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Amphiphilic and Magnetic Properties of a New Class of Cluster‐Bearing [L 2 Cu 4 (μ 4 ‐O)(μ 2 ‐carboxylato) 4 ] Soft Materials

2007; Wiley; Volume: 13; Issue: 35 Linguagem: Inglês

10.1002/chem.200700875

1521-3765

R. Shakya, S.S. Hindo, Libo Wu, Suolong Ni, M. ALLARD, Mary Jane Heeg, Sandro R. P. da Rocha, G.T. Yee, Hrant P. Hratchian, Cláudio N. Verani,

Physics of Superconductivity and Magnetism

A general approach toward amphiphilic systems bearing multimetallic clusters and their ability to form Langmuir-Blodgett films is presented. The synthetic strategy to stabilize these clusters involves the use of a ligand (HL) containing an N(2)O-donor set and long octadecanoic chains to obtain the carboxylate-supported [L(2)Cu(4)(mu(4)-O)(mu(2)-OAc)(4)]EtOH (1) and [L(2)Cu(4)(mu(4)-O)(mu(2)-OBz)(4)] (2) in which OAc(-) and OBz(-) represent acetate (1) and benzoate (2) co-ligands. These species were thoroughly characterized and had their structures solved by X-ray crystallography. We observed that the mu-oxo Cu(4) cluster is antiferromagnetically coupled and used broken-symmetry density functional theory (DFT) calculations to describe the main superexchange pathways of the tetracopper core. We also describe the amphiphilic properties of the ligand and the cluster-containing systems by means of area versus pressure isotherms and show that these cluster-bearing species can be transferred onto solid substrates yielding homogeneous Langmuir-Blodgett films, as characterized by atomic force microscopy and contact angle measurements.