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Pinho EKS, Silva Filho JGD, Sousa FF, Freire PTC, Lima JA, Dos Santos AO, Filho PFF. Phase transitions of L-histidinium hydrogen oxalate crystal under high pressures investigated by Raman spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc 2023; 298:122800. [PMID: 37156174 DOI: 10.1016/j.saa.2023.122800] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/27/2023] [Accepted: 04/26/2023] [Indexed: 05/10/2023]
Abstract
L-histidinium hydrogen oxalate (L-HisH)(HC2O4) crystal is formed from amino acid. L-histidine with oxalic acid whose vibrational high pressures behavior have not yet been investigated in the literature. Here we synthesized (L-HisH)(HC2O4) crystal by slow solvent evaporation method in a 1:1 ratio of L-histidine and oxalic acid. In addition, a vibrational study of (L-HisH)(HC2O4) crystal as a function of pressure was performed via Raman spectroscopy in the pressure range of 0.0-7.3 GPa. From analysis of the behavior of the bands within 1.5-2.8 GPa, characterized by the disappearance of lattice modes, the occurrence of a conformational phase transition was noted. A second phase transition, now from structural type, close to 5.1 GPa was observed due to the incidence of considerable changes in lattice and internal modes, mainly in vibrational modes related to imidazole ring motions.
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Affiliation(s)
- E K S Pinho
- Centro de Ciências de Imperatriz, Universidade Federal do Maranhão, CEP, 65900-410 Imperatriz, MA, Brazil
| | - J G da Silva Filho
- Centro de Ciências de Imperatriz, Universidade Federal do Maranhão, CEP, 65900-410 Imperatriz, MA, Brazil
| | - F F Sousa
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP, 66075-110 Belém, PA, Brazil
| | - P T C Freire
- Departamento de Física, Universidade Federal do Ceará, CEP, 60455-970 Fortaleza, CE, Braazil
| | - J A Lima
- Departamento de Física, Universidade Federal do Ceará, CEP, 60455-970 Fortaleza, CE, Braazil
| | - A O Dos Santos
- Centro de Ciências de Imperatriz, Universidade Federal do Maranhão, CEP, 65900-410 Imperatriz, MA, Brazil
| | - P F F Filho
- Centro de Ciências de Imperatriz, Universidade Federal do Maranhão, CEP, 65900-410 Imperatriz, MA, Brazil.
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2
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de Oliveira RC, Ferreira Júnior MNG, Calligaris GA, Dos Santos AO, Remédios CMR. Synchrotron radiation X-ray diffraction and Raman spectroscopy study of l-asparagine monohydrate doped with Fe(III) at high pressure. Spectrochim Acta A Mol Biomol Spectrosc 2022; 283:121716. [PMID: 35961206 DOI: 10.1016/j.saa.2022.121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Crystals of l-asparagine monohydrate doped with Fe(III) were studied by Raman spectroscopy in a diamond anvil cell (DAC) in the spectral range from 100 to 3200 cm-1 and pressures up to 9.2 GPa. The behavior of external modes suggests conformational changes between 3.0 and 4.0 GPa mainly affecting the CH2 group. X-ray diffraction measurements with synchrotron radiation were performed in the angular range from 3 to 12 degrees (2θ) up to 9.3 GPa. The lattice parameters contract up to 9.3 GPa, with the exception of parameter b, which exhibits expansion from 7.2 GPa. The lattice parameters exhibit discontinuities between 3.0 and 4.0 GPa, this effect is compatible with conformational changes. Such modifications occur without a change in symmetry, at least up to 9.3 GPa. Under decompression, down to atmospheric pressure, the original Raman spectrum is recovered, showing that the conformational change and the other changes are all reversible.
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Affiliation(s)
- R C de Oliveira
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, 60740-000 Belém, PA, Brazil.
