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A new series of 4-methyl-2-{2-[(aryl)methylidene]hydrazinyl}-1,3-thiazole (2a-i), N-(4-acetyl-5-aryl)4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamides (3a-b) and N-(5-(4-(substituted phenyl)-1,3,4-thiadiazol-2-yl)acetamides (3c-i) were synthesized by the reaction of 2-((aryl)methylene)hydrazine-1-carbothioamides (1a-i) and acetic anhydride or chloroacetone. The cytotoxic activities of the products were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against Hela cervical cancer, MCF-7 breast carcinoma and HT-29 colorectal cancer cell lines. Thiazole based compounds 2a, 2b, 2f and 2i, bearing 4-bromothiophen-2-yl, naphthalen-2-yl, 2,5-difluorophenyl and 4-(trifluoromethoxy)phenyl moieties, respectively; also N-(4-acetyl-5-(naphthalen-2-yl)-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide (3b) and N-(5-(2,6-difluorophenyl)-1,3,4-thiadiazol-2-yl)acetamide (3d) exhibited significant anticancer activity against three cancer cell lines. Moreover, these active compounds were further evaluated by apoptotic protein levels. The results showed that these thiazole and thiadiazole compounds induced apoptosis of cancer cells.

The five new Ru(II)(eta(6)-p-cymene) complexes (1-5 ) were successfully synthesized, characterized by FT-IR, elemental analysis, electronic spectra, proton and carbon NMR, mass spectra and thermal analysis, and applied in the transfer hydrogenation of ketones. In addition, enzyme inhibitory and antioxidant activities of novel Ru(II)(eta(6)-p-cymene) complexes were evaluated using several in vitro methods. The stabilities of complexes were checked by UV-Vis. spectroscopy. The results of enzyme assays showed that novel Ru(II)(eta(6)-p-cymene) complexes had effective inhibitions against the tyrosinase and pancreatic lipase enzymes. The IC50 values of five different (1-5) for tyrosinase were found as 34.65 +/- 1.2 mu M, 31.51 +/- 1.7 mu M, 49.50 +/- 3.1 mu M, 19.25 +/- 0.9 mu M, and 63.01 +/- 3.3 mu M, respectively. Furthermore, ABTS, CUPRAC, DPPH, and FRAP in vitro methods were utilized to assess the antioxidant capabilities of the compounds. The powerful antioxidant potentials of the synthesized compounds were detected compared to the standards, such as BHA, BHT, ascorbic acid, and a-tocopherol. This study provides a valuable potential of the novel Ru(II)(eta(6)-p-cymene) complexes for pharmacological studies with further analytical experiments to explore their full properties. (C) 2022 Elsevier B.V. All rights reserved.

In this study, we have designed, synthesized and full characterized a novel biological based acidic nano organocatalyst via condensations reaction of uric acid and phosphorous acid. The obtained compound was named theacrine tetrakis(phosphonic acid) (TTPA) and prepared under refluxing ethanol. This new nano organocatalyst was applied as an efficient and recyclable catalyst for the preparation of novel pyridines with indole moieties via a cooperative vinylogous anomeric based oxidation with good to excellent yields.

The impact of various degrees of acetylation on improving the thermal stability of xylan isolated from different botanical source has been studied; methylglucuronoxylan from birch and eucalyptus, arabinoglucuronoxylan from spruce and glucuronoarabinoxylan from sugarcane bagasse and straw. The lower molecular weight of nonacetylated methylglucuronoxylan (17.7-23.7 kDa) and arabinoglucuronoxylan (16.8 kDa) meant that they were more soluble in water than glucuronoarabinoxylan (43.0-47.0 kDa). The temperature at the onset of degradation increased by 17-61 degrees C and by 75-145 degrees C for low and high acetylated xylans respectively, as a result of acetylation. A glass transition temperature in the range of 121-132 degrees C was observed for the samples non-acetylated and acetylated at low degree of acetylation (0.0-0.6). The acetylation to higher degrees (1.4-1.8) increased the glass transition temperature of the samples to 189-206 degrees C. Acetylation proved to be an efficient method for functionalization of the xylan to increase the thermal stability.

