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A library of stereodefined 2-tetrazolyl azetidines has been synthesized starting from readily available enantiopure amino alcohols. This library was then screened to assess catalytic activity in a benchmark asymmetric aldol reaction between 4-nitrobenzaldehyde and acetone. The azetidine derived from (1 S ,2 R)-(+)-norephedrine exhibited the best balance between good reactivity and a high level of enantioselectivity in this reaction. 2-Tetrazolyl azetidines were targeted as potential organocatalysts. A library of such azetidines were synthesized from β-amino alcohols and then screened for catalytic activity in the asymmetric aldol reaction between 4-nitrobenzaldehyde and acetone. Good reactivity and a high level of enantioselectivity were obtained for the azetidine derived from (1 S ,2 R)-(+)-norephedrine. [Display omitted] [ABSTRACT FROM AUTHOR]

Hypervalent iodine compounds are described with perfluoroalkyl chains and S‐perfluoromethyl sulfoximines as ligands of the halogen. The influence of these groups on the stability of the cyclic structure is studied. The crucial role of the trifluoromethyl chain is clearly highlighted as an efficient ligand for the hypervalency. The structure and the reactivity of the new skeletons are discussed in detail. [ABSTRACT FROM AUTHOR]

An efficient domino polycyclization combining different classes of pericyclic reactions leads to complex spiroxindoles under mild conditions. This domino process represents a rare example of an in situ formation of cyclopentadienol derivatives from an interrupted iso-Nazarov electrocyclization of 2,4-dienals and their use in [4 + 2] cycloaddition reactions. According to the reaction conditions, different polycyclic architectures are obtained in good yields and excellent diastereoselectivities. [ABSTRACT FROM AUTHOR]

A series of enantioenriched phenalene-derived compounds were accessed by a Friedel-Crafts/cyclization strategy. Starting from α,β-unsaturated aldehydes and 2-naphthol derivatives, high levels of enantioselectivity were obtained through iminium-enamine catalysis. The catalytic system composed of a diphenylprolinol silyl ether organocatalyst and triethylamine as a base was applied to a combination of diversely functionalized substrates. The obtained phenalene-derived architectures are promising building blocks for reaching natural products and exhibit fluorescence properties. [ABSTRACT FROM AUTHOR]

A new family of indole-based fluorescent dyes has been easily synthesized from readily available substrates. The structures of all new compounds were confirmed by NMR, IR, and HRMS and a crystallographic structure has been obtained for the 2,6-dicyanoaniline derivative 3. UV/vis absorption and photoluminescence spectroscopy analyses were performed on push–pull indole derivatives 1, 2 and 4. While the absorption maxima were almost independent of the solvent, the emission energy decreased while increasing the solvent polarity. A linear correlation between the orientation polarizability (Δf) of the solvent and the Stokes shifts was observed and DFT calculations were carried out to study the influence of the planarity of the structures on the fluorescent quantum yields. [ABSTRACT FROM AUTHOR]

The first example of an asymmetric aminocatalyzed aza-Michael addition of 1H-indazole derivatives to α,β-unsaturated aldehydes is described. The iminium/enamine cascade process lies at the heart of our strategy, leading to enantioenriched fused polycyclic indazole architectures. Variations on both the α,β-unsaturated aldehydes and the indazole-7-carbaldehyde heterocycles were studied in order to broaden the scope of the transformation in synthetically interesting directions. The fused polycyclic indazoles exhibit fluorescence properties and can undergo synthetic transformations. [ABSTRACT FROM AUTHOR]

Activation of β-lactams can be achieved by simple Lewis-base catalysis to trigger an unprecedented reaction based on the formal dipolar behaviour of a strained amide bond. A new synthetic route for 1,3-oxazinan-6-ones is presented by reaction of β-lactams with ethylglyoxylate, which after methodological optimizations identified 4-pyrrolidinopyridine as the catalyst of choice in aprotic polar solvents. Mechanistic details are also discussed in light of the intrinsic limitations identified for this transformation. [ABSTRACT FROM AUTHOR]

The synthesis and the characterization of a new octanuclear carboxylated titanium oxo-cluster [Ti8O10(OOC R)12] [ R = CH(CH3)2 and CCl3] is reported. The structure was characterized by single-crystal X-ray diffraction. It consists in four vertices-linked pairs of edge-sharing TiO6 octahedra, presenting μ2 and μ3 oxygen atoms. 17O and 13C liquid state NMR was performed with results in full accordance with the structure determined by X-ray diffraction. During synthesis, solvothermal conditions and a large excess of carboxylic acid allow to remove all alkoxo ligands of the titanium alkoxide precursor and lead to stable purely carboxylate clusters. This family of clusters can therefore be considered as interesting SBUs to elaborate new metal-organic frameworks. [ABSTRACT FROM AUTHOR]

