Syntheses, structures, and magnetic properties of homodinuclear lanthanide complexes based on dinucleating Schiff base ligands

2015 ◽  
Vol 44 (46) ◽  
pp. 20232-20241 ◽  
Author(s):  
Feng Gao ◽  
Feng-Lei Yang ◽  
Guang-Zhou Zhu ◽  
Yue Zhao
Keyword(s):  
Magnetic Properties ◽  
Schiff Base ◽  
Lanthanide Complexes ◽  
Antiferromagnetic Coupling ◽  
Magnetic Studies ◽  
Schiff Base Ligands

Two series of homodinuclear lanthanide(iii) complexes were synthesized and characterized. Magnetic studies reveal the weakly antiferromagnetic coupling between paramagnetic Ln ions and enhanced relaxation of magnetization for Dy2 complexes.

scholarly journals In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 728
Author(s):  
Alberto Aragón-Muriel ◽  
Yamil Liscano ◽  
Yulieth Upegui ◽  
Sara M. Robledo ◽  
María Teresa Ramírez-Apan ◽  
...  
Keyword(s):  
Schiff Base ◽  
Molecular Docking ◽  
Lanthanide Complexes ◽  
Human Tumor ◽  
Model Membranes ◽  
Leishmania Braziliensis ◽  
Cytotoxic Activities ◽  
Schiff Base Ligands ◽  
Major Interest

Metal-based drugs, including lanthanide complexes, have been extremely effective in clinical treatments against various diseases and have raised major interest in recent decades. Hence, in this work, a series of lanthanum (III) and cerium (III) complexes, including Schiff base ligands derived from (1H-benzimidazol-2-yl)aniline, salicylaldehyde, and 2,4-dihydroxybenzaldehyde were synthesized and characterized using different spectroscopic methods. Besides their cytotoxic activities, they were examined in human U-937 cells, primate kidney non-cancerous COS-7, and six other, different human tumor cell lines: U251, PC-3, K562, HCT-15, MCF-7, and SK-LU-1. In addition, the synthesized compounds were screened for in vitro antiparasitic activity against Leishmania braziliensis, Plasmodium falciparum, and Trypanosoma cruzi. Additionally, antibacterial activities were examined against two Gram-positive strains (S. aureus ATCC® 25923, L. monocytogenes ATCC® 19115) and two Gram-negative strains (E. coli ATCC® 25922, P. aeruginosa ATCC® 27583) using the microdilution method. The lanthanide complexes generally exhibited increased biological activity compared with the free Schiff base ligands. Interactions between the tested compounds and model membranes were examined using differential scanning calorimetry (DSC), and interactions with calf thymus DNA (CT-DNA) were investigated by ultraviolet (UV) absorption. Molecular docking studies were performed using leishmanin (1LML), cruzain (4PI3), P. falciparum alpha-tubulin (GenBank sequence CAA34101 [453 aa]), and S.aureus penicillin-binding protein 2a (PBP2A; 5M18) as the protein receptors. The results lead to the conclusion that the synthesized compounds exhibited a notable effect on model membranes imitating mammalian and bacterial membranes and rolled along DNA strands through groove interactions. Interactions between the compounds and studied receptors depended primarily on ligand structures in the molecular docking study.

scholarly journals Nitronyl Nitroxide Biradical-Based Binuclear Lanthanide Complexes: Structure and Magnetic Properties

2020 ◽  
Vol 6 (4) ◽  
pp. 48
Author(s):  
Lu Xi ◽  
Jing Han ◽  
Xiaohui Huang ◽  
Licun Li
Keyword(s):  
Magnetic Properties ◽  
Magnetic Relaxation ◽  
Lanthanide Complexes ◽  
Magnetic Data ◽  
Antiferromagnetic Coupling ◽  
Zero Field ◽  
Nitronyl Nitroxide ◽  
Ferromagnetic Exchange ◽  
Binuclear Structure ◽  
Slow Magnetic Relaxation

Employing a new nitronyl nitroxide biradical NITPhPzbis(NITPhPzbis = 5-(1-pyrazolyl)-1,3-bis(1’-oxyl-3’-oxido-4’,4’,5’,5’-tetramethyl-4,5-hydro-1H-imidazol-2-yl)benzene), a series of 2p-4f complexes [Ln2(hfac)6(H2O)(NITPhPzbis)] (LnIII = Gd1, Tb2, Dy3; hfac = hexafluoroacetylacetonate) were successfully synthesized. In complexes 1–3, the designed biradical NITPhPzbis coordinates with two LnIII ions in chelating and bridging modes to form a four-spin binuclear structure. Direct-current magnetic study of Gd analogue indicates that ferromagnetic exchange exists between the Gd ion and the radical while antiferromagnetic coupling dominates between two mono-radicals. Dynamic magnetic data show that the χ” signals of complex 3 exhibit frequency dependence under zero field, demonstrating slow magnetic relaxation behavior in complex 3. And the estimated values of Ueff and τ0 are about 8.4 K and 9.1 × 10−8 s, respectively.

Fluorescent lanthanide complexes of Schiff base ligands possessingN-aryl moiety: influence of chain length on crossover (calamitic to discotic) phase behaviour

2010 ◽  
Vol 37 (11) ◽  
pp. 1393-1410 ◽  
Author(s):  
Nandiraju V.S. Rao ◽  
Trirup D. Choudhury ◽  
Rahul Deb ◽  
Manoj K. Paul ◽  
Thatavarthi R. Rao ◽  
...  
Keyword(s):  
Schiff Base ◽  
Chain Length ◽  
Lanthanide Complexes ◽  
Phase Behaviour ◽  
Schiff Base Ligands

A low-temperature study of the magnetic properties of the molecular cations O2+, Br2+, and I2+

1989 ◽  
Vol 67 (11) ◽  
pp. 1942-1948 ◽  
Author(s):  
M. S. R. Cader ◽  
R. C. Thompson ◽  
F. Aubke
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Magnetic Moment ◽  
Photoelectron Spectroscopy ◽  
Theoretical Models ◽  
Antiferromagnetic Coupling ◽  
Paramagnetic Species ◽  
Magnetic Studies ◽  
Suggested Keywords ◽  
Molecular Cations

Magnetic susceptibility measurements to 4.2 K are reported forO2+[AsF6]−, Br2+[Sb3F16]−, and I2+[Sb2F11]−. The data are interpreted utilizing previous results from photoelectron spectroscopy, known crystal structures, magnetic studies on the superoxide ion and the ozonide ion, and in the case of O2+[AsF6]−, previous ESR studies. The magnetic properties of the three materials are quite different. Br2+[Sb3F16]− obeys Curie–Weiss law between 80 and 4 K: Cm = 0.49 ± 0.01 cm3 mol−1 K and 9 = −0.74 ± 0.01 K (with TIP = 120 × 10−6 cm3 mol−1). The magnetic moment decreases slightly from 2.04 μB at room temperature to 1.93 μB at 4 K. I2+[Sb2F11]− exhibits relatively strong antiferromagnetic coupling with a maximum in χM observed at −54 K. The magnetic moment (corrected for a TIP contribution of 68 × 10−6 cm3 mol−1) decreases from 1.92 μB at 124 K to 0.41 μB at 4 K. Experimental susceptibilities for this compound over the range 300–4 K have been compared to values calculated using three different theoretical models for extended chains of antiferromagnetically coupled paramagnetic species. O2+[AsF6]− exhibits Curie–Weiss behaviour over the range 60–2 K (Cm = 0.34 ± 0.01 cm3 mol−1 K, θ = −1.90 ± 0.01 K). The magnetic moment, uncorrected for TIP, varies from 1.63 μB at 80 K to 1.17 μB at 2 K, and the presence of weak antiferromagnetic coupling in this material is suggested. Keywords: magnetic susceptibilities, dihalogen cations, dioxygenyl cation, low temperature behaviour.

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