| | - M N G Ferreira Júnior
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, 60740-000 Belém, PA, Brazil; Instituto Federal de Educação, Ciência e Tecnologia do Pará, 67125-000 Ananindeua, PA, Brazil
| | - G A Calligaris
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), 13083-970 Campinas, SP, Brazil
| | - A O Dos Santos
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, 65900-410 Imperatriz, MA, Brazil
| | - C M R Remédios
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, 60740-000 Belém, PA, Brazil
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Penteado RMC, Costa TGR, Mendes CEA, Silva E, Villarinho AAR, Aranda VF, Santos AOD, Bento LC, Constantino NR, Guerra JCC. PERFORMANCE DOS TESTES DE COAGULAÇÃO CONVENCIONAIS UTILIZANDO DIFERENTES METODOLOGIAS EM AMOSTRAS VISIVELMENTE HEMOLISADAS, ICTÉRICAS E LIPÊMICAS. Hematol Transfus Cell Ther 2022. [DOI: 10.1016/j.htct.2022.09.923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Ferreira Junior MNG, Paraguassu W, Dos Santos AO, Remédios CMR. Pressure-induced phase transitions in MBANP crystal: A study by synchrotron radiation X-ray diffraction and Raman spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc 2022; 272:120944. [PMID: 35151163 DOI: 10.1016/j.saa.2022.120944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Raman spectroscopy and synchrotron radiation X-ray diffraction have been used to study the effect of pressure on 2-(-α-methylbenzylamino)-5-dinitropyridine (MBANP). Several changes are observed with increasing pressure in the Raman spectra of this system, such as splitting of various bands and disappearance of bands. Discontinuous shifts in wavenumber vs pressure plot indicate that a conformational phase transition takes place around 0.5 GPa. The behavior of the Raman spectra indicates that MBANP molecules present conformational phase transition at high-pressure. X-ray diffraction, performed with synchrotron radiation, confirms the conformational changes observed by Raman experiments around 0.5 GPa. The pressure provokes a rotational movement of the benzene ring which can be associated with the conformational phase transition.
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Affiliation(s)
- M N G Ferreira Junior
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 60740-000, Belém-PA, Brazil; Instituto Federal de Educação Ciência e Tecnologia do Pará, CEP 67125-000 Ananindeua - PA, Brazil
| | - W Paraguassu
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 60740-000, Belém-PA, Brazil
| | - A O Dos Santos
- CCSST, Universidade Federal do Maranhão, 65900-410 Imperatriz, MA, Brazil
| | - C M R Remédios
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 60740-000, Belém-PA, Brazil.
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Rodrigues JAO, Oliveira Neto JG, Santos CC, Nogueira CES, de Sousa FF, de Menezes AS, Dos Santos AO. Phase changes of tris(glycinato)chromium(III) monohydrate crystal systematically studied by thermal analyses, XRPD, FTIR, and Raman combined with ab initio calculations. Spectrochim Acta A Mol Biomol Spectrosc 2022; 271:120883. [PMID: 35042044 DOI: 10.1016/j.saa.2022.120883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Tris(glycinato)chromium(III) monohydrate [Cr(C2H4NO2)3·H2O] crystals were grown through the slow solvent evaporation method. The crystals were studied by Fourier transform infrared (FTIR) and Raman spectroscopy at room temperature. The assignments of vibration modes were performed using the Density Functional Theory (DFT). Thermal analyses (TGA, DTA, and DSC), X-ray diffraction (XRD), and Raman were used to study the phase changes on the crystals under high- and low-temperature conditions. Temperature-dependent XRPD measurements were carried out in the interval of 473-12 K. Several changes were observed in the patterns, like the appearance of new peaks and the disappearance of peaks occurring within 373-393 K due to water loss. In addition, the Raman measurements were performed in the 423-10 K interval. Several changes on the inter and intramolecular vibration bands during the cooling, such as decreasing bands' intensities, the appearance of vibration modes, and discontinuities on the modes' behavior, were observed. These spectral modifications occurred at about 370 K and within 120-220 K, thus, confirming that the crystals undergo two phase changes, one being structural and the other one conformational, respectively, at high- temperature and low-temperature conditions. Finally, thermal investigations corroborated the structural and vibrational results under high temperatures.
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Affiliation(s)
- J A O Rodrigues
- Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-410, Brazil
| | - J G Oliveira Neto
- Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-410, Brazil
| | - C C Santos
- Departamento de Física, Universidade Federal do Maranhão, CCET, São Luís, MA 65080-805, Brazil
| | - C E S Nogueira
- Universidade Regional da Cariri, Crato, CE 63010-970, Brazil
| | - F F de Sousa
- Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-410, Brazil; Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, 66075-110 Belém, PA, Brazil.