An enantioselective organocatalytic reaction of indole‐derived‐1‐azadienes with aldehydes leading the formation of enantioenriched cyclic N,O‐acetals is reported. The corresponding products can be obtained with high levels of stereoselectivity (de >95 %, 65–99 % ee, 8–98 % yield). Furthermore, fused tetracyclic scaffolds can also be obtained by implementing a one‐pot strategy involving an additional oxa‐Michael reaction from aldehydes bearing an α,β‐unsaturated ketone group. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of the [Mo2O2S2(OH2)6]2+ aqua cation and [WO4]2− with the trivacant ion [α-B-AsW9O33]9− in acidic condition (pH=1.4) leads to the formation of a {Mo2S2O2}-supported polyoxotungstate. The mixed salt NMe4K12[(α–AsW9O33)3(WO(OH2))3(Mo2O2S2(H2O)4)]•20H2O (noted TMAK 12 –1) has been obtained as single crystals and structurally characterized by X-ray diffraction analysis. The structural analysis of TMAK 12 -1 reveals a molecular polyoxotungsto-arsenate (III) framework consisting of three α-{AsW9O33} subunits mutually linked by three {O=W-OH2}4+ groups. The resulting triangular arrangement delimits a large “open-space”, lined on the periphery by six terminal oxygen atoms. The central cavity is partially filled by a single {Mo2O2S2(OH2)4}2+ which spans two {AsW9O33} subunits. Furthermore, three potassium ions have been located, one being embedded within the central cavity and the other two, symmetrically distributed at the periphery of the central cavity. In the solid state, two anions 1 interact through hydrogen bonds and ionic contacts to give a large dimeric arrangement bordered by two TMA+ cations. 1 has been characterized in solution (Li+ salt) by its 183W NMR spectrum which contains 16 lines in agreement with the C s idealized symmetry assumed for the isolated anion 1. Infrared data and elemental analysis are also supplied. [Copyright &y& Elsevier]

The chemical system based on the [Mo2O2S2(OH2)6]2+ aqua cation (noted L) and the trivacant [AsW9O33]9- polyoxometalate (noted POM) has been investigated. Depending upon the ionic strength and the nature of the alkali cations, these complementary components assemble to yield three different architectures derived as hexamer (1), tetramer (2), and dimer (3). This series of clusters displays the same stoichiometry {POM6L9}36-, {POM4L6}24-, and {POM2L3}12- for 1, 2, and 3, respectively, and their conditions of formation differ mainly by the nature and the concentration of the alkali cation (from Li to Cs). Structural characterizations of 1 reveal a large hexameric supramolecular scaffold (about 25 Å in diameter), which encloses a large internal hole (about 200 ų) filled by water molecules and alkali cations (Na+ or K+). The hexameric scaffold 1 exhibits a rare flexibility property evidenced in the solid state by two distinct conformations, either eclipsed (1a) or staggered-off (1b). Both conformations appear clearly separated by a large twist angle (~40°) and depend mainly on the composition of the internal hole. Structure of anion 2 shows a tetrahedral arrangement where the four POM units and the six connecting {Mo2O2S2} linkers are located at the corners and at the edges, respectively. The structure of anion 3 corresponds to the simplest arrangement, described as a dimeric association of two POM units linked by three {Mo2S2O2} pillars. Stability of the hexameric scaffold has been investigated in solution by 183W and 39K NMR and by UV-vis, showing that stability of 1 depends strongly on the proportion of potassium ions, which interfere through host-guest exchange. Density functional methodology (DFT) has been applied to compute the geometries and energies of dimer (3), tetramer (2) and hexamer (1) based on {AsW9O33} (POM) and {Mo2O2S2} (L) units. Calculations tend to show that internal cations act as "glue" to maintain the POM units connected through the conformationally inward-directed {Mo2O2S2} linkers. [ABSTRACT FROM AUTHOR]

Abstract: Using an imine condensation strategy, hexaazacryptands were prepared from an aromatic triamine and various dialdehydes. The global shape of these cages can be modified by simple alkylation of the six nitrogen atoms. The cavity is thus elongated and rendered hydrophobic. [Copyright &y& Elsevier]

Abstract: Reaction at pH=2.3 of the [Mo2O2S2(OH2)6]2+ aqua cation with the tetravacant ion [β-B-HAs2W8O31]7− leads to the formation of a red solid from which three mixed salts have been obtained as single crystals and characterized by X-ray diffraction analysis. Three mixed salts K-5a, RbNa-5b, DMACs-5c exhibit a similar molecular arrangement consisting in three {β-HAs2W9O34} subunits mutually linked by three {Mo2O2S2} groups. The triangular arrangement delimits a large open-cavity, lined on the periphery by three outer {As–OH} groups and closed at the bottom by a small hexagonal pocket formed by six terminal oxygen atoms. The central hexagonal cavity is filled either by a potassium, a rubidium or a cesium cation. The outer {As–OH} groups are pointed towards two directions labelled up and down, respectively. In K-6a the three {As–OH} bonds are in up configuration leading to the {up, up, up} isomer. The structure of RbNa-5b is rather consistent with the superposition of the two {up, up, up} and {down, up, up} isomers disordered over the same crystallographic site, while only the {down, up, up} isomer is present in DMACs-5c. In solution, 183W NMR characterization of 6a as sodium salt results in a complicated spectrum consistent with the simultaneous presence of the four isomers, {up, up, up}, {down, up, up}, {down, down, up} and {down, down, down}, respectively. 5a reacts with three equivalents of iodine to give CsNa-6 isolated as single crystals. In 6, four β-{AsW9O33} moieties are located at the corner of a super tetrahedron and are mutually connected by six {Mo2O2S2} linkers. The three outer {As–OH} groups can be selectively removed by iodine, this oxidation reaction consisting in fact in a deprotecting process permitting the extension of the arrangement from triangular to tetrahedral. [Copyright &y& Elsevier]

