A Series of Novel Pentagonal-Bipyramidal Erbium(III) Complexes with Acyclic Chelating N3O2 Schiff-Base Ligands: Synthesis, Structure, and Magnetism

Tamara A Bazhenova; Vyacheslav A Kopotkov; Denis V Korchagin; Yuriy V Manakin; Leokadiya V Zorina; Sergey V Simonov; Ilya A Yakushev; Vladimir S Mironov; Alexander N Vasiliev; Olga V Maximova; Eduard B Yagubskii

doi:10.3390/molecules26226908

A Series of Novel Pentagonal-Bipyramidal Erbium(III) Complexes with Acyclic Chelating N₃O₂ Schiff-Base Ligands: Synthesis, Structure, and Magnetism

Molecules. 2021 Nov 16;26(22):6908. doi: 10.3390/molecules26226908.

Authors

Tamara A Bazhenova¹, Vyacheslav A Kopotkov¹, Denis V Korchagin¹, Yuriy V Manakin¹, Leokadiya V Zorina^{1

2}, Sergey V Simonov^{1

2}, Ilya A Yakushev^{1

3}, Vladimir S Mironov^{1

4}, Alexander N Vasiliev^{5

6}, Olga V Maximova⁶, Eduard B Yagubskii¹

Affiliations

¹ Institute of Problems of Chemical Physics, IPCP RAS, Chernogolovka 142432, Russia.
² Institute of Solid State Physics, ISSP RAS, Chernogolovka 142432, Russia.
³ Kurnakov Institute of General and Inorganic Chemistry, IGIC RAS, Moscow 119333, Russia.
⁴ Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" RAS, Moscow 119333, Russia.
⁵ Laboratory of Quantum Functional Materials, National University of Science and Technology "MISiS", Moscow 119049, Russia.
⁶ Lomonosov Moscow State University, Moscow 119991, Russia.

Abstract

A series of six seven-coordinate pentagonal-bipyramidal (PBP) erbium complexes, with acyclic pentadentate [N₃O₂] Schiff-base ligands, 2,6-diacetylpyridine bis-(4-methoxybenzoylhydrazone) [H₂DAPMBH], or 2,6-diacethylpyridine bis(salicylhydrazone) [H₄DAPS], and various apical ligands in different charge states were synthesized: [Er(DAPMBH)(C₂H₅OH)Cl] (1); [Er(DAPMBH)(H₂O)Cl]·2C₂H₅OH (2); [Er(DAPMBH)(CH₃OH)Cl] (3); [Er(DAPMBH)(CH₃OH)(N₃)] (4); [(Et₃H)N]⁺[Er(H₂DAPS)Cl₂]^- (5); and [(Et₃H)N]⁺[Y₀.₉₅Er₀.₀₅(H₂DAPS)Cl₂]^- (6). The physicochemical properties, crystal structures, and the DC and AC magnetic properties of 1-6 were studied. The AC magnetic measurements revealed that most of Compounds 1-6 are field-induced single-molecule magnets, with estimated magnetization energy barriers, U_eff ≈ 16-28 K. The experimental study of the magnetic properties was complemented by theoretical analysis based on ab initio and crystal field calculations. An experimental and theoretical study of the magnetism of 1-6 shows the subtle impact of the type and charge state of the axial ligands on the SMM properties of these complexes.

Keywords: DC and AC magnetic properties; Er(III) complexes; crystal structure; field-induced single-molecular magnets; ligands H2DAPMBH and H4DAPS; seven-coordinate complexes.

Abstract

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