92 results on '"Van Meervelt, Luc"'
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2. Synthesis, crystal structure and Hirshfeld surface analysis of 2-({5-[(naphthalen-1-yl)methyl]-4-phenyl-4H-1,2,4-triazol-3-yl}sulfanyl)-1-(4-nitrophenyl)ethanone.
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Trong Duc Le, Tien Cong Nguyen, Thi Kim Dung Hoang, Minh Khoi Huynh, Quang Thang Phan, and Van Meervelt, Luc
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CRYSTAL structure ,MOLECULAR shapes ,SURFACE structure ,DIHEDRAL angles ,SPACE groups ,SURFACE analysis - Abstract
The title compound, C
27 H20 N4 O3 S, crystallizes in the monoclinic system, space group P21 /n, with Z = 4. The global shape of the molecule is determined by the orientation of the substituents on the central 4H-1,2,4-triazole ring. The nitrophenyl ring, phenyl ring, and naphthalene ring system are oriented at dihedral angles of 82.95 (17), 77.14 (18) and 89.46 (15)°, respectively, with respect to the triazole ring. The crystal packing features chain formation in the b-axis direction by S...O interactions. A Hirshfeld surface analysis indicates that the highest contributions to surface contacts arise from contacts in which H atoms are involved. [ABSTRACT FROM AUTHOR]- Published
- 2024
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3. Unusual reaction of (E)-2-[(benzo[d]thiazol-2-ylimino)methyl]-5-(diethylamino)phenol with triphenylborane: crystal structures and optical properties.
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Hai Le Thi Hong, Thao Le Phuong, Thong Van Pham, Hue Minh Thi Nguyen, and Van Meervelt, Luc
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CRYSTAL optics ,MOLECULAR crystals ,MOLECULAR structure ,PHENOL ,CRYSTAL structure ,TETRAHYDRONAPHTHALENE - Abstract
The molecular and crystal structure of (E)-2-[(benzo[d]thiazol-2-ylimino)- methyl]-5-(diethylamino)phenol (C
18 H19 N3 O2 S, Et2 N-Bz) and its unexpected reaction product with triphenylborane, 2,2-diphenyl-1,3-dioxa-2-borata-1,2-dihydronaphthalene [systematic name: N,N-diethyl-2,2-diphenyl-2H-1,3λ³,2λ4 -benzodioxaborinin-7-amine, C23 H24 BNO2 , (I)] are described. For Et2N-Bz, the hydroxyl group is involved in an intramolecular hydrogen bond with the imino nitrogen atom and the C N bond displays an E configuration. The crystal packing is characterized by layers of inversion dimers parallel to the (101) plane and chains of molecule in the a-axis direction formed through C--H⋯O interactions. Complex (I) crystallizes with two molecules (A and B) in the asymmetric unit, which differ in the orientation of the ethyl groups. The 1,3- dioxa-2-borata-1,2,3,4-tetrahydronaphthalene ring displays a slight envelope conformation with the boron atom as the flap. In the crystal packing, chains of alternating A and B molecules formed by C--H⋯O hydrogen bonds run in the b-axis direction. The UV--vis absorption and emission properties of the compounds are discussed and their aggregation-induced emission properties are further investigated. [ABSTRACT FROM AUTHOR]- Published
- 2023
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4. Parallel and Antiparallel (G·GC)$_2$ Triple Helix Fragments in a Crystal Structure
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Vlieghe, Dominique, Van Meervelt, Luc, Dautant, Alain, Gallois, Bernard, Précigoux, Gilles, and Kennard, Olga
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- 1996
5. Crystal structure and Hirshfeld surface analysis of N-{N-[amino(dimethylamino)methyl]carbamimidoyl}- 3-bromobenzenesulfonamide.
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Kexin Su, Jiangshui Luo, and Van Meervelt, Luc
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SURFACE analysis ,CRYSTAL structure ,SURFACE structure ,TYPE 2 diabetes ,HYDROGEN bonding - Abstract
The title compound, C
10 H14 BrN5 O2 S, is the bromobenzenesulfonamide derivative of the type 2 diabetes drug metformin. The asymmetric unit contains two molecules with almost identical conformations but a different orientation of the bromophenyl moiety. Both molecules exhibit intramolecular N--H· · ·N and N--H· · ·O hydrogen bonds. The molecular packing features chain formation in the a-axis direction by alternating N--H· · ·N and N--H· · ·O interactions. In addition, ring motifs consisting of four molecules and π-π interactions between the phenyl rings contribute to the three-dimensional architecture. A Hirshfeld surface analysis shows that the largest contributions to surface contacts arise from contacts in which H atoms are involved. [ABSTRACT FROM AUTHOR]- Published
- 2023
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6. An unusual disulfide‐linked dimerization in the fluorescent protein rsCherryRev1.4.
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Bui, Thi Yen Hang, Dedecker, Peter, and Van Meervelt, Luc
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FLUORESCENT proteins ,DIMERIZATION ,PROTEIN crosslinking ,GEL electrophoresis ,CRYSTAL structure - Abstract
rsCherryRev1.4 has been reported as one of the reversibly photoswitchable variants of mCherry, and is an improved version with a faster off‐switching speed and lower switching fatigue at high light intensities than its precursor rsCherryRev. However, rsCherryRev1.4 still has some limitations such as a tendency to dimerize as well as complex photophysical properties. Here, the crystal structure of rsCherryRev1.4 was determined at a resolution of 2 Å and it was discovered that it forms a dimer that shows disulfide bonding between the protomers. Mutagenesis, gel electrophoresis and size‐exclusion chromatography strongly implicate Cys24 in this process. Replacing Cys24 in rsCherryRev1.4 resulted in a much lower tendency towards dimerization, while introducing Cys24 into mCherry correspondingly increased its dimerization. In principle, this finding opens the possibility of developing redox sensors based on controlled dimerization via disulfide cross‐linking in fluorescent proteins, even though the actual application of engineering such sensors still requires additional research. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Synthesis and characterization of some novel polythiophene derivatives containing pyrazoline.
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Trung, Vu Quoc, Duong, Tran Thi Thuy, Dua, Nguyen Thi, Linh, Nguyen Ngoc, Cuong, Lai Dang, Thao, Dao Phuong, Huy, Vo Khac, Phuong, Nguyen Hoang Ha, Hien, Nguyen, Linh, Duong Khanh, Manh, Vu Quoc, Chinh, Nguyen Thuy, Hoang, Thai, and Van Meervelt, Luc
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POLYTHIOPHENES ,THIOPHENE derivatives ,ELECTRIC conductivity ,OXIDATIVE coupling ,RAMAN spectroscopy ,THERMAL stability ,OPTICAL properties - Abstract
Eight polythiophene derivatives containing pyrazoline side groups were synthesized by a chemical oxidative coupling polymerization using FeCl
3 . The crystal structures of four monomers were determined which confirm the almost perpendicular orientation of the thiophene and pyrazoline rings, while the other substituents are more coplanar. Analyses of IR,1 H-NMR, Raman and UV-Vis spectra demonstrated that the suggested polymerization was successful to generate the synthesized polythiophenes with the expected structures. The morphology of the synthesized polythiophenes was studied by SEM. The different substituents attached to the 1- and 3-positions of the pyrazoline side chain led to differences in optical properties, electrical conductivity, and thermal stability of the synthesized polythiophenes. By adding a pyrazoline side chain to polythiophenes, some polymers achieve good solubility, electrical conductivity of about 1.3 × 10–6 S/cm, high fluorescence intensity (above 40,000 a.u.) at 505–550 nm and thermal stability up to 590°C in the air. [ABSTRACT FROM AUTHOR]- Published
- 2022
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8. Reaction Pathways of Diplatinum Complexes Bearing a Phenylpropene‐ Derived π / σ ‐Chelator with Weak/Strong σ‐Donor Neutral Ligands.
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Chi, Nguyen Thi Thanh, Van Thong, Pham, Cuong, Ngo Tuan, and Van Meervelt, Luc
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ARYL group ,SINGLE crystals ,CHEMICAL shift (Nuclear magnetic resonance) ,BIOCHEMICAL substrates ,PROTONS ,SPECTRUM analysis ,LIGANDS (Chemistry) ,CHELATING agents - Abstract
The reaction of complexes [Pt(μ‐Cl)(arylolefin)]2 with various either weak σ‐donor LN,S,O ligands or strong σ‐donor NHCs ligands results in [PtCl(arylolefin)(LN,S,O)] with LN,S,O in a cis position to the C=C group (series A) or [PtCl(arylolefin)(NHC)] with NHC in a trans position to the C=C group (series B), respectively. The reaction directions are decided by the nature of the reactants, and not by the reaction conditions. Analyses of NMR spectra, XRD and DFT results indicate that the formation of series B is strongly dominated by electronic properties, while steric factors direct the reaction to form series A. The chemical shifts of ethylenic protons and carbons as well as the values of 2JPtH, 3JPtH for the allyl protons and the 3JPtH value for H6 in the aryl group are unambiguously different for series A and series B. In addition, one complex [Pt(μ‐Cl)(EtEug)]2 and five complexes [PtCl(arylolefin)(NHC)] have been characterized by single crystal XRD. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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9. Synthesis, crystal structures and anticancer activities of Cu(II), Zn(II) and Cd(II) complexes containing bis(2-pyridyl)-di(4-methoxyphenyl)ethene.
