Wu DF, Liu Z, Ren P, Liu XH, Wang N, Cui JZ, Gao HL. A new family of dinuclear lanthanide complexes constructed from an 8-hydroxyquinoline Schiff base and β-diketone: magnetic properties and near-infrared luminescence.
Dalton Trans 2019;
48:1392-1403. [PMID:
30623947 DOI:
10.1039/c8dt04384a]
[Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Six phenoxo-O bridged dinuclear lanthanide(iii) complexes have been assembled utilizing the 2-[(4-nitrophenyl)imino]methyl-8-hydroxyquinoline (HL) and dibenzoylmethane (Hdbm) ligands: [Ln2(dbm)4L2] (Ln = Nd (1), Eu (2), Gd (3), Tb (4), Dy (5) and Er (6)). Complexes 1 and 6 exhibit the characteristic emission peaks of the corresponding Nd3+ and Er3+ ions, respectively. Meanwhile, the excitation wavelength (470 nm) for complex 1 is located in the visible-light region, confirming a practical application value. The studies on magnetic properties reveal that complex 3 features a magnetocaloric effect with a magnetic entropy change of -ΔSm = 14.36 J kg-1 K-1 at 4 K for ΔH = 7 T. What's more, the dynamic magnetic studies for complex 5 show that it exhibits slow magnetic relaxation behavior, typical of SMM behavior, resulting in an energy barrier of ΔE/kB = 75 K with the pre-exponential factor τ0 = 2.2 × 10-7 s. Meanwhile, this research demonstrates that the magnetic properties can be modulated by regulating the electron-donating/withdrawing effects of the substituents on the ligands.
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