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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Hybrid Ni-Al layered double hydroxide: Characterization and in situ synchrotron XRD and vibrational spectroscopic studies under high-pressure

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de Matos, Caroline S. [1] ; Nobrega, Marcelo M. [1] ; Temperini, Marcia L. A. [1] ; Constantino, Vera R. L. [1]
Total Authors: 4
[1] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Ave Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: APPLIED CLAY SCIENCE; v. 174, p. 152-158, JUN 15 2019.
Web of Science Citations: 0

Anions from 2-aminoterephthalic acid (ATA), an aniline derivative, were intercalated into layered double hydroxide (LDH), and submitted to high-pressures by using a diamond anvil cell to access possible transformations of guest species in confined environment. The hybrid material, constituted by Ni2+ and Al3+ in a molar ratio equal to 2 (Ni2Al-ATA), was characterized by mass spectrometry coupled thermal analysis (TGA-DSC-MS), X-ray diffractometry (XRD) and vibrational spectroscopy (infrared and Raman) at ambient pressure. The response of Ni2Al-ATA to the pressure stimuli was monitored by in situ synchrotron XRD and in situ vibrational spectroscopies (infrared and Raman), during the compression-decompression cycle up to 14-16 GPa. XRD reflections related to (00l) stacking planes of hybrid material presented broadening and intensities decreasing, pointing out a pressure-induced amorphization. XRD profile of Ni2Al-ATA was not recovered after decompression, indicating that the structural modification promoted by the pressure to the inorganic matrix is irreversible. In-situ vibrational spectroscopy as a function of pressure revealed a minor modification in the spectrum of ATA anion confined into LDH (for example, the Raman intensity decreasing (without shift) of the 1612 cm(-1) band). Spectral features were recovered after the decompression, suggesting no decomposition or reactivity of the organic guest species between the LDH layers. On the other hand, Raman spectrum of 2-aminoterephthalic acid (non-intercalated) changed expressively during the decompression step and sample become completely luminescent at 1.7 GPa and at ambient pressure. Probably LDH decreases the guest reactivity by a steric blockage imposed by ATA arrangement in the confined environment, which can improve the guest stability submitted to high-pressure stimulus. (AU)

FAPESP's process: 16/21070-5 - Vibrational spectroscopy with spatial resolution
Grantee:Mauro Carlos Costa Ribeiro
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 11/50318-1 - Development of compounds with pharmacological or medicinal interest and of systems for their transport, detection and recognition in biological media
Grantee:Ana Maria da Costa Ferreira
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 15/09763-2 - High pressure synthesis and reactivity of aniline and polyaniline-gold composites
Grantee:Marcelo Medre Nobrega
Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 14/04816-8 - Development of hierarchical structures with nanoarchitectures based on inorganic layered units
Grantee:Caroline Silva de Matos
Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
FAPESP's process: 14/15107-8 - High pressure Raman spectroscopy, from aromatics amines to conducting polymers.
Grantee:Marcelo Medre Nobrega
Support Opportunities: Scholarships in Brazil - Post-Doctoral