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Hong, Hai Le Thi, Huu, Thinh Nguyen, Anh, Tho Duong, Nhat, Khanh Nguyen, Pham Quoc, Long, Thanh Dang, Tuan, Nguyen, Hien, and Van Meervelt, Luc
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CADMIUM compounds ,ANTINEOPLASTIC agents ,COPPER ,CRYSTAL structure ,CHLORIDE ions ,CELL lines ,NUCLEAR magnetic resonance spectroscopy - Abstract
Three new complexes of Cu(II), Zn(II) and Cd(II) with bis(2-pyridyl)-di(4-methoxyphenyl)ethene (KT1), bis(µ
2 -chloro)-dichloro-bis(2-(2,2-di(4-methoxyphenyl)-1-(pyridin-2-yl)vinyl)pyridine)-di-copper(II) (CuKT1), dichloro-2-(2,2-di(4-methoxyphenyl)-1-(pyridin-2-yl)vinyl)pyridine-zinc(II) (ZnKT1) and hexakis(µ2 -chloro)-dichloro-tetrakis(2-(2,2-di(4-methoxyphenyl)-1-(pyridin-2-yl)vinyl)pyridine)-tetra-cadmium(II) (CdKT1) were synthesized and characterized by IR spectroscopy,1 H NMR spectroscopy and single-crystal X-ray diffraction. The results reveal that ZnKT1 is a mononuclear complex, while CuKT1 and CdKT1 are binuclear and tetranuclear complexes, respectively. The central metal ions are surrounded by two N atoms of bis(2-pyridyl)-di(4-methoxyphenyl)ethene and Cl− ions including pendant and bridged ones. In the ZnKT1 complex, a distorted tetrahedral geometry is formed with Zn(II) as central ion and two chloride ions plus two nitrogen atoms of KT1 as surrounding atoms. CuKT1 is a binuclear complex with two square pyramids formed around the two Cu(II) ions. CdKT1 is a tetranuclear complex with two Cd(II) cations having coordination number six (distorted octahedral geometry) and the other two having coordination number five (distorted trigonal-bipyramidal geometry). The anticancer activity tests on four cancer cell lines, including KB, Hep-G2, Lu and MCF-7, show that ZnKT1 and CuKT1 are active against Hep-G2 and Lu but do not considerably damage KB and MCF-G7. CuKT1 has a considerable effect on two cancer cell lines, Hep-G2 and Lu, with IC50 values of 16(2) and 13(1) μM, respectively. CdKT1 exhibits excellent activity against all four cancer cell lines, with IC50 values ranging from 3.5(2) to 8.8(5) μM, which are lower than those of cisplatin. These complexes exhibit low cytotoxic activity on the normal cell line HEK-293A with IC50 values ranging from 10(1) to 74(5) µM. [ABSTRACT FROM AUTHOR]- Published
- 2022
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10. Crystal structure, Hirshfeld surface analysis and density functional theory study of 6-methyl-2-[(5-methylisoxazol-3-yl)methyl]-1H-benzimidazole.
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Idrissi, Ahlam, Chkirate, Karim, Abad, Nadeem, Djerrari, Bahia, Achour, Redouane, Essassi, El Mokhtar, and Van Meervelt, Luc
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DENSITY functional theory ,SURFACE analysis ,FRONTIER orbitals ,CRYSTAL structure ,FUNCTIONAL analysis - Abstract
In the title molecule, C
13 H13 N3 O, the isoxazole ring is inclined to the benzimidazole ring at a dihedral angle of 69.28 (14)°. In the crystal, N--H⋯N hydrogen bonds between neighboring benzimidazole rings form chains along the a-axis direction. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (48.8%), H⋯C/C⋯H (20.9%) and H⋯N/N⋯H (19.3%) interactions. The optimized structure calculated using density functional theory at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap is 4.9266 eV. [ABSTRACT FROM AUTHOR]- Published
- 2021
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11. Protein-assisted formation and stabilization of catalytically active polyoxometalate species
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Vandebroek, Laurens, de Zitter, Elke, De zitter, Elke, Ly, Hong Giang Thi, Conić, Dragan, Mihaylov, Tzvetan, Sap, Annelies, Proost, Paul, Pierloot, Kristine, Van meervelt, Luc, Parac-Vogt, Tatjana, Department of Chemistry [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Groupe Dynamique et Cinétique des processus moléculaires (IBS-DYNAMOP ), Institut de biologie structurale (IBS - UMR 5075 ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Microbiology and Immunology, Rega Institute, Groupe Dynamique et Cinétique des processus moléculaires (IBS-DYNAMOP), Institut de biologie structurale (IBS - UMR 5075), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
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[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM] ,010405 organic chemistry ,Hydrogen bond ,Organic Chemistry ,General Chemistry ,Crystal structure ,010402 general chemistry ,01 natural sciences ,Catalysis ,Dissociation (chemistry) ,0104 chemical sciences ,chemistry.chemical_compound ,Residue (chemistry) ,Crystallography ,Hydrolysis ,Monomer ,chemistry ,Polyoxometalate ,Peptide bond ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; The effect of the protein environment on the formation and stabilization of an elusive catalytically active polyoxometalate (POM) species, K$_6$[Hf($\alpha_2$-P$_2$W$_{17}$O$_{61}$)] (1), is reported. In the co-crystal of hen egg-white lysozyme (HEWL) with 1, the catalytically active monomeric species is observed, originating from the dimeric 1:2 POM form, while it is intrinsically unstable under physiological pH conditions. The protein-assisted dissociation of the dimeric POM was rationalized by means of DFT calculations. The dissociation process is unfavorable in bulk water, but becomes favorable in the protein–POM complex due to the low dielectric response at the protein surface. The crystal structure shows that the monomeric form is stabilized by electrostatic and water-mediated hydrogen bonding interactions with the protein. It interacts at three distinct sites, close to the aspartate-containing hydrolysis sites, demonstrating high selectivity towards peptide bonds containing this residue.
- Published
- 2018
12. Influence of ligand composition on crystal structure formation – isostructurality and morphotropism.
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Arhangelskis, Mihails, Van Meervelt, Luc, and Dobrzańska, Liliana
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CRYSTAL structure , *METAL crystals , *METHYL groups , *SPACE groups , *METAL complexes - Abstract
Two new Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)benzene (L1) and 1,3-bis(imidazol-1-ylmethyl)-5-methylbenzene (L2), namely {[AgL1]CF3SO3}n (1) and {[AgL2]CF3SO3}n (2), were synthesised and characterised by SCXRD to uncover the effect that introducing a methyl group to the benzene core of the ligand has on the molecular/crystal structure of the metal complex. The studies revealed a high level of isostructurality of the formed Ag(I) complexes, consisting of 1D cationic chains with the charge neutralised by the counterions applied. These results triggered structural investigations of the parent ligands, which, as revealed by SCXRD, crystallise as dihydrates in different space groups of a monoclinic system. Further analyses revealed that the motifs in their molecular packing in general stay the same. However, some morphotropic/positional adjustments are taking place in L2 to accommodate the presence of the methyl substituent. [ABSTRACT FROM AUTHOR]
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- 2021
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13. Hybrid assemblies of a symmetric designer protein and polyoxometalates with matching symmetry.
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Vandebroek, Laurens, Noguchi, Hiroki, Kamata, Kenichi, Tame, Jeremy R. H., Van Meervelt, Luc, Parac-Vogt, Tatjana N., and Voet, Arnout R. D.
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POLYOXOMETALATES ,SYMMETRY ,PROTEIN engineering ,PROTEINS ,CRYSTAL structure - Abstract
Novel bioinorganic hybrid materials based on proteins and inorganic clusters have enormous potential for the development of hybrid catalysts that synergistically combine properties of both materials. Here we report the creation of hybrid assemblies between a computationally designed symmetrical protein Pizza6-S and different polyoxometalates with matching symmetry: the tellurotungstic Anderson-Evans (Na
6 [TeW6 O24 ]·22H2 O) (TEW); Keggin (H4 [SiW12 O40 ]·6H2 O) (STA); and 1 : 2 CeIII -substituted Keggin (K11 [CeIII [PW11 O39 ]2 ]·20H2 O) (Ce-K). This results in the formation of complexes with clearly defined stoichiometries in solution. Crystal structures validate the complexes as building blocks for the formation of larger assemblies. [ABSTRACT FROM AUTHOR]- Published
- 2020
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14. Synthesis, structure and in vitro cytotoxicity testing of some 2‐aroylbenzofuran‐3‐ols.
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Cong, Nguyen Tien, Trang, Huynh Thi Xuan, Dung, Pham Duc, Phuong, Tran Hoang, Trung, Vu Quoc, Dat, Nguyen Dang, Anh, Dang Thi Tuyet, Tuyen, Nguyen Van, and Van Meervelt, Luc
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NUCLEAR magnetic resonance spectroscopy ,MASS spectrometry ,CELL lines ,CANCER cells ,X-ray diffraction - Abstract
Five 2‐aroyl‐5‐bromobenzo[b]furan‐3‐ol compounds (two of which are new) and four new 2‐aroyl‐5‐iodobenzo[b]furan‐3‐ol compounds were synthesized starting from salicylic acid. The compounds were characterized by mass spectrometry and 1H NMR and 13C NMR spectroscopy. Single‐crystal X‐ray diffraction studies of four compounds, namely, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐fluorophenyl)methanone, C15H8BrFO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐chlorophenyl)methanone, C15H8BrClO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐bromophenyl)methanone, C15H8Br2O3, and (4‐bromophenyl)(3‐hydroxy‐5‐iodobenzofuran‐2‐yl)methanone, C15H8BrIO3, were also carried out. The compounds were tested for their in vitro cytotoxicity on the four human cancer cell lines KB, Hep‐G2, Lu‐1 and MCF7. Six compounds show good inhibiting abilities on Hep‐G2 cells, with IC50 values of 1.39–8.03 µM. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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15. Synthesis and structure of ethyl 2-[(4-oxo-3-phenyl- 3,4-dihydroquinazolin-2-yl)sulfanyl]acetate.
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Cong Nguyen Tien, Quang Nguyen Tan, Dung Pham Duc, Phuong Tran Hoang, Dat Nguyen Dang, Luong Truong Minh, and Van Meervelt, Luc
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DIHEDRAL angles ,METHYL groups ,ACETATES ,HYDROGEN bonding ,THIOAMIDES - Abstract
The title compound, C
18 H16 N2 O3 S, was synthesized by reaction of 2-mercapto-3- phenylquinazolin-4(3H)-one with ethyl chloroacetate. The quinazoline ring forms a dihedral angle of 86.83 (5)° with the phenyl ring. The terminal methyl group is disordered by a rotation of about 60° in a 0.531 (13): 0.469 (13) ratio. In the crystal, C--H…O hydrogen-bonding interactions result in the formation of columns running in the [010] direction. Two parallel columns further interact by C--H…O hydrogen bonds. The most important contributions to the surface contacts are from H…H (48.4%), C…H/H…C (21.5%) and O…H/H…O (18.7%) interactions, as concluded from a Hirshfeld analysis. [ABSTRACT FROM AUTHOR]- Published
- 2020
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16. Synthesis, crystal structure and Hirshfeld surface analysis of 4-[3-(4-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-5-yl]-2-methoxyphenol monohydrate.