| | - A S de Menezes
- Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-410, Brazil; Departamento de Física, Universidade Federal do Maranhão, CCET, São Luís, MA 65080-805, Brazil
| | - A O Dos Santos
- Programa de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-410, Brazil
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Santos CAAS, Lima RJC, Paraguassu W, da Silva Filho JG, Dos Santos AO, Lima JA, Freire PTC, Filho PFF. High-pressures study by Raman spectroscopy and DFT calculations of L-tyrosine hydrobromide crystal. Spectrochim Acta A Mol Biomol Spectrosc 2021; 263:120142. [PMID: 34273890 DOI: 10.1016/j.saa.2021.120142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/24/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
The high-pressure Raman spectra of L-tyrosine hydrobromide crystal (LTHBr) were obtained from 1.0 atm to 8.1 GPa in the 100-3200 cm-1 spectral region. The structural conformation and dimensions of the monoclinic unit cell were estimated using the powder X-ray diffraction (PXRD) method and Rietveld refinement using the GSAS program. At atmospheric pressure, the Raman spectrum was obtained in the spectral range of 100-3200 cm-1 and the assignment of the normal modes based on density functional theory calculations was provided. Large wavenumber shifts of modes at 106, 123, and 157 were observed, which were interpreted as the large displacement of the atoms, making the molecule a flexible structure. The change in the slope (dɷ / dP) of these bands between the pressures of 3.0 and 4.0 GPa and the appearance of a mode of low wavenumber indicate the occurrence of a structural phase transition. A band initially observed at 181 cm-1 in the spectrum recorded at 0.7 GPa change the relative intensity with a band at 280 cm-1 (recorded at 5.8 GPa), indicating a conformational transition. In the region of the internal modes, the spectra show changes that reinforce the conformational phase transition since the bands initially at 1247 and 1264 cm-1 observed at 1.0 GPa have their intensities reversed, and at 3.0 GPa it is observed the fusion of the bands at 1264 and 1290 cm-1 (values recorded at ambient pressure). Thus, we can assume that the LTHBr crystal has undergone a structural phase transition and a conformational phase transition in the pressure range investigated.
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Affiliation(s)
- C A A S Santos
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410, Brazil; Centro de Ciências Humanas Sociais Tecnologias e Letras, Universidade Estadual da Região Tocantina do Maranhão, Açailândia, MA 65930-000, Brazil; Núcleo de Engenharias - Faculdade de Imperatriz, Imperatriz, MA 65900-120, Brazil.
| | - R J C Lima
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410, Brazil
| | - W Paraguassu
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA 66075-110, Brazil
| | - J G da Silva Filho
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410, Brazil
| | - A O Dos Santos
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410, Brazil
| | - J A Lima
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE 60455-760, Brazil
| | - P T C Freire
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE 60455-760, Brazil
| | - P F Façanha Filho
- Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410, Brazil
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Peonorio PEM, Penteado RMC, Aranda VF, Santos AOD, Villarinho AAR, Mendes CEA, Campos DDALS, Rosseto EA, Matsuo PM, Guerra JCC. VALIDAÇÃO DO TESTE DE ADAMTS13 POR QUIMILUMINESCÊNCIA E PESQUISA DE INIBIDOR POR MÉTODO DE BETHESDA. Hematol Transfus Cell Ther 2021. [DOI: 10.1016/j.htct.2021.10.743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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8
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Victor FMS, Rêgo FSC, de Paiva FM, Dos Santos AO, Polian A, Freire PTC, Lima JA, Filho PFF. Pressure-induced phase transitions in DL-glutamic acid monohydrate crystal. Spectrochim Acta A Mol Biomol Spectrosc 2020; 230:118059. [PMID: 32000059 DOI: 10.1016/j.saa.2020.118059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 06/10/2023]
Abstract
DL-glutamic acid monohydrate crystal was synthesized from an aqueous solution by slow evaporation technique. The crystal was submitted to high-pressure (1 atm-14.3 GPa) to investigate its vibrational behavior and the occurrence of phase transitions. We performed Raman spectroscopy as probe and through the analysis of the spectra we discovered three structural phase transitions. The first one occurs around 0.9 GPa. In this phase transition, glutamic acid molecules suffer modifications in their conformations while water molecules are less affected. The second phase transition at 4.8 GPa involves conformational changes related to CO2-, NH3+ units and the water molecules, while the third one, between 10.9 and 12.4 GPa, involves motions of several parts of the glutamic acid as well as the water molecules. Considering the dynamic of high pressure, the second phase of DL-glutamic acid monohydrate crystal presented a better stability compared with the second phase of its polymorphs α and β L-glutamic acid. In addition, water molecules seem to play important role on this structural stability. All changes are reversible.