The pyrolytic sugar fraction, obtained by an aqueous extraction of pyrolysis oil, is an attractive source for sugar-derived platform chemicals. However, solids (humin) formation occurs to a significant extent during hydrolysis and subsequent acid-catalyzed conversion processes. In this study, we report investigations on possible conversion routes (pyrolysis, liquefaction) of such humin byproducts to biobased chemicals. Experiments were carried out with a model humin made from a representative technical pyrolytic sugar and the product was characterized by elemental analysis, GPC, TGA, HPLC, GC-MS, FT-IR and NMR. The obtained humin sample is soluble in organic solvents (dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and isopropanol (IPA)), in contrast to typical more condensed humins from glucose and fructose, allowing characterization using NMR and GPC. All analyses reveal that the humins are oligomeric in nature (M-w of about 900 g/mol) and consist of sugar and furanic fragments linked with among others (substituted) aliphatic, ester units and, in addition, phenolic fragments with methoxy groups. The humins were used as a feed for catalytic pyrolysis and catalytic liquefaction experiments. Catalytic pyrolysis experiments (mg scale, programmable temperature vaporizer (PTV)-GC-MS, 550 degrees C) with HZSM-5 50 as the catalyst gave benzene-toluene-xylene-naphthalene-ethylbenzene mixtures (BTXNE) in 5.1 wt% yield based on humin intake. Liquefaction experiments (batch reactor, 350 degrees C, 4 h, isopropanol as both the solvent and hydrogen donor and Pt/CeO2 (4.43 wt% Pt) catalyst) resulted in 80 wt% conversion of the humin feed to a product oil with considerable amounts of phenolics and aromatics (ca. 24.7 % based on GC detectables in the humin oil). These findings imply that the techno-economic viability of pyrolysis oil biorefineries can be improved by converting humin type byproducts to high value, low molecular weight biobased chemicals.

In this communication, we investigate the reaction between seleno- and thiourea, derived from N-heterocyclic carbenes, with the interhalogen iodine monochloride. The formation of all three products was confirmed by NMR spectroscopy, while single-crystal X-ray analyses were able to establish a charge-transfer coordination type, which showed a linear Se/S-I-Cl arrangement, for all adducts formed. Based on a detailed crystallographic analysis, we can deduce the zwitterionic character of these compounds.

Hydrogels find application in many areas of technology and research due to their ability to combine responsiveness and robustness. A detailed understanding of their molecular structure and dynamics (which ultimately underpin their functional properties) is needed for their design to be optimized and these hydrogels to be exploited effectively. In this review, we shed light on the unique capabilities of solid-state NMR spectroscopy to reveal this information in molecular detail. We review recent literature on the advancements in solid-state NMR techniques in resolving the structure, degree of grafting, molecular organization, water-biopolymer interactions and internal dynamical behavior of hydrogels. Among various solid-state NMR techniques, 13C cross polarization (CP) magic angle spinning (MAS) NMR is examined for its ability to probe the hydrogel and its trapped solvent. Although widely applicable to many types of polymeric and supramolecular hydrogels, the current review focuses on polysaccharide-based hydrogels.

New mononuclear complexes [Mn(NO3)(sac)(H2O)(bzimpy)]center dot 2DMF (Mn), [Fe(sac)(2)(H2O)(bzimpy)]center dot 2H(2)O (Fe), [Co(bzimpy)(2)](sac)(2)center dot 2H(2)O (Co), [Ni(bzimpy)(2)](sac)(2)center dot H2O center dot i-PrOH (Ni) and [Cu(sac)(2)(bzimpy)]center dot 3DMF (Cu) (sac = saccharinate and bzimpy = 2,6-bis(2-benzimidazolyl)pyridine) were synthesized and structurally characterized by elemental analysis, UV-Vis, IR, ESI-MS and X-ray diffraction. The anticancer activity of the metal complexes against A549 (lung), MCF-7 (breast), HT29 (colon) cancer cells and MCF10A (normal human breast epithelial) cells was tested and compared with those of cisplatin and bzimpy. The complexes displayed potent cytotoxic activity especially in MCF-7 and A549 cell lines, but they were practically inactive against the normal cells. Mechanistic studies with Mn and Cu complexes on A549 cells indicated that the complexes induced G0/G1 arrest. Both complexes increased intracellular ROS (reactive oxygen species) levels and successfully caused both mitochondrial dysfunction and doublestrand DNA breaks. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-3/7 activation and reduced Fas expression indicated that Mn and Cu induced ROS-dependent mitochondria-mediated intrinsic apoptosis in A549 cells. (C) 2020 Elsevier Masson SAS. All rights reserved.

