Fine-tuning the magnetocaloric effect and SMMs behaviors of coplanar RE₄ complexes by β-diketonate coligands

Abstract

By introducing different β-diketonate coligands, Gd4 complexes show cryogenic magnetic refrigeration properties, whereas Dy4 clusters exhibit different SMMs behaviors.

Single‐Molecule Magnetism in Three Dy2 Complexes from the Use of a Pentadentate Schiff Base Ligand and Different Benzoates

“…For complexes 2 and 3,f requency-dependent peaks were determined between 5( 1Hz) and 14 K( 1000 Hz), which also suggested slow magnetic relaxation and SMM behavior for 2 and 3 (Figure 3b and c). [19,20] The single relaxation processes can be clearlyi dentified in Cole-Cole plots for 1-3 under zero-field conditions (Figure 4ac). For an Orbach-type relaxation, the relaxation time and barrier will follow Arrhenius law [Eq.…”

Magnetic and Luminescence Properties of 8-Coordinate Holmium(III) Complexes Containing 4,4,4-Trifluoro-1-Phenyl- and 1-(Naphthalen-2-yl)-1,3-Butanedionates

“…The lanthanide cations (Ln 3+ ) as hard Lewis acids exhibit a strong binding affinity for O -donor ligands such as β-diketone compounds (HL) [ 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. Typically electrically neutral tris complexes, Ln(L) 3 are most likely to be formed [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ], but in some cases, the anionic tetrakis complexes, (Cat + )[Ln(L) 4 ] − are also formed [ 49 , 56 , 57 , 58 , 59 ]. The two categories of these compounds exhibit good luminescent properties [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ].…”

“…Typically electrically neutral tris complexes, Ln(L) 3 are most likely to be formed [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ], but in some cases, the anionic tetrakis complexes, (Cat + )[Ln(L) 4 ] − are also formed [ 49 , 56 , 57 , 58 , 59 ]. The two categories of these compounds exhibit good luminescent properties [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. The luminescence efficiency of the β-diketonato complexes can be enhanced by the appropriate choice of the substituents on the β-diketone ligand because, in this way, the ligands’ triplet levels can be tuned to provide efficient energy transfer between the diketonato ligand and the lanthanide ion [ 60 , 61 , 62 , 63 ].…”

Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate

“…Following Pearson's HSAB theory, lanthanide cations are hard Lewis acids, and thus exhibit strong binding affinity for Lewis bases derived from O-donor and N-containing ligands. A large number of Ln(III) complexes have been isolated and structurally characterized with the indicated ligands and specifically with β-diketonate species [21][22][23][24][25][26][27][28][29][30]. Herein, we report the synthesis, structural characterization of a novel series of La(III), Eu(III) and Tb(III) complexes based on 4,4,4trifluoro-1-phenyl-butane-1,3-dione (Hbtfa) and their pyridine derivatives (4,4 -Mt 2 bipy = 4,4 -dimethoxybipyridine, 4,4 -Me 2 bipy = 4,4 -dimethylbipyridine, 5,5 -Me 2 bipy = 5,5dimethylbipyridine, phen = 1,10-phenanthrolinene, terpy = 2,2 :6 , 2 -terpyridine, 2-benzpy = 2-(2-pyriyl)-benzimidazole) as well as the photoluminescent properties of Tb(III) and Eu(III) compounds.…”