Abstract: The cluster [Mo3S4(HNTA)3]2 − reacts in acidic solution with LaCl3 to form a new hybrid layered compound La0.75Cl0.25[Mo3S4(HNTA)3]·18H2O (1) as crystals. Compound 1 has been structurally characterized by XRD, FTIR, TGA and elemental analysis. 1 crystallizes in the chiral P6(3) space group with a =19.319(4)Å, c =31.094(14)Å, V =10,050(5)Å3 and Z =8. The asymmetric unit contains four independent [Mo3S4(HNTA)3]2− anions. Three of them are directly connected to the La3+ cations through the carbonyl groups belonging to the coordinated carboxylates to give a 2D arrangement. The stacking of the 2D arrangements gives rise to the 3D network through hydrogen bonds between water molecules and the remaining hanging protonated carboxylate ligands. The resulting hexagonal network draws large channels (about 12Å in diameter), filled by the fourth [Mo3S4(HNTA)3]2 − unit, which appears uncoordinated and then could be viewed as a guest component. [Copyright &y& Elsevier]

In a recent systematic study on the influence of the reaction temperature on the structure formation in the system CdCI2/H(HO3PCH2)2NH—CH2C6H4—COOH (H5L) /NaOH, [Cd3(H2O)3((O3PCH2)2NH—CH2C6H4—COOH)2]· 11H2O was obtained as a microcrystalline compound. We have now been able to elucidate the structure from single-crystal data: triclinic, P1ā; a = 5.4503(9), b = 12.880(2), and c = 16.417(3) Å; α = 67.841(6)°, β = 80.633(6)°, γ = 87.688(8)°, V 1052.9(3) ų· Z = 1; R1 = 0.1143, R2 = 0.2108 (all data); 0.0705, 0.1823 ((I > 2σ(I)). The structure of [Cd3(H2O)3((O3PCH2)2NH—CH2C6H4—COOH)2]·11H2O is built up of cadmium phosphonate layers connected by water-mediated hydrogen bonds between aryl-carboxylic acid groups and water molecules coordinated to Cd2+ ions of adjacent layers (C—OH···H2O···H2O—Cd2+). The title compound was characterized by IR spectroscopy and energy dispersive X-ray, elemental, and thermogravimetric analyses. Furthermore, temperature-dependent X-ray diffraction data are presented. [Cd3(H2O)3((O3PCH2)2NH—CH2C6H4—COOH)2)·11H2O can be reversibly dehydrated, and mechanical stress and grinding in the presence of water leads to the intercalation of additional water molecules. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of C6H5NCS with led to the formation of a dinuclear complex of molybdenum(V) with two dithiocarboimidate ligands, (NEt4)2[Mo2(S)2(μ-S)2(η2-S2CN(C6H5))2]·0.5CO(CH3)2. The crystallization of 1 is systematically accompanied by the formation of 4-phenyl-3,5-diphenylimino[1,2,4]-dithiazolidine [(C6H5)3N3C2S2] (2). The two compounds have been structurally characterized by XRD and a reaction scheme is proposed. [Copyright &y& Elsevier]

Abstract: Reaction of two transition metal cations M (M=VV, FeIII) on the open Wells–Dawson anion α-[{K(H2O)2}Si2W18O66]15– leads to dinuclear and tetranuclear complexes, respectively. The molecular anions [{KV2O3(H2O)2}(Si2W18O66)]11– and [{Fe4(OH)6}(Si2W18O66)]10– have been structurally characterized by single crystal X-ray diffraction. The oxo/hydroxometallic clusters [KV2O3(H2O)2]5+ and [Fe4(OH)6]6+ are included in the pocket between the two subunits of [Si2W18O66]16–. The FeIII atoms of the iron complex can be reduced to FeII by a single four-electron step. To cite this article: N. Leclerc-Laronze et al., C. R. Chimie 9 (2006) . [Copyright &y& Elsevier]

Abstract: Two fluorinated aluminophosphates called ULM-4 (Al6(PO4)6F4⋅2H3N(CH2)3NH3⋅H2O) and MIL-64 (Al10(PO4)4(HPO4)6F9(H2O)4⋅ OH⋅4N2C3H12) have been prepared in the presence of HF and 1,3-diaminopropane as a structure-directing agent under hydrothermal conditions (autogeneous pressure, 180 °C, 8–48 hours and 1 months, respectively). ULM-4 crystallises from a F/Al ratio of 1 whereas MIL-64 is obtained with F/Al=2. The structures have been determined using room temperature single crystal X-ray diffraction data. ULM-4 is described in the noncentric monoclinic space group P21 (n° 4) with the unit cell parameters: , , , , and MIL-64 crystallizes in the monoclinic space group C2/m (n° 12) with , , , and . Both structures exhibit a three-dimensional framework. For ULM-4, it consists of hexameric units Al3(PO4)3F2 in which the aluminium atoms exhibits two types of surrounding (one octahedron, AlO4F2 and two trigonal bipyramids, AlO4F). The fluorine atoms link the aluminium atoms together. This building unit is similar to that observed in the iron and gallium analogues. The connection of the hexameric units delimits rectangular-shaped 10-ring channels along [010] and 8-ring channels along [100] in which the 1,3-diaminopropane molecules are located. The subnetwork of the amines induces a non-centric symmetry. The second compound MIL-64 is composed of inorganic layers consisting of infinite zigzag chains corner-sharing (via fluorine) aluminum octahedra (AlO4F2, AlO2F3(H2O) and AlO3F2(H2O)) with the cis–trans sequence, connected to each other through fluorine and phosphate groups. The resulting sheets are linked to each other via additional AlO4 and PO4 tetrahedral units and this generates a three-dimensional network with cavities, encapsulating the molecular species OH2⋯H2N(CH2)NH3/OH⋯H3N(CH2)NH3. [Copyright &y& Elsevier]

