title: Palladium(II) complexes with tris(2-carboxyethyl)phosphine, structure, reactions and cytostatic activity.
abstract: Water soluble and air stable P(RCOOH)3 (R=C2H4) (TCEP) is an efficient reducing agent used in biochemistry to break S-S bond in peptides, proteins and other compounds containing S-S bonds. The similarity between the coordination chemistry of Pd(II) and Pt(II) led to the investigations of antitumor activity of palladium(II) compounds however the Pd(II) complexes with TCEP were not investigated. New palladium(II) complexes with (TCEP): trans-[PdCl2(TCEP)2] (1) and trans-[Pd2(μ-Cl)2Cl2(TCEP)2] (2) were fully characterized by (1)H, (13)C, (31)P NMR, IR and ESI-MS spectroscopic techniques. Complexes are stable in non-aqueous DMSO and DMF. In aqueous solutions Cl ligands are substituted by COO groups of phosphines. Complex 2, after crystallization from water gives polymeric compound with bridging phosphine ligand [PdCl{P(RCOO-κO-μ-O')(RCOOH)2-κP}] (3). Structures of trans-[PdCl2{P(RCOOD)3}2] (1a), trans-[Pd2(μ-Cl)2PdCl2{P(RCOOD)3}2] (2a), and [PdCl{P(RCOO-κO-μ-O')(RCOOD)2-κP}]n (3a) have been determined by X-ray crystallography. NMR and ESI-MS spectra reveal that [PdP2(RCOO-κO)2(RCOO)n(RCOOH)4-n](n)(-) complexes are formed in aqueous solution of 1. Geometry optimization in the gas phase at the B3LYP/3-21G** level indicated that complex 2 with butterfly structure is more stable than that with coplanar coordination. In aqueous solution of 2, the main products [Pd2{P(RCOO-κO-μ-O')(RCOO-κO)(RCOOH)}2] and [Pd{P(RCOO-κO)2(RCOOH)}(H2O)] exist in equilibrium which depends on temperature: content of mononuclear compound increases as the temperature is raised. Complexes 1 and 2 are active agents against melanoma and breast cancer cells.
authors.affiliation: Department of Physics and Biophysics, Wroclaw University of Environmental and Life Sciences, ul. Norwida 25, 50-375 Wrocław, Poland. Electronic address: hanna.pruchnik@up.wroc.pl.
authors.forename: Hanna
authors.initials: H
authors.lastname: Pruchnik
authors.affiliation: Faculty of Chemistry, University of Wrocław, ul. Joliot-Curie 14, 50-383 Wrocław, Poland.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.affiliation: Faculty of Pharmacy, Medical University of Silesia, ul. Narcyzów 1, 41-200 Sosnowiec, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Latocha
authors.affiliation: Faculty of Pharmacy, Medical University of Silesia, ul. Narcyzów 1, 41-200 Sosnowiec, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Zielińska
authors.affiliation: Faculty of Chemistry, University of Wrocław, ul. Joliot-Curie 14, 50-383 Wrocław, Poland.
authors.forename: Florian P
authors.initials: FP
authors.lastname: Pruchnik
mesh_terms: D018360:Crystallography, X-Ray; D054697:Cytostatic Agents / Q000737:chemistry*; D008958:Models, Molecular; D010165:Palladium / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D054697:Cytostatic Agents; D010720:Phosphines; D010165:Palladium; C044646:phosphine
keywords: Antitumor; DFT calculations; Palladium; Phosphine