Browsing by Author "Golbedaghi, Reza"

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Open Access
Experimental Characterization and Finite Element Investigation of SiO2 Nanoparticles Reinforced Dental Resin Composite
(Nature Portfolio, 2024) Jaleh, Babak; Kashfi, Mohammad; Mohazzab, Behnaz Feizi; Niaee, Morteza Shakhsi; Vafaee, Fariborz; Fakhri, Parisa; Golbedaghi, Reza; FAUSTO, RUI
In this study, a commercial dental resin was reinforced by SiO2 nanoparticles (NPs) with different concentrations to enhance its mechanical functionality. The material characterization and finite element analysis (FEA) have been performed to evaluate the mechanical properties. Wedge indentation and 3-point bending tests were conducted to assess the mechanical behavior of the prepared nanocomposites. The results revealed that the optimal content of NPs was achieved at 1% SiO2, resulting in a 35% increase in the indentation reaction force. Therefore, the sample containing 1% SiO2 NPs was considered for further tests. The morphology of selected sample was examined using field emission scanning electron microscopy (FE-SEM), revealing the homogeneous dispersion of SiO2 NPs with minimal agglomeration. X-ray diffraction (XRD) was employed to investigate the crystalline structure of the selected sample, indicating no change in the dental resin state upon adding SiO2 NPs. In the second part of the study, a novel approach called iterative FEA, supported by the experiment wedge indentation test, was used to determine the mechanical properties of the 1% SiO2-dental resin. Subsequently, the accurately determined material properties were assigned to a dental crown model to virtually investigate its behavior under oblique loading. The virtual test results demonstrated that most microcracks initiated from the top of the crown and extended through its thickness.
Open Access
A New Azide-Bridged Polymeric Manganese (III) Schiff Base Complex with an Allylamine-Derived Ligand: Structural Characterization and Activity Spectra
(MDPI, 2024) Talebi, Aynaz; Salehi, Mehdi; Jesus, A. J. Lopes; Kubicki, Maciej; FAUSTO, RUI; Golbedaghi, Reza
This paper reports the synthesis and structural characterization of a novel azide-bridged polymeric manganese (III) Schiff base complex, using 2-((allylimino)methyl)-6-ethoxyphenol as a ligand. The crystal structure of the synthesized compound, elucidated by single-crystal X-ray diffraction analysis, indicates that it crystallizes in the monoclinic space group P21/c. The complex is found to display an octahedral geometry in which the central manganese Mn(III) coordinates with two bidentate donor Schiff base ligands via oxygen and nitrogen atoms. In addition, the metallic centers are linked together to form a one-dimensional chain bridged by end-to-end azide ligands. To offer a more thorough characterization of the synthesized compound, the study incorporates experimental data from FT-IR, UV-Vis, and cyclic voltammetry, alongside computational results from Hirshfeld surface analysis and DFT calculations conducted for both the ligand and complex. The computational analyses provided valuable insights into the intrachain and interchain interactions within the crystal structure, clarified the conformational characteristics of the isolated ligand molecule, and aided in the interpretation of the experimental IR spectra. Furthermore, an assessment of the compound’s drug-like properties was conducted using activity spectra for substances (PASS) predictions, revealing potential pharmacological activities. © 2024 by the authors.
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A New Tetramine Bis(2-Naphthol)-Derivative Fluorescent Chemosensor for Aluminum Ion (Al3+)
(Elsevier, 2022) Golbedaghi, Reza; ILDIZ, GÜLCE ÖĞRÜÇ; Azadbakht, Reza; Fausto, Rui
A new tetramine bis(2-naphthol)-derivative was synthesized and its structure investigated by H-1- and C-13 NMR, UV-Vis absorption and fluorescence spectroscopies, as well as through density functional theory calculations (including time-dependent DFT). The effect of a series of metal ions (Ag+, Al3+, Ba2+, Ca2+, Cd2+, Co2+, Cs (+), Cu2+, Fe2+, Fe3+, K+, Mg2+, Mn2+, Ni2+, Pb2+ and Zn2+) on the fluorescence spectra of the synthesized compound was then investigated and it was observed that the presence of Al3+ ion causes a strong increase in the fluorescence emission of the ligand, by about 70 times. This exceptional intensification is specific for Al3+ within the whole series of ions investigated, together with the selectivity found for many of the remaining ions (in particular the ions of Groups I and II of the Periodic Table and Mn2+), makes the compound a promising candidate to act as chemosensor for Al3+. Possible structures for the ligand:Al3+ complex are suggested based on DFT results. TD-DFT calculations performed on these structures suggest that the fluorescence enhancement upon binding of Al3+ to the ligand results most probably from metal-to-ligand charge transfer where the acceptor groups of the ligand are the naphthol moieties. (C) 2021 Elsevier B.V. All rights reserved.
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Synthesis, Characterization and Sensing Mechanism of a Novel Fluorescence Probe for Fe(III) in Semi-Aqueous Solution Based on a Schiff Base Hexadentate Receptor
(Elsevier Science SA, 2023) Ooshall, Farkhondeh; Jamehbozorgi, Saeed; Golbedaghi, Reza; Justino, Licinia L. G.; Feshalame, Keyvan Mirzaei; Liyaghati-Delshad, Mozhdeh; Anaraki-Ardakani, Hossein; Jaleh, Babak; FAUSTO, RUI
A new acyclic Schiff base chemosensor L was synthesized by the one pot condensation reaction of 2-[3-(formyl phenoxy)2-hydroxypropoxy]benzaldehyde and 2-aminophenol in a 1:2 molar ratio and was characterized by elemental analysis, FTIR, 1H- and 13C NMR, and fluorescence spectroscopies. These studies were complemented with a thorough conformational study at the molecular mechanics and density functional theory (DFT) levels of theory to further elucidate the structure of the compound in solution. The chemosensor L displays high sensitivity and selectivity for Fe3+ in semi-aqueous (H2O-DMF, 1:1) solution, except in the presence of a significant amount of Ni2+, with the presence of Fe3+ being signaled through the total fluorescence quenching of the fluorophore when Fe3+ binds to the recognition unit. The synthesized ligand also shows high selectivity for Fe3+ compared to the metal ions Cu2+, Zn2+, Mg2+, Mn2+, Pb2+, Hg2+, Na+, Ba2+ and Cd2+, and reasonable selectivity in the presence of Ag+, Co2+ and Cr3+. The stoichiometry and structure of the complex formed between Fe3+ and the probe L were determined from a Job's plot and DFT calculations, respectively. The complex was characterized as a high-spin 1:1 octahedral species, in which the ligand coordinates to the metal through the two ether oxygen atoms, two nitrogen atoms and two terminal hydroxyl groups. Time dependent (TD-DFT) calculations were performed to provide information on the type of mechanism causing the quenching of the fluorescence in the presence of Fe3+.