Abstract: A new convenient synthesis of substituted 2,6,9-trioxabicyclo[3.3.1]-nona-3,7-dienes is described. These new ‘bridged bis-dioxines’ were obtained in moderate to good yields by dimerization of the corresponding arylmalondialdehydes in the presence of 0.5equiv of TMSOTf. The structure of the nitro derivative 1e has been proven by X-ray crystallography. A mechanism for this reaction is proposed. [Copyright &y& Elsevier]

Abstract: The action of succinate and fumarate ions as template on the self-condensation of the {Mo2O2S2} building block led to the bis-templated ring [Mo12O12S12(OH)12(C4H4O4)2]4– (1) (noted [Mo12-succ2]4–) and the mono-templated ring [Mo12O12S12(OH)12(OH2)4(C4H2O4)]2– (2) (noted [Mo12-fum]2–), respectively. Compounds 1 and 2 have been isolated as rubidium salt and structurally characterized by single crystal X-ray diffraction study. Both the compounds have been characterized in solution by 1H NMR, in D2O. Such a study reveals that a dynamic exchange exists for 1, involving successive transfers of a succinate ion through the open-cavity delimited by the Mo12-ring. Thermodynamic data for such successive exchange are given. Nevertheless, variable temperature 1H NMR experiments in CD3CN for 1 and 2 show that no conformational change has been detected between 303 and 227 K for the alkyl chain of the central fumarate and succinate ions. A short discussion was begun upon the structural relationships between the size of the alkyl chain and the nuclearity of the inorganic host. To cite this article: S. Floquet et al., C. R. Chimie 8 (2005) [Copyright &y& Elsevier]

Abstract: The two Zn(II) complexes Zn(dppt)Cl2·0.5 H2O (1) and Zn(dppt)2Cl2·2 H2O (2) were obtained by reaction of 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine (dppt) with zinc chloride. Complex (2) could be obtained from (1) by addition of an excess of dppt. These complexes have been characterized by 1D and 2D 1H NMR spectroscopy, mass spectrometry, and in the solid state by IR and X-ray diffraction. In (1), the Zinc atom is bound to one ligand through the N atom of the pyridyl ring and one of the N atoms of the triazine ring, and to two chlorine atoms in a distorted tetrahedral coordination geometry. Instability of crystals of compound (2) (namely, the lost of crystallization solvent molecules) did not allow their analysis by X-ray diffraction. Structure and stoichiometry of (2) were determined by 2D COSY 1H NMR and mass spectrometry. Two magnetically equivalent ligands (dppt) are coordinated to the metal center. To cite this article: V. Béreau et al., C.R. Chimie 8 (2005). [Copyright &y& Elsevier]

Abstract: A new polyoxovanadate species formulated [V16O42]4– was isolated in DMF solvent. Its structure was solved at 100 K by single-crystal X-ray diffraction in the centrosymmetric monoclinic C2/c (no. 15) space group with lattice parameters a = 25.554(6) Å, b = 14.227(3) Å, c = 28.485(6) Å, β = 113.21(1)°, V = 9518(4) Å3. The refinement of the structure of [(SO4) ⊂ V16O42]·(SO4)2((CH3)2NH2)10((CH3)2NCHO)4 using 11 389 independent I > 2σ(I) reflections led to reliability factors R 1(F o) and wR 2(F o 2), respectively, equal to 0.0434 and 0.1269. The structure of the V16 polyanion, templated by a tetrahedral sulphate group, is built up from one ring of 12 edge-shared VVO5 square pyramids capped on each side by a dimeric unit. Each entity carries out a six-negative charge, the neutrality of the structure is ensured by the appropriate amount of dimethyl ammonium ions. To cite this article: J. Marrot et al., C.R. Chimie 8 (2005). [Copyright &y& Elsevier]

The dimer α-[{K(H2O)2}(Si2W18O66)]15- (1), synthesized by reacting K10A-α.-[SiW9O34] with two equivalents of H+ in aqueous solution, has been characterized by polarography and 183W NMR spectroscopy. Nine resonance signals have been observed with the tetrabutylammonium salt in dimethylformamide/acetonitrile solution, in agreement with the crystal structure of the anion which consists of two A-α-[SiW9O34]10- associated through two W-O-W junctions. This anion derives from the Wells-Dawson structure by breaking four W-O-W junctions. The pocket between the two-half-anions can be filled by several metal cations. Reaction of transition-metal cations with 1 leads to the formation of [{M(H2O)}(μ-H2O)2K(Si2W18O66)]13- (1M) (M = Co, Ni, Cu) and [{M(H2O)}(μ-H2O)2K-{M(H2O)4}(Si2W18O66)]11- (1M2) (M = Mn, Co, Ni) complexes. One potassium is always included in the pocket with one or two transition metals. Because of the shift of the potassium cation to one side of the anion, the coordination modes of the two transition metals are different. Crystals of 1, 1M, and 1Co2 potassium salts are triclinic (P-1, Z = 2) and crystals of 1M2 potassium salts are monoclinic (P2(1)/n, Z = 4). The symmetry of 1M and 1M2 complexes is C1 and they are present in the crystal as racemate inversion pairs. [ABSTRACT FROM AUTHOR]

Studies cation-directed synthesis of tungstosilicates. Influence of the nature of alkali metal ions on the structure of the species obtained from the trivacant precursor A-alpha-[SiW[sub 9]O[sub 34]][sup 10]. Crystal structure of the compounds; Stability in aqueous solution.