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Linh Duong Khanh, My Hanh Trinh Thi, Thuy Quynh Bui Thi, Trung Vu Quoc, Vuong Nguyen Thien, and Van Meervelt, Luc
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SURFACE analysis ,CRYSTAL structure ,SURFACE structure ,HYDROGEN bonding ,ATOMS - Abstract
In the title pyrazoline derivative, C
16 H16 N2 O3 ·H2 O, the pyrazoline ring has an envelope conformation with the substituted sp² C atom on the flap. The pyrazoline ring makes angles of 86.73 (12) and 13.44 (12)° with the trisubstituted and disubstituted benzene rings, respectively. In the crystal structure, the molecules are connected into chains running in the b-axis direction by O—H∙∙∙N hydrogen bonding. Parallel chains interact through N—H∙∙∙O hydrogen bonds and π–π stacking of the trisubstituted phenyl rings. The major contribution to the surface contacts are H∙∙∙H contacts (44.3%) as concluded from a Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]- Published
- 2019
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17. Synthesis and redetermination of the crystal structure of salicylaldehyde N(4)-morpholinothiosemicarbazone.
- Author
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Dang Tran Buu, Vu Duong Ba, Minh Khoi Nguyen Hoang, Trung Vu Quoc, Linh Duong Khanh, Yen Oanh Doan Thi, and Van Meervelt, Luc
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CRYSTAL structure ,SURFACE analysis ,HYDROGEN bonding - Abstract
The structure of the title compound (systematic name: N-{[(2-hydroxyphenyl)methylidene]amino}morpholine-4-carbothioamide), C
12 H15 N3 O2 S, was previously determined (Koo et al., 1977) using multiple-film equi-inclination Weissenberg data, but has been redetermined with higher precision to explore its conformation and the hydrogen-bonding patterns and supramolecular interactions. The molecular structure shows intramolecular O—H···N and C—H···S interactions. The configuration of the C=N bond is E. The molecule is slightly twisted about the central N—N bond. The best planes through the phenyl ring and the morpholino ring make an angle of 43.44 (17)°. In the crystal, the molecules are connected into chains by N—H···O and C—H···O hydrogen bonds, which combine to generate sheets lying parallel to (002). The most prominent contribution to the surface contacts are H···H contacts (51.6%), as concluded from a Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]- Published
- 2019
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18. Crystal structure of two N'-(1-phenylbenzylidene)-2-(thiophen-3-yl)acetohydrazides.
- Author
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Trung Vu Quoc, Linh Nguyen Ngoc, Duong Tran Thi Thuy, Manh Vu Quoc, Thien Vuong Nguyen, Yen Oanh Doan Thi, and Van Meervelt, Luc
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CRYSTAL structure ,DIHEDRAL angles ,MOLECULAR crystals ,MOLECULAR structure ,HYDROGEN bonding - Abstract
The synthesis, spectroscopic data, crystal and molecular structures of two N'-(1-phenylbenzylidene)-2-(thiophen-3-yl)acetohydrazides, namely N'-[1-(4-hydroxyphenyl)benzylidene]-2-(thiophen-3-yl)acetohydrazide, C
13 H10 N2 O2 S,(3a), and N'-[1-(4-methoxyphenyl)benzylidene]-2-(thiophen-3-yl)acetohydrazide, C14 H14 N2 O2 S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thiophene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C= N bond is E. The thiophene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C--C--C--N torsion angle is -ac for (3a) and -sc for (3b), while the C6--C7--N9--N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N--H···O hydrogen bonds, resulting in the formation of chains of molecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface. [ABSTRACT FROM AUTHOR]- Published
- 2019
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19. Noncovalent Complexes Formed between Metal‐Substituted Polyoxometalates and Hen Egg White Lysozyme.
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Vandebroek, Laurens, Mampaey, Yentl, Antonyuk, Svetlana, Van Meervelt, Luc, and Parac‐Vogt, Tatjana N.
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POLYOXOMETALATES ,LYSOZYMES ,CRYSTALLIZATION ,SUBSTITUTION reactions ,CRYSTAL structure ,METAL-organic frameworks - Abstract
Four Wells–Dawson type metal‐substituted polyoxometalates (MSPs), 1:2 ZrIV‐Wells–Dawson [ZrIV(α2‐P2W17O61)]8– (1), 1:1 CoII‐Wells–Dawson [CoII(α2‐P2W17O61)]10– (2), 1:1 NiII‐Wells–Dawson [NiII(α2‐P2W17O61)]10– (3) and 1:1 CuII‐Wells–Dawson [CuII(α2‐P2W17O61)]10– (4), which differ in the nature of the imbedded metal ion, were examined in co‐crystallization experiments with a protein Hen Egg White Lysozyme (HEWL). Single crystal X‐ray structures of four noncovalent complexes between POMs and HEWL have been determined, and the influence of the type of substituted metal on the mode of POM binding to a protein was investigated. All crystal structures exhibited a high degree of similarity, suggesting that the interaction is largely independent on the nature of substituted metal within the same polyoxometalate (POM) archetype. The main driving force for the formation of the noncovalent complex is electrostatic attraction between POM and HEWL surface regions. Stabilization is further provided by direct and water mediated hydrogen bonding between terminal oxygen atoms of the POM framework and flexible HEWL residues. Single crystal X‐ray structures of four noncovalent complexes between POMs and HEWL were determined, and the influence of the type of substituted metal on the mode of POM binding to a protein was investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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20. Mixed natural arylolefin–quinoline platinum(II) complexes: synthesis, structural characterization and in vitro cytotoxicity studies.
- Author
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Chi, Nguyen Thi Thanh, Thong, Pham Van, Mai, Truong Thi Cam, and Van Meervelt, Luc
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QUINOLINE ,PLATINUM ,CELL-mediated cytotoxicity - Abstract
Five new platinum(II) complexes bearing a eugenol and a quinoline derivative, namely [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]‐trans‐dichlorido(quinoline‐κN)platinum(II), [PtCl2(C15H20O4)(C9H7N)], (2), {η2‐4‐allyl‐2‐methoxy‐1‐[(propan‐2‐yloxy)carbonylmethoxy]benzene}‐trans‐dichlorido(quinoline‐κN)platinum(II), [PtCl2(C15H19O4)(C9H7N)], (3), [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]chlorido(quinolin‐8‐olato‐κ2N,O)platinum(II), [Pt(C9H6NO)Cl(C15H20O4)], (4), {η2‐4‐allyl‐2‐methoxy‐1‐[(propan‐2‐yloxy)carbonylmethoxy]benzene}chlorido(quinolin‐8‐olato‐κ2N,O)platinum(II), [Pt(C9H6NO)Cl(C15H20O4)], (5), and [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]chlorido(quinolin‐2‐carboxylato‐κ2N,O)platinum(II), [Pt(C10H6NO2)Cl(C15H20O4)], (6), have been synthesized and fully characterized spectroscopically. A single‐crystal X‐ray diffraction study was carried out for complexes (2) and (4)–(6). PrEug [or 4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene] in (2), (4) and (6), and iPrEug (the propan‐2‐yloxy analogue of PrEug) in (3) and (5) coordinate with PtII at the ethylenic double bond of the allyl group. In (2)–(6), the donor N atom of the amine group occupies a trans position with respect to the double bond. A comparison of the IC50 values of 0.38–29.23 µM for (2)–(6) with cisplatin, as well as other platinum(II) complexes, indicates an excellent in vitro cytotoxicity against the KB, LU, Hep‐G2 and MCF‐7 cancer cell lines, with the highest cytotoxic effect (IC50 = 0.38–1.99 µM) being for complexes (4) and (5) bearing a quinolin‐8‐olate ligand. The syntheses and structures of five new platinum(II) complexes bearing (iso)propyl eugenoxyacetate and quinolines are presented, as well as their in vitro cytotoxicity on four human cancer cell lines. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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21. Synthesis, structure and in vitro cytotoxicity testing of some 1,3,4‐oxadiazoline derivatives from 2‐hydroxy‐5‐iodobenzoic acid.
- Author
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Nguyen Tien, Cong, Nguyen Van, Thin, Le Duc, Giang, Vu Quoc, Manh, Vu Quoc, Trung, Pham Chien, Thang, Nguyen Huy, Hung, Dang Thi Tuyet, Anh, Nguyen Van, Tuyen, and Van Meervelt, Luc
- Subjects
OXADIAZOLINES ,BENZOIC acid ,CONFORMATIONAL analysis - Abstract
The syntheses of nine new 5‐iodosalicylic acid‐based 1,3,4‐oxadiazoline derivatives starting from methyl salicylate are described. These compounds are 2‐[4‐acetyl‐5‐methyl‐5‐(3‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6a), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6b), 2‐(4‐acetyl‐5‐methyl‐5‐phenyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl)‐4‐iodophenyl acetate, C
19 H17 IN2 O4 (6c), 2‐[4‐acetyl‐5‐(4‐fluorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C19 H16 FIN2 O4 (6d), 2‐[4‐acetyl‐5‐(4‐chlorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C19 H16 ClIN2 O4 (6e), 2‐[4‐acetyl‐5‐(3‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6f), 2‐[4‐acetyl‐5‐(4‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6g), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐methylphenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6h) and 2‐[5‐(4‐acetamidophenyl)‐4‐acetyl‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6i). The compounds were characterized by mass,1 H NMR and13 C NMR spectroscopies. Single‐crystal X‐ray diffraction studies were also carried out for 6c, 6d and 6e. Compounds 6c and 6d are isomorphous, with the 1,3,4‐oxadiazoline ring having an envelope conformation, where the disubstituted C atom is the flap. The packing is determined by C—H…O, C—H…π and I…π interactions. For 6e, the 1,3,4‐oxadiazoline ring is almost planar. In the packing, Cl…π interactions are observed, while the I atom is not involved in short interactions. Compounds 6d, 6e, 6f and 6h show good inhibiting abilities on the human cancer cell lines KB and Hep‐G2, with IC50 values of 0.9–4.5 µM. [ABSTRACT FROM AUTHOR]- Published
- 2018
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22. Crystal structure of (E)-N'-[1-(4-aminophenyl)-ethylidene]-2-hydroxy-5-iodobenzohydrazide methanol monosolvate.
