Jorge Luis Borges and Wilhem Ostwald. Notes for an alliance between science and the humanities

Jorge Luis Borges (1899-1986) de nacionalidad argentina, fue escritor, poeta y filósofo de fama mundial. Wilhelm Ostwald (1853-1932), de nacionalidad alemana, fue uno de los fundadores de la físicoquímica. También fue filósofo, pintor y premio Nobel de Química (1909). Los dos hombres enriquecieron el diálogo entre ciencia y humanidades gracias a sus obras y sus discursos, a pesar de que nunca se conocieron personalmente. Un simposio en la ciudad de Leipzig, en cuya universidad Wilhelm Ostwald se desempeñó durante 20 años como catedrático principal de físicoquímica, realizado en octubre de 2001, tenía el título: «Jorge Luis Borges. Ciencia y filosofía»

Química de coordinación de las 3-benzoiltio (seleno) ureas

Las 3-benzoiitlo (seleno) ureas-1,1-dlsustltuldas forman quelatos metálicos. Aquí se describen la síntesis y las propiedades de los ligandos y de algunos derivados, considerando especialmente la estructura en solución. La estructura molecular de los quelatos metálicos fue investigada por rayos X. La energía libre de activación para la rotación Impedida del grupo Et2N alrededor del enlace N-C(X) (X = S, Se) fue determinada por espectroscopia RMN^H. La barrera rotacional en los quelatos es mayor que la de los ligandos libres. Algunos aspectos del enlace químico y de la distribución electrónica en los quelatos fueron Investigados por espectroscopia fotoelectrónlca de rayos X. Se propone un nuevo método para la determinación de la estabilidad termodinámica de los quelatos azufrados de níquel (11), utilizando los valores M'''^% de la espectroscopia de masas. Mediciones calorimétricas de la formación de los aductos de blspirldlna de los complejos de níquel (11) con los ligandos mencionados y sus CH-análogos muestran diferencias significativas entre los dos tipos. Los resultados ESCA de los aductos NO metálicos confirman ia carga negativa sobre el NO. Las 3-benzolltloúreas-1-monosustltuldas pueden coordinarse con los átomos S/0 ; N/OoSsólo

Ein Plädoyer für Dienstleistungspolitik: Analysen, Strategien und Beispiele für Beschäftigung durch Innovation im Tertiären Sektor

Die Autoren versuchen zu begründen, warum zur Realisierung der Potentiale des Dienstleistungssektors politischer Handlungsbedarf besteht und Ziele einer Handlungsstrategie und das zu ihrer Umsetzung erforderliche Instrumentarium zu entwickeln. Dies erfolgt in einem ersten Schritt für den Dienstleistungsbereich insgesamt und in einem zweiten Schritt exemplarisch für eine Dienstleistungsbranche - und zwar für die Versicherungswirtschaft. Die Versicherungswirtschaft steht aus verschiedenen Gründen vor Strukturbrüchen und weist darum wie gezeigt wird - einen spezifischen Handlungsbedarf auf. (IAB2

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 (L1−3)2 and platinum (II) tetranuclear Pt4(L4)4 complexes of benzaldehyde thiosemicarbazone derivatives have been synthesized, and characterized by elemental analysis and IR, FAB(+)-mass and NMR (1H, 13C) spectroscopy. The complex Pd(L2)2 [HL2 = m-CN-benzaldehyde thiosemicarbazone] shows a square-planar geometry with two deprotonated ligands (L) coordinated to PdII through the nitrogen and sulphur atoms in a transarrangement, while the complex Pt4(L4)4 [HL4 = 4-phenyl-1-benzaldehyde thiosemicarbazone] has a tetranuclear geometry with four tridentate ligands coordinated to four PtII 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 IC50 values at the range of 0.07–3.67 μM. The tetranuclear complex Pt4(L4)4, with the phenyl group in the terminal amine of the ligand, showed higher antiproliferative activity (CI50 = 0.07–0.12 μM) than the other tested palladium (II) complexes

Síntesis y caracterización del diperclorato de monometilcarbonato pentammincobalto (iii)

Se presenta la síntesis y caracterización de una nueva sustancia de la familia de las carbonatoamminas del Cobalto (III): [Co (NH3)5 OCO2 CH3 ] (C104)2 de interés para estudios comparativos cinético-mecanísticos

Synthesis, Characterization And Antitumor Activity Of Copper(II) Complexes, [CuL2] [HL1-3=N,N-Diethyl-N'-(R-Benzoyl)Thiourea (R=H, o-Cl and p-NO2)]

The copper (II) complexes (CuL2) were prepared by reaction of Cu(CH3COO)2 with the corresponding derivatives of acylthioureas in a Cu:HL molar ratio of 1:2. Acylthiourea ligands, N,N-diethyl-N'-(R-benzoyl) thiourea (HL1-3) [R=H, o-Cl and p-NO2] were synthesized in high yield (78-83%) and characterized by elemental analysis, infrared spectroscopy, 1H and 13C NMR spectroscopy. The complexes CuL2 were characterized by elemental analysis, IR, FAB(+)-MS, magnetic susceptibility measurements, EPR and cyclic voltammetry. The crystal structure of the complex Cu(L2)2 shows a nearly square-planar geometry with two deprotonated ligands (L) coordinated to CuII through the oxygen and sulfur atoms in a cis arrangement. The antitumor activity of the copper(II) complexes with acylthiourea ligands was evaluated in vitro against the mouse mammary adenocarcinoma TA3 cell line. These complexes exhibited much higher cytotoxic activity (IC50 values in the range of 3.9-6.9 μM) than their corresponding ligands (40-240 μM), which indicates that the coordination of the chelate ligands around the CuII enhances the antitumor activity and, furthermore, this result confirmed that the participation of the nitro and chloro substituent groups in the complex activities is slightly relevant. The high accumulation of the complexes Cu(L2)2 and Cu(L3)2 in TA3 tumor cells and the much faster binding to cellular DNA than Cu(L1)2 are consistent with the in vitro cytotoxic activities found for these copper complexes

Synthesis, Characterization and Antitumor Activity of cis-bis(acylthioureato) platinum(II) Complexes, cis-[PtL2] [HL1=N,N-Diphenyl-N'-Benzoylthiourea or HL2=N,N-diphenyl-N'-(p-nitrobenzoyl)thiourea]

A low-molecular weight chromium-containing fraction of the material resulting from dichromate reduction by bovine liver homogenate was investigated by NMR and ES-MS. The ES-MS spectrum showed a readily detectable peak at m/z 786.1. The same molecular weight reasonably agreed with the relatively low diffusion coefficient measured by NMR-DOSY experiments on the main species observed in the 1H NMR spectrum. At least two downfield shifted and broad paramagnetic signals were apparent in the 1H NMR spectrum. Temperature dependence of chemical shift was exploited in order to estimate the diamagnetic shift of the signals in the diamagnetic region of the spectrum. 2D TOCSY, NOESY, COSY and 1H-13C HMQC spectra revealed the presence of aromatic protons (which were assigned as His residues), Gly and some other short chain amino-acids. Combinations of the molecular masses of such components together with acetate (which is present in the solution) and chromium atoms allowed a tentative proposal of a model for the compound

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