scholarly journals Mononuclear Lanthanide(III)-Salicylideneaniline Complexes: Synthetic, Structural, Spectroscopic, and Magnetic Studies

2018 ◽  
Vol 4 (4) ◽  
pp. 45 ◽  
Author(s):  
Ioannis Mylonas-Margaritis ◽  
Diamantoula Maniaki ◽  
Julia Mayans ◽  
Laura Ciammaruchi ◽  
Vlasoula Bekiari ◽  
...  

The reactions of hydrated lanthanide(III) [Ln(III)] nitrates and salicylideneaniline (salanH) have provided access to two families of mononuclear complexes depending on the reaction solvent used. In MeCN, the products are [Ln(NO3)3(salanH)2(H2O)]·MeCN, and, in MeOH, the products are [Ln(NO3)3(salanH)2(MeOH)]·(salanH). The complexes within each family are proven to be isomorphous. The structures of complexes [Ln(NO3)3(salanH)2(H2O)]·MeCN (Ln = Eu, 4·MeCN_Eu, Ln = Dy, 7·MeCN_Dy; Ln = Yb, 10·MeCN_Yb) and [Ln(NO3)3(salanH)2(MeOH)]·(salanH) (Ln = Tb, 17_Tb; Ln = Dy, 18_Dy) have been solved by single-crystal X-ray crystallography. In the five complexes, the LnIII center is bound to six oxygen atoms from the three bidentate chelating nitrato groups, two oxygen atoms from the two monodentate zwitterionic salanH ligands, and one oxygen atom from the coordinated H2O or MeOH group. The salanH ligands are mutually “cis” in 4·MeCN_Eu, 7·MeCN_Dy and 10·MeCN_Yb while they are “trans” in 17_Tb and 18_Dy. The lattice salanH molecule in 17_Tb and 18_Dy is also in its zwitterionic form with the acidic H atom being clearly located on the imine nitrogen atom. The coordination polyhedra defined by the nine oxygen donor atoms can be described as spherical tricapped trigonal prisms in 4·MeCN_Eu, 7·MeCN_Dy, and 10·MeCN_Yb and as spherical capped square antiprisms in 17_Tb and 18_Dy. Various intermolecular interactions build the crystal structures, which are completely different in the members of the two families. Solid-state IR data of the complexes are discussed in terms of their structural features. 1H NMR data for the diamagnetic Y(III) complexes provide strong evidence that the compounds decompose in DMSO by releasing the coordinated salanH ligands. The solid complexes emit green light upon excitation at 360 nm (room temperature) or 405 nm (room temperature). The emission is ligand-based. The solid Pr(III), Nd(III), Sm(III), Er(III), and Yb(III) complexes of both families exhibit LnIII-centered emission in the near-IR region of the electromagnetic spectrum, but there is probably no efficient salanH→LnIII energy transfer responsible for this emission. Detailed magnetic studies reveal that complexes 7·MeCN_Dy, 17_Tb and 18_Dy show field-induced slow magnetic relaxation while complex [Tb(NO3)3(salanH)2(H2O)]·MeCN (6·MeCN_Tb) does not display such properties. The values of the effective energy barrier for magnetization reversal are 13.1 cm−1 for 7·MeCN_Dy, 14.8 cm−1 for 17_Tb, and 31.0 cm−1 for 18_Dy. The enhanced/improved properties of 17_Tb and 18_Dy, compared to those of 6_Tb and 7_Dy, have been correlated with the different supramolecular structural features of the two families. The molecules [Ln(NO3)3(salanH)2(MeOH)] of complexes 17_Tb and 18_Dy are by far better isolated (allowing for better slow magnetic relaxation properties) than the molecules [Ln(NO3)3(salanH)2(H2O)] in 6·MeCN_Tb and 7·MeCN_Dy. The perspectives of the present initial studies in the Ln(III)/salanH chemistry are discussed.

2012 ◽  
Vol 65 (10) ◽  
pp. 1436 ◽  
Author(s):  
Feng Luo ◽  
Yu-Mei Song ◽  
Hai-Xiao Huang ◽  
Xiao-Zhao Tian ◽  
Gong-Ming Sun ◽  
...  