[(PW[sub 11]O[sub 39])[sub 2](Mo[sub 4]S[sub 4]O[sub 4](OH[sub 2])[sub 2])][sup 10-] anions were obtained through the stereospecific addition of the [Mo[sub 2]S[sub 2]O[sub 2]][sup 2+] oxothiocation to the monovacant α-[PW[sub 11]O[sub 39]][sup 7-] anion. K[sub 10][(PW[sub 11]O[sub 39])[sub 2]Mo[sub 4]S[sub 4]O[sub 4](OH[sub 2])[sub 2])]·25H[sub 2]O has been isolated as crystals and characterized by X-ray diffraction. The structure revealed a "sandwich-like" dimer of two α-[PW[sub 11]O[sub 39]][sup 7-] subunits assembled by the noteworthy central cluster {H[sub 4]Mo[sub 4]S[sub 4]O[sub 6]}. The crystallization of the crude product produces an isomerically pure compound, which was characterized by [sup 31]P and [sup 183]W NMR. IR data were also supplied. In solution, the compound isomerizes, giving a second diastereoisomer. A kinetic experiment, carried out by [sup 31]P NMR, allowed the conditions of the thermodynamic equilibrium to be determined. A structural relationship between the two isomers is proposed, fully consistent with NMR data. Cisoid and transoid isomers result in the relative disposition of each [PW[sub 11]O[sub 39]][sup 7-] subunit, either staggered or eclipsed. An investigation of the formation of the [Mo[sub 2]O[sub 2]S[sub 2]][sup 2+] unit from the polycondensed cyclic precursor [Mo[sub 10]S[sub 10]O[sub 10](OH)[sub 10](H[sub 2]O)[sub 5]] and the aggregation process resulting in the oxothio [(PW[sub 11]O[sub 39])[sub 2](Mo[sub 4]S[sub 4]O[sub 4](OH[sub 2])[sub 2])][sup 10-] compound has been undertaken. The studies were monitored by [sup 31]P NMR and UV-vis spectroscopies. The reaction is quantitative in nearly stoichiometric conditions. [ABSTRACT FROM AUTHOR]

The fluorinated gallium phosphates ULM-3 and TREN-GaPO were hydrothermally synthesized in the presence of organic templates (1,3-diaminopropane, dap, or tris(2-aminoethyl)amine, tren) and alkali metals (Rb, Cs). The solids were structurally characterized by single-crystal X-ray diffraction, and the structure examination indicates that the amine molecules are partially replaced by alkali cations. In ULM-3 (Mδ[Ga3(PO4)3(F,OH)2], (1−δ/2)N2C3H12, (1−δ/2)H2O; M=Rb, Cs), the alkali metals are located within the 10-ring channels and partially occupy the positions of water and amine molecules (δ≈0.07 for Rb and δ≈0.18 for Cs). In TREN-GaPO (M0.5[Ga3(PO4)3(F,OH)2], 0.5N4C6H21, H2O; M=Rb, Cs), the alkali cations reside in the 8-ring channels, whereas the tren molecule is trapped within the 12-ring channels. The positions of rubidium and cesium atoms are compared with those of pyridine previously reported for TREN-GaPO. [Copyright &y& Elsevier]

The nickel arsenatotungstate K10[As2W19(H2O){Ni(H2O)}2O67]·18H2O (1) has been synthesized. Due to its instability in water, attempts to obtain crystals of 1 suitable for X-ray diffraction have failed. The stabilization of the [As2W19(H2O){Ni(H2O)}2O67]10− core has been reached by synthesizing the analogue mixed {CsK} salt. The crystal structure of Cs6K2[Ni(H2O)6][As2W19(H2O){Ni(H2O)}2O67]·17H2O (2) has been resolved. It consists of two [α-AsW9O33]9− sub-units linked via a belt containing a tungsten and two nickel cations. Comparison of infrared and electronic absorption spectroscopic data for 1 and 2 has confirmed the structure proposed for 1. The instability of 1 led us to investigate the behavior of 1 in water. UV–Vis spectroscopy revealed that the formation of this complex is a multi-step reaction. An intermediate, the complex K8[Ni(H2O)6]1.5[As2W19(H2O){K(H2O)}{Ni(H2O)4}O67]·21H2O (3), has been isolated and characterized by elemental analysis, UV–Vis and infrared spectroscopies, and X-ray diffraction. In 3, the two vacant sites of the [As2W19O67]14− anion are occupied by a nickel and a potassium, forming a {WNiK} belt. It follows that the stability of 2 in water is due to the large ionic radius of Cs+, which prevents the inclusion of the alkaline cation into the cavity of the [As2W19O67]14− anion. The complex 3 represents a unique example of a fully characterized intermediate leading to the formation of a sandwich-type polyoxometalate. [Copyright &y& Elsevier]