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Affiliation(s)
- F M S Victor
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil
| | - F S C Rêgo
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, Fortaleza, CE 60455-760, Brazil
| | - F M de Paiva
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, Fortaleza, CE 60455-760, Brazil; Faculdade de Educação, Ciências e Letras de Iguatu, FECLI, Universidade Estadual do Ceará, Iguatu, CE 63502-253, Brazil
| | - A O Dos Santos
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil
| | - A Polian
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, F-75005 Paris, France
| | - P T C Freire
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, Fortaleza, CE 60455-760, Brazil
| | - J A Lima
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, Fortaleza, CE 60455-760, Brazil
| | - P F Façanha Filho
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil.
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Baldez TS, Remédios CMR, de Menezes AS, Dos Santos AO, de Sousa FF. New structural phases of [bis(L-alaninato) diaqua] nickel(II) dihydrate crystal. Spectrochim Acta A Mol Biomol Spectrosc 2019; 214:294-301. [PMID: 30802790 DOI: 10.1016/j.saa.2019.02.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/27/2018] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
The study of [bis(L‑alaninato) diaqua] nickel(II) dihydrate crystal using Raman scattering and X-ray diffraction as a function of temperature is reported in this paper. Thermal analysis (TGA and DSC) complementary measurements were also performed in order to obtain information on structural changes and mass loss occurred in this material. It was identified that the crystal undergoes loss of water at two different temperatures: ~340 and 393 K. X-ray diffraction measurements showed two phase transformations related to these two water loss events. After heating up to 423 K, the sample was cooled down to 298 K and its diffraction pattern presented the same pattern at 423 K, evidencing an irreversible phase transformation. The diffraction results also showed that crystal goes to monohydrate and anhydrous phases. Furthermore, cell lattice parameters and space groups of both phases were determined by applying Rietveld refinement through Le Bail method, demonstrating that their structures belong to the P21 and C2/c space groups, both with monoclinic symmetry. In addition, assignments of Raman spectra vibrational bands (at 300 K) are provided. The high-temperature Raman spectra were obtained in the 100-3500 cm-1 range, where it was observed several abrupt changes in the intensity of low-wavenumber bands and the appearance/disappearance of some vibrational modes that have coupling with OH⋯O hydrogen bonds. These spectral changes are in good agreement with X-ray diffraction and thermal analyses data. Finally, we obtained Raman measurements at low temperatures, from which we identified that the crystal structure is extremely stable throughout the temperature range of 293-10 K.
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Affiliation(s)
- T S Baldez
- Instituto Federal do Maranhão, CEP 65950-000 Barra do Corda, MA, Brazil
| | - C M R Remédios
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 66075-110 Belém, PA, Brazil
| | - A S de Menezes
- Departamento de Física, Universidade Federal do Maranhão, CCET, CEP 65080-805 São Luis, MA, Brazil
| | - A O Dos Santos
- Universidade Federal do Maranhão, CCSST, CEP 65900-410 Imperatriz, MA, Brazil
| | - F F de Sousa
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 66075-110 Belém, PA, Brazil.
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Pinheiro GS, Ferreira Júnior MNG, Dos Santos AO, Freire PTC, Lima JA, Nogueira CES, Cardoso LP, Sherwood JN, Remédios CMR. Low-temperature Raman spectra of the 2-(α-methylbenzylamino)-5-nitropyridine crystal. Spectrochim Acta A Mol Biomol Spectrosc 2017; 183:209-217. [PMID: 28454073 DOI: 10.1016/j.saa.2017.04.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 03/25/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
The polar organic 2-(α-methylbenzylamino)-5-nitropyridine crystal (MBANP) has been studied by Raman spectroscopy at low temperatures (from 300 to 10K). The effect of temperature change on the vibrational spectrum is discussed with the aid of DFT calculations. The behavior of the Raman spectra indicates that MBANP molecules present a different conformation at low temperatures associated with the rotation of the phenyl and pyridine rings. Temperature-dependent X-ray measurements and differential scanning calorimetry (DSC) analysis were utilized as complementary techniques to investigate the structural stability of MBANP crystal.
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Affiliation(s)
- G S Pinheiro
- Departamento de Física, Campus Ministro Petrônio Portella, Universidade Federal do Piauí, CEP 64049-550 Teresina, PI, Brazil.
