Estudio del comportamiento coordinante del 1-naftaldehido isonicotinoil hidrazona hacia el pt(II) mediante métodos espectroscópicos y simulaciones computacionales

Las acilhidrazonas muestran una amplia variedad de modos de coordinación con varios tipos de iones metálicos, donde las isomerías de conformación y configuración; además del número y el tipo de los sustituyentes del ligando; influyen en su denticidad y en su capacidad coordinante. La presente tesis estudia el comportamiento coordinante del ligando 1- Naftaldehído isonicotinoil hidrazona (L) hacia el Pt(II) mediante métodos espectroscópicos y simulaciones computacionales. Para realizar este estudio, se sintetizó el ligando orgánico y su respectivo complejo de Pt (II), a los cuales se realizaron los análisis espectroscópicos experimentales (FT-IR, 1H-RMN, UV-Vis y MS) y se complementaron con las simulaciones computacionales (Análisis poblacional y análisis de reactividad). La información obtenida a partir del análisis espectroscópico y computacional muestra al ligando orgánico en una mezcla isomérica cisE/transE, donde el arreglo mayoritario en fase solvente es el transE. En el complejo, el ligando se encuentra desprotonado (L-1H) en su arreglo transE y monocoordinado al Pt(II) a través del átomo de oxígeno (O8) de la amida, y comparte la esfera de coordinación, en fase gas, con 3 ligandos cloro provenientes de la sal de síntesis, generando un complejo teórico [Pt(Cl)3(L-1H)]2- . En fase solvente, el ligando comparte la esfera de coordinación con un ligando cloro y dos moléculas de DMSO, generando un complejo de geometría cuadrada plana [Pt(Cl)(L-1H)(DMSO)2], forma explicada a través de la complementariedad de los resultados de los análisis espectroscópicos y estudios teóricos computacionales. Este estudio aporta información relevante para conocer el comportamiento coordinante del 1-Naftaldehído isonicotinoil hidrazona frente al Pt(II)

Phenylisoxazole-3/5-Carbaldehyde Isonicotinylhydrazone Derivatives: Synthesis, Characterization, and Antitubercular Activity

14 pags, 5 figs, 3 tabs, 1 schEight new phenylisoxazole isoniazid derivatives, 3-(2′-fluorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (1), 3-(2′-methoxyphenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (2), 3-(2′-chlorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (3), 3-(3′-clorophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (4), 3-(4′-bromophenyl)isoxazole-5-carbaldehyde isonicotinylhydrazone (5), 5-(4′-methoxiphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (6), 5-(4′-methylphenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (7), and 5-(4′-clorophenyl)isoxazole-3-carbaldehyde isonicotinylhydrazone (8), have been synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR, and mass spectral data. The 2D NMR (1H-1H NOESY) analysis of 1 and 2 confirmed that these compounds in acetone-d6 are in the trans(E) isomeric form. This evidence is supported by computational calculations which were performed for compounds 1-8, using DFT/B3LYP level with the 6-311++G(d,p) basis set. The in vitro antituberculous activity of all the synthesized compounds was determined against the Mycobacterium tuberculosis standard strains: sensitive H37Rv (ATCC-27294) and resistant TB DM97. All the compounds exhibited moderate bioactivity (MIC = 0.34-0.41 μM) with respect to the isoniazid drug (MIC = 0.91 μM) against the H37Rv sensitive strain. Compounds 6 (X = 4′-OCH3) and 7 (X = 4′-CH3) with MIC values of 12.41 and 13.06 μM, respectively, were about two times more cytotoxic, compared with isoniazid, against the resistant strain TB DM97.W. H. and F. C. acknowledge Universidad de Lima Scientific Research Institute for the financial support to carry out this research work. E. S. thanks Financiamiento Basal para Centros Cientificos y Tecnologicos de Excelencia, AFB10008. J. Z. D. thanks Consejo Superior de Investigacion Cientifica (CSIC, Spain). S. O. thanks Ministerio de Ciencias, Innovacion y Universidades (MICINN (RTI2018-094356-B-C21)) and Cabildo de Tenerife (Agust ' in de Betancourt Program).Peer reviewe

Indole-3-carbaldehyde Semicarbazone Derivatives: Synthesis, Characterization, and Antibacterial Activities

9 pags., 2 figs., 2 tabs.Four indole-3-carbaldehyde semicarbazone derivatives, 2-((5-bromo-1H-indol-3-yl)methylene)hydrazinecarboxamide (1), 2-((5-chloro-1H-indol-3-yl)methylene)hydrazinecarboxamide (2), 2-((5-methoxy-1H-indol-3-yl)methylene)hydrazinecarboxamide (3), and 2-((4-nitro-1H-indol-3-yl)methylene)hydrazinecarboxamide (4) were synthesized and characterized by ESI-MS and spectroscopic (FT-IR, H NMR, and C NMR) techniques. The two-dimensional NMR (in acetone-d) spectral data revealed that the molecules 1 and 2 in solution are in the cisE isomeric form. This evidence is supported by DFT calculations at the B3LYP/6-311++G(d,p) level of theory where it was shown that the corresponding most stable conformers of the synthesized compounds have a cisE geometrical configuration, in both the gas and liquid (acetone and DMSO) phases. The in vitro antibacterial activity of compounds 1-4 was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Among all the tested semicarbazones, 1 and 2 exhibited similar inhibitory activities against Staphylococcus aureus (MIC = 100 and 150 μg/mL, respectively) and Bacillus subtilis (MIC = 100 and 150 μg/mL, respectively). On the other hand, 3 and 4 were relatively less active against the tested bacterial strains compared with 1, 2, and tetracycline.W. H. and F. C. thank the Universidad de Lima Scientific Research Institute for financial support to carry out this research work. E. S. thanks Financiamiento Basal para Centros Cientıficos y Tecnologicos de Excelencia, FB0807. ´ J. Z. D. thanks the Consejo Superior de Investigacion´ Cientıfica (CSIC) of Spain. S.O. thanks the Ministry of Science, Innovation, and Universities (MICINN (RTI2018- 094356-B-C21) as well as the Cabildo de Tenerife (Agustın de Betancourt Program) for financial support

Indole-3-carbaldehyde Semicarbazone Derivatives: Synthesis, Characterization, and Antibacterial Activities

The two-dimensional NMR (in acetone-d6) spectral data revealed that the molecules 1 and 2 in solution are in the cisE isomeric form. This evidence is supported by DFT calculations at the B3LYP/6-311++G(d,p) level of theory where it was shown that the corresponding most stable conformers of the synthesized compounds have a cisE geometrical configuration, in both the gas and liquid (acetone and DMSO) phases. The in vitro antibacterial activity of compounds 1-4 was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Among all the tested semicarbazones, 1 and 2 exhibited similar inhibitory activities against Staphylococcus aureus (MIC = 100 and 150 µg/mL, respectively) and Bacillus subtilis (MIC = 100 and 150 µg/mL, respectively). On the other hand, 3 and 4 were relatively less active against the tested bacterial strains compared with 1, 2, and tetracycline. © 2020 Fernando Carrasco et al