- Author
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Cong Nguyen Tien, Huong Le Thi Thu, Thin Nguyen Van, Trung Vu Quoc, Manh Vu Quoc, Thang Pham Chien, and Van Meervelt, Luc
- Subjects
HYDRAZIDES ,HYDROXYBENZOIC acid ,CRYSTAL structure - Abstract
In the title compound, C
15 H14 IN3 O2 ·CH3 OH, two aromatic rings are linked by an N-substituted hydrazide function. The dihedral angle between the aromatic rings is 10.53 (8)°. The stereochemistry about the imine function is E. The methanol molecule forms an O-H...O hydrogen bond to the hydrazide O atom. In the crystal, chains of molecules running along the c-axis direction are formed by O-H...O hydrogen bonds. Adjacent chains are linked through N-H...O hydrogen bonds and π-π stacking interactions. The intermolecular interactions in the crystal packing were investigated using Hirshfeld surface analysis, which indicated that the most significant contacts are H...H (38.2%), followed by C...H/H...C (20.6%), O...H/H...O (11.1%) and I...H/H...I (9.7%). [ABSTRACT FROM AUTHOR]- Published
- 2018
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23. Synthesis, structure and in vitro cytotoxicity of platinum(II) complexes containing eugenol and a quinolin-8-ol-derived chelator.
- Author
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Nguyen Thi Thanh, Chi, Truong Thi Cam, Mai, Pham Van, Thong, Nguyen, Long, Nguyen Ha, My, and Van Meervelt, Luc
- Subjects
PLATINUM compounds ,QUINOLINE derivatives ,COMPLEX compounds synthesis - Abstract
The synthesis of potassium (η
2 -4-allyl-2-methoxyphenol)trichloridoplatinate(II), K[PtCl3 (C10 H12 O2 )], ( 1), starting from Zeise's salt and Ocimum sanctum L. oil has been optimized. Starting from ( 1), three new platinum(II) complexes, namely (η2 -4-allyl-2-methoxyphenol)chlorido(2-methylquinolin-8-olato-κ2 N, O)platinum(II), ( 2), (η2 -4-allyl-2-methoxyphenol)chlorido(5-nitroquinolin-8-olato-κ2 N, O)platinum(II), ( 3), and (η2 -4-allyl-2-methoxyphenol)chlorido(5,7-dichloroquinolin-8-olato-κ2 N, O)platinum(II), [Pt(C9 H4 Cl2 NO)Cl(C10 H12 O2 )], ( 4), containing eugenol and a quinolin-8-ol derivative (R-OQ), have been synthesized and characterized by elemental analyses, MS, IR,1 H NMR and NOESY spectra. For ( 1) and ( 4), single-crystal X-ray diffraction studies were also carried out. Complexes ( 2)-( 4) show good inhibiting abilities on three human cancer cell lines, i.e. KB, Hep-G2 and LU, with IC50 values of 1.42-17.8 µ M. Complex ( 3) gives an impressively high activity against KB, Hep-G2, LU and MCF-7, with IC50 values of 1.42-4.91 µ M, which are much lower than those of cisplatin and some other platinum(II) complexes. [ABSTRACT FROM AUTHOR]- Published
- 2017
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24. Crystal structure of 4-amino-3-(thiophen-3-ylmethyl)- 1H-1,2,4-triazole-5(4H)-thione.
- Author
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Trung Vu Quoc, Linh Nguyen Ngoc, Vy Do Truc, Linh Duong Khanh, Hung Ha Manh, Chien Thang Pham, and Van Meervelt, Luc
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THIOPHENES ,TRIAZOLES ,DIHEDRAL angles ,DIMERS ,NITROGEN - Abstract
In the title compound, C
7 H8 N4 S2 , the thiophene ring shows rotational disorder over two orientations in a 0.6957 (15):0.3043 (15) ratio. The plane of the 1,2,4- triazole ring makes a dihedral angle of 75.02 (17)º with the major-disorder component of the thiophene ring. In the crystal, two types of inversion dimers, described by the graph-set motifs R²2 (8) and R²2 (10), are formed by N--H ... S interactions. Chains of molecules running in the [101] direction are linked by weaker N--H ... N interactions. The thiophene ring is involved in π--π and C-- H ... π interactions. [ABSTRACT FROM AUTHOR]- Published
- 2017
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25. Crystal structure of 5-benzyl-8-bromo-2-methyl-1,3-oxazolo[4,5-c][1,8]naphthyridin-4(5H)-one.
- Author
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Vrijdag, Johannes, An Van den Bogaert, De Borggraeve, Wim, and Van Meervelt, Luc
- Subjects
CRYSTAL structure ,PYRIDONE ,OXAZOLONE ,PHENYL compounds ,MOIETIES (Chemistry) - Abstract
The title compound, C
17 H12 BrN3 O2 , was unexpectedly isolated during an attempt to synthesize pyridodiazepinediones and identified as an oxazolo-naphthyridinone derivative. The almost planar oxazolonaphthyridinone ring (r.m.s. deviation = 0.016 Å) makes a dihedral angle of 61.6 (2)° with the phenyl ring. In the crystal, columns of molecules stacked along the a axis are formed by π-π interactions between the six-membered rings of the oxazolonaphthyridone moieties [centroid-to-centroid distances = 3.494 (2)-3.906 (3) Å], which further interact through C--H⋯π contacts with the phenyl rings. [ABSTRACT FROM AUTHOR]- Published
- 2017
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26. Crystal structures of three 4-substituted-2,2'-bipyridines synthesized by Sonogashira and Suzuki-Miyaura cross-coupling reactions.
- Author
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Thuy Luong Thi Thu, Ngan Nguyen Bich, Hien Nguyen, and Van Meervelt, Luc
- Subjects
BIPYRIDINE derivatives ,CRYSTAL structure ,SONOGASHIRA reaction - Abstract
Facile synthetic routes for three 4-substituted 2,2'-bipyridine derivatives, 4-[2-(4-methylphenyl)ethynyl]-2,2,-bipyridine, C
19 H14 N2 , (I), 4-[2-(pyridin-3-yl)ethynyl]-2,2'-bipyridine, C17 H11 N3 , (II), and 4-(indol-4-yl)-2,2'-bipyridine, C18 H13 N3 , (III), via Sonogashira and Suzuki-Miyaura cross-coupling reactions, respectively, are described. As indicated by X-ray analysis, the 2,2'-bipyridine core, the ethylene linkage and the substituents of (I) and (II) are almost planar [dihedral angles between the two ring systems: 8.98 (5) and 9.90 (6)° for the two molecules of (I) in the asymmetric unit and 2.66 (14)° for (II)], allowing π-conjugation. On the contrary, in (III), the indole substituent ring is rotated significantly out of the bipyridine plane [dihedral angle = 55.82 (3)°], due to steric hindrance. The crystal packings of (I) and (II) are dominated by π-π interactions, resulting in layers of molecules parallel to (302) in (I) and columns of molecules along the a axis in (II). The packing of (III) exhibits zigzag chains of molecules along the c axis interacting through N--H...N hydrogen bonds and π-π interactions. The contributions of unknown disordered solvent molecules to the diffraction intensities in (II) were removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9-18] algorithm of PLATON. The given chemical formula and other crystal data do not take into account these solvent molecules. [ABSTRACT FROM AUTHOR]- Published
- 2017
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27. Crystal structures of two platinum(II) complexes containing ethyl eugenoxyacetate and 2-aminopyridine.
- Author
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Hai Le Thi Hong, Thao Nguyen Thu, Nguyen, Hien, and Van Meervelt, Luc
- Subjects
PLATINUM compounds ,CRYSTAL structure ,AMINOPYRIDINES - Abstract
In the title complexes, trans-(2-aminopyridine-κN)dichlorido{4-ethoxycarbonyl-methoxy-3-methoxy-1-[(2,3-ŋ)-prop-2-en-1-yl]benzene}platinum(II), [PtCl
2 -(C5 H6 N2 )(C14 H18 O4 )], (I), and (2-aminopyridine-κN)chlorido{5-ethoxycarbonylmethoxy-4-methoxy-1-[(2,3-ŋ)-prop-2-en-1-yl]phenyl-κC¹}platinum(II), [Pt-(C14 H17 O4 )Cl(C5 H6 N2 )], (II), the central PtII metal atom displays a distorted square-planar coordination, with the Ptn atom coordinated by the pyridine N atom, the C=C double bond of the eugenol ligand and two Cl atoms for (I) or one Cl atom and a C atom of the phenyl ring for (II). The allyl fragment in (I) is disordered, with population parameters 0.614 (14) and 0.386 (14) for the two positions of the central C atom. The least-squares planes through the two aromatic ring systems make a dihedral angle of 51.10 (13)° for (I) and 78.5 (2)° for (II). Intramolecular N -- H...O and N--H...π interactions occur in (I). In (I), inversion dimers formed by C--H...Cl interactions are further linked into chains parallel to the b axis by C--H..O hydrogen bonds. Both aromatic rings are involved in π - π interactions, with centroid-to-centroid distances of 3.508 (3) and 3.791 (3) Å. In (II), inversion dimers form chains parallel to the b axis by C--H...O interactions. [ABSTRACT FROM AUTHOR]- Published
- 2017
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28. Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)platinum(II)].
