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CPP: Chemische Physik und Polymerphysik

CPP 19: Poster: New Methods, Thin Polymer Films, Monolayers

CPP 19.28: Poster

Thursday, April 5, 2001, 12:30–15:00, AT1

ESR on supra-molecular grid structures with Cu(II) centers — •W. Bietsch and A. Mirea — Lehrstuhl fuer Experimentalphysik II, Universitaet Bayreuth, 95440 Bayreuth

Metall organic compounds consisting of functionalized terpyridine or bis(bipyridyl)-pyrimidine-ligands are potential building blocks for two dimensional nano-structured polymers. We report ESR and ENDOR investigations of these novel grid structures with Cu(II) centers depending on the functionalization of the organic ligands. We found that the intra molecular antiferromagnetic coupling (T-Neel = 30 K) between the four Cu(II) ions in a square planar arrangement is crucially determined by the functionalization of the pyrimidine rings. By ESR on the mono analogue Cu(II)-complexes with functionalized terpyridine ligands of magnetically diluted samples (Cu(II)concentration < 1 %) we succeeded for the first time in resolving the superhyperfine structure due to the interaction of the Cu(II) spin with the nuclear spins of the nitrogens in the surrounding organic ligands. Thus we could determine the temperature dependence of the A- and g-Tensors which give insight in possible intra molecular antiferromagnetic coupling mechanisms.