Synthesis, characterization, and in vitro cytotoxic activities of benzaldehyde thiosemicarbazone derivatives and their palladium(II) and platinum(II) complexes against various human tumor cell lines

The palladium (II) bis-chelate Pd (L 1 - 3) 2 and platinum (II) tetranuclear Pt 4 (L 4) 4 complexes of benzaldehyde thiosemicarbazone derivatives have been synthesized, and characterized by elemental analysis and IR, FAB (+) -mass and NMR (1 H, 13 C) spectroscopy. The complex Pd (L 2) 2 [H L 2 = m -CN-benzaldehyde thiosemicarbazone] shows a square-planar geometry with two deprotonated ligands (L) coordinated to Pd II through the nitrogen and sulphur atoms in a transarrangement, while the complex Pt 4 (L 4) 4 [H L 4 = 4 -phenyl-1-benzaldehyde thiosemicarbazone] has a tetranuclear geometry with four tridentate ligands coordinated to four Pt II ions through the carbon (aromatic ring), nitrogen, and sulphur atoms where the ligands are deprotonated at the NH group. The in vitro antitumor activity of the ligands and their complexes was determined against different human tumor cell lines, which revealed that the palladium (II) and platinum (II) complexes are more cytotoxic than their ligands with IC 50 values at the range of 0.07-3.67 µM. The tetranuclear complex Pt 4 (L 4) 4, with the phenyl group in the terminal amine of the ligand, showed higher antiproliferative activity (CI 50 = 0.07-0.12 µM) than the other tested palladium (II) complexes

Synthesis and Characterization of New Palladium(II) Complexes with Ligands Derived from Furan-2-carbaldehyde and Benzaldehyde Thiosemicarbazone and their in vitro Cytotoxic Activities against Various Human Tumor Cell Lines

With the ligands 4-phenyl-1-(furan-2-carbaldehyde)thiosemicarbazone, HTSC1, (1), 4-phenyl-1- (5 -phenyl-furan-2-carbaldehyde)thiosemicarbazone, HTSC2 (2), o-methoxy-benzaldehydethiosemicarbazone, HTSC3 (3), and o-cyano-benzaldehydethiosemicarbazone, HTSC4 (4), the corresponding palladium(II) complexes, Pd(TSC1)2 (5), Pd(TSC2)2 (6), Pd(TSC3)2 (7), and Pd(TSC4)2 (8) were synthesized and characterized by elemental analysis and spectroscopic techniques. The crystal structure of Pd(TSC3)2 (7) was determined by single-crystal X-ray diffraction. Complex 7 shows a squareplanar geometry, where two deprotonated ligands are coordinated to the PdII center through the nitrogen and sulfur atoms in a trans arrangement. In vitro antitumor studies against different human tumor cell lines have revealed that the palladium(II) complexes 5– 8 are more cytotoxic (IC50 values in the range of 0.21 – 3.79 µM) than their corresponding ligands (1 – 4) (> 60 µM). These results indicate that the antiproliferative activity is enhanced when thiosemicarbazone ligands are coordinated to the metal. Among the studied palladium(II) complexes, 8 exhibits high antitumor activity on K562 chronic myelogenous leukemia cells with a low value of the inhibitory concentration (IC50 = 0.21 µM)

Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines

The palladium(II) bis-chelate complexes of the type [Pd(TSC1-5)2] (6–10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC1 (1), 4-phenyl-1-(2'-chloro-benzaldehyde)-thiosemicarbazone, HTSC2 (2), 4-phenyl-1-(3'-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC3 (3), 4-phenyl-1-(2'-naphthaldehyde)-thiosemicarbazone, HTSC4 (4), and 4-phenyl-1-(1'-nitro-2'-naphthaldehyde)-thiosemicarbazone, HTSC5 (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and 1H- and 13C-NMR). The molecular structure of HTSC3, HTSC4, and [Pd(TSC1)2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (–9.87¿M) exhibited higher antiproliferative activity than their free ligands (–70.86 and >250¿M) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC3)2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02¿M, resp.)