- Author
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Nguyen Thi Thanh, Chi, Pham Van, Thong, Le Thi Hong, Hai, and Van Meervelt, Luc
- Subjects
COMPLEX compounds synthesis ,METAL complexes ,PLATINUM compounds ,CRYSTALLIZATION ,LIGANDS (Chemistry) ,MOLECULAR structure - Abstract
Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η
2 -2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1 )platinum(II)], [Pt2 (C15 H19 O4 )2 Cl2 ], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κ N)(η2 -2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1 )chloridoplatinum(II) monohydrate, [Pt(C15 H19 O4 )Cl(CH3 CN)]·H2 O, (η2 -2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1 )chlorido(dimethylformamide-κ O)platinum(II), [Pt(C15 H19 O4 )Cl(C2 H7 NO)], and (η2 -2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1 )chlorido(dimethyl sulfoxide-κ S)platinum(II), determined as the analogue {η2 -2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κ C1 }chlorido(dimethyl sulfoxide-κ S)platinum(II), [Pt(C14 H17 O4 )Cl(C2 H6 OS)]. The crystal structures confirm that acetonitrile interacts with the PtII atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of the aromatic ring. [ABSTRACT FROM AUTHOR]- Published
- 2016
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29. Crystal structures and thermal behaviour of lanthanide(III) hexanoate 1,10-phenanthroline complexes, [M(C5H11CO2)(3)(phen)] and [Tm(C5H11CO2)(2)(NO3)(phen)]
- Author
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Jongen, Liesbet, Bromant, Claudia, Hinz-Hübner, Dirk, Meyer, Gerd, Robeyns, Koen, Van Hecke, Kristof, Van Meervelt, Luc, and Binnemans, Koen
- Subjects
rare earths ,crystal structure ,1,10-phenanthroline ,terbium ,lanthanides ,alkanoates ,thulium ,metal soaps - Abstract
Lanthanide(III) hexanoate 1,10-phenanthroline complexes crystallise in the space group P2(1)/n. The compounds consist of dimers, whereby two lanthanide ions are held together by two bidentate bridging and two tridentate bridging carboxylate groups. The first coordination sphere of the lanthanide ions is completed by one bidentate chelating carboxylate group and by one bidentate 1,10-phenanthroline molecule, resulting in the coordination number 9. The dimers have a spherical form, which has important consequences for the thermal properties of complexes. The basic idea behind the preparation of this type of compounds is the stabilisation of the ionic lanthanide layer, so that the smaller lanthanide ions (from which the normal alkanoates do not show mesomorph-ism because they are too small) show liquid crystallinity. The stabilisation of the ionic layer was successful, expressed by the high melting temperatures, but mesomorphism is not observed. The absence of mesomorphism is related to the isotropic structure of the compounds. A lower symmetry is obtained when a hexanoate group is replaced by a nitrate group. Thulium(III) dihexanoate nitrate 1, 10-phenanthroline crystallises in the space group P (1) over bar. However, this compound also shows a spherical dimeric structure, but no mesomorphism. ispartof: Zeitschrift für Anorganische und Allgemeine Chemie vol:629 issue:6 pages:975-980 status: published
- Published
- 2003
30. Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75.
- Author
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Thu Hoai Le, Brooks, Neil R., Binnemans, Koen, Blanpain, Bart, Muxing Guo, and Van Meervelt, Luc
- Subjects
APATITE synthesis ,CALCIUM compounds ,X-ray powder diffraction - Abstract
The title compound, Ca
2+x Nd8-x (SiO4 )6O2-0.5x (x = 0.49), was synthesized at 1873K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space group P63/m and has the composition Ca2.49 Nd7.51 (SiO4 )6 O1.75 [dicalcium octaneodymium hexakis(orthosilicate) dioxide], being isotypic with natural apatite and the previously reported Ca2 Nd8 (SiO4 )6O2 and Ca2.2 Nd7.8 (SiO4 )6O1.9 . The solubility limit of calcium in the equilibrium state at 1873K was found to occur at a composition of Ca2+x Nd8-x (SiO4 )6O2-0.5x , where x = 0.49. [ABSTRACT FROM AUTHOR]- Published
- 2016
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31. Homodiselenacalix[4]arenes: Molecules with Unique Channelled Crystal Structures.
- Author
-
Thomas, Joice, Dobrzańska, Liliana, Van Meervelt, Luc, Quevedo, Mario Alfredo, Woźniak, Krzysztof, Stachowicz, Marcin, Smet, Mario, Maes, Wouter, and Dehaen, Wim
- Subjects
AROMATIC compounds ,ORGANIC cyclic compounds ,NUCLEOPHILIC aromatic photosubstitution ,CRYSTAL structure ,CRYSTALLOGRAPHY - Abstract
A synthetic route towards homodiselenacalix[4]arene macrocycles is presented, based on the dynamic covalent chemistry of diselenides. The calixarene inner rim is decorated with either alkoxy or tert-butyl ester groups. Single-crystal X-ray analysis of two THF solvates with methoxy and ethoxy substituents reveals the high similarity of their molecular structures and alterations on the supramolecular level. In both crystal structures, solvent channels are present and differ in both shape and capacity. Furthermore, the methoxy-substituted macrocycle undergoes a single-crystal-to-single-crystal transformation during which the molecular structure changes its conformation from 1,3-alternate (loaded with THF/water) to 1,2-alternate (apohost form). Molecular modelling techniques were applied to explore the conformational and energetic behaviour of the macrocycles. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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32. Crystal structures of hydrated rare-earth bis(trifluoromethylsulfonyl)imide salts.
- Author
-
Vander Hoogerstraete, Tom, Brooks, Neil R., Onghena, Bieke, Van Meervelt, Luc, and Binnemans, Koen
- Subjects
CRYSTAL structure ,RARE earth metals ,IMIDES ,SALTS ,IONS - Abstract
Crystals of hydrated bis(trifluoromethylsulfonyl)imide (Tf
2 N) salts of the naturally occurring trivalent rare-earth ions were grown from aqueous solution and analysed by X-ray diffraction. Their structures can be classified into three main groups. The lighter lanthanides La–Gd (except Sm) have a cubic crystal structure with the formula Ln(H2 O)3 (Tf2 N)3 , which has Tf2 N anions coordinating in a bidentate fashion. The middle and heavy lanthanides (Sm, Tb, Dy, Er, Yb) have a monoclinic crystal structure with formula Ln(H2 O)5 (Tf2 N)3 , where the Tf2 N anions are coordinating in a monodentate fashion. The heavy lanthanides Gd–Lu (except Tb, Tm) crystallise with very large unit cells making structural identification difficult. Partial structure solution of one of these compounds indicates that the structures contain fully hydrated Ln3+ ions and very disorderd Tf2 N anions. Y was found to behave as the heavy lanthanides and Sc was found in a crystal structure of formula [Sc(H2 O)7 ][Tf2 N]3 ·H2 O. In addition, La was found in a hexagonal crystal structure of formula La(H2 O)3 (Tf2 N)3 ·2.5H2 O, when a small amount of residual HTf2 N was present during crystallisation. [ABSTRACT FROM AUTHOR]- Published
- 2015
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33. Stacking patterns of thieno[3,2- b]thiophenes functionalized by sequential palladium-catalyzed Suzuki and Heck cross-coupling reactions.
- Author
-
Nguyen, Hien, Nguyen Bich, Ngan, Dang, Tung T., and Van Meervelt, Luc
- Subjects
STACKING interactions ,THIOPHENES ,PALLADIUM catalysts ,SUZUKI reaction ,HECK reaction ,COUPLING reactions (Chemistry) - Abstract
The crystal structures of three 5-alkenyl-2-arylthieno[3,2- b]thiophenes, namely 3,6-dibromo-5-(4- tert-butylstyryl)-2-(naphthalen-1-yl)thieno[3,2- b]thiophene, C
28 H22 Br2 S2 , (I), 3,6-dibromo-5-(4-methylstyryl)-2-(naphthalen-1-yl)thieno[3,2- b]thiophene, C25 H16 Br2 S2 , (II), and 3,6-dibromo-2-(4- tert-butylphenyl)-5-(4-methylstyryl)thieno[3,2- b]thiophene, C25 H22 Br2 S2 , (III), have been determined in order to evaluate the geometry of the molecules. The π-conjugated system containing the thieno[3,2- b]thiophene skeleton, the ethylene bridge and the phenyl rings is almost planar. The aromatic ring directly attached to the thieno[3,2- b]thiophene moiety is not coplanar with the thieno[3,2- b]thiophene moiety itself due to steric hindrance of the bromo substituent. The crystal packings are characterized by π-π stacking [only for (II)] and C-Br...π interactions. The long axes of the molecules in (I) are oriented in two directions; for the two other structures the long axis is oriented in one direction only. [ABSTRACT FROM AUTHOR]- Published
- 2014
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34. Enantioselective Assembly of a Ruthenium(II) Polypyridyl Complex into a Double Helix.
- Author
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Van Hecke, Kristof, Cardinaels, Thomas, Nockemann, Peter, Jacobs, Jeroen, Vanpraet, Louis, Parac ‐ Vogt, Tatjana N., Van Deun, Rik, Binnemans, Koen, and Van Meervelt, Luc
- Subjects
ENANTIOSELECTIVE catalysis ,DNA structure ,RUTHENIUM ,CRYSTAL structure ,STACKING interactions ,RACEMIC mixtures - Abstract
Evolution can increase the complexity of matter by self-organization into helical architectures, the best example being the DNA double helix. One common aspect, apparently shared by most of these architectures, is the presence of covalent bonds within the helix backbone. Here, we report the unprecedented crystal structures of a metal complex that self-organizes into a continuous double helical structure, assembled by non-covalent building blocks. Built up solely by weak stacking interactions, this alternating tread stairs-like double helical assembly mimics the DNA double helix structure. Starting from a racemic mixture in aqueous solution, the ruthenium(II) polypyridyl complex forms two polymorphic structures of a left-handed double helical assembly of only the Λ-enantiomer. The stacking of the helices is different in both polymorphs: a crossed woodpile structure versus a parallel columnar stacking. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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35. Carbene formation upon reactive dissolution of metal oxides in imidazolium ionic liquids.
