Promising anticancer mono- and dinuclear ruthenium(III) dithiocarbamato complexes: systematic solution studies

During the last decade, our research group has prepared a number of metal dithiocarbamato derivatives of Pt, Pd and Au that were expected to resemble the main features of cisplatin together with higher activity, improved selectivity and bioavailability, and lower side-effects. Furthermore, we have already published the synthesis, characterization and in vitro cytotoxicity studies of novel ruthenium(III) dithiocarbamato complexes such as [RuL(3)] monomers (11) and α-[Ru(2)L(5)]Cl dimers (12) with five different dithiocarbamate ligands. As both the monomer and the dinuclear complexes have shown significant antitumor activity in different human tumor cell lines, we decided to widen the characterization studies and to analyse thoroughly their behavior in physiological-like medium by UV-visible and CD spectroscopy. In the present paper we report on the crystal structure of [Ru(DMDT)(3)], [Ru(PDT)(3)] and [Ru(ESDT)(3)] complexes and we determine the spin state of the paramagnetic Ru(III) by means of Evans' method. Then, we discuss in detail the UV-visible spectral data of the complexes in different medium. All the studied complexes are stable in dimethyl sulfoxide, and show low solubility in phosphate buffered saline solution, particularly the monomer species, even at low concentration, while increased solubility for both types of complexes have been found in the presence of bovine serum albumin (BSA). Moreover, no changes on the coordination sphere of the metal, as well as no direct interaction between the BSA protein and the complex have been identified by UV-visible spectroscopy. However, some conformational changes on the BSA structure, induced by the ruthenium(III) complexes have been confirmed by CD spectroscopy, indicating a probable secondary electrostatic interaction between the metal complex and the peptide. In addition, no significant interaction has been demonstrated with the components of Dulbecco's Modified Eagle's Medium, used for the in vitro assays.     

On the antibacterial activity of roots of Capparis spinosa L

A decoction of Capparis spinosa L. roots, widely used in the traditional folk medicine of southern Italy, was prepared and submitted to antibacterial activity tests, which showed an interesting bacteriostatic activity on the growth of Deinococcus radiophilus. Heterocyclic compounds were also recovered from the chloroformic extract of the roots.     

Using multiple short-end injections to develop fast electrophoretic separations--applications in iodide analysis

The aim of this study was to develop a fast CE separation method by using multiple short-end injections in a capillary coated with quaternary ammonium chitosan (HACC), in order to determine the iodide content of pharmaceutical formulations. The BGE was composed of 20 mM tris(hydroxymethyl)aminomethane and 11 mM hydrochloric acid, at pH 8. The internal standard used was thiocyanate. Separations were performed in a fused silica capillary (32 cm total length, 8.5 cm effective length and 50 μm i.d.) coated with HACC and direct UV detection at 220 nm. EOF was modified by flushing the capillary with polymeric solution, resulting in a semi-permanent coating of controlled and stable EOF. The EOF was anodic at pH 8. Different strategies, using single and multiple injection short-end configurations, were studied to develop a CE method that resulted in a maximum number of iodide samples analyzed per hour: one plug and flush (Sflush) 35 samples/h, one plug without flush (SWflush) 76 samples/h, four plugs and flush (Mflush) 61 samples/h, and four plugs without flush (MWflush) 80 samples/h. Using the multiple injection configuration, it was possible to inject up to four plugs using spacer electrolytes with good separation efficiency and selectivity. The voltage application time needed to separate the eight peaks (iodide and thiocyanate) with MWflush was only 12s. The method was validated and samples were analyzed using MWflush. Good linearity (R(2)>0.999); a limit of detection 0.4 mg L(-1); intermediate precision better than 3.8% (peak area) and recovery in the range of 99-102% were obtained.     

Evaluation of a glycerol derived biofuel by thermal analysis

This work describes thermal analysis evaluation of a glycerol derived compound (fatty acid esters of (2,2-dimethyl-1,3-dioxolan-4-yl) methanol) developed to work as a biofuel. Mixtures of these ketal–glyceryl esters with fatty acid methyl esters typical of soybean biodiesel were prepared and evaluated in relation to biodiesel critical thermal properties such as temperature of crystallization, thermal stability and volatilization measured by differential scanning calorimetry and thermogravimetric analysis. The volatility of the products containing fatty acid methyl esters and (2,2-dimethyl-1,3-dioxolan-4-yl) methyl esters could be predicted by thermogravimetric analyses conducted in nitrogen that avoided time consuming distillation and greatly reduced material expenditure.     

Strategic simulation models as a new methodological approach: an application to information technologies integration,lean/just-in-time and lead-time

Central European Journal of Operations Research - Hypothesis contrast using statistical models with Structural Equations is a technique widely used in Supply Chain Management research. However,...     

The Cohomology of the Universal Steenrod Algebra

The mod 2 universal Steenrod algebra Q is a homogeneous quadratic algebra closely related to the ordinary mod 2 Steenrod algebra and the Lambda algebra introduced in [1]. In this paper we show that Q is Koszul. It follows by [7] that its cohomology, being purely diagonal, is isomorphic to a completion of Q itself with respect to a suitable chain of two-sided ideals.     

Proceedings of the conference on organic chemistry at clusters and surfaces

The Proceedings of the Conference on Organic Chemistry at Clusters and Surfaces will comprise Volume 3, Number 3 (September 1992); Volume 3, Number 4 (December 1992); and Volume 4, Number 1 (March 1993).     

F?F coupling constants in dichlorotetrafluorocyclopropanes

The ¹⁹F NMR spectra of the cis- ( 1 ) and the trans-isomer ( 2 ) of the 1,2-dichlorotetrafluorocyclopropane and that of the 1,1-dichlorotetrafluorocyclopropane ( 3 ) have been investigated at different temperatures and in several solvents. From chemical shift calculations the two geminal fluorines in the cis-isomer ( 1 ) could be assigned and on this basis the two vicinal coupling constants of 1 , J_trans (ca. 140°) and J_cis (ca. 0°), were unequivocally distinguished. By frequency sweep double resonance J_trans has been shown to be of opposite sign to J_gem, whereas for J_cis the situation has been found to be reversed. Therefore J_trans is presumably negative and J_cis positive. Only the N(J_cis + J_trans) value could be extracted from the vicinal coupling constant in the fragment ? CFCl? CFCl? could be evaluated. It has been noted that J_cis is more sensitive to changes in temperature than is J_trans. The variations of J_cis and J_trans induced by solvents are, on the contrary, small and irregular and no correlation with the dielectric constant of the medium has been noted. The different temperature dependence of J_cis and J_trans can be useful for assigning the vicinal F? F coupling constants in cyclopropane derivatives and also for defining their signs. This method was applied to the coupling constants extracted from the ¹³C satellite spectrum of isomer 3 . The coupling constants results were compared with some literature data already known, and some rationalisation and correlations from the trends was attempted.     

Formamidines and triazenes as precursors for the preparation of rhenium imido-complexes

Summary The rhenium(V) imido-complexes [Re(NR)Cl₃(PPh₃)₂] have been obtained by heating the rhenium(V) derivative [ReOCl₃(PPh₃)₂] with RNHCHNR R = Ph (1a), p-MeC₆H₄ (1b), p-ClC₆H₄ (1c) andp-FC₆H₄ (1d) in THF under reflux. [Re(NR)Cl₃(PPh₃)₂] (R =p-MeQ₆H₄) has also been obtained by heating the rhenium(III)-triazenido complex [ReCl₂(RN N NR)(PPh₃)₂] in CCl₄ under reflux.