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An efficient and recyclable oxidative desulfurization process (ODS) to remove the most refractory sulfur-compounds (dibenzothiophene, 1-benzothiophene and 4,6-dimethyldibenzothiophene) from fuel is reported. The ODS process was catalyzed by terbium-polyoxometalate [Tb(PW11O39)(2)](11-) (Tb(PW11)(2)) and its composite Tb(PW11)(2)@MIL-101. The tetrabutylammonium (TBA) salt of Tb(PW11)(2) was prepared and further incorporated in the porous metal-organic framework MIL-101(Cr). The TBA compound and its composite were characterized by various techniques (powder X-ray diffraction, FT-IR, FT-Raman, SEM and elemental analysis), and their electrochemical behavior was investigated, indicating that the structure of the polyoxometalate anion must be retained after immobilization. The studied ODS process was based on a biphasic system formed by a model oil with various refractor sulfur-compounds and an extracting solvent using H2O2 as the oxidant. Two main steps in the process were carefully investigated: the initial extraction and the oxidative catalytic stage. The optimization of the ODS process was performed by the analysis of the most suitable extracting solvent and also comparing the desulfurization performance of the homogeneous Tb(PW11)(2) and the heterogeneous Tb(PW11)(2)@MIL-101 catalysts. Acetonitrile was selected as the best solvent because it allowed the highest desulfurization rate, conciliating good initial extraction and high catalytic performance. The presence of the porous catalyst Tb(PW11)(2)@MIL-101 seemed not to influence the initial extraction step; however, with this porous hybrid catalyst were obtained higher desulfurization rates during the catalytic stage. Remarkably, using Tb(PW11)(2)@MIL-101 and the oil-acetonitrile system complete desulfurization of oil was achieved only after 5 h. The recyclability of the solid catalyst was investigated for three consecutive ODS cycles and its stability was confirmed by several techniques

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Isostructural modular microporous Na2[Y(hedp)(H2O)0.67] and Na4[Ln2(hedp)2(H2O)2]‚nH2O (Ln ) La, Ce, Nd, Eu, Gd, Tb, Er) framework-type, and layered orthorhombic [Eu(H2hedp)(H2O)2]‚H2O and Na0.9[Nd0.9Ge0.10(Hhedp)(H2O)2], monoclinic [Ln(H2hedp)(H2O)]‚3H2O (Ln ) Y, Tb), and triclinic [Yb(H2-hedp)]‚H2O coordination polymers based on etidronic acid (H5hedp) have been prepared by hydrothermal synthesis and characterized structurally by (among others) single-crystal and powder X-ray diffraction and solid-state NMR. The structure of the framework materials comprises eight-membered ring channels filled with Na + and both free and lanthanide-coordinated water molecules, which are removed reversibly by calcination at 300°C (structural integrity is preserved up to ca. 475°C), denoting a clear zeolite-type behavior. Interesting photoluminescence properties, sensitive to the hydration degree, are reported for Na4[Eu2(hedp)2-(H2O)2]‚H2O and its fully dehydrated form. The 3D framework and layered materials are, to a certain extent, interconvertable during the hydrothermal synthesis stage via the addition of HCl or NaCl: of the 3D framework Na4[Tb2(hedp)2(H2O)2]‚nH2O, affords layered [Tb(H2hedp) (H2O)]‚3H2O, whereas layered [Tb(H2-hedp)(H2O)2]‚H2O reacts with sodium chloride yielding a material similar to Na4[Tb2(hedp)2(H2O)2]‚nH2O. In layered [Y(H2hedp)(H2O)]‚3H2O, noncoordinated water molecules are engaged in cooperative waterto-water hydrogen-bonding interactions, leading to the formation of a (H2O)13 cluster, which is the basis of an unprecedented two-dimensional water network present in the interlayer space.

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The hydrothermal reaction between lanthanide nitrates and 2,3-pyrazinedicarboxylic acid led to a new series of two-dimensional (2D) lanthanide-organic frameworks: [Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) [where 2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate, and Ln(III) = Ce, Nd, Sm, Eu, Gd, Tb, or Er]. The structural details of these materials were determined by single-crystal X-ray diffraction (for Ce(3+) and Nd(3+)) that revealed the formation of a layered structure. Cationic monolayers of {(infinity)(2)[Ln(2,3-pzdc)(H(2)O)](+)} are interconnected via the ox(2-) ligand leading to the formation of neutral (infinity)(2)[Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)] bilayer networks; structural cohesion of the crystalline packing is reinforced by the presence of highly directional O-H...O hydrogen bonds between adjacent bilayers. Under the employed hydrothermal conditions 2,3-pyrazinedicarboxylic acid can be decomposed into ox(2-) and 2-pyrazinecarboxylate (2-pzc(-)), as unequivocally proved by the isolation of the discrete complex [Tb(2)(2-pzc)(4)(ox)(H(2)O)(6)].10H(2)O. Single-crystal X-ray diffraction of this latter complex revealed its co-crystallization with an unprecedented (H(2)O)(16) water cluster. Photoluminescence measurements were performed for the Nd(3+), Sm(3+), Eu(3+), and Tb(3+) compounds which show, under UV excitation at room temperature, the Ln(3+) characteristic intra-4f(N) emission peaks. The energy level of the triplet states of 2,3-pyrazinedicarboxylic acid (18939 cm(-1)) and oxalic acid (24570 cm(-1)) was determined from the 12 K emission spectrum of the Gd(3+) compound. The (5)D(0) and (5)D(4) lifetime values (0.333 +/- 0.006 and 0.577 +/- 0.017 ms) and the absolute emission quantum yields (0.13 +/- 0.01 and 0.05 +/- 0.01) were determined for the Eu(3+) and Tb(3+) compounds, respectively. For the Eu(3+) compound the energy transfer efficiency arising from the ligands' excited states was estimated (0.93 +/- 0.01).

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A series of tetrabutylammonium (TBA) salts of the transition metal mono-substituted silicotungstates [SiW 11 M(H 2 O)O 39 ] nÀ , M = Co II , Fe III , Mn III , (SiW 11 M) were explored as homogeneous catalysts for the oxidation of geraniol and styrene with H 2 O 2 . The most active homogeneous catalysts (SiW 11 Co and SiW 11 Fe) were immobilized onto an amine-functionalized SBA-15 (aptesSBA-15) and the resulting composites were characterized using several techniques (FT-IR, FT-Raman, UV-Vis/DRS, elemental analysis, powder XRD, SEM and N 2 adsorption-desorption isotherms). The catalytic performance of the new composites SiW 11 Co@aptesSBA-15 and SiW 11 Fe@aptesSBA-15 was investigated under similar experimental conditions to those used for homogeneous counterparts. 2,3-Epoxygeraniol and benzaldehyde were the main products obtained from geraniol and styrene oxidation, respectively, for all the catalysts. SiW 11 Co and SiW 11 Co@aptesSBA-15 showed to be the most active catalysts for the oxidation of geraniol and styrene.The recyclability of the composite SiW 11 Co@aptesSBA-15 was investigated for three reaction cycles. The stability of the composites was confirmed using several techniques after catalytic cycles.