Synthesis structure magnetic properties of [Cu5(bta)6L4] (bta=benzotriazolate;L=β-diketonate) Clusters
作者:Mark Murrie、David Collison、C.David Garner、Madeleine Helliwell、Peter A Tasker、Scott S Turner
DOI:10.1016/s0277-5387(98)00161-2
日期:1998.8
Reaction of [CuL2] (LH: tfpbdH = 4,4,4-trifluoro-1-phenyl-1,3-butanedione; tropH = tropolone; or acacH =acetylacetone; Ph/Me-pdH = I-phenyl-l,3-butanedionel Ph/Ph-pdH = 1,3-diphenyl-1,3-propanedione; or C4H3S/CF3-pdH =4,4,4-trifluoro-1-(2-thienyl-1,3-butanedione)) with benzotriazole (btaH) in CH2Cl2 yields the corresponding compound [Cu-5(bta)(6)L-4] (L = tfpbd, 1; trop, 2; acac, 3; (Ph/Me-pd) 4 (Ph/Ph-pd) 5; (C4H3S/CF3-pd) 6). The structures of 1 and 2 have been determined by single crystal X-ray diffraction revealing a distorted tetrahedral arrangement of four Cu(II) centered on a fifth Cu(II). Each of the six bta ligands spans an edge of the Cu, tetrahedron and is ligated to the central Cu through its central nitrogen. Solid-state magnetic susceptibility studies from 2-300 K have been accomplished for 1, 2 and 3 and reveal a weak antiferromagnetic intramolecular interaction between the five Cu(II) centres. The tridentate (mu(3)-bridging) bonding motif of bta is well suited for the formation of a protective monolayer of bta(-) ions on oxidised copper surfaces. Furthermore, the flexibility in this mode of coordination exhibited by bta(-) ions, as manifest within the structures of 1, 2, and 3 (the structure of which was determined previously), is advantageous and would allow benzotriazolate to adapt to the various surface topographies which could well be presented by lightly oxidized copper surfaces. (C) 1998 Elsevier Science Ltd. All rights reserved.