Polylactide (PLA) is a high potential bioplastic that can replace oil‐based plastics in a number of applications. To date, in spite of its known toxicity, a tin catalyst is used on industrial scale which should be replaced by a benign catalyst in the long run. Germanium is known to be unharmful while having similar properties as tin. Only few germylene catalysts are known so far and none has shown the potential for industrial application. We herein present Ge complexes in combination with zinc and copper, which show amazingly high polymerization activities for lactide in bulk at 150 °C. By systematical variation of the complex structure, proven by single‐crystal XRD and DFT calculations, structure–property relationships are found regarding the polymerization activity. Even in the presence of zinc and copper, germanium acts as the active site for polymerizing probably through the coordination–insertion mechanism to high molar mass polymers., On the route towards a benign production of PLA, we came across Germanium. With its similar properties to tin due to its close position in the periodic table, germanium, being completely nontoxic, is a promising, but so far rather neglected candidate for an alternative catalyst for industrial lactide polymerization. With high molar masses after 1 h of polymerization at 150 °C in bulk, these examples show the high efficiency germanium catalysts can reach (see scheme).

The discovery of sustainable and scalable synthetic protocols leading to gold-aryl compounds bearing N-heterocyclic carbene (NHC) ligands sparked an investigation of their reactivity and potential utility as organometallic synthons. The use of a mild base and green solvents provide access to these compounds, starting from widely available boronic acids and various [Au(NHC)Cl] complexes, with reactions taking place under air, at room temperature and leading to high yields with unprecedented ease. One compound, (N,N'-bis[2,6-(di-isopropyl)phenyl]imidazol-2-ylidene)(4-methoxyphenyl)gold, ([Au(IPr)(4-MeOC6 H4 )]), was synthesized on a multigram scale and used to gauge the reactivity of this class of compounds towards C-H/N-H bonds and with various acids, revealing simple pathways to gold-based species that possess attractive properties as materials, reagents and/or catalysts.

Samarocene sandwich complexes with superbulky penta-arylcyclopentadienyl ligands have been prepared and were structurally characterized: [(4-EtC6H4)(5)C-5](2)Sm (1) and [(4-iPrC(6)H(4))(5)C-5](2)Sm (2). Analogous to the previously reported synthesis of [(4-nBuC(6)H(4))(5)C-5](2)Sm, reaction of (DMAT)(2)center dot Sm(THF)(2) (DMAT = 2-Me2N-alpha-Me3Si-benzyl) and the appropriate Ar5C5H ligand gave 1 (66% yield) and 2 (59% yield). In contrast to the high reactivity of Cp*Sm-2, complex 1 has been shown to be surprisingly stable toward reaction with a large variety of reagents. Even under forcing conditions, no reaction with N-2, CO, CO2, pyrazine, trans-stilbene, pyridine, P-4, and benzophenone was observed. Complex 1 reacts with cuminil ArC(O)C(O)Ar (Ar = 4-iPrC(6)H(4)) to yield the Sm(III) sandwich complex [(4-EtC6H4)(5)C-5](2)Sm[ArC(O)C(O)Ar] (3), which could be isolated in 83% yield as a dark-red crystalline material. Complex 2 reacts with oxygen in the presence of phenazine to yield the bimetallic Sm(III) complex [(4-iPrC(6)H(4))(5)C5Sm(eta(1)-phenazine)]2(mu:eta(2)-eta(2)-O-2)(2) (4) in 25% yield as dark-red crystals. The unusually high redox-stability of deca-arylsamarocenes originates from steric hindrance of the Sm metal center.

International audience; Herein we report the synthesis of new ditopic ligands, which consist of a phenoxy group and N,N,N'trisubstituted amidines linked by a methylene spacer (L1-L4). Their coordination chemistry has been studied/investigated with Zn(II) and Al(III). Alkane elimination route between the phenol-amidine proligands (L1H-L4H) and Et2Zn led to dinuclear complexes [(L1-L4)ZnEt]2 (1a-4a) in which the Zn centers are chelated by phenoxyamidine ligands and bridged through the oxygen atom of the phenoxy groups. Salt metathesis reaction between two equivalents of the sodium amidine phenate L1Na and ZnCl2 led to a bis-chelate chiral spiro-complex (L12Zn) 1a'. Analogous alkane elimination route between AlMe3 and the phenol-amidine proligands L1H-L4H allowed the preparation of the mononuclear complexes [(L1-L4)AlMe2] (1b-4b). The phenoxyamidine-Al and Zn complexes have been characterized by NMR spectroscopy, elemental analysis and/or high resolution ESI-MS. The solid state structures of the proligands [L1H2][Br] and L2H as well as of six complexes have been established by single crystal X-ray diffraction analysis. Fluxional properties of the proligands L1H-L2H and of the complexes 1a and 2b have been investigated by VT NMR experiments. In the presence of an alcohol source, complexes 1a-4a and 1b-4b were used as initiators for the controlled ring-opening polymerization (ROP) of rac-lactide to afford atactic polylactic acid (PLA).