Fifteen new coordination binuclear compounds of copper(II) were synthesized based on substituted 4-tert-butyl-2,6-bis(N4-thiosemicarbazonyl)phenol (H3L1–3) ditopic ligands. The complexes were characterized using FT-IR spectroscopy, elemental analysis, MALDI-TOF analysis and X-ray diffraction studies highlighting the formation of dinuclear species with various bridging ligands between the two copper(II) atoms and in some cases the dimerization of these species into tetranuclear complexes. The antioxidant, antimicrobial and antifungal activities of ligands and their copper(II) coordination complexes have been investigated. In particular, the complexes show similar or better antimicrobial and antifungal properties than the drugs commonly used in this field. The structure–biological activity relationship is discussed based on the nature of the ligand and the copper salt used in the synthesis of the complexes. [ABSTRACT FROM AUTHOR]

The accumulation of chiral ammonium‐oxocarbenium dications in superacid is evidenced by low‐temperature NMR spectroscopy, X‐ray diffraction analysis and confirmed by DFT calculations. Its potential for the diastereoselective remote hydrofunctionalization of non‐activated alkene is also explored. [ABSTRACT FROM AUTHOR]

The accumulation of chiral ammonium‐oxocarbenium dications in superacid is evidenced by low‐temperature NMR spectroscopy, X‐ray diffraction analysis and confirmed by DFT calculations. Its potential for the diastereoselective remote hydrofunctionalization of non‐activated alkene is also explored. [ABSTRACT FROM AUTHOR]

Two BODIPY‐C60‐peptide assemblies were synthesized by CuAAC reactions of BODIPY‐C60 dyads and a helical peptide functionalized with a terminal alkyne group and an azide group, respectively. The helical peptide within these assemblies was functionalized at its other end by a disulfide group, allowing formation of self‐assembled monolayers (SAMs) on gold surfaces. Characterizations of these SAMs, as well as those of reference molecules (BODIPY‐C60‐alkyl, C60‐peptide and BODIPY‐peptide), were carried out by PM‐IRRAS and cyclic voltammetry. BODIPY‐C60‐peptide SAMs are more densely packed than BODIPY‐C60‐alkyl and BODIPY‐peptide based SAMs. These findings were attributed to the rigid peptide helical conformation along with peptide‐peptide and C60‐C60 interactions within the monolayers. However, less dense monolayers were obtained with the target assemblies compared to the C60‐peptide, as the BODIPY entity likely disrupts organization within the monolayers. Finally, electron transfer kinetics measurements by ultra‐fast electrochemistry experiments demonstrated that the helical peptide is a better electron mediator in comparison to alkyl chains. This property was exploited along with those of the BODIPY‐C60 dyads in a photo‐current generation experiment by converting the resulting excited and/or charge separated states from photo‐illumination of the dyad into electrical energy. [ABSTRACT FROM AUTHOR]

Host‐guest complexes between native cyclodextrins (α‐, β‐ and γ‐CD) and hybrid Lindqvist‐type polyoxovanadates (POVs) [V6O13((OCH2)3C−R)2]2– with R = CH2CH3, NO2, CH2OH and NH(BOC) (BOC = N‐tert‐butoxycarbonyl) were studied in aqueous solution. Six crystal structures determined by single‐crystal X‐ray diffraction analysis revealed the nature of the functional R group strongly influences the host–guest conformation and also the crystal packing. In all systems isolated in the solid‐state, the organic groups R are embedded within the cyclodextrin cavities, involving only a few weak supramolecular contacts. The interaction between hybrid POVs and the macrocyclic organic hosts have been deeply studied in solution using ITC, cyclic voltammetry and NMR methods (1D 1H NMR, and 2D DOSY, and ROESY). This set of complementary techniques provides clear insights about the strength of interactions and the binding host‐guest modes occurring in aqueous solution, highlighting a dramatic influence of the functional group R on the supramolecular properties of the hexavanadate polyoxoanions (association constant K1:1 vary from 0 to 2 000 M−1) while isolated functional organic groups exhibit only very weak intrinsic affinity with CDs. Electrochemical and calorimetric investigations suggest that the driving force of the host‐guest association involving larger CDs (β‐ and γ‐CD) is mainly related to the chaotropic effect. In contrast, the hydrophobic effect supported by weak attractive forces appears as the main contributor for the formation of α‐CD‐containing host‐guest complexes. In any cases, the origin of driving forces is clearly related to the ability of the macrocyclic host to desolvate the exposed moieties of the hybrid POVs. [ABSTRACT FROM AUTHOR]

A series of enantioenriched 4,5,6,7‐tetrahydrofuro[2,3‐b]pyridines were accessed by a cycloisomerization/cycloaddition strategy. Starting from ynamide derivatives and aldehydes, yields ranging from 27 to 90% and high levels of stereoselectivity (de>95%, 93–99% ee) were obtained through sequential relay catalysis. The concurrent use of a gold complex with a diphenylprolinol silyl ether was applied to a combination of diversely functionalized substrates. [ABSTRACT FROM AUTHOR]

A general protocol for the synthesis of S‐trifluoromethyl S‐arylsulfoximine thioglycosides has been reported. This protocol is based on a Pd‐catalyzed Migita cross‐coupling between o‐iodo S‐trifluoromethyl S‐arylsulfoximines and a broad range of 1‐thiosugars. This method gives access to a series of functionalized S‐trifluoromethyl S‐arylsulfoximine thioglycosides in moderate to good yields. Moreover, both diastereoisomers were easily separated by simple crystallization or by HPLC and full characterizations are provided for each pure trifluoromethylsulfoximine. [ABSTRACT FROM AUTHOR]

