Synthesis of a series of hetero-multi-spin Ln2Cu3 complexes based on a methyl-pyrazole nitronyl nitroxide radical with slow magnetic relaxation behaviors

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.

A metal-radical hetero-tri-spin SCM with methyl-pyrazole-nitronyl nitroxide bridges

The preparation, crystal structures, and magnetic properties of a family of hetero-tri-spin 1-D coordination polymers with the formula [Ln(hfac)₃Cu(hfac)₂(4-NIT-MePyz)₂] (Ln = Gd, 1, Tb, 2, Dy, 3; hfac = hexafluoroacetylacetonate; 4-NIT-MePyz = 2-{4-(1-methyl)-pyrazolyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) are reported. In these complexes, the 4-NIT-MePyz radical acts as a linker to bridge the Cu^II and Ln^III ions through its pyrazole and aminoxyl groups to form a chain structure. Magnetic properties typical of spin-chains are observed for Dy and Tb derivatives but single-chain magnet (SCM) behavior was evidenced only for the Tb compound which is characterized by an energy gap for demagnetization Δ_τ/k_B of 31 K.