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The interaction of 3-(4-X-phenyl)-2-sulfanylpropenoic acids [H2(X-pspa); X = -F, -Cl, -Br, -I, -OCH3, -OCF3, -OH] with lead(II) acetate in an alcoholic medium was explored in the search for new chelating agents for the Pb2+ ion. The direct reactions afforded [Pb(X-pspa)] complexes in yields of 67 (X = -Br) to 95 % (X = -OCH3). When the PbII/H2(X-pspa) reaction was performed in the presence of diisopropylamine (Q), the derivatives [HQ]2[Pb(X-pspa)2] (X = Cl, Br) were obtained. All of the complexes were characterized by spectrometric (FAB-MS and ESI-MS) and spectroscopic (IR, 1H and 13C NMR spectroscopy) methods and these showed the permanence of the O,S coordination of the ligands to the metal ion in dimethyl sulfoxide (DMSO) solution. H2(Cl-pspa), [HQ]2[Pb(Cl-pspa)2] and [HQ]2[Pb(Br-pspa)2] were also fully characterized in the solid state by X-ray diffraction. The importance of the stereochemically active lone electron pair of the PbII ion in the supramolecular arrangement of [HQ]2[Pb(X-pspa)2] (X = Cl, Br) is discussed. [ABSTRACT FROM AUTHOR]

Macroalgae have been commercially exploited as food and for the production of phycocolloids, but they also contain compounds with potential in pharmaceutical, nutraceutical, cosmetic, chemical and energetic applications. The biorefinery concept applied to seaweed facilitates the extraction of different constituents ensuring full utilization of resources and generating few residues through a succession of steps. Seaweed biorefineries are less advanced than those based on terrestrial biomass and the design of efficient processes requires further study. This review presents practical successful examples to obtain two or more commercially valuable components from red seaweeds. The selected processes consist on cascading stages of both conventional and alternative techniques to illustrate different possible valorization strategies. [ABSTRACT FROM AUTHOR]

Abstract: The compound [PbPh2(NO3)2(H2O)2] was synthesized and characterized by spectroscopic methods (IR; 1H, 13C and 207Pb NMR) and mass spectrometry. An X-ray diffraction study showed that the crystal is a supramolecular tridimensional network of hydrogen-bonded PbPh2(NO3)2(H2O)2 units in which the Pb atom is octacoordinated and adopts a distorted hexagonal bipyramidal geometry, with four O (bidentate nitrate) and two O (water) atoms in equatorial positions and two C-phenyl atoms in axial positions. The crystal of [PbMe3(NO3)(H2O)], obtained as a byproduct in the synthesis of PbMe2(NO3)2, contains chains of hydrogen-bonded PbMe3(NO3)(H2O) units in which the Pb atom is pentacoordinated with a slightly distorted trigonal bipyramidal environment. In this arrangement the three C-methyl atoms are equatorial and the O atoms from the monodentate nitrate and the water molecule are axial. [Copyright &y& Elsevier]