We describe the preparation of S‐perfluoroalkyl benzodithiazole trioxides as radical perfluoroalkylating reagents. Their syntheses were performed on a multi‐gram scale by an oxidative cyclization connecting the nitrogen of a sulfoximine and a sulfur atom previously introduced in the ortho position of this group. The structures and properties of these new molecules were carefully examined by X‐Ray diffraction, DFT calculations and cyclic voltammetry. These data clearly highlight the enhanced reactivity of these cyclic sulfoximines compared to their open analogues. This was confirmed by photoredox catalysis experiments that revealed interesting reactivity, most especially for the introduction of di‐ and monofluoroalkyl chains. [ABSTRACT FROM AUTHOR]

The trifluoromethylthio group is of rising interest in medicinal, agrochemical, and materials chemistry. Although several strategies for the introduction of this functional group have been described, new synthetic methods are needed. A novel ionic liquid, 1- n-butyl-3-methylimidazolium trifluoromethylthiolate, has been developed and is herein reported as an efficient and recyclable in situ generated trifluoromethylthiolating reagent for alkyl halides, sulfonates, and even unactivated alcohols under solvent-free conditions. [ABSTRACT FROM AUTHOR]

Five new tartrate-containing Keplerate compounds have been synthesized and characterized in the solid state and in solution. These characterizations evidenced the total replacement of inner sulfate ligands by L- or D-tartrate ligands in aqueous medium under heating during several days. To our knowledge these compounds correspond to the first Keplerate molecules incorporating chiral ligands. The H NMR studies supported by X-ray crystallographic analysis are consistent with the coordination of 24-30 tartrates within the Mo capsule which are located in close vicinity. The NMR signals of the encapsulated ligands appear particularly broad which precludes the use of advanced NMR methodologies but the solid state NMR provided further characterization of ligand substitution within the capsule by carboxylates. To our knowledge it is the first time that a solid state NMR study of a Keplerate is reported in the literature. [ABSTRACT FROM AUTHOR]

A convenient one-pot synthesis of unsymmetrical sulfamides via a Lossen-like rearrangement is reported. The protocol operates under simple conditions at room temperature and does not require an inert atmosphere and a dry solvent. The ability of N-hydroxy arenesulfonamide O-derivatives to generate under mild conditions N-sulfonylimine intermediates was a trigger point for developing a general synthetic strategy towards unsymmetrical sulfamides. The synthetic potential of the methodology has been investigated by preparing cyclic sulfamides and new potential chiral organocatalysts. [ABSTRACT FROM AUTHOR]

A solvent- and catalyst-free synthesis of nitrogen-containing bicyclic derivatives through a three-bond forming process is reported. Starting from dienals and readily available diazenes, the strategy involving the hemiaminal formation/hetero-Diels-Alder reaction affords the bicyclic products in a highly diastereoselective manner. This simple and green procedure has been applied to a selection of substrates, giving rise to 12 examples of nitrogen-containing bicyclic architectures. These products underwent various synthetic transformations. A sequence involving the cleavage of the hydrazine allowed the preparation of a hydantoin motif bearing an aminopropyl side chain, which is a structure found in natural products. A mechanism has also been suggested to explain the observed selectivities. [ABSTRACT FROM AUTHOR]

Abstract: The alkylation of indoles by aziridinium ions generated in situ from β-amino chlorides was explored. The outcome of this reaction strongly relied on the substitution pattern of the starting β-amino chloride and requires silver tetrafluoroborate activation to proceed in reasonable yield. Ephedrine- and pseudoephedrine-derived N-cyanomethyl-β-amino chlorides afforded the corresponding tryptamines in a regio- and stereoselective manner and subsequent silver(I)-promoted Pictet–Spengler reactions produced 4-phenyl substituted THBCs in good yields. Unexpected epimerization at C-3 was found in these reactions, producing trans-3,4-disubstituted THBCs stereoselectively. [Copyright &y& Elsevier]

Abstract: New series of acridines and phenanthrolines have been prepared from β-chlorovinyl aldehydes and various aniline derivatives allowing the installation of valuable substituents, such as ketone, nitro or amino groups at the heterocyclic core. X-ray analyses confirmed the structures of acridines and phenanthrolines as well as the presence of partially hydrogenated rings and their crucial impact on the overall shape of the acridine-based architectures. 1H NMR revealed the helical behaviour of several acridine motives. Comparison of UV data between architectures and influence of number of partially hydrogenated rings is also described. [Copyright &y& Elsevier]

The complexes [MoOS(OH)(abtc)(HO)] ( 1) and [MoOS(OH)(abtc)(HO)] ( 2) (abtc = 3,5-dicarboxyl-(3′,5′-dicarboxyazophenyl)benzene) have been obtained from the condensation of the [MoOS] cluster in the presence of abtc ligand. Compounds 1 and 2 were characterized structurally, revealing host-guest architectures containing one or two encapsulated abtc ligands. In 1, the guest abtc moieties appears firmly coordinated to the ring by the four carboxylato groups, giving a nearly planar conformation which fall in the plane of the sixteen Mo atoms of the inorganic macrocycle. Conversely, the two equivalent abtc ligands in 2 exhibit an asymmetric mode of coordination, where two carboxylato groups are coordinated to the {Mo} ring and the two remaining hang outer the open cavity. Anions 1 and 2 have been characterized by H NMR in solution, revealing for 1 an enhancement of the symmetry likely due to some molecular dynamic, while the compound 2 easily converts into 1 with a consecutive release of one abtc ion. Furthermore, a solution study showed that the formal linkage of the two isophatlate moieties through an azo {N=N} unit brings a drastic stability increase of the host-guest assembly compared to the bis-isophtalate containing {Mo} ring. Synthesis, elemental analysis, and infrared spectra are also supplied. [ABSTRACT FROM AUTHOR]

