Role of alkyl substituents in the structure and luminescence properties of discrete terbium(III)-lithium(I) Β-Diketonates

Perfluoroalkyl Chain Length Effect on Crystal Packing and [LnO8] Coordination Geometry in Lanthanide-Lithium β-Diketonates: Luminescence and Single-Ion Magnet Behavior

Functionalized perfluoroalkyl lithium β-diketonates (LiL) react with lanthanide(III) salts (Ln = Eu, Gd, Tb, Dy) in methanol to give heterobimetallic Ln-Li complexes of general formula [(LnL₃)(LiL)(MeOH)]. The length of fluoroalkyl substituent in ligand was found to affect the crystal packing of complexes. Photoluminescent and magnetic properties of heterobimetallic β-diketonates in the solid state are reported. The effect of the geometry of the [LnO₈] coordination environment of heterometallic β-diketonates on the luminescent properties (quantum yields, phosphorescence lifetimes for Eu, Tb, Dy complexes) and single-ion magnet behavior (U_eff for Dy complexes) is revealed.

Structure and Properties of Heterometallics Based on Lanthanides and Transition Metals with Methoxy-β-Diketonates

The possibility of obtaining volatile polynuclear heterometallic complexes containing lanthanides and transition metals bound by methoxy-β-diketonates was studied. New compounds were prepared by cocrystallization of monometallic complexes from organic solvents. Ln(tmhd)₃ were used as initial monometallic complexes (Ln = La, Pr, Sm, Gd, Tb, Dy, Lu; tmhd = 2,2,6,6-tetramethylheptane-3,5-dionate) in combination with TML₂ in various ratios (TM = Cu, Co, Ni, Mn; L: L¹ = 1,1,1-trifluoro-5,5-dimethoxypentane-2,4-dionate, L² = 1,1,1-trifluoro-5,5-dimethoxy-hexane-2,4-dionate, L³ = 1,1,1-trifluoro-5-methoxy-5-methylhexane-2,4-dionate). Heterometallic complexes of the composition [(LnL₂tmhd)₂TM(tmhd)₂] were isolated for light lanthanides Ln= La, Pr, Sm, Gd, and L= L¹ or L². By single crystal XRD, it has been established that heterometallic compounds containing La, Pr, Cu, Co, and Ni are isostructural linear coordination polymers of alternating mononuclear transition metal complexes and binuclear heteroleptic lanthanide complexes, connected by donor-acceptor interactions between oxygen atoms of the methoxy groups and transition metal atoms. A comparison of powder XRD patterns has shown that all heterometallic complexes obtained are isostructural. Havier lanthanides Ln = Tb, Dy, Lu did not form heterometallics. Instead, homometallic complexes Ln(L³)₃ were identified for Ln = Dy, Lu as well as for Ln = La. The thermal properties of the complexes were investigated by TG-DTA and vacuum sublimation tests. The heterometallic complexes were found to be not volatile and decomposed under heating to produce inorganic composites of TM oxides and Ln fluorides. In contrast, Ln(L³)₃ is volatile and may be sublimed in a vacuum. Results of magnetic measurements are discussed for several heterometallic and homometallic complexes.

Heterometallic Molecular Architectures Based on Fluorinated β-Diketone Ligands

This review summarizes the data on the synthesis of coordination compounds containing two or more different metal ions based on fluorinated β-diketonates. Heterometallic systems are of high interest in terms of their potential use in catalysis, medicine and diagnostics, as well as in the development of effective sensor devices and functional materials. Having a rich history in coordination chemistry, fluorinated β-diketones are well-known ligands generating a wide variety of heterometallic complexes. In this context, we focused on both the synthetic approaches to β-dicarbonyl ligands with additional coordination centers and their possible transformations in complexation reactions. The review describes bi- and polynuclear structures in which β-diketones are the key building blocks in the formation of a heterometallic framework, including the examples of both homo- and heteroleptic complexes.

[Tb4(OH)4]-Cuboid Complex Dianion Stabilized with Six Carboxylate Bridges and Four Diketonate Caps

A cubane-like complex dianion [Tb4(OH)4(tfa)6(hfac)4]2− was synthesized, accompanied by two counter cations of [Ni(hfac)(2pyIN)2]+, where Htfa, Hhfac, and 2pyIN stand for trifluoroacetic acid, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, and 4,4,5,5-tetramethyl-2-pyridylimidazolin-1-oxyl, respectively. In the complex anion, each Tb ion was capped with hfac, and each Tb···Tb diagonal was bridged with tfa, thus forming an approximate Td symmetry, though the whole molecular formula was crystallographically independent in an orthorhombic Pbca space group. The ionic charge was −2 in total. The magnetic study revealed that the complex ions were magnetically isolated from each other. Practically no 4f–4f superexchange interaction was operative, while the 2p–3d ferromagnetic coupling seemed to be appreciable, as anticipated from the proposed magnetostructural relationship.