Synthesis,structural characterization and cytotoxic activity of organotin derivatives of indomethacin

The synthesis, characterization and cytotoxic properties in vitro of tri‐n‐butyltin 1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indole‐3‐acetate ( 1 ), tri‐phenyltin 1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indole‐3‐acetate ( 2 ), tetra‐n‐butyltin[bis‐1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indole‐3‐acetato]distannoxane ( 3 ) and di‐n‐butyltin bis‐1‐(4‐chlorobenzoyl)‐5‐methoxy‐2‐methyl‐1H‐indole‐3‐acetate ( 4 ) are described. These compounds have been characterized by ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy in solution and ¹¹⁹Sn NMR in the solid state, infrared spectroscopy, elemental analysis and X‐ray diffraction for compound 1 . The growth inhibition effects of compounds 1–4 against the lung adenocarcinoma cell line SK‐LU‐1 as well as the cervical cancer cell line HeLa were determined. Compounds 1 and 2 exhibit cytotoxic activity, whereas compounds 3 and 4 are inactive. Copyright © 2008 John Wiley & Sons, Ltd.     

Suzuki cross‐coupling reaction of aryl and heterocyclic bromides and aromatic polybromides on a Pd(II)‐hydrotalcite catalyst

The Suzuki cross‐coupling reaction of various bromine‐containing substrates and phenylboronic acid in toluene at 90 °C on a Pd(AcO)₂Py₂ catalyst supported on an Mg? Al hydrotalcite, using K₂CO₃ as the base, was studied. The conversion and selectivity results obtained for many of the substrates were excellent and similar to those provided by more active or even homogeneous catalysts. The reactions of aryl polybromides and phenylboronic acid gave the corresponding polyaromatic compounds in variable yields depending on the particular substrate. Arylation occurred in a consecutive manner by substitution of the different Br atoms. ICP‐MS measurements of the palladium content of the catalyst performed prior to and after the reaction revealed that part of the metal is incorporated into the bulk solution; therefore, the catalytic process is not purely heterogeneous. Copyright © 2008 John Wiley & Sons, Ltd.     

Structural and electronic study of neutral,positive, and negative small rhodium clusters [Rhn,Rh, and Rh]

We have carried out a systematic study for the determination of the structure and the fundamental state of neutral and ionic small rhodium clusters [Rh_n, Rh, Rh (n = 5–10)] using ab initio Hartree‐Fock methods with a LANL2DZ basis set. A range of spin multiplicities is studied for each cluster. We present the bond lengths and angles and geometric configuration adopted for the clusters in its minimum energy conformation showing the differences when the clusters have different number of unpaired electrons. In addition, we report the vertical ionization potential and the adiabatic potential calculated by the Koopman's theorem. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2541–2547, 2010     

A multidimensional real Schwarz Lemma for the Hilbert metric

We present a real multidimensional version of the Schwarz Lemma on a bounded convex domain D of ℝ ⁿ endowed with the Hilbert metric. We provide as an application an extension of a Birkhoff’s Theorem on mappings contracting the Hilbert metric.     

Homoclinic bifurcations of endomorphisms: The codimension one case

In this note, we consider the dynamic that appears when we unfold a quadratic degenerate homoclinic point of a generic one-parameter family of endomorphisms f_μ. This is done through a rescaling technique. Among other facts, it follows from our theorem the abundance of strange expanding sets.     

Elevated tri(n-butyl)tin concentrations in shellfish and sediments from Suva Harbour,Fiji

Tri(n-butyl)tin (TBT) concentrations were determined in sediments and selected shellfish from Suva Harbour, Fiji. Sediments in the immediate vicinity of foreshore slipways and boatyards were exceedingly contaminated, with a maximum observed level of 38μ g^?1 TBT-Sn. Concentrations were much lower in surficial sediments from commercial docks and yacht mooring areas, namely 16–83 ng g^?1 TBT-Sn. Mangrove oysters (Crassostrea mordax), gastropods (Thais mancinella), and bivalves (Anadara scapha) were found to have accumulated TBT. Concentrations as high as 3180 ng g^?1 TBT-Sn were found in mangrove oysters. With respect to the mangrove oyster, its widespread distribution, abundance and proclivity to accumulate TBT suggest that it is likely to be the best bioindicator species of TBT contamination in Fijian coastal waters.     

Specific activity and derived intervention levels for Cesium-137 in Costa Rican export goods: Tuna fish, coffee and powdered milk

Cesium-137 is a fission product of ²³⁵U and ²³⁹Pu. After a major nuclear accident, it is released into the atmosphere and in the far field region it will produce radioactively contaminated food and drinking water. This paper will study the specific activity of ¹³⁷Cs in three Costa Rican export products: tuna fish, coffee and powdered milk. The average specific activities found are as follows: 0.89±0.41, 1.16±0.76 and 4.53±2.00 Bq kg⁻¹. They represent low values compared to their derived intervention levels: 1.25 × 10⁷, 1.25 × 10⁷ and 2.44 × 10⁵ Bq kg⁻¹, respectively.     

Simultaneous Differential Pulse Adsorptive Stripping Determination of Imipramine and Its Metabolite Desipramine by the PLS‐1 Multivariate Method

A method, using stripping differential pulse voltammetry, for the simultaneous determination of Imipramine and its metabolite Desipramine is reported. Both compounds produce, at glassy carbon electrode, an electrochemical signal due to an adsorptive‐oxidative process. The voltammograms show a very high overlap degree between IM and DE peaks. The multivariate calibration method PLS‐1 was employed for the simultaneous determination of both compounds. An experimental design together with the response surface methodology has been used to find the optimum experimental conditions. The developed procedure has been utilized in the analysis of fortified human serum samples with good recovery values for each analyte.     

Ion Mobility Measurements of Nondenatured 12–150 kDa Proteins and Protein Multimers by Tandem Differential Mobility Analysis–Mass Spectrometry (DMA-MS)

The mobilities of electrosprayed proteins and protein multimers with molecular weights ranging from 12.4 kDa (cytochrome C monomers) to 154 kDa (nonspecific concanavalin A hexamers) were measured in dry air by a planar differential mobility analyzer (DMA) coupled to a time-of-flight mass spectrometer (TOF-MS). The DMA determines true mobility at atmospheric pressure, without perturbing ion structure from that delivered by the electrospray. A nondenaturing aqueous 20 mM triethylammonium formate buffer yields compact ions with low charge states, moderating polarization effects on ion mobility. Conversion of mobilities into cross-sections involves a reduction factor ξ for the actual mobility relative to that associated with elastic specular collisions with smooth surfaces. ξ is known to be 1.36 in air from Millikan’s oil drop experiments. A similar enhancement effect ascribed to atomic-scale surface roughness has been found in numerical simulations. Adopting Millikan’s value ξ = 1.36 and assuming a spherical geometry yields a gas-phase protein density ρ _p = 0.949 ± 0.053 g cm⁻³ for all our protein data. This is substantially higher than the 0.67 g cm⁻³ found in recent low-resolution DMA measurements of singly charged proteins. DMA-MS can distinguish nonspecific protein aggregates formed during the electrospray process from those formed preferentially in solution. The observed charge versus diameter relation is compatible with a protein charge reduction mechanism based on the evaporation of triethylammonium ions from electrosprayed drops.