In this work, we present two new one-dimensional Dy(iii) compounds, namely [Dy3(L1)9]n (1, HL1 = benzoic acid) and {[Dy4(L2)14][Fe(phen)3]}n (2, HL2 = 3-nitrobenzoic acid, phen = 1,10-phenanthroline). In 1, three distinct coordination polyhedra for Dy(iii) sites including a six-coordinated DyO6 octahedron, a seven-coordinated DyO7 pentagonal bipyramid, and eight-coordinated DyO8 dodecahedron, are observed. These Dy(iii) ions are in turn bridged by L1––carboxylate to give rise to the 1D helical chain structure. Within 2, there are two crystallography-independent Dy(iii) ions that take the mono-capped trigonal bipyramidal geometry. Through L2-carboxylate bridges the Dy(iii) ions are associated together, resulting in the 1D chain structure. Direct current magnetic susceptibilities reveal ferromagnetic interactions, whilst dynamic magnetic studies via alternating current measurements disclose slow magnetic relaxation of these structures.


2019 ◽  
Vol 43 (33) ◽  
pp. 12941-12949 ◽  
Author(s):  
Wen-Min Wang ◽  
Li Zhang ◽  
Xian-Zhen Li ◽  
Li-Yuan He ◽  
Xin-Xin Wang ◽  
...  

A family LnIII4 clusters were successfully synthesized and structurally characterized. Magnetic studies show that Gd4 cluster displays magnetic refrigeration, while Dy4 cluster demonstrates two distinct slow magnetic relaxation processes.


2019 ◽  
Vol 7 (14) ◽  
pp. 4164-4172 ◽  
Author(s):  
Szymon Chorazy ◽  
Jakub J. Zakrzewski ◽  
Mateusz Reczyński ◽  
Koji Nakabayashi ◽  
Shin-ichi Ohkoshi ◽  
...  

Functional materials incorporating cyanido-bridged DyIIICoIII molecules combine visible photoluminescence and slow magnetic relaxation, both switchable by the level of humidity within the reversible room temperature dehydration process.


Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1221
Author(s):  
Rina Takano ◽  
Takayuki Ishida

Polymeric terbium(III) squarate hydrate [{Tb2(C4O4)3(H2O)8}n] was prepared from TbCl3 or Tb2O3 and squaric acid. The crystal structure was determined in a monoclinic Pc space group, and the whole molecular arrangement gives a sandwiched two-dimensional structure. The coordination polyhedra are described as a square antiprism. The solid complex emits green light under UV irradiation at room temperature with the quantum yield of 25%. Although Tb3+ is a non-Kramers ion, the alternating-current magnetic susceptibility showed frequency dependence in a 2000-Oe DC field, and the effective energy barrier for magnetization reorientation was 33(2) K. Thus, [{Tb2(C4O4)3(H2O)8}n] displayed functions of a potential luminescent magnet.


2017 ◽  
Vol 46 (14) ◽  
pp. 4786-4795 ◽  
Author(s):  
Nannan Mao ◽  
Biquan Zhang ◽  
Fan Yu ◽  
Xi Chen ◽  
Gui-lin Zhuang ◽  
...  

A novel 3D coordination polymer containing 2D cobalt–carboxylate layer had been constructed, exhibiting slow magnetic relaxation.


2014 ◽  
Vol 38 (7) ◽  
pp. 3006-3014 ◽  
Author(s):  
Javeed Ahmad Sheikh ◽  
Amit Adhikary ◽  
Sanjit Konar

Three tetranuclear lanthanide cages featuring either hemicubane (1 and 2) or distorted hemicubane (3) like cores are reported. Magnetic studies reveal significant magnetic entropy changes for complex 1 and a slow relaxation of magnetisation for 3.


2020 ◽  
Vol 49 (27) ◽  
pp. 9516-9528 ◽  
Author(s):  
Aparup Paul ◽  
Marta Viciano-Chumillas ◽  
Horst Puschmann ◽  
Joan Cano ◽  
Subal Chandra Manna

Two novel mixed valence di/tri nuclear CoII–CoIII complexes were synthesized and characterized by single crystal X-ray diffraction. Magnetic studies at low temperature revealed that both complexes show slow magnetic relaxation.


2018 ◽  
Vol 42 (21) ◽  
pp. 17652-17658 ◽  
Author(s):  
Min-Xia Yao ◽  
Li-Zheng Cai ◽  
Xiao-Wei Deng ◽  
Wei Zhang ◽  
Sui-Jun Liu ◽  
...  

Four rare structurally novel octanuclear quad(double-strands) cluster helicates containing Ln8 polyhedron cores have been synthesized. Magnetic studies show that the Gd derivative exhibits the magnetocaloric effect and the Dy derivative shows slow magnetic relaxation under zero dc field.


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