Examinando por Autor "Paredes-Garcia, V."

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    Magnetic behavior of lamellar mnps3 and cdps3 composites with a paramagnetic manganese(iii) macrocyclic guest
    (Sociedad Chilena de Química, 2013) Valencia, P.; Manzur, J.; Garcia, A. M,; Paredes-Garcia, V.; ...[et al.].
    Six new composites derived from the intercalation of the MPS3 phases (M = MnII, CdIII) with the macrocyclic manganese(III) complex [MnL(H2O)2].NO3(H2O) (LH2 = Schiff base macrocyclic ligand derived from the condensation of 2-hydroxy-5-methy1-1,3-benzene-dicarbaldehyde and 1,2-diamine-benzene) were obtained by two different synthetic procedures: a conventional and a microwave assisted method. The composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1), and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (2) were obtained by the conventional method, after stirring a suspension of the corresponding potassium precursor and the macrocyclic complex for two weeks, while [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3) and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (4) after stirring for four weeks at room temperature. Using a microwave assisted reaction permitted to obtain in a shorter period of time as compared with the conventional method, composites [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5) and [MnL]0.15K0.15Cd 0. 80PS3(H2O)~0.5 (6). All the M = MnII, MnIII composites show a bulk antiferromagnetic behavior. However, the spontaneous magnetization present at low temperature in the potassium precursor K0.40Mn0.80 PS3(H2O)~1.0 is observable in composite [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5), while it is completely absent in composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1) and [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3). Keywords: Intercalation; MPS3 phases; MnIII macrocyclic complex; microwave assisted synthesis; magnetic properties.
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    Ítem
    Magnetic properties of composites based on the intercalation of ZnII and CuII bimetallic macrocyclic complexes in the MnPS3 phase
    (RSC Advances, 2017) Fuentealba, P.; Paredes-Garcia, V.; Venegas-Yazigi, D.; Silva, I.D.A.; Magon, C.J.; Costa De Santana, R.; Audebrand, N.; Manzur, J.; Spodine, E.
    Asymmetric macrocyclic complexes of the type [M2LCl2]·xH2O have been obtained and intercalated using the potassium precursor phase K0.4Mn0.8PS3·H2O (M: ZnII or CuII; LH2: macrocyclic ligand derived from 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and two different amines, namely, ethylenediamine and o-phenylenediamine). The intercalation of the layered phase K0.4Mn0.8PS3·H2O by the macrocyclic species was carried out by a microwave-assisted reaction and enabled the partial exchange of the hydrated potassium ions located in the interlayer space to obtain the composites K0.32[Zn2L]0.04Mn0.8PS3 (1) and K0.24[Cu2L]0.08Mn0.8PS3 (2). These magnetic materials were studied by DC and AC magnetization measurements and electron paramagnetic resonance (EPR) spectroscopy. In comparison with the potassium precursor, both composites gave rise to broader and less intense spontaneous magnetization curves at low temperatures. The composite K0.32[Zn2L]0.04Mn0.8PS3 (1) exhibited spontaneous magnetization in the form of one broad asymmetric maximum at 27 K. However, K0.24[Cu2L]0.08Mn0.8PS3 (2) had two defined maxima at 24 and 12 K. The observation of a maximum in the imaginary part of the AC susceptibility data implies the existence of a spin canting phenomenon that would be responsible for the spontaneous magnetization. The EPR results are qualitatively consistent with the magnetization data and reveal that exchange narrowing effects were responsible for the narrowing and broadening of the line shapes. © 2017 The Royal Society of Chemistry.