PUB - Publikationen an der Universität Bielefeld

The tris(tetradentate) triplesalacen ligand H(6)talacen and its trinuclear copper complex, namely [(talacen) Cu-3(II)], were synthesized and its molecular and electronic structure determined. The ligand is prepared by the triple condensation of 2,4,6-trisacetyl-1,3,5-trihydroxybenzene (1) and excess acacen half-unit (2). The molecular structure of [(talacen)Cu-3(II)] exhibits a strong ligand folding around the central Cu-II-phenolate bonds. This ligand folding is stronger than that observed in the trinuclear copper triplesalen complexes. The electronic absorption spectrum exhibits a prominent intense band at 32 400 cm (1) and d-d transitions around 19 000 cm (1). These spectral features are related to the ligand folding, which opens an O-Ph(p(z))-Cu-II (d(x2-y2)) bonding pathway. Electrochemical studies provide an irreversible oxidation at a relatively low potential of 0.17 V versus Fc(+)/Fc, which is assigned to a ligand-centered oxidation of the central phloroglucinol backbone. A ferromagnetic coupling of J = 1.20 cm (1) (H = Sigma(i