| | - M N G Ferreira Júnior
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 60740-000 Belém, PA, Brazil
| | - A O Dos Santos
- Centro de Ciências Sociais Saúde e Tecnologia, Universidade Federal do Maranhão, CEP 65900-410 Imperatriz, MA, Brazil
| | - P T C Freire
- Departamento de Física, Universidade Federal do Ceará, CEP 60455-900 Fortaleza, CE, Brazil
| | - J A Lima
- Departamento de Física, Universidade Federal do Ceará, CEP 60455-900 Fortaleza, CE, Brazil
| | - C E S Nogueira
- Departamento de Física, Universidade Regional do Cariri, CEP 63010-970 Juazeiro do Norte, CE, Brazil
| | - L P Cardoso
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, CEP 13083-859 Campinas, SP, Brazil
| | - J N Sherwood
- WESTCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, Scotland
| | - C M R Remédios
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, CEP 60740-000 Belém, PA, Brazil
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Carvalho JO, Moura GM, Dos Santos AO, Lima RJC, Freire PTC, Façanha Filho PF. High pressure Raman spectra of monoglycine nitrate single crystal. Spectrochim Acta A Mol Biomol Spectrosc 2016; 161:109-114. [PMID: 26967511 DOI: 10.1016/j.saa.2016.02.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 02/15/2016] [Accepted: 02/28/2016] [Indexed: 06/05/2023]
Abstract
Single crystal of monoglycine nitrate has been studied by Raman spectroscopy under high pressures up to 5.5 GPa. The results show changes in lattice modes in the pressure ranges of 1.1-1.6 GPa and 4.0-4.6 GPa. The first change occurs with appearance of bands related to the lattice modes as well as discontinuity in the slope of dΩ/dP of these modes. Moreover, bands associated with the skeleton of glycine suggest that the molecule undergoes conformational modifications. The appearance of a strong band at 55 cm(-1) point to a second phase transition associated with the lattice modes, while the internal modes remain unchanged. These anomalies are probably due to rearrangement of hydrogen bonds. Additionally, decompression to ambient pressure shows that the phase transitions are reversible. Finally, the results show that the nitrate anions play an important role on the stability of the monoglycine nitrate crystal.
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Affiliation(s)
- J O Carvalho
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil; Instituto Federal do Tocantins, Araguaína, TO 77826-170, Brazil
| | - G M Moura
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil; Universidade Federal do Sul e Sudeste do Pará, ICEN, Marabá, PA 68505-080, Brazil
| | - A O Dos Santos
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil
| | - R J C Lima
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil
| | - P T C Freire
- Universidade Federal do Ceará, Campus do Pici, Fortaleza, CE 60455-760, Brazil
| | - P F Façanha Filho
- Universidade Federal do Maranhão, CCSST, Imperatriz, MA 65900-000, Brazil.
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Gomes EJL, Moreira SGC, de Menezes AS, Dos Santos AO, Pereira DP, de Oliveira PC, Remédios CMR. KDP:Mn piezoelectric coefficients obtained by X-ray diffraction. J Synchrotron Radiat 2010; 17:810-812. [PMID: 20975229 DOI: 10.1107/s0909049510039956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/06/2010] [Indexed: 05/30/2023]
Abstract
Crystals of pure potassium dihydrogen phosphate KH(2)PO(4) (KDP) and Mn-doped KDP (KDP:Mn) were grown from a water solution by the slow evaporation method and their piezoelectric properties were studied by X-ray diffraction methods. The results have shown an increase in the piezoelectric coefficients with the doping.
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Affiliation(s)
- E J L Gomes
- Faculdade de Física, Universidade Federal do Pará, Belém-PA 60740-000, Brazil
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da Silva LM, Dos Santos AO, Medina AN, Coelho AA, Cardoso LP, Gandra FG. A study of pressure and chemical substitution effects on the magnetocaloric properties of the ferromagnetic compound UGa(2). J Phys Condens Matter 2009; 21:276001. [PMID: 21828503 DOI: 10.1088/0953-8984/21/27/276001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on pressure effects on the magnetic and magnetocaloric properties of the compound UGa(2). Using a mean field approximation, we were able to calculate the isothermal entropy change and the adiabatic temperature change. Neither the applied pressure nor the chemical substitution experiments within the ranges studied revealed a remarkable improvement on the magnetocaloric effect (MCE) except for the Al substitutions. Nevertheless, we found that mechanical pressure and chemical pressure are equivalent in terms of the Curie temperature shift when Al, Ge and Si are substituted for Ga, but a different behavior is found when Ni, Fe and Co are used. Our results also show that a composite to operate between 80 and 120 K can be obtained using different concentrations of U(Ga,Ni)(2).
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Affiliation(s)
- L M da Silva
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas-UNICAMP, 13083-970, Campinas, SP, Brazil. Centro de Ciências Sociais, Saúde e Tecnologia (CCSST), Universidade Federal do Maranhão-UFMA, R. Urbano Santos, s/n, 65900-000, Imperatriz, MA, Brazil
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