title: Palladium(II) complexes of 2-benzoylpyridine-derived thiosemicarbazones: spectral characterization, structural studies and cytotoxic activity.
abstract: Palladium(II) complexes of 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N4-methyl (H2Bz4M) and N4-phenyl (H2Bz4Ph) derivatives were obtained and fully characterized. [Pd(2Bz4DH)Cl] (1) crystallizes in the monoclinic space group P21/c with a=11.671(1), b=10.405(1), c=13.124(1), beta=115.60(1) degrees and Z=4; [Pd(2Bz4M)Cl] (2) in the monoclinic space group P21/c with a=9.695(1), b=15.044(1), c=10.718(1) A, beta=105.38(1) degrees and Z=4 and [Pd(2Bz4Ph)Cl] (3) in the triclinic space group P1 with a=9.389(1), b=13.629(1), c=15.218(1) A, alpha=70.25(1), beta=73.46(1), gamma=83.57(1) degrees and two independent molecules per asymmetric unit (Z=4). All complexes show a quite similar planar fourfold environment around palladium(II). A negatively charged organic molecule acts as a tridentate ligand and binds to the metal through the pyridine nitrogen, the imine nitrogen and the sulfur atom. A chloride ion occupies the fourth coordination site. The planar complexes stack nearly parallel to one another in the lattice conforming a layered crystal structure. The cytotoxic activity of the thiosemicarbazones and their metal complexes was tested against the MCF-7, TK-10 and UACC-62 human tumor cell lines. The ligands exhibit lower values of GI50 and LC50 than the complexes, H2Bz4Ph being the most active with GI50<0.003 microM; LC50=13.4 microM; GI50=9.3 microM, LC50=12.9 microM; GI50<0.003, LC50=13.8 microM in the MCF-7, TK-10 and UACC-62 cell lines, respectively. Among the complexes, [Pd(2Bz4Ph)Cl] (3) exhibited the lowest values of GI50 in the three studied cell lines.
authors.affiliation: Departamento de Química, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil.
authors.forename: Anayive P
authors.initials: AP
authors.lastname: Rebolledo
authors.forename: Marisol
authors.initials: M
authors.lastname: Vieites
authors.forename: Dinorah
authors.initials: D
authors.lastname: Gambino
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Piro
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Castellano
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Zani
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Souza-Fagundes
authors.forename: Letícia R
authors.initials: LR
authors.lastname: Teixeira
authors.forename: Alzir A
authors.initials: AA
authors.lastname: Batista
authors.forename: Heloisa
authors.initials: H
authors.lastname: Beraldo
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D002412:Cations / Q000737:chemistry; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008024:Ligands; D008670:Metals / Q000737:chemistry; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000494:pharmacology; D010165:Palladium / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013057:Spectrum Analysis; D013882:Thiosemicarbazones / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D002412:Cations; D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D011725:Pyridines; D013882:Thiosemicarbazones; D010165:Palladium; D009584:Nitrogen; C023666:pyridine