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1.
Univ. sci ; 23(2): 141-169, May-Aug. 2018. tab, graf
Article in English | LILACS, COLNAL | ID: biblio-979543

ABSTRACT

Abstract This paper reports the synthesis and detailed characterization of six novel lanthanide complexes of La(III), Eu(III) and Nd(III) with N(4)-substituted thiosemicarbazones derived from the 2-carboxybenzaldehyde. The IR, 1H-NMR and 13C-NMR spectroscopic studies confirmed the coordination of the thiocarbonyl (C=S), azomethine (C=N) and carboxylate (COO-) groups to the metal centers, and the carboxylate was coordinated in a bidentate manner. The elemental and thermal analyses suggest that lanthanide complexes were formed in 1:2 molar ratios (metal:ligand). The molar conductivity values confirmed the non-electrolytic nature of the complexes. The interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by UV absorption and viscosity measurements. It was found that the Eu(HI) and Nd(nI) complexes could roll along the DNA strands through groove interactions. Furthermore, lanthanide complexes could promote the oxidative cleavage of plasmid pBR322 in a high-oxidative stress environment. Finally, the Schiff base ligands (L) and their complexes were evaluated for their antibacterial activities against gram-positive and gram-negative bacteria using a microdilution procedure. The results indicate that the lanthanide complexes exhibit more potent antibacterial activity than the free ligands.


Resumen Este articulo reporta la síntesis y caracterización detallada de seis nuevos complejos lantánidos de La(III), Eu(III) y Nd(III) con tiosemicarbazonas N(4)-sustituidas derivadas del 2-carboxibenzaldehído. Los estudios espectroscópicos de IR, 1H-NMR y 13C-NMR confirmaron la coordinación de los grupos tiocarbonilo (C=S), azometina (C=N) y carboxilato (COO-) a los centros metálicos, y el carboxilato se coordinó de forma bidentada. Los análisis elemental y térmico sugieren que los complejos lantánidos se formaron en proporciones molares 1:2 (metal:ligando). Los valores de conductividad molar confirmaron la naturaleza no eléctrica de los complejos. Por medio de medidas de absorción UV y de viscosidad se investigó la interacción entre estos complejos con DNA de timo de ternera (CT-DNA). Se encontró que los complejos Eu(III) y Nd(III) podrían correr a lo largo de cadenas de DNA a través de interacciones en el surco. Además, los complejos lantánidos podrían promover el clivaje oxidativo del plásmido pBR322 en un ambiente de alto estrés oxidativo. Finalmente, se evaluaron las actividades antibacteriales de las bases de Schiff como ligandos (L) y sus complejos contra bacterias gram-positivas y gram-negativas usando un procedimiento de microdilución. Los resultados indican que los complejos lantánidos exhiben una actividad antibacterial más potente que los ligandos libres.


Resumo Este artigo reporta a síntese e caracterização detalhada de seis novos complexos lantanídeos de La(III), Eu(III) e Nd(III) com tiosemicarbazonas N(4)-substituídas derivadas do 2-carboxibenzaldeído. Os estudos espectroscópicos de IR, 1H-RMN e 13C-RMN confirmaram a coordenação dos grupos tiocarbonilos (C = S), azometina (C=N) e carboxilato (COO-) com os centros metálicos, e o carboxilato se coordenou de forma bidentada. As análises elementares e térmicas sugerem que os complexos lantanídeos se formaram em proporções molares 1:2 (metal:ligante). Os valores de condutividades molar confirmaram a natureza não-elétrica dos complexos. Se avaliou a interação entre estes complexos com DNA de vitela (CT-DNA) por meio de medidas de absorção UV e de viscosidade. Se observou que os complexos Eu(III) e Nd(III) poderiam deslocar-se ao longo da cadeia de DNA através de interações no sulco. Adicionalmente, os complexos lantanídeos poderiam promover a clivagem oxidativa do plasmídeo pBR322 em um ambiente de alto estresse oxidativo. Finalmente, se avaliaram as atividades antibacterianas das bases de Schiff como ligantes (L) e seus complexos contra bactérias gram-positivas e gram- negativas, usando o método de microdiluição. Os resultados indicam que os complexos lantanídeos exibem uma atividade antibacteriana mais potente que os ligantes livres.


Subject(s)
Thiosemicarbazones , DNA , Lanthanoid Series Elements/chemistry , Anti-Bacterial Agents
2.
Braz. j. med. biol. res ; 51(3): e7050, 2018. tab, graf
Article in English | LILACS | ID: biblio-889043

ABSTRACT

A new microporous lanthanide metal-organic framework, {[Yb(BTB)(H2O) (DEF)2}n (1, DEF=N,N-Diethylformamide), with 1D nano-sized channels has been constructed by bridging helical chain secondary building units with 1,3,5-benzenetrisbenzoic acid (H3BTB) ligand. Structural characterization suggests that this complex crystallizes in the hexagonal space group P6122 and possesses 1D triangular channels with coordinated water molecules pointing to the channel center. In addition, anti-myocarditis properties of compound 1 were evaluated in vivo. The results showed that compound 1 can improve hemodynamic parameters of, and it may be a good therapeutic option for heart failure in the future.


Subject(s)
Animals , Male , Mice , Anti-Inflammatory Agents/chemistry , Crystallography, X-Ray , Lanthanoid Series Elements/chemistry , Metal-Organic Frameworks/chemistry , Myocarditis/therapy , Anti-Inflammatory Agents/therapeutic use , Metal-Organic Frameworks/therapeutic use , Models, Molecular , Powder Diffraction , Thermogravimetry , X-Ray Diffraction
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