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Trinuclear NiII-LnIII-NiII Complexes with Schiff Base Ligands: Synthesis, Structure, and Magnetic Properties
| Content Provider | MDPI |
|---|---|
| Author | Georgopoulou, Anastasia N. Pissas, Michael Psycharis, Vassilis Sanakis, Yiannis Raptopoulou, Catherine P. |
| Copyright Year | 2020 |
| Description | The reaction of the Schiff base ligand $o-OH-C_{6}H_{4}-CH=N-C(CH_{2}OH)_{3}$, $H_{4}$L, with $Ni(O_{2}CMe)_{2}·4H_{2}$O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes $[Ni_{2}Ln(H_{3}L)_{4}(O_{2}CMe)_{2}](NO_{3}$) (Ln = Sm (1), Eu (2), Gd (3), Tb (4)). The complex cations contain the strictly linear $Ni^{II}-Ln^{III}-Ni^{II}$ moiety. The central $Ln^{III}$ ion is bridged to each of the terminal $Ni^{II}$ ions through two deprotonated phenolato groups from two different ligands. Each terminal $Ni^{II}$ ion is bound to two ligands in distorted octahedral $N_{2}O_{4}$ environment. The central lanthanide ion is coordinated to four phenolato oxygen atoms from the four ligands, and four carboxylato oxygen atoms from two acetates which are bound in the bidentate chelate mode. The lattice structure of complex 4 consists of two interpenetrating, supramolecular diamond like lattices formed through hydrogen bonds among neighboring trinuclear clusters. The magnetic properties of 1–4 were studied. For 3 the best fit of the magnetic susceptibility and isothermal M(H) data gave $J_{NiGd}$ = +0.42 $cm^{−1}$, D = +2.95 $cm^{−1}$ with $g_{Ni}$ = $g_{Gd}$ = 1.98. The ferromagnetic nature of the intramolecular Ni···Gd interaction revealed ground state of total spin S = 11/2. The magnetocaloric effect (MCE) parameters for 3 show that the change of the magnetic entropy $(−ΔS_{m}$) reaches a maximum of 14.2 J $kg^{−1}$ $K^{−1}$ at 2 K. A brief literature survey of complexes containing the $Ni^{II}-Ln^{III}-Ni^{II}$ moiety is discussed in terms of their structural properties. |
| Starting Page | 2280 |
| e-ISSN | 14203049 |
| DOI | 10.3390/molecules25102280 |
| Journal | Molecules |
| Issue Number | 10 |
| Volume Number | 25 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2020-05-12 |
| Access Restriction | Open |
| Subject Keyword | Molecules Inorganic Chemistry Heterotrinuclear Complexes Nickel Lanthanides Schiff Base Magnetic Properties Crystal Structure |
| Content Type | Text |
| Resource Type | Article |
