Showing papers by "Paula Brandão published in 2022"
TL;DR: Two butterfly-shaped Dy4 and Zn2Dy2 complexes displaying slow relaxation of magnetization have been synthesized from a new methyl substituted o-vanillin based ligand, enlarging the scope for finding better SMMs as mentioned in this paper .
Abstract: Two butterfly-shaped Dy4 and Zn2Dy2 complexes displaying slow relaxation of magnetization have been synthesized from a new methyl substituted o-vanillin based ligand, enlarging the scope for finding better SMMs.
6 citations
TL;DR: Three angular trinuclear Zn2Dy complexes, derived from a methyl substituted o-vanillin based Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,2-phenylenediamine (H2L), have been synthesized and magneto-structurally constructed as mentioned in this paper .
Abstract: Three new angular trinuclear Zn2Dy complexes, [Dy{Zn(L)Cl}2(H2O)2]Cl∙3H2O (1), [Dy{Zn(L)Br}2(H2O)2](NO3)∙4H2O (2) and [Dy{Zn(L)I}2(H2O)2](NO3)∙4H2O (3), derived from a methyl substituted o-vanillin based Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,2-phenylenediamine (H2L), have been synthesized and magneto-structurally...
4 citations
12 Apr 2022
4 citations
TL;DR: The perchlorate salt of (4-methoxy phenyl)-2-(1-pyridine-2-yl)ethylidene)hydrazinyl)thiazole (PytH·ClO4) and its metal perchlorates derivatives have been synthesized and characterized through single X-ray crystallography and spectroscopic methods as discussed by the authors .
Abstract: The perchlorate salt of (4-(4-methoxy phenyl)-2-(2-(1-pyridine-2-yl)ethylidene)hydrazinyl)thiazole (PytH·ClO4) and its metal perchlorate derivatives, namely, [Co(Pyt)2]ClO4 (1), [Mn(PytH)2](ClO4)2 (2), and [Ni(PytH)2](ClO4)2 (3), have been synthesized and characterized through single X-ray crystallography and spectroscopic methods. The ligand crystallizes in a space group P21/n in a nearly planar structure. The overall geometry of the complex salts is described as a distorted octahedron with a MN6 chromophore. The ligand (PytH·ClO4) behaves as a neutral N,N,N-tridentate donor toward the "soft" Mn(II) and Ni(II) centers, whereas the deprotonated ligand stabilizes the "hard" Co(III) center. The DNA binding constant (Kb) values of PytH·ClO4, 1, 2, and 3 are determined using the UV-vis spectroscopic method, and the Kb values are 9.29 × 105, 7.11 × 105, 8.71 × 105, and 7.82 × 105 mol-1, respectively, indicating the intercalative mode of interactions with CT-DNA. All the derivatives show effective antiproliferative activity against U-937 human monocytic tumor cells with IC50 values 4.374 ± 0.02, 5.583 ± 0.12, 0.3976 ± 0.05, and 11.63 ± 0.01 μM for PytH·ClO4, 1, 2, and 3, respectively. The best apoptosis mode of cell death is shown by 2 followed by PytH·ClO4 and 1 at an equivalent concentration of IC50 values. The combined molecular docking and dynamics simulation study evaluates the binding energies of anticancer agents, providing groove binding property with DNA. The 20 ns molecular dynamics simulation study reveals the maximum DNA binding stability of 2 corroborating the experimental results. The new class of metal derivatives of pyridine-thiazole can be used for advanced cancer therapeutics.
4 citations
TL;DR: Three different sets of isomorphous dinuclear Gd/Dy complexes with an uncommon macrocyclic ligand and β-diketonate co-ligands were reported in which Dy2 analogues are zero field SMMs as discussed by the authors .
Abstract: Three different sets of isomorphous dinuclear Gd/Dy complexes with an uncommon macrocyclic ligand and β-diketonate co-ligands were reported in which Dy2 analogues are zero field SMMs.
3 citations
TL;DR: In this article , three coordination polymers (CPs 1-3) are prepared based on diverse electron-donating properties and coordination arrangements of conjugated ligands, which are also reflected in their photophysical properties.
Abstract: Three coordination polymers (CPs 1-3) are prepared based on diverse electron-donating properties and coordination arrangements of conjugated ligands. Interestingly, this is also reflected in their photophysical properties. The distinguishable high emissive nature of the luminescent coordination polymer shows its potentiality toward the detection of the perilous substance 2,4,6-trinitrophenol (TNP) or picric acid (PA). TNP has a higher propensity among explosive nitroaromatic compounds (epNACs) due to its significant π···π interaction with the free benzene moieties present in the CPs. Among CPs 1-3, 2 exhibits the highest sensitivity and selectivity toward TNP because of the most favorable π-π stacking with the conjugated organic linker. The calculated limit of detection (LOD) and corresponding quenching constant (KSV) from the Stern-Volmer (SV) plot for 1, 2, and 3 are found to be 0.68 μM and 7.49 × 104 M-1, 0.41 μM and 8.01 × 104 M-1, and 1.18 μM and 8.1 × 104 M-1, respectively. The fluorescence quenching mechanism is also highly influenced by their structure and coordination arrangement.
2 citations
TL;DR: In this article, a ligand-centered redox-controlled strategy for the synthesis of an unusual binuclear diradical cobalt(III) complex, [Co2III(L•3-)2] (1), featuring two three-electron reduced trianionic monoradical 2,9-bis(phenyldiazo)-1,10-phenanthroline ligands (L• 3-) and two intermediate spin cobalt (III) centers having a Co-Co bond.
Abstract: Herein we report a ligand-centered redox-controlled strategy for the synthesis of an unusual binuclear diradical cobalt(III) complex, [Co2III(L•3-)2] (1), featuring two three-electron reduced trianionic monoradical 2,9-bis(phenyldiazo)-1,10-phenanthroline ligands (L•3-) and two intermediate-spin cobalt(III) centers having a Co-Co bond. Controlled ligand-centered oxidation of 1 afforded two mononuclear complexes, [CoII(L•-)(L0)]+ ([3])+ and [CoII(L0)2]2+ ([2]2+), which upon further ligand-centered reduction yielded a di-azo-anion diradical complex, [CoII(L•-)2] (4). In complex 1, two three-electron reduced di-azo-anion monoradical ligands (L•3-) bridge two intermediate Co(III) centers at a distance of 2.387(2) Å, while upon oxidation, one of the coordinating azo-arms of L becomes pendent, and in complexes [2]2+, [3]+, and 4, two tetradentate ligands coordinate a single Co(II) center in a tridentate meridional fashion with one uncoordinated azo-arm from each of the ligands. In the presence of reducing agents, the monomers [2]2+, [3]+, and 4 undergo ligand-centered reduction to form azo-anion radicals, and the otherwise pendent azo-arms in the presence of cobalt(II)-salts like Co(ClO4)2 or CoCl2 bind the second Co(II)-ion; further internal electron transfer from the cobalt center to the arylazo backbone produces the binuclear complex 1. Spectroscopic analysis, DFT studies, and control experiments were performed to understand the electronic structures and the ligand-centered redox-controlled interconversion. The application of complex 1 as a molecular memory device (memristor) was also explored. Complex 1 showed encouraging results as a memristor with a current ON/OFF ratio > 104 and is highly promising for resistive RAM/ROM applications.
2 citations
TL;DR: In this article , the salt effect on the solubility of amino acids in KCl and (NH 4 ) 2 SO 4 aqueous solutions was studied at 298.2 K and 2.0 mol·kg −1 , respectively.
2 citations
TL;DR: In this paper , the crucial role of supramolecular interactions in determining the structure of heteroleptic Cu(II) complex was investigated using Schiff base and imidazole co-ligands.
Abstract: The crucial role of supramolecular interactions in determining the supramolecular layer architecture of heteroleptic Cu(II) complex [Cu(L)(imid)(ClO4)]n synthesized from ortho-vaniline based Schiff base and imidazole co-ligands has been investigated through...
2 citations
TL;DR: Two copper azido complexes [Cu4(L1)4(µ1,1-N3)3(N3)]n have been synthesized by the reaction of aqueous solution of sodium azide to a methanolic solution of copper perchlorate hexahydrate and corresponding Schiff-base ligands as mentioned in this paper.
2 citations
TL;DR: In this article , a tripodal pyridyl-pyrazole based N,N,O donor ligand (L) has been designed, and it's copper(II) complex, [Cu(L1)Cl2]2.(dmpzH)2] have been synthesized and characterized by a combination of various spectroscopy, X-ray crystallography, electrochemical, thermogravimetric and density functional theory.
TL;DR: In this paper , four new heterometallic ZnDy complexes were synthesized from a methyl substituted o-vanillin based compartmental Schiff base, and they are shown to have the same properties as the ones described in this paper.
Abstract: Four new heterometallic ZnDy complexes, [ZnDy(L)(NO3)3(py)]∙CH2Cl2 (1) (py stands for pyridine), [ZnDy(L)(-OAc)(OAc)2]∙3H2O (2), [ZnDy(L)(-OAc)(OAc)(NO3)] (3), and [ZnDy(L)(-piv)(piv)2][ZnDy(L)(-piv)(piv)(OAc)]∙1.5H2O (4), have been synthesized from a methyl substituted o-vanillin based compartmental Schiff base...
TL;DR: In this paper , a 1D Gd-based coordination polymer was synthesized and crystallized in a 2C1 topology with 5-phenyl-1,3,4-oxadiazole-propionate ligand and water.
TL;DR: In this article , the solubilities of glycine, leucine, l-phenylalanine, and l-aspartic acid were measured in aqueous MgCl2, Mg(NO3)2, CaCl2,, and Ca(NO 3)2 solutions with concentrations ranging from 0 to 2 mol/kg at 298.2 K.
Abstract: The solubilities of glycine, l-leucine, l-phenylalanine, and l-aspartic acid were measured in aqueous MgCl2, Mg(NO3)2, CaCl2,, and Ca(NO3)2 solutions with concentrations ranging from 0 to 2 mol/kg at 298.2 K. The isothermal analytical method was used combined with the refractive index measurements for composition analysis guaranteeing good accuracy. All salts induced a salting-in effect with a higher magnitude for those containing the Ca2+ cation. The nitrate anions also showed stronger binding with the amino acids, thus increasing their relative solubility more than the chloride anions. In particular, calcium nitrate induces an increase in the amino acid solubility from 2.4 (glycine) to 4.6 fold (l-aspartic acid) compared to the corresponding value in water. Amino acid solubility data in aqueous MgCl2 and CaCl2 solutions collected from the open literature were combined with that from this work, allowing us to analyze the relations between the amino acid structure and the salting-in magnitude.
TL;DR: In this paper, the role of weak noncovalent interactions in the crystal packing of mononuclear nickel(II) complexes has been investigated using DFT calculations in combination with the quantum theory of atoms-in-molecules (QTAIM) and NCI plot index computational tools.
TL;DR: In this article , the tetradentate Schiff-base ligand was synthesized by condensation of o-vanillin and D -(-)- threo -2-amino-1-(4-nitrophenyl)-1,3-propanediol.