Immunomodulatory effects of palladium(II) complexes of 1,2,4-triazole on murine peritoneal macrophages

Abstract

Os complexos polinucleares [{PdCl 2 (µ-Htrz)} n ] (1) e [{PdBr 2 (µ-Htrz)} n ] (2) (Htrz = 1,2,4-triazol) foram sintetizados neste trabalho. O composto 1 foi preparado a partir da substituição da acetonitrila do precursor [PdCl 2 (MeCN) 2 ] pelo 1,2,4-triazol. A adição posterior de brometo de potássio ao meio reacional resultou na formação do complexo 2. Os complexos inéditos foram isolados, purificados e caracterizados por análise elementar, espectroscopias vibracional no infravermelho e eletrônica no UV-visível e curvas de análise termogravimétrica (TG). Os resultados experimentais sugerem que, em ambos os casos, a coordenação do 1,2,4-Htrz ocorra via átomos N(2) e N(4), atuando como pontes entre centros de paládio. O poliedro de coordenação quadrado-planar ao redor do paládio(II) é determinado pelos dois átomos de N do heterociclo e por dois ligantes cloro (1) ou bromo (2), em uma provável configuração trans. As curvas TG indicaram que a natureza do ligante aniônico não afeta significativamente a estabilidade térmica de 1 e 2. Os produtos finais de decomposição térmica foram identificados como paládio metálico pela técnica de difratometria de raios X de pó. Testes preliminares envolvendo a avaliação dos efeitos dos compostos 1, 2 e Htrz na produção de H 2 O 2 e NO em culturas de macrófagos peritoneais de camundongos BALB/c foram realizados in vitro.The 1,2,4-triazolyl-bridged polynuclear complexes [{PdCl 2 (µ-Htrz)} n ] (1) and [{PdBr 2 (µ-Htrz)} n ] (2) have been obtained in this work. Compound 1 is prepared by the displacement of acetonitrile from [PdCl 2 (MeCN) 2 ] by 1,2,4-triazole (Htrz). Further addition of potassium bromide to the reaction medium afforded complex 2. The new complexes have been isolated, purified and characterized by means of elemental analysis, IR and UV-visible electronic spectroscopies and thermogravimetric (TG) curves. The experimental data suggested that, in both cases, the coordination of 1,2,4-Htrz takes place through the N(2) and N(4) atoms, bridging the palladium centers. The square-planar coordination polyhedron of palladium(II) is determined by two nitrogen atoms from the triazole ligands, while the other two coordination positions are occupied by the chloro (1) or bromo (2) ligands. TG curves indicated that the nature of the anionic ligand does not affect significantly the thermal stability of 1 and 2. The final products of the thermal decompositions were identified as metallic palladium by X-ray powder diffractometry. Preliminary tests involving the evaluation of the effects of compounds 1, 2 and Htrz on H 2 O 2 and NO production in cultures of peritoneal macrophages from BALB/c mice were carried out in vitro.

Pyrazolyl Pd(II) complexes containing triphenylphosphine: Synthesis and antimycobacterial activity

“…The precursor [PdCl 2 (MeCN) 2 ] was prepared as previously described [25]. Pyrazolyl ligands and triphenylphosphine were purchased from Sigma Aldrich or Merck.…”

Synthesis of Calixarene‐Based Bis(iminophosphoranes) and Their Use in Suzuki–Miyaura Cross‐Coupling

“…5,17-Bis(diphenylphosphanyl)-25,26,27,28-tetrabenzyloxycalix [4]arene (1), [37] [AuCl(THT)] [38] and [PdCl 2 (MeCN) 2 ] [39] were prepared according to literature procedures. Solvents were dried by conventional methods and distilled immediately prior to use.…”

3,5-Dimethyl-1-thiocarbamoylpyrazole and its Pd(II) complexes: Synthesis, spectral studies and antitumor activity

“…All solvents were dried and stored over molecular sieves prior to use. Literature procedures were followed for the synthesis of 1-thiocarbamoyl-3,5-dimethylpyrazole (tdmPz) [29] and [PdCl 2 (MeCN) 2 ] [30].…”