Syntheses, structures, and magnetic properties of acetate-bridged lanthanide complexes based on a tripodal oxygen ligand

Four homodinuclear lanthanide complexes, Dy(2) (L(OEt))(2)(OAc)(4) (1), Tb(2) (L(OEt))(2)(OAc)(4) (2), Ho(2)(L(OEt))(2)(OAc)(4) (3), and Gd(2) (L(OEt))(2)(OAc)(4) (4), have been synthesized and characterized based on a tripodal oxygen ligand Na [(η(5)-C(5)H(5))Co(P(O)(OC(2)H(5))(2))(3)] (NaL(OEt)). Structural analyses show that the acetate anions bridge two symmetry-related Ln(3+) ions in the μ(2):η(1):η(1) and μ(2):η(1):η(2) coordination patterns, and each lanthanide (III) ion owns a twisted square antiprism (SAPR) conformation. Static magnetic measurements reveal the weak intramolecular ferromagnetic interaction between dysprosium (III) ions in 1 and antiferromagnetic Ln(3+)···Ln(3+) couplings in the other three complexes. Through the analysis of the ligand-field effect and magnetic anisotropy axis orientation, the reasons for the lack of dynamic magnetic behavior in 1 were identified.