A systematic investigation was conducted on the structures of tetra- and di-nuclear copper(II) complexes with three stereoisomers of sulflnylcalix arenes (H4L), the isomerism of which is determined by the disposition of the sulfinyl oxygen with respect to a reference oxygen from the mean plane containing four sulfur atoms. The sulfinylcalixarene with a trans-cis-trans S-0 orientation H4Lrtct reacted with Cu(OAc)2 to form [CuII4(Lrtct)(OAc)3(μ- MeO)(MeOH)] (1), in which Lrtct4- adopts a cone conformation to afford tetrakis/aotridentate coordination through four phenoxo oxygens and four sulfinyl groups giving a square CuII4 core. Ligands H 4Lrccc and H4Lrctt having cis-cis-cis and cis-trcms-trans configurations formed [CuII 4(Lrccc)(OAc)3(μ-OH)] (2) and [Cu II4(Lrctt)(OAc)3(μ-OH)] (3), respectively, which have common features, such as a cone-type conformation of L4-, tetrakis fac-tri dentate coordination fashion, and tetra- copper(II) core in a square-pyramidal geometry. The similarities among 1-3 clearly show that sulfinylcalixarenes can coordinate to CuII in a fac-tridentate fashion via a donor atom X (O or S) from a sulfinyl group and two flanking phenoxo O-s and that X is simply determined by the X-Cu distance. Using [Cu(acac)?] as a copper(II) source, H4L rctt formed [CuII2(H2L rctt)2] (4), suggesting the significance of auxiliary ligand for bridging copper(II) centers to assemble the core, that is, the acetato ligands in complexes 1-3 are needed to form the core structure. Metal-metal interactions were investigated by means of magnetic susceptibility, and it was found that both ferro- and antiferromagnetic interactions occur in tetracopper(II) complex 3. In contrast, antiferromagnetic interaction is present in dicopper(II) complex 4.
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