypentO)(pym)(μ3-OH)2(μ-Oac)2(NCS)2(OH2)] cubane-like complex has been prepared, and its structure and magnetic properties have been studied (pypentO and pym are the deprotonated forms of 1,5-bis[(2-pyridylmethyl)amino]pentane-3-ol and 2-pyridylmethanol, respectively). The X-ray diffraction analysis of this novel nickel complex (C61H74N14O25.5S4Ni8, monoclinic, P21, a = 13.9375(14) A, b = 20.6604(18) A, c = 16.6684(19) A, β = 110.619(12)°, Z = 2) showed a Ni4O4 cubane arrangement of four nickel atoms, four μ3-O bridging ligands (one pypentO, one pym, and two OH-), two syn−syn bridging acetates, and three terminal monodentate ligands (two NCS- and one OH2). In this low-symmetry elongated cubane, the four Ni−Ni long distances (3.18 A) correspond to the faces of the cube including two μ3-OR bridges, and the two Ni−Ni short distances (2.94 A) correspond to the faces including two μ3-OR and one acetate bridges. The temperature dependence of the magnetic susceptibility was fitted with J1 =...