The combination of oxidative dearomatization and trienamine/enamine activation in a single vessel is described. Under these conditions, a three-bond forming process generates functionalized tricyclic architectures with up to six contiguous stereocenters with excellent stereoselectivities from readily available planar substrates. [ABSTRACT FROM AUTHOR]

The preparation of new thienyl-, oxazolyl-, and pyridyl-fused benzo[ c]fluorenones has been developed from a unique and easily available common precursor. Starting from bromotetralone, a short sequence allowed the construction of various heterocycles followed by Suzuki coupling and final acid-promoted formation of the central cyclopentanone unit. The flexible strategy allowed the selective preparation of fused penta- to hepta-cyclic architectures. Fully aromatic targets have been obtained through the application of an oxidation process. The influence of structural modulations on the photophysical properties are described. [ABSTRACT FROM AUTHOR]

The reaction of {SbW9O33}9- with {Mo2O2S2}2+ has been studied. The {SbW9O33}{Mo2O2S2} products are labile in solution and very sensitive to experimental conditions. Two new hybrids, {Mo2O2S2}-containing tungstoantimonate anions, namely [(SbW9O33)2(Mo2O2S2)3]12- and [K(SbW9O33)2(Mo2O2S2)WO(H2O)]11-, have been fully characterized in the solid state and in solution by 183W NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The solvothermal synthesis of a novel mixed-s-block metal-organic framework is described, with crystallization brought about by use of the sodium salt of the benzo-(1,2;3,4;5,6)-tris(thiophene-2′-carboxylate) linker in combination with a lithium salt. The structure of the material was determined by single-crystal X-ray diffraction, which reveals an expanded version of the β-cristobalite topology, with supertetrahedral building units made up of clusters of sodium and lithium ions. Outgassing under vacuum gives permanent porosity to the solid structure with a BET surface area of 1191 m2 g-1 measured by nitrogen adsorption. [ABSTRACT FROM AUTHOR]

Abstract: A robust and practical synthesis of each enantiomer of 2-methyl-azetidine-2-carboxylic acid, based on the use of (S)-phenylglycinol as resolving agent, is described. This synthesis affords practical quantities of this quaternary amino acid suitably N- and C-protected for use in further peptide coupling. Synthetic highlights include the formation of the azetidine ring by intramolecular alkylation and the facile separation of the diastereoisomeric amides derived from phenylglycinol. [Copyright &y& Elsevier]

Abstract: Chalcogenide cluster [Mo3S4(HNTA)3]2− was used as precursor to generate new organic–inorganic hybrid material. La2Cl[Mo3S4(NTA)3]⋅17H2O (1) was obtained by hydrothermal synthesis starting from [Mo3S4(NTA)3]5− and La3+ cation. Compound (1) was fully characterised by XRD, FTIR, TGA and elemental analysis. (1) crystallises in the P-1 space group with a =11.2219(3)Å, b= 13.2435(3)Å, c =17.6351(5)Å, α =82,365(1)°, β =72,787(1)°, γ =68,608 (1)°, V =2330.11(11)Å3 and Z =2. Single-crystal X-ray diffraction analyses evidenced that the resulting 3D network consists of [Mo3S4(NTA)3]5− units connected through La3+ cations. [Copyright &y& Elsevier]

Reaction of the cyclic lacunary [H7P8W48O184]33- anion (noted P8W48) with the [Mo2S2O2(H2O)6]2+ oxothiocation led to two compounds, namely, [K4{Mo4O4S4(H2O)3(OH)2}2(WO2)(P8W48O184)]30- (denoted 1) and [{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]36- (denoted 2), which were characterized in the solid state and solution. In the solid state, the structure of [K4{Mo4O4S4(H2O)3(OH)2}2(WO2)(P8W48O184)]30- reveals the presence of two disordered {Mo4O4S4(H2O)3(OH)2}2+ "handles" connected on both sides of the P8W48 ring. Such a disorder is consistent with the presence of two geometrical isomers where the relative disposition of the two {Mo4O4S4(H2O)3(OH)2}2+ handles are arranged in a perpendicular or parallel mode. Such an interpretation is fully supported by 31P and 183W NMR solution studies. The relative stability of both geometrical isomers appears to be dependent upon the nature of the internal alkali cations, i.e., Na+ vs K+, and increased lability of the two {Mo4O4S4(H2O)3(OH)2}2+ handles, compared to the oxo analogous, was clearly identified by significant broadening of the 31P and 183W NMR lines. Solution studies carried out by UV-vis spectroscopy showed that formation of the adduct [{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]36- occurs in the 1.5-4.7 pH range and corresponds to a fast and quantitative condensation process. Furthermore, 31P NMR titrations in solution reveal formation of the "monohandle" derivative [{Mo4O4S4(H2O)3(OH)2}(P8W48O184)]38- as an intermediate prior to formation of the "bishandle" derivatives. Furthermore, the electrochemical behavior of [{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]36- was studied in aqueous medium and compared with the parent anion P8W48. [ABSTRACT FROM AUTHOR]