title: Metal-Metal Interactions in Trinuclear Copper(II) Complexes [Cu3(RCOO)4(H2TEA)2] and Binuclear [Cu2(RCOO)2(H2TEA)2]. Syntheses and Combined Structural, Magnetic, High-Field Electron Paramagnetic Resonance, and Theoretical Studies.
abstract: The trinuclear [Cu3(RCOO)4(H2TEA)2] copper(II) complexes, where RCOO(-) = 2-furoate (1), 2-methoxybenzoate (2), and 3-methoxybenzoate (3, 4), as well as dimeric species [Cu2(H2TEA)2(RCOO)2]·2H2O, have been prepared by adding triethanolamine (H3TEA) at ambient conditions to hydrated Cu(RCOO)2 salts. The newly synthesized complexes have been characterized by elemental analyses, spectroscopic techniques (IR and UV-visible), magnetic susceptibility, single crystal X-ray structure determination and theoretical calculations, using a Difference Dedicated Configuration Interaction approach for the evaluation of magnetic coupling constants. In 1 and 2, the central copper atom lies on an inversion center, while in the polymorphs 3 and 4, the three metal centers are crystallographically independent. The zero-field splitting parameters of the trimeric compounds, D and E, were derived from high-field, high-frequency electron paramagnetic resonance spectra at temperatures ranging from 3 to 290 K and were used for the interpretation of the magnetic data. It was found that the dominant interaction between the terminal and central Cu sites J12 is ferromagnetic in nature in all complexes, even though differences have been found between the symmetrical or quasi-symmetrical complexes 1-3 and non-symmetrical complex 4, while the interaction between the terminal centers, J23, is negligible.
authors.affiliation: National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ozarowski
authors.affiliation: Departamento de Química Física, Universidad de Sevilla , c/Prof. García González, s/n, 41012 Sevilla, Spain.
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Calzado
authors.affiliation: Department of Chemistry, Panjab University , Chandigarh 160014, India.
authors.forename: Raj Pal
authors.initials: RP
authors.lastname: Sharma
authors.affiliation: Department of Chemistry, Panjab University , Chandigarh 160014, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Faculty of Chemistry, Wroclaw University , 14 F. Joliot Curie Str., 50-383 Wroclaw, Poland.
authors.forename: Julia
authors.initials: J
authors.lastname: Jezierska
authors.forename: Celestino
authors.initials: C
authors.lastname: Angeli
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, Università di Ferrara , Via Saragat 1, I-44122 Ferrara, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Spizzo
authors.forename: Valeria
authors.initials: V
authors.lastname: Ferretti