- Author
-
Wellens, Sil, Brooks, Neil R., Thijs, Ben, Van Meervelt, Luc, and Binnemans, Koen
- Subjects
CARBENES ,METALLIC oxides ,IONIC liquids ,CRYSTAL structure ,HYDROGEN atom - Abstract
Metal oxides were found to dissolve in different imidazolium ionic liquids with a hydrogen atom in the C2 position of the imidazolium ring, but not if a methyl substituent was present in the C2 position. The crystal structure of the product that crystallised from an ionic liquid containing dissolved silver(I) oxide showed that this was a silver(I) carbene complex. The presence of carbenes in solution was proven by
13 C NMR spectroscopy and the reactions were also monitored by Raman spectroscopy. The dissolution of other metal oxides, namely copper(II) oxide, zinc(II) oxide and nickel(II) oxide, was also studied in imidazolium ionic liquids and it was found that stable zinc(II) carbenes were formed in solution, but these did not crystallise under the given experimental conditions. A crystalline nickel(II) carbene complex could be obtained from a solution of nickel(II) chloride dissolved in a mixture of 1-butyl-3-methylimidazolium and 1-ethyl-3-methylimidazolium acetate. [ABSTRACT FROM AUTHOR]- Published
- 2014
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36. Hydrogen-bonded chains in three cis-dichloridoplatinum(II) complexes bearing piperidine and amine ligands.
- Author
-
Nguyen Thi Thanh, Chi, Nguyen Bich, Ngan, and Van Meervelt, Luc
- Subjects
HYDROGEN bonding ,PIPERIDINE ,AMINES ,CRYSTAL structure ,CANCER chemotherapy ,QUINOLINE - Abstract
The crystal structures of cis-dichlorido(ethylamine-κ N)(piperidine-κ N)platinum(II), [PtCl
2 (C2 H7 N)(C5 H11 N)], (I), cis-dichlorido(3-methoxyaniline-κ N)(piperidine-κ N)platinum(II), [PtCl2 (C5 H11 N)(C7 H9 NO)], (II), and cis-dichlorido(piperidine-κ N)(quinoline-κ N)platinum(II), [PtCl2 (C5 H11 N)(C9 H7 N)], (III), have been determined at 100 K in order to verify the influence of the nonpiperidine ligand on the geometry and crystal packing. The crystal packing is characterized by N-H...Cl hydrogen bonding, resulting in the formation of chains of molecules connected in a head-to-tail fashion. Hydrogen-bonding interactions play a major role in the packing of (I), where the chains further aggregate into planes, but less so in the case of (II) and (III), where π-π stacking interactions are of greater importance. [ABSTRACT FROM AUTHOR]- Published
- 2014
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37. Isolation, pharmacological activity and structure determination of physalin B and 5β,6β-epoxyphysalin B isolated from Congolese Physalis angulata L.
- Author
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Mangwala Kimpende, Peter, Lusakibanza, Mariano, Mesia, Kahunu, Tona, Lutete, Tits, Monique, Angenot, Luc, Frédérich, Michel, and Van Meervelt, Luc
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PHYSALINS ,HERBAL medicine ,CRYSTAL structure ,ANTIFIBRINOLYTIC agents ,ANTINEOPLASTIC agents ,SOLANACEAE - Abstract
Physalis angulata L., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, ( X) and ( Y), were isolated from a crude CH
2 Cl2 extract of dried Congolese Physalis angulata L. plants and crystallized from acetone for structure elucidation. Compound ( X) corresponds to a physalin B dimer acetone solvate hydrate (2C28 H30 O9 ·C3 H6 O·0.22H2 O), while compound ( Y) crystallizes as a mixed crystal containing two physalin B molecules which overlap with 5β,6β-epoxyphysalin B, also known as physalin F, and one acetone molecule in the asymmetric unit (1.332C28 H30 O9 ·0.668C28 H30 O10 ·C3 H6 O). Antiplasmodial activity, cytotoxic activity and selectivity indices were determined for crude extracts and the two isolated products ( X) and ( Y). [ABSTRACT FROM AUTHOR]- Published
- 2013
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38. Synthetic Protocols towards Selenacalix[3]triazines.
- Author
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Thomas, Joice, Van Rossom, Wim, Van Hecke, Kristof, Van Meervelt, Luc, Smet, Mario, Dehaen, Wim, and Maes, Wouter
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ORGANIC synthesis ,TRIAZINES ,SELENIUM compounds ,CRYSTAL structure ,X-ray diffraction ,RING formation (Chemistry) ,CHEMICAL reactions ,SODIUM compounds - Abstract
Selenium-bridged heteracalixarenes were synthesized by convenient one-pot S
N Ar reactions starting from variously 2-substituted 4,6-dichloro-1,3,5-triazine building blocks. Reactions of these precursors with sodium hydroselenide afforded the selenacalix[ 3]triazines as the only macrocyclic products. Yields of the cyclotrimers were significantly increased by optimization of the macrocyclization conditions, the optimum parameters being dependent on the triazine functionalization pattern. X-ray diffraction studies allowed unambiguous identification of the structures and comparison with the solid-state features of analogous heteracalixarenes [ABSTRACT FROM AUTHOR]- Published
- 2013
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39. Structural basis for the influence of a single mutation K145N on the oligomerization and photoswitching rate of Dronpa.
- Author
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Nguyen Bich, Ngan, Moeyaert, Benjamien, Van Hecke, Kristof, Dedecker, Peter, Mizuno, Hideaki, Hofkens, Johan, and Van Meervelt, Luc
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CRYSTAL structure ,GENETIC mutation ,OLIGOMERIZATION ,FLUORESCENT proteins ,PHOTOCHROMISM ,DIMERIZATION ,CHROMOPHORES - Abstract
The crystal structure of the on-state of PDM1-4, a single-mutation variant of the photochromic fluorescent protein Dronpa, is reported at 1.95 Å resolution. PDM1-4 is a Dronpa variant that possesses a slower off-switching rate than Dronpa and thus can effectively increase the image resolution in subdiffraction optical microscopy, although the precise molecular basis for this change has not been elucidated. This work shows that the Lys145Asn mutation in PDM1-4 stabilizes the interface available for dimerization, facilitating oligomerization of the protein. No significant changes were observed in the chromophore environment of PDM1-4 compared with Dronpa, and the ensemble absorption and emission properties of PDM1-4 were highly similar to those of Dronpa. It is proposed that the slower off-switching rate in PDM1-4 is caused by a decrease in the potential flexibility of certain β-strands caused by oligomerization along the AC interface. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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40. N- tert-Butyl- N′-[5-cyano-2-(4-methylphenoxy)phenylsulfonyl]urea, a new TXA2 receptor antagonist.
- Author
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Bambi-Nyanguile, Sylvie-Mireille, Mangwala Kimpende, Peter, Pirotte, Bernard, and Van Meervelt, Luc
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BUTYL group ,SULFONYLUREAS ,HYDROGEN bonding ,SPACE groups ,THROMBOXANE receptors ,MOLECULAR conformation ,CRYSTAL structure ,UREA derivatives - Abstract
The title compound, C
19 H21 N3 O4 S, crystallizes in the space group P2/ c with two molecules in the asymmetric unit. The conformation of both molecules is very similar and is mainly determined by an intramolecular N-H...O hydrogen bond between a urea N atom and a sulfonyl O atom. The O and second N atom of the urea groups are involved in dimer formation via N-H...O hydrogen bonds. The intramolecular hydrogen-bonding motif and conformation of the C-SO2 -NH(C=O)-NH-C fragment are explored and compared using the Cambridge Structural Database and theoretical calculations. The crystal packing is characterized by π-π stacking between the 5-cyanobenzene rings. [ABSTRACT FROM AUTHOR]- Published
- 2013
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41. Synthesis, structure, photophysical properties and DFT investigation of novel Zn(II) complexes bearing π-extended 8-hydroxyquinoline-derived ligands.
- Author
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Hien, Nguyen, Ninh, Nguyen Hoang, Hieu, Le Minh, Linh, Nguyen Thi Bang, Pham, Van Thong, Dung, Tran Ngoc, Van Meervelt, Luc, Chi, Nguyen Thi Thanh, and Hai, Le Thi Hong
- Subjects
- *
ATOMS , *FLUORESCENCE yield , *QUANTUM computing , *STOKES shift , *X-ray diffraction , *ELECTRONIC structure - Abstract
• Six new [Zn(2,4-diarylquinolin-8-olato) 2 ] complexes were synthesized. • Structures were characterized by ESI-MS, 1H NMR spectra and SC XRD. • Complexes exhibit fluorescence and electron-donating substituents enhance quantum yield. • Quantum chemical computations were consistent with experimental observations. Six new Zn(II) complexes (Zn1–Zn6) were synthesized from 2,4-diaryl-8-hydroxyquinoline derivatives (HQ1–HQ6) and structurally characterized by ESI-MS, 1H NMR spectra and SC XRD. The analysis of NMR and XRD results revealed that all the complex geometries are tetrahedral in which the ligands coordinated with Zn(II) via the N and O atoms. The investigation of photophysical properties showed that the ligands themself are non-fluorescent, while the complexes displayed a strong emission at 597–628 nm, characterized by a fluorescence quantum yield of 0.36–0.98 with a large Stokes shift of 174–202 nm, except complex Zn2. Notably, the quantum yields of the complexes in the solvents and emission intensity in the solid state tend to increase in the presence of electron-donating substituents. Quantum chemical computations were conducted to investigate the electronic structure and optical characteristics of the compounds, yielding outcomes consistent with experimental observations. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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42. Synthesis, crystal structures, and cytotoxicity against cancer cell lines of metal (Co, Cu, Zn, Cd) complexes containing 1,1′-diaryl-2,2′dipyridylethene derivatives.
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Nguyen, Hien, Dang, Tung T., Mai, Chi P., Do, Trung T., Tran, Hung V., Van Meervelt, Luc, and Le, Hai T.H.
