Lanthanide cymantrenecarboxylate complexes with an Ln:Mn ratio of 1:2 as precursors for LnMn2O5 phases. Synthesis, structure, physicochemical properties, and thermal decomposition

• Published in: Polyhedron 2013-11, Vol.65, p.110-121
• Main Authors: Koroteev, Pavel S., Dobrokhotova, Zhanna V., Ilyukhin, Andrey B., Efimov, Nikolay N., Kirdyankin, Denis I., Tyurin, Aleksandr V., Velikodny, Yury A., Kovba, Maksim L., Novotortsev, Vladimir M.
• Format: Article
• Language: English
• Subjects: Cymantrenecarboxylate; Magnetic properties; Rare earth manganite; Standard thermodynamic functions; Thermal decomposition; X-ray diffraction study
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2013.08.024

Novel 3d–4f heterometallic binuclear complexes, [Ln2(μ-OOCCym)4(η2-NO3)2(η2-DME)2], where Ln=Pr, Eu, Gd, Tb, Dy, Ho, Er, Yb, Cym=(η5-C5H4)Mn(CO)3, and DME=CH3OCH2CH2OCH3, and trinuclear complex [Yb3(μ-О,η2-OOCCym)2(μ2-OOCCym)4(η2-NO3)3(η2-DME)2(H2O)2] were synthesized and characterized by X-ray diffraction and various physical methods. Thermal decomposition of the complexes in air affords pure LnMn2O5 phases. The magnetic properties of LnMn2O5 phases (Ln=Gd, Ho) prepared by thermolysis of the corresponding precursors were studied. New binuclear rare-earth cymantrenecarboxylate complexes [Ln2(μ2-OOCCym)2(μ-О,η2-OOCCym)2(η2-NO3)2(η2-DME)2], Ln=Pr (1), Eu (2), Gd (3), Tb (4a), Dy (5), Ho(6a), Er (7); [Ln2(μ2-OOCCym)4(η2-NO3)2(η2-DME)2], Ln=Tb (4b), Ho(6b,c), Yb (8) and the trinuclear complex [Yb3(μ-О,η2-OOCCym)2(μ2-OOCCym)4(η2-NO3)3(η2-DME)2(H2O)2] (9) (Cym=(η5-C5H4)Mn(CO)3), DME=CH3OCH2CH2OCH3) were synthesized and characterized by X-ray diffraction. The magnetic properties of 3 are indicative of antiferromagnetic exchange between the Gd atoms. Complexes 4a and 6a were found to exhibit significant ferromagnetic interactions. It was shown that the luminescence of Eu3+ in 2 is efficiently quenched by the cymantrenecarboxylate moiety which determines the luminescent properties of this complex. For complex 4a standard thermodynamic functions were calculated from adiabatic calorimetry data. The thermal decomposition of the complexes in air affords pure LnMn2O5 phases as the final products. The magnetic properties of the LnMn2O5 phases (Ln=Gd, Ho) prepared by the thermal decomposition of 3 and 6a were studied.