Lipids are a large and highly diverse family of biomolecules, which play essential structural, storage and signalling roles in cells and tissues. Although traditional mass spectrometry (MS) approaches used in lipidomics are highly sensitive and selective, lipid analysis remains challenging due to the chemical diversity of lipid structures, multiple isobaric species and incomplete separation using many forms of chromatography. Ion mobility (IM) separates ions in the gas phase based on their physicochemical properties. Addition of IM to the traditional lipidomic workflow both enhances separation of complex lipid mixtures, beneficial for lipid identification, and improves isomer resolution. Herein, we discuss the recent developments in IM-MS for lipidomics.

A series of novel 4-ferrocenyl-1,2,3,4-tetrahydroquinolines were synthesized in high-to-excellent yields (up to 99%) starting from the corresponding ferrocenoylethyl aryl amines. These Mannich bases were reduced (NaBH4) to the corresponding 3-(arylamino)-1-ferrocenylpropan-1-ols and submitted to an intramolecular cyclization prompted by acetic acid, proceeding via the corresponding alpha-ferrocenyl carbenium ion intermediates. Subsequently, the obtained tetrahydroquinolines were smoothly oxidized (aromatized) by means of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to provide the corresponding 4-ferrocenylquinolines (up to 93%). (C) 2017 Elsevier Ltd. All rights reserved.

A catalyst screening study is reported on the liquefaction of humins, the solid byproducts from C6 sugar biorefineries for levulinic acid and 5-hydroxymethylfurfural production. Experiments were carried out in a batch reactor using an artificial model of humin derived from glucose with isopropanol (IPA) as the solvent at 400 degrees C for a 3 h batchtime. Initial studies using noble metal catalysts (Rh, Pt, Pd, Ru) on a carbon support revealed that Pt was the best catalyst in terms of humin conversion (77%) and amounts of alkylphenolics and aromatics in the product oil (GCxGC-FID). Subsequent support screening studies (TiO2, ZrO2, CeO2) were performed using Pt as the active metal and the results were compared with Pt/C. Detailed liquid product analysis (GPC, GC-MS, GCxGC) including blank reactions in the absence of humins revealed that the humins are mainly converted to monomeric alkylphenolics and aromatics oligomers (GPC) and (GC). IPA was shown not to be inert and is converted to acetone and hydrogen, and the latter is the hydrogen source for the various metal catalysed hydrogenolysis and hydro(deoxy) genation reactions. In addition, acetone is converted to aldolcondensation products (like methylisobutylketone, MIBK) and hydrogenation products derived thereof. The best results were obtained with Pt/C when considering humin conversion. However, Pt/CeO2 was shown to be more attractive when considering the amounts of alkylphenolics in the product oils (20.4 wt% based on humin intake).

Reaction of (TBBP)AlMe⋅THF with [Cp*2 Zr(Me)OH] gave [(TBBP)Al(THF)-O-Zr(Me)Cp*2 ] (TBBP=3,3',5,5'-tetra-tBu-2,2'-biphenolato). Reaction of [DIPPnacnacAl(Me)-O-Zr(Me)Cp2 ] with [PhMe2 NH](+) [B(C6 F5 )4 ](-) gave a cationic Al/Zr complex that could be structurally characterized as its THF adduct [(DIPPnacnac)Al(Me)-O-Zr(THF)Cp2 ](+) [B(C6 F5 )4 ](-) (DIPPnacnac=HC[(Me)C=N(2,6-iPr2 -C6 H3 )]2 ). The first complex polymerizes ethene in the presence of an alkylaluminum scavenger but in the absence of methylalumoxane (MAO). The adduct cation is inactive under these conditions. Theoretical calculations show very high energy barriers (ΔG=40-47 kcal mol(-1) ) for ethene insertion with a bridged AlOZr catalyst. This is due to an unfavorable six-membered-ring transition state, in which the methyl group bridges the metal and ethene with an obtuse metal-Me-C angle that prevents synchronized bond-breaking and making. A more-likely pathway is dissociation of the Al-O-Zr complex into an aluminate and the active polymerization catalyst [Cp*2 ZrMe](+) .

Rationale By taking advantage of the gas-phase decompositions of polymer ions, tandem mass spectrometry of polymers allows us to obtain more accurate structural information than from a simple mass measurement. Applied to a model polymer, the goal of this work was to evaluate the performances of an activation technique based on ultraviolet (UV) irradiation, as an alternative to conventional collisional activation. Methods Sodiated poly(ethylene glycol) produced by electrospray ionization was isolated in a linear ion trap, then submitted to synchrotron UV irradiation over a range of wavelengths (52 to 248 nm). Fragmentation pathways resulting from UV photoactivation were investigated. The proposed mechanisms take into account: (i) the comparison with collision-induced dissociation (CID) product ions, (ii) the effect of wavelength-tunable UV activation, and (iii) deuterium-labeling and various other complementary experiments. For the highest molecular weight compounds, ion mobility spectrometry was used before UV photoactivation. Results Synchrotron UV irradiation can induce dissociation of poly(ethylene glycol) sodiated ions without the requirement of the presence of a specific chromophore, if the photon energy is above 10 eV. UV photoactivation of poly(ethylene glycol) ions can yield fragmentations that differ from those in classical low-energy CID, especially from higher masses (>4000 g mol-1 ). A successful coupling of UV photoactivation with ion mobility pre-filtering was presented. Conclusions UV activation combined or not with pre-filtering ion mobility is a promising alternative approach for the structural characterization of polymers. UV synchrotron radiation with a tunable wavelength was a great opportunity to study the effect of the photon energy, and to probe the mechanisms of ion decomposition from poly(ethylene glycol).

Aim of this study was to produce hydrophilic breathable polyurethane membranes providing antibacterial property permanently by incorporation of a quaternary ammonium salt diol (QAS). The study was carried out by synthesis of nine different polyurethanes by solution polymerization through variations of their QAS and isocyanate contents. Fully amorphous membranes at a thickness of 30m were produced from the synthesized polymers and their thermal and morphological characteristics were determined. The effect of morphological structures on the membrane water vapor transmission rates (WVTR) and antibacterial properties were correlated. The WVTR increased with the increased temperature in all membranes over 10-40 degrees C, all produced membranes showed water resistance up to a pressure of 2100 cmH2O and WVTR values above 60g/m(2) h at 30 degrees C. The WVTR increased by increasing amount of QAS including cationic groups and decreased by increasing isocyanate amount reducing the molecular chain flexibility. In addition, while the unmodified membranes did not show any antibacterial activity, the QAS-added membranes provided significant inactivation against Staphylococcus aureus and Escherichia coli of about 104CFU within 5h of contact time. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47133.

New anthracene derived dinuclear Au(I)-diacetylide complex (1) has been synthesized in which two Au(I) units are attached at 9,10-positions of ethynyl anthracene moiety. 1 exhibits rare non-covalent intermolecular Au center dot center dot center dot H-C interactions, leading to the formation of a supramolecular 2D-network. Further, to understand the effect of C CAuPPh3 units at different position, complexes (2) and (3) were synthesized, where C CAuPPh3 units are attached to 2,6-and 1,8-positions of anthracene, respectively. The absorption and emission spectra of 1-3 have been studied and surprisingly 1 was found to be highly fluorescent with high quantum yield compared to 2 and 3, this may be due to more perturbation of Au(I) on pi system. Complexes 1-3 have been characterized by elemental analysis, NMR and Mass spectroscopy and authenticated by their single-crystal X-ray structures. (C) 2016 Elsevier B.V. All rights reserved.

Metal-organic frameworks (MOFs) are usually synthesized using a single type of metal ion, and MOFs containing mixtures of different metal ions are of great interest and represent a methodology to enhance and tune materials properties. We report the synthesis of [Ga-2(OH)(2)(L)] (H4L = biphenyl-3,3',5,5'-tetracarboxylic acid), designated as MFM-300(