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COPPER , *CADMIUM compounds , *CELL lines , *CYTOTOXINS , *CRYSTAL structure , *TRANSITION metals , *CANCER cells - Abstract
[Display omitted] A series of complexes between bis(2-pyridyl)-di(4- n -butylphenyl)ethene (KT4) and bis(2-pyridyl)-di(3-methoxyphenyl)ethene (KT18) with transition metals Co(II), Cu(II), Zn(II), and Cd(II) were synthesized and crystallized. The structures of these compounds were confirmed based on IR, NMR, and MS spectra. Moreover, crystals were obtained for ZnKT18, CoKT18, CuKT18, CdKT18, and CdKT4. Single-crystal X-ray diffraction (XRD) demonstrated the ability of these pyridine-based ligands to coordinate to metal ions via two nitrogen atoms in the aromatic heterocycles. Depending on the central metal, they can form different structures. Zn(II) and Co(II) form mononuclear complexes with KT18 , where the metal coordinates to two N atoms and two chloride ions in a tetrahedral geometry (coordination number 4). The complexes CuKT18 , CdKT18 , and CdKT4 are binuclear complexes with one pendant chloride and two bridging chlorides coordinating with the metal ion (coordination number 5). The cytotoxic properties of free ligands and complexes were tested on four cancer lines, including KB, Hep-G2, Lu, and MCF-7. In general, the free ligands have no cytotoxic activity, while all complexes present strong to medium effects on these cancer lines. Several complexes are comparable in activity to cisplatin, a commercial drug used in the treatment of cancer. Specifically, ZnKT4 selectively inhibits the activities of the KB and Hep-G2 cell lines. CdKT4 has a high impact on Hep-G2 and Lu (IC 50 < 5 μM) while CdKT18 exhibits effective anticancer activity against the KB and MCF-7 cell lines. CuKT18 strongly inhibits the growth progress of the KB cancer cell (IC 50 = 9.52 μM). These IC 50 values are lower than those of cisplatin. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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43. Synthesis, structure and α-glucosidase inhibitor activity evaluation of some acetamide derivatives starting from 2-(naphthalen-1-yl) acetic acid, containing a 1,2,4-triazole.
- Author
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Le, Trong Duc, Nguyen, Tien Cong, Bui, Thi My Nuong, Hoang, Thi Kim Dung, Vu, Quoc Trung, Pham, Chien Thang, Dinh, Chau Phi, Alhaji, Jibril Abdullahi, and Van Meervelt, Luc
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- *
ACETAMIDE derivatives , *ACETAMIDE , *ACETIC acid , *BINDING sites , *MOLECULAR docking , *SINGLE crystals , *CRYSTAL structure - Abstract
• Nine novel acetamide derivatives containing a 1,2,4-triazole were designed and synthesized. • Their structure was confirmed by spectroscopic methods such as NMR, IR and HR-MS. • The crystal structure of four compounds was determined by single crystal X-ray diffraction. • Activity against enzyme α-glucosidase was evaluated. • Docking studies were conducted to analyze the interactions with the active site of the enzyme. A series of nine novel N -aryl 2-{[5-(naphthalen-1-ylmethyl)-4-phenyl-4 H -1,2,4-triazol-3-yl]thio}- N -phenylacetamide derivatives were prepared from 5-(naphthalen-1-ylmethyl)-4-phenyl-4 H -1,2,4-triazole-3-thiol which was obtained from 2-(naphthalen-1-yl)acetohydrazide synthesized starting from 2-(naphthalen-1-yl)acetic acid. The structures of these heterocyclic compounds were confirmed by IR, 1H NMR, 13C NMR and HR-MS spectra. Additionally, the crystal structures of four compounds (3, 5a, 5c, and 5i) were determined using X-ray diffraction. Compound 3 and a series of acetamide derivatives that contain the 1,2,4-triazole heterocycle 5a-i were evaluated for their ability to inhibit the enzyme α-glucosidase. All compounds demonstrated good inhibition activity with IC 50 values ranging from 0.11 ± 0.04 µM to 21.89 ± 1.28 µM, and were found to be more active than the positive control Voglibose (IC 50 = 35.12 ± 1.69 µM). Among these compounds, compound 5b possessing a 2-methyl group on the N -phenylacetamide moiety, was found to be the most potent inhibitor in this series of derivatives with an IC 50 value of 0.11 ± 0.04 µM. Conversely, compound 5a , which lacks a substituent on the N -phenylacetamide moiety, showed the lowest activity with an IC 50 value of 21.89 ± 1.28 µM. To gain insights into the mechanism of how these compounds affect the enzyme α-glucosidase, molecular docking studies were conducted to analyze the interactions of these compounds with the active site of the enzyme. The results indicate that compounds 3 and 5a-i can bind to the binding pocket of the enzyme, and compound 5b was found to have stronger binding through the formation of hydrogen bonds with residue Arg404. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2023
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44. Oxygen-induced chromophore degradation in the photoswitchable red fluorescent protein rsCherry.
- Author
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Bui, Thi Yen Hang, De Zitter, Elke, Moeyaert, Benjamien, Pecqueur, Ludovic, Srinivasu, Bindu Y., Economou, Anastassios, Fontecave, Marc, Van Meervelt, Luc, Dedecker, Peter, and Pedre, Brandán
- Subjects
- *
MASS spectrometry , *MOIETIES (Chemistry) - Abstract
Reversibly switchable monomeric Cherry (rsCherry) is a photoswitchable variant of the red fluorescent protein mCherry. We report that this protein gradually and irreversibly loses its red fluorescence in the dark over a period of months at 4 °C and a few days at 37 °C. We also find that its ancestor, mCherry, undergoes a similar fluorescence loss but at a slower rate. X-ray crystallography and mass spectrometry reveal that this is caused by the cleavage of the p -hydroxyphenyl ring from the chromophore and the formation of two novel types of cyclic structures at the remaining chromophore moiety. Overall, our work sheds light on a new process occurring within fluorescent proteins, further adding to the chemical diversity and versatility of these molecules. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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45. Synthesis, crystal structure and evaluation of anticancer activities of some novel heterocyclic compounds based on thymol.
- Author
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Laamari, Yassine, Bimoussa, Abdoullah, Fawzi, Mourad, Oubella, Ali, Rohand, Taoufik, Van Meervelt, Luc, Ait Itto, My Youssef, Morjani, Hamid, and Auhmani, Aziz
- Subjects
- *
HETEROCYCLIC compounds , *THIOSEMICARBAZONES , *CRYSTAL structure , *THYMOL , *ANTINEOPLASTIC agents , *CELL cycle - Abstract
• Novel heterocyclic compounds was synthesized using Thymol as a starting material and characterized by HRMS, FT-IR, UV-Visible, 1H and 13C NMR and confirmed by single crystal X-ray diffraction method. • The cytotoxic activity of the novel heterocyclic compounds was evaluated on four human cancer cell lines. A series of novel 1,3,4-thiadiazole, 1,3-thiazole and 1,3-thiazolidin-4-one derivatives bearing thymol were synthesized via cyclization of the corresponding thiosemicarbazones with acetic anhydride, ethyl bromoacetate, dimethyl acetylene dicarboxylate and phenacyl bromides. The structures of the newly synthesized compounds have been confirmed by IR, 1H NMR, 13C NMR, HRMS and single crystal X-ray diffraction analyses. All new thiosemicarbazones and their heterocyclic derivatives were evaluated for their in vitro cytotoxicity against four selected human cancer cell lines, namely, breast adenocarcinoma (MCF-7, MDA-MB- 231), lung carcinoma (A-549) and fibrosarcoma (HT-1080) cell line and compared with reference drug doxorubicine. The data illustrate that most target compounds show moderate to high cytotoxicity activities against the four human cancer cell lines. Especially, thiosemicarbazones 4b showed significant cytotoxicity on HT-1080 and A-549 cancer cell line with an IC 50 values of 7.10 ± 0.32 and 14.40 ± 0.36 µM, respectively. Notably, induction of apoptosis by the compound 4b on HT-1080 and A-549 cells was evaluated using different staining techniques such as annexin V-FITC/PI. Moreover, flow-cytometric analysis also revealed that compound 4b caused arrest at the G2/M phase of the cell cycle and caspase-dependent apoptosis in HT-1080 and A-549 cells. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. Crystal structure of apatite type Ca2.49Nd7.51(SiO4)6O1.75.
