Ultrasound for the remediation of contaminated waters with persistent organic pollutants: A short review.

The rising amount of persistent organic contaminants released into water reservoirs in the last years became a cause of concern for the industry, academy, and public administration, due to their bioaccumulation, mutagenicity, and photosynthesis reduction. Therefore, the search for processes that efficiently remove such contaminants became of primary importance. In this context, ultrasound (US) is one of the most promising and economically viable alternatives to degrade organic pollutants in varied environments. Whereas the use of other advanced oxidation processes (AOPs), such as Fenton and photocatalysis, has been widely reported for this purpose, only a few papers deal with ultrasound application as a possible AOP. In this review, a general overview of ultrasound is provided, covering the last twenty years. It includes fundamental aspects of ultrasound and applications, individually or combined with other AOPs, to deplete organic pollutants from various classes in an aqueous environment. Finally, the review concludes by indicating that additional research should be conducted worldwide to explore the full potential of ultrasound as a useful AOP.

Air and moisture stable covalently-bonded tin(ii) coordination polymers.

Four covalently-bonded tin(ii) coordination polymers, (1)-(4), were hydrothermally prepared in aqueous alkaline media by the reactions of SnSO4 with 1,2,4,5-benzenetetracarboxylic acid (1), 1,3,5-benzenetricarboxylic acid (2), 4-hydroxypyridine-2,6-dicarboxylic acid (3), and 1,3,5-cyclohexanetricarboxylic acid (4). All products were structurally authenticated by single-crystal X-ray diffraction, and the number of different tin centres and their oxidation states were confirmed by 119Sn Mössbauer spectroscopy. In addition, the comparison between experimental and simulated X-ray powder diffraction patterns confirmed the authenticity of the samples. Our crystallographic results for (1)-(4) show that the Sn(ii) centres are tetracoordinated and exhibit distorted disphenoidal geometries, corroborating the presence of one stereochemically active lone electron pair at each metal site. Products (1) and (2) display bi-dimensional polymeric structures, (3) exhibits a one-dimensional architecture, whereas (4) shows a remarkable three-dimensional coordination network. Hirshfeld surface and supramolecular analyses for the repeating units of (1)-(4) were also performed in order to identify structurally important non-covalent interactions.

Experimental and theoretical studies of the thermal behavior of titanium dioxide-SnO2 based composites.

In this paper we report experimental and theoretical studies concerning the thermal behavior of some organotin-Ti(IV) oxides employed as precursors for TiO(2)/SnO(2) semiconducting based composites, with photocatalytic properties. The organotin-TiO(2) supported materials were obtained by chemical reactions of SnBu(3)Cl (Bu = butyl), TiCl(4) with NH(4)OH in ethanol, in order to impregnate organotin oxide in a TiO(2) matrix. A theoretical model was developed to support experimental procedures. The kinetics parameters: frequency factor (A), activation energy, and reaction order (n) can be estimated through artificial intelligence methods. Genetic algorithm, fuzzy logic, and Petri neural nets were used in order to determine the kinetic parameters as a function of temperature. With this in mind, three precursors were prepared in order to obtain composites with Sn/TiO(2) ratios of 0% (1), 15% (2), and 30% (3) in weight, respectively. The thermal behavior of products (1-3) was studied by thermogravimetric experiments in oxygen.

Platinum and palladium complexes of thiosemicarbazones derived of 2-acetylthiophene: Synthesis and spectral studies.

The reaction of 2-acetylthiophene thiosemicarbazone (2-HATT) and 2-acetylthiophene 4-phenylthiosemicarbazone (2-HAT-4-FT) with Pd(COD)Cl(2) (COD = 1,5-cyclooctadiene) and trans-Pt(2)PEt(3)Cl(4) yielded four new metal complexes: [Pd(2-HATT)Cl(2)] (1), [Pd(2-ATT)(2)] (2), [Pd(2-AT-4-FT)Cl] (3) and [Pt(2-ATT)(PEt(3))Cl] (4). Apart from compound 3 all the others were characterised by (1)H and (13)C{(1)H} NMR, infrared spectroscopy, and elemental analysis. Multinuclear NMR experiments of (31)P{(1)H} and (195)Pt{(1)H} of complex 4 have revealed that the ligand 2-HATT behaves as a bidentate chelating agent towards Pd(COD)Cl(2) and trans-Pt(2)PEt(3)Cl(4) whereas ligand 2-HAT-4-FT forms a tridentate chelating complex with Pd(COD)Cl(2).

Tin(IV) complexes of pyrrolidinedithiocarbamate: synthesis, characterisation and antifungal activity.

The reaction of ammonium pyrrolidinedithiocarbamate, [NH4{S2CN(CH2)4}], with SnCl2, [Sn(C6H5)2Cl2], [Sn(C6H5)3Cl], [Sn(C4H9)2Cl2] and [Sn(C6H11)3Cl] produced in good yield the compounds [Sn{S2CN(CH2)4}2Cl2] (1), [Sn{S2CN(CH2)4}2Ph2] (2), [Sn{S2CN(CH2)4}Ph3] (3), [Sn{S2CN(CH2)4}2 n-Bu2] (4) and [Sn{S2CN(CH2)4}Cy3] (5). The complexes were characterised by infrared, multinuclear NMR (1H, 13C{1H} and 119Sn{1H}) and 119Sn Mössbauer spectroscopies. In addition, the crystal structure of 4 was determined by X-ray crystallography. The in vitro antifungal activity of the tin(IV) complexes as well of the ligand was performed on human pathogenic fungi, Candida albicans, in concentrations of 0.025; 0.050; 0.100; 0.200; 0.400; 0.800; 1.600 and 3.200 mM. The microorganism presented resistance to the dithiocarbamate ligand and all tin(IV) complexes tested were actives. The highest activity was found for compounds 1 and 4.

The synthesis and characterisation of Sn(IV) complexes of 2,6-pyridine dicarboxylate--the molecular structure of divinyltin(IV) derivative.

A series of organotin(IV) derivatives were obtained employing 2,6-pyridinedicarboxylate as ligand: [{SnBu3(OOC)2C5H3N}n] (1), [SnBuCl(OOC)2C5H3N] (2) and [Sn(CHCH2)2(OOC)2C5H3N] (3). They were fully characterised by multinuclear NMR [1H, 13C{1H}, and 119Sn{1H}], IR spectroscopies and elemental analysis. In addition suitable crystals of (3) have shown a dimmeric arrangement by X-ray crystallographic studies, held together by Sn-O intermolecular interactions which persists in solution. The crystal packing shows hydrogen bonds joining the dimmers, forming two infinite one-dimensional chain. Each monomer comprises a Sn(IV) centre bonded to a pyridinecarboxylate-containing ring, through both nitrogen and oxygen donor atoms. It is also co-ordinated by a water molecule and two vinyl groups.

The synthesis and structural characterisation of [Ru(eta-Cp)(dppf)SnBr3].

The reaction of [Ru(eta-Cp)(dppf)N(3)] (1) with equimolar amount of SnBr(2) yielded an interesting heterotrimetallic compound [Ru(eta-Cp)(dppf)SnBr(3)] (2) (dppf: 1,1'-bis-diphenylphosphinoferrocene). Compounds 1 and 2 were characterised by IR, NMR (1H, 13C, 31P and 119Sn), and 2, additionally, by 57Fe and 119Sn Mössbauer spectroscopy and X-ray crystallography. The latter results were as follows: monoclinic, C2/c, a = 32.8879(4)A, b = 11.9888(2)A, c = 20.8986(3)A, beta = 92.545(1)degrees, V = 8231.9(2)A(3), Z =8.

[Program of community integration: search for new strategies and new life styles]. / Programa de integração comunitária: em busca de novas estratégias e novos sentidos à vida.

The Program of Community Integration of the Municipal Bureau of Health of the city of Ribeirão Preto aims at promoting health, directing its actions for the change of life styles. The purpose of this study is to look, in the light of the framework of Health Promotion and through declarations of users of the program, how it has been formed as an important strategy to increase the autonomy and emancipation of the population. The analysis reveals that the program has improved the autonomy and emancipation of the population, as an important instrument for life defence.