Effect of Fe (III) on L-asparagine monohydrate investigated under low- and high-temperature conditions.

Autor: Gomes EJ; Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 66075-110 Belém, PA, Brazil., Lima JA Jr; Departamento de Física, Universidade Federal do Ceará, P.O. Box 6030, Fortaleza, CE, 60455-900, Brazil., Freire PTC; Departamento de Física, Universidade Federal do Ceará, P.O. Box 6030, Fortaleza, CE, 60455-900, Brazil., Pinheiro GS; Departamento de Física, Campus Ministro Petrônio Portella, Bloco 03, Universidade Federal do Piauí, CEP 64049-550 Teresina, PI, Brazil., de Sousa FF; Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 66075-110 Belém, PA, Brazil., Remédios CMR; Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 66075-110 Belém, PA, Brazil. Electronic address: remedios@ufpa.br.
Jazyk: angličtina
Zdroj: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy [Spectrochim Acta A Mol Biomol Spectrosc] 2020 Nov 05; Vol. 241, pp. 118643. Date of Electronic Publication: 2020 Jun 25.
DOI: 10.1016/j.saa.2020.118643
Abstrakt: Raman spectra of Fe-doped L-asparagine monohydrate (LAM:Fe) crystal were studied under several temperatures varying from 17 to 490 K. The effect of Fe (III) ion on the stability of the crystal in changing temperature through the vibrational spectra was discussed. The behavior of inter and intra-molecular vibration modes has indicated two phase transitions and an amorphous transformation. These effects were also clarified by X-ray powder diffraction measurements which corroborate very well the Raman data. In addition, we have determinated the lattice parameters of all phases and verified that under low temperature conditions the crystal undergoes a conformational transition whereas under high temperatures its structure transforms from the orthorhombic (P2 1 2 1 2 1 -space group) to the monoclinic (P2 1 -space group) symmetry and, after this process, it goes to an amorphous phase due to the start of the decomposition. Finally, differential scanning calorimetry analysis was utilized as complementary technique to investigate the structural stability of LAM:Fe and results are in a good agreement with the Raman and the X-ray diffraction data.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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