Showing papers by "Oscar E. Piro published in 2019"
TL;DR: In this paper, the tridentate N-acyhydrazone derived from 4-hydroxy-benzohydrazide and 2-hydroxyl-3-methoxybenzaldehyde (H2L) was synthesized and characterized in the solid state and in solution by spectroscopic (FTIR, Ra, UV-vis, EPR) methods.
34 citations
TL;DR: In this paper, an N,N,O,O donor base blocking ligand has been used to synthesize mononuclear [CuL]·H2O (2) and [VO(L)] (3) complexes.
Abstract: An N,N,O,O donor Schiff base blocking ligand [H2L = 6,6′-((1E,1′E)-(ethane-1,2-diylbis(azaneylylidene))bis(methaneylylidene))bis(3-(diethylamino)phenol), 1] has been used to synthesize mononuclear [CuL]·H2O (2) and [VO(L)] (3) complexes. The ligand and complexes have been characterized by elemental, spectral (FTIR and UV-vis) and thermogravimetric analysis. The molecular structures of 1 and 2 have been confirmed by single crystal X-ray diffraction studies. The crystal structure of the ligand (1) indicates that the molecule is sited on a crystallographic inversion centre and the planar conformation of the salicylideneimine moiety is favored by two intramolecular O–H⋯N1 hydrogen bonds forming S(6) ring motifs. The copper(II) center in complex 2 is coordinated in a square planar fashion. The presence of an extended π-system in the complex (two chelate rings and two phenyl rings) facilitates the formation of chelate ring (CR)⋯π non-covalent interactions. DFT calculations have been performed to explore the energetic features of unconventional CR⋯π and hydrogen bonding interactions that are observed and described in the solid state of 2. Moreover, we have studied how the energy of the CR⋯π interaction is influenced by the substituent of the phenyl ring. In addition, the cytotoxic effect of the compounds has been tested against MG-63 (human osteosarcoma), HT-29 (human colorectal) and MCF7 (breast) cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.
18 citations
TL;DR: The keto-enamino form, in which the keto group integrate a cyclohexadienone moiety and the aromaticity of the phenol is loss, was the only tautomer in the crystal lattice according to single-crystal X-ray diffraction, vibrational spectroscopy, and diffuse reflectance results.
Abstract: The strange tautomeric equilibrium behavior exhibited by a new o-hydroxyphenyl diazepine derivative when the compound is analyzed both in solution and solid state opens the structural study of the enol-imino-keto-enamine forms and the influence of the intermolecular interactions in their equilibrium. The expected enol-imino form, in which the enol is part of a phenyl system and a strong O-H···N intramolecular hydrogen bond is established, results the most stable tautomer in gas phase (theoretical calculations) and was detected by NMR spectroscopy when the compound was dissolved in aprotic solvents. Nevertheless, the keto-enamine form ,in which the keto group integrates a cyclohexadienone moiety and the aromaticity of the phenol is lost, was the only tautomer in the crystal lattice according to single-crystal X-ray diffraction, vibrational spectroscopy, and diffuse reflectance results. The last form was also found as the main tautomer in UV-vis and NMR spectroscopy when a protic solvent was employed.
16 citations
TL;DR: In this article, the crystal structure of the cobalt(II) complex, for short [Co(SDZ)2(DMF)2], was determined by X-ray diffraction methods.
16 citations
TL;DR: The most active and selective compound of the new series showed no in vivo toxicity in zebrafish embryos, and the inclusion of the organometallic co-ligand led to lower toxicity in mammalian cells and higher selectivity towards both parasites when compared to the free HL compounds.
Abstract: In the search for a more effective chemotherapy for the treatment of Chagas’ disease and human African trypanosomiasis, caused by Trypanosoma cruzi and Trypanosoma brucei parasites, respectively, the use of organometallic compounds may be a promising strategy. In this work, eight new heterobimetallic compounds are described including four 5-nitrofuryl containing thiosemicarbazones as bioactive ligands (HL1–HL4) and dppf = 1,1′-bis(diphenylphosphino) ferrocene as an organometallic co-ligand. Complexes of the formula [MII(L)(dppf)](PF6) with M = Pd or Pt were synthesized and fully characterized in the solid state and in solution, including the determination of the molecular structure of four of them by single crystal X-ray diffraction methods. Most compounds showed activity in the low micromolar or submicromolar range against both parasites, with the platinum compounds being more active than the palladium analogues. Activity was significantly increased by generation of the M-dppf compounds (3–24 fold increase with respect to free ligands HL for T. cruzi and up to 99 fold increase with respect to HL for T. brucei). The inclusion of the organometallic co-ligand also led to lower toxicity in mammalian cells and higher selectivity towards both parasites when compared to the free HL compounds. The complexes interact with DNA and affect the redox metabolism of the parasites. Furthermore, the most active and selective compound of the new series showed no in vivo toxicity in zebrafish embryos.
11 citations
TL;DR: In this paper, two new acylthiourea derivatives (Ar-CO, NH-CS-NH-R) were derived from X-ray, NMR, UV-Vis, Raman and IR spectroscopy.
9 citations
TL;DR: In this paper, two new thiourea derivatives, substituted with 2-trifluoromethyl-4H-chromen-3-yl moieties at defined positions, were obtained by convenient synthetic methodologies.
Abstract: Two new thiourea (1) and urea (2) derivatives, substituted with 2-trifluoromethyl-4H-chromen-3-yl moieties at defined positions, were obtained by convenient synthetic methodologies. The pure compou...
7 citations
TL;DR: In this paper, the crystal structure of 2-(difluoromethyl)-3-methylchromone and 3-methyl-2-(perfluoroethyl)chromone determined by X-ray diffraction methods were used to calculate their intermolecular interactions and crystal lattice energies.
Abstract: The novel 2-(difluoromethyl)-3-methylchromone, 2-(dichloromethyl)-3-methylchromone, and 3-methyl-2-(perfluoroethyl)chromone were synthesized by a one-pot method and characterized through MS spectrometry, cyclic voltammetry, and vibrational (IR, Raman), UV–Vis, fluorescence, and NMR (1H, 13C, and 19F) spectroscopy. The crystal structure of 2-(difluoromethyl)-3-methylchromone and 2-(dichloromethyl)-3-methylchromone determined by X-ray diffraction methods were used to calculate their intermolecular interactions and crystal lattice energies together with the Hirshfeld surface analysis.
4 citations
TL;DR: In this paper, the 1-4-dihydropyridine moiety of the ligand was oxidized to pyridine and its copper(II) complex [Cu(oxntd)2Cl2] (Cuoxntp), has been obtained.
2 citations
TL;DR: Isatin in a solution of dry N,N-dimethylformamide/NaClO4 is electroreduced in the presence of CH3I and N-methylisatoic anhydride is obtained in quantitative molar yield and high current efficiency by controlled potential electrolysis (CPE).
Abstract: Fil: Martinez Suarez, Jaime Fernando. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas; Argentina
1 citations
TL;DR: The solid state molecular structure of dilapacholate diaquo cobalt (II) di-dimethylformamide, for short [Co(Lap)2(H2O)2]·2DMF, was determined by X-ray diffraction methods as discussed by the authors.