- Author
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Thu Hoai Le, Brooks, Neil R., Binnemans, Koen, Blanpain, Bart, Muxing Guo, and Van Meervelt, Luc
- Subjects
- *
APATITE synthesis , *CALCIUM compounds , *X-ray powder diffraction - Abstract
The title compound, Ca2+xNd8-x(SiO4)6O2-0.5x (x = 0.49), was synthesized at 1873K and rapidly quenched to room temperature. Its structure has been determined using single-crystal X-ray diffraction and compared with results reported using neutron and X-ray powder diffraction from samples prepared by slow cooling. The single-crystal structure from room temperature data was found to belong to the space group P63/m and has the composition Ca2.49Nd7.51(SiO4)6O1.75 [dicalcium octaneodymium hexakis(orthosilicate) dioxide], being isotypic with natural apatite and the previously reported Ca2Nd8(SiO4)6O2 and Ca2.2Nd7.8(SiO4)6O1.9. The solubility limit of calcium in the equilibrium state at 1873K was found to occur at a composition of Ca2+xNd8-x(SiO4)6O2-0.5x, where x = 0.49. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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47. Structure–function dataset reveals environment effects within a fluorescent protein model system
- Author
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Alison G. Tebo, Sam Duwé, Peter Dedecker, Luc Van Meervelt, Siewert Hugelier, Elke De Zitter, Wim Vandenberg, Groupe Dynamique et Cinétique des processus moléculaires (IBS-DYNAMOP), Institut de biologie structurale (IBS - UMR 5075), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Department of Chemistry [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Hasselt University (UHasselt), Janelia Research Campus [Ashburn] (HHMI Janelia), Howard Hughes Medical Institute (HHMI), European Project: 714688,NanoCellActivity, Tebo, Alison/0000-0003-0788-5617, Duwe, Sam/0000-0003-3768-1877, Van, Meervelt, Luc/0000-0003-2186-5209, Vandenberg, Wim/0000-0002-5888-9100, Dedecker, Peter/0000-0002-1882-2075, De Zitter, Elke, Hugelier, Siewert, DUWE, Sam, Vandenberg, Wim, Tebo, Alison G., Van Meervelt, Luc, and Dedecker, Peter
- Subjects
Models, Molecular ,Structure-Function Relationships ,Polarity (physics) ,fluorescent proteins ,Protein Conformation ,Crystal structure ,010402 general chemistry ,01 natural sciences ,Catalysis ,biophysics ,0103 physical sciences ,Molecule ,function relationships ,Spectroscopy ,ComputingMilieux_MISCELLANEOUS ,structure– ,010304 chemical physics ,[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM] ,010405 organic chemistry ,Hydrogen bond ,Chemistry ,Hydrogen Bonding ,General Chemistry ,Protein engineering ,General Medicine ,photochromism ,Fluorescence ,Photochromism ,0104 chemical sciences ,[SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics ,Luminescent Proteins ,Principal component analysis ,Biological system - Abstract
Anisotropic environments can drastically alter the spectroscopy and photochemistry of molecules, leading to complex structure-function relationships. We examined this using fluorescent proteins as easy-to-modify model systems. Starting from a single scaffold, we have developed a range of 27 photochromic fluorescent proteins that cover a broad range of spectroscopic properties, including the determination of 43 crystal structures. Correlation and principal component analysis confirmed the complex relationship between structure and spectroscopy, but also allowed us to identify consistent trends and to relate these to the spatial organization. We find that changes in spectroscopic properties can come about through multiple underlying mechanisms, of which polarity, hydrogen bonding and presence of water molecules are key modulators. We anticipate that our findings and rich structure/spectroscopy dataset can open opportunities for the development and evaluation of new and existing protein engineering methods. We are grateful to Gerrit Groenhof (University of Jyvaskyla), Jeremy Harvey (KU Leuven), Raffaele Vitale (Universite de Lille), and Dominique Bourgeois (Institut de Biologie Structurale) for critical insights and discussion. E.D.Z. and L.V.M. thank the beamline staff from X06DA at the Swiss Light Source (Villigen, Switzerland), Proxima1 and Proxima2A at synchrotron Soleil (Gif-sur-Yvette, France), XRD1 at Elettra (Trieste, Italy) and I03 at Diamond Light Source (Oxfordshire, UK) for assistance during X-ray diffraction data collection. E.D.Z., S.H., and S.D. thank the Research Foundation Flanders (FWO) for a doctoral fellowship and postdoctoral fellowships (12X7919N and 12R2817N). This work was supported through funding from the Research Foundation Flanders through grants 1514319 N, G090819N, G0B8817N, and the European Research Council through grant 714688 NanoCellActivity. Dedecker, P (corresponding author), Katholieke Univ Leuven, Dept Chem, Celestijnenlaan 200G Box 2403, B-3001 Leuven, Belgium. peter.dedecker@kuleuven.be
- Published
- 2021
48. New gem‑dichlorocyclopropane-pyrazole hybrids with monoterpenic skeleton: Synthesis, crystal structure, cytotoxic evaluation, molecular dynamics and theoretical study.
- Author
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Oubella, Ali, Laamari, Yassine, Hachim, Mouhi Eddine, Byadi, Said, Auhmani, Aziz, Morjani, Hamid, Riahi, Abdelkhalek, Podlipnik, Crtomir, Rohand, Taoufik, Van Meervelt, Luc, and Ait Itto, My Youssef
- Subjects
- *
MOLECULAR dynamics , *THIOSEMICARBAZONES , *PHASE-transfer catalysis , *CRYSTAL structure , *MOLECULAR docking , *BREAST , *LUNGS , *RING formation (Chemistry) - Abstract
• New gem‑dichlorocyclopropane-pyrazole hybrids were synthesized diastereoselectively. • A theoretical study was carried out to explain the non-reactivity of the hybrids towards thiosemicarbazide. • The newly synthesized hybrids revealed interesting antiproliferative activities. • Molecular docking and molecular dynamics confirmed the empirical test results. A new series of four gem -dichlorocyclopropane-pyrazole hybrids 3a-d have been synthesized from (R)-carvone, using a two-step procedure consisting of dichlorocyclopropanation under phase transfer catalysis conditions followed by a 1,3-dipolar cycloaddition reaction of the obtained cyclopropanic product with diarylnitrilimines. The structure of the target products 3a-d was fully established via spectroscopic analysis (1H- & 13C NMR and HRMS) as well as an X-ray crystallographic study carried out on compound 3d An attempt to prepare the corresponding thiosemicarbazones was unsuccessful. So, a succinct theoretical study was carried out to explain the non-reactivity of the hybrids 3a-d vis a vis thiosemicarbazide. Furthermore, all the compunds were evaluated for their anticancer activity against HT-1080 fibrosarcoma, breast adenocarcinoma (MCF-7 and MDA-MB231), and lung carcinoma A-549 cells. The four newly synthesized compounds (3a-d) exhibited interesting antiproliferative activities with IC 50 values ranging from 25.78 ± 0.24 µM to 37.13 ± 0.47 µM. Molecular docking and molecular dynamics confirmed the empirical test results and confirmed the stability of the complex during inhibition of the anti-apoptotic protein for killing cancer cells. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. 8-HaloBODIPYsand Their 8-(C, N, O,S) Substituted Analogues: Solvent Dependent UV–Vis Spectroscopy,Variable Temperature NMR, Crystal Structure Determination, and QuantumChemical Calculations.
- Author
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Boens, Noël, Wang, Lina, Leen, Volker, Yuan, Peijia, Verbelen, Bram, Dehaen, Wim, Van der Auweraer, Mark, De Borggraeve, Wim D., Van Meervelt, Luc, Jacobs, Jeroen, Beljonne, David, Tonnelé, Claire, Lazzaroni, Roberto, Ruedas-Rama, Maria J., Orte, Angel, Crovetto, Luis, Talavera, Eva M., and Alvarez-Pez, Jose M.
- Subjects
- *
BORON compounds , *HALOGENATION , *SUBSTITUTION reactions , *SOLVENTS , *CRYSTAL structure , *QUANTUM chemistry , *ULTRAVIOLET-visible spectroscopy , *NUCLEAR magnetic resonance spectroscopy - Abstract
The UV–vis electronic absorptionand fluorescence emissionproperties of 8-halogenated (Cl, Br, I) difluoroboron dipyrrin (or8-haloBODIPY) dyes and their 8-(C, N, O, S) substituted analoguesare reported. The nature of the meso-substituenthas a significant influence on the spectral band positions, the fluorescencequantum yields, and lifetimes. As a function of the solvent, the spectralmaxima of all the investigated dyes are located within a limited wavelengthrange. The spectra of 8-haloBODIPYs display the narrow absorptionand fluorescence emission bands and the generally quite small Stokesshifts characteristic of classic difluoroboron dipyrrins. Conversely,fluorophores with 8-phenylamino (7), 8-benzylamino (8), 8-methoxy (9), and 8-phenoxy (10) groups emit in the blue range of the visible spectrum and generallyhave larger Stokes shifts than common BODIPYs, whereas 8-(2-phenylethynyl)BODIPY(6) has red-shifted spectra compared to ordinary BODIPYdyes. Fluorescence lifetimes for 6, 8, and 10have been measured for a large set of solvents and thesolvent effect on their absorption and emission maxima has been analyzedusing the generalized Catalán solvent scales. Restricted rotationabout the C8–N bond in 7and 8hasbeen observed via temperature dependent 1H NMR spectroscopy,whereas for 10the rotation about the C8–O bondis not hindered. The crystal structure of 8demonstratesthat the short C8–N bond has a significant double characterand that this N atom exhibits a trigonal planar geometry. The crystalstructure of 10shows a short C8–O bond and anintramolecular C–H···π interaction. Quantum-chemicalcalculations have been performed to assess the effect of the meso-substituent on the spectroscopic properties. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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- View/download PDF
50. Synthesis, spectroscopic characterization, DFT, molecular docking and in vitro antibacterial potential of novel quinoline derivatives.
- Author
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Bouzian, Younos, Sert, Yusuf, Khalid, Karrouchi, Van Meervelt, Luc, Chkirate, Karim, Mahi, Lhassane, Ahabchane, Noureddine Hamou, Talbaoui, Ahmed, and Essassi, El Mokhtar
- Subjects
- *
MOLECULAR docking , *ANTIBACTERIAL agents , *FRONTIER orbitals , *ENTEROCOCCUS faecalis , *ELECTRIC potential , *QUINOLINE derivatives , *QUINOLINE - Abstract
• Three novel quinoline derivatives were synthesized and characterized by FT-IR, 1H NMR, 13C NMR and single-crystal XRD. • DFT calculations were performed. • Hirshfeld surfaces analysis was investigated. • The title compounds were also evaluated in vitro for their antibacterial activities. • Molecular docking studies between the title molecules and 2ZCQ protein were performed. In this work, three new quinolone derivatives were prepared by alkylation of 2-oxo-1,2-dihydroquinoline-4-carboxylic acid with ethyl 2-bromoacetate. The synthesized compounds 2-4 were characterized by using FT-IR, 1H NMR, 13C NMR and mass spectrometry. Crystal structure of 4 was determined by single crystal X-ray diffraction. The optimized structures of 2-4 in gas phase, 1H and 13C NMR chemical shifts, molecular electrostatic potential (MEP), frontier orbitals and non-linear properties (NLO) have been investigated by using the B3LYP/6-311++G(d,p) method. All compounds were evaluated in vitro for their antibacterial activities against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC4157, Streptococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 25923 bacterial strains. The tested compounds exhibited a good to moderate antibacterial activity with MIC values between 6.25 and 50 μg/mL, when compared to references Ampicillin and Chloramphenicol. Among the three compounds, compound 4 showed the most potent antibacterial activity against S. aureus with MIC value of 6.25 μg/mL. In addition, molecular docking studies of compounds 2-4 were performed within the active site of PDB: 2ZCQ protein to analyze the binding interactions responsible for their activities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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