Structural diversity of copper complexes with angular and linear dipyridyl ligands

The versatile coordination properties of the 2,2' and 4,4'-Iong conjugated bidentate ligands 2,5-bis(2-pyridylethynyl)thiophene (LI), 2,2'-dipyridyldisulfide (L-2) and 4,4'-dipyridyldisulfide (L-3) with copper acetate has been investigated. Reactions with 2,5-bis(2-pyridylethynyl)thiophene (LI) and 4,4'-dipyridyldisulfide (L3) leads to two types of complexes. So, when methanol solutions of Cu(OAC)(2) (.) H2O were allowed to diffuse into a solution of L-1 or L-3 (ratio 1:1), green crystals of the molecular 1:2 adduct Cu-2(mu-OAc)(4)(L-1)(2) (1) and the infinite coordination polymer [Cu-2(mu-OAc)(4)(L-3)](n) (2) were obtained. The reaction with L-2, under reflux in MeOH, affords the copper(I) cluster Cu-6(SC5H4N)(6) (3) and the dimer [Cu(mu-S)(L-2)](2) (4). Compound 3 was already known by reaction of the copper(I) salt [Cu(NCMe)(4)]PF6 with SC5H4NH in acetone. The structures were determined by X-ray crystallography and their magnetic properties examined. (C) 2007 Elsevier Ltd. All rights reserved.