Nuevos materiales bioorgánicos de actividad antitumoral

El presente trabajo describe la síntesis, caracterización y evaluación de la actividad antitumoral in vitro de nuevos compuestos orgánicos derivados del 4-R-fenil-1-(X-tiazol-2/5-carbaldehído) tiosemicarbazona (R=H, fenilo; X=fenilo, o-/m-/p-OCH3-fenilo, p-Cl/F-fenilo, morfolinilo, Cl, N(CH3)2, metilo) y Xtriazol- 5-carbaldehído tiosemicarbazona (X=H, fenilo, p-Cl-fenilo). La preparación de estos compuestos se realizó mediante la reacción de condensación entre la tiosemicarbazida o 4-feniltiosemicarbazida y los derivados tiazol-2/5-carbaldehído o triazol-5-carbaldehído, para lo cual se empleó como solvente el metanol. La caracterización química se realizó mediante análisis elemental, espectrometría de masas, técnicas espectroscópicas de infrarrojo (FT-IR) y resonancia magnética nuclear (1H, 13C), y difracción de rayos X.El presente trabajo describe la síntesis, caracterización y evaluación de la actividad antitumoral in vitro de nuevos compuestos orgánicos derivados del 4-R-fenil-1-(X-tiazol-2/5-carbaldehído) tiosemicarbazona (R=H, fenilo; X=fenilo, o-/m-/p-OCH3-fenilo, p-Cl/F-fenilo, morfolinilo, Cl, N(CH3)2, metilo) y Xtriazol- 5-carbaldehído tiosemicarbazona (X=H, fenilo, p-Cl-fenilo). La preparación de estos compuestos se realizó mediante la reacción de condensación entre la tiosemicarbazida o 4-feniltiosemicarbazida y los derivados tiazol-2/5-carbaldehído o triazol-5-carbaldehído, para lo cual se empleó como solvente el metanol. La caracterización química se realizó mediante análisis elemental, espectrometría de masas, técnicas espectroscópicas de infrarrojo (FT-IR) y resonancia magnética nuclear (1H, 13C), y difracción de rayos X

Epoxidation of styrene with iodosylbenzene in the presence of copper(II) Schiff-base complexes

Copper(II) complexes with salen Schiff-base ligands derived from ethylenediamine or (S,S)-1,2-diphenylethylenediamine and salicylaldehyde or 5-methoxy, 5-bromo and 5-nitrosalicylaldehyde have been tested as catalysts for the epoxidation of styrene with iodosylbenzene, in dichoromethane as a solvent. The reactions were followed by gas chromatographic analysis and mass spectrometry. Catalytic activities were found to be dependent upon both the Lewis acidity of the metal complexes and the presence of phenyl substituents on the ethylene moiety. Moderate styrene conversions and epoxide yields were obtained. Pseudo-first-order kinetics was observed for the styrene conversion. Possible reaction mechanisms are outlined. © 2003 Elsevier Science Ltd. All rights reserved

Effect of phenanthroline substituents on the rate of oxygen uptake by copper(I) complexes

The values of the rate constant for the oxidation reaction are reported for a series of substituted bis(phenanthroline)copper(I) complexes. The rate constant increases along the series: 2,9-diCH3 phen < 5-Cl phen < phen < 5-CH3 phen < 4,7-diC6H5 phen < 5,6-diCH3 phen. A correlation is developed between the experimental rate constants obtained and the acid dissociation constants for the ligands. The reaction fits a Hammett linear free energy relationship with ρ{variant} = -0.71. The rate determining step in each reaction is attributed to the electron transfer to the oxygen molecule, which is influenced principally by changes in electron density at the metal site. © 1976

Electronic and magnetic properties of iron (III) dinuclear complexes with carboxylate bridges

A series of dinuclear iron (III) complexes with carboxylate bridges, of the type [Fe2L2(H20)4](NO 3)2(H2O)m (m=1-3), where L=Schiff base derived from L-α-amino acids and salicylaldehyde have been prepared and characterised by different spectroscopic techniques, magnetic susceptibility, conductivity, and electrochemical measurements. The dimeric iron complexes contain hexacoordinated iron (III), with the metal ion surrounded by water molecules, the salicylidenimine ligand, and the bridging carboxylate groups. The inequivalence of the iron atoms is detected by Mössbauer spectroscopy and this is reflected by the presence of two overlapping quadrupole doublets (δ1∼0.52-0.67 mms-1, δ2∼0.64-0.80 mms-1, ΔEQ1∼0. 38-0.80 mms-1, and ΔEQ2 (∼0.68-1.01 mms -1), with an approximate intensity ratio of 1:1 for all complexes. The magnetic susceptibilities of the complexes were determined over the temperature interval 5-300 K and revealed a decrease in the effective magnetic moment with decreasing temp

Síntesis y caracterización fotofísica y fotoquímica de complejos de cobre(I) con ligantes mixtos, aminas heterocíclicas (NN) y trifenilfosfina (PPh3).

El estudio fotofísico, en diclorometano (296 K), de los complejos mononucleares con ligantes mixtos del tipo [Cu(PPh3)2(NN)]ClO4* dinucleares con ligantes mixtos del tipo[Cu2(PPh3)2(NN)(NN)(4,4*-BP)] (ClO4)2 y[Cu2(NN)2(4,4*-BP)] (ClO4)2 donde NN corresponde a 2,2*-bipiridina (BP),2,2*-bipiridilamina (BPA), di(2-piridil)etano (DPE) i di(2-piridil)metano (DPM), muestra que al excitados con radiaciones de longitud de onda entre 280 y 335 nm estructuradas, entre 415 y 50 nm las que pueedn ser atribuídas a transferencia de carga metal ligante de los estados 3 d-r. Los ensayos fotoquímicos de la serie de complejos monoméricos [Cu(PPh3)2(NN)]ClO4 en presencia del oxidante ion metilviológeno permiten comprobar que todos los complejos, excepto aquel con NN=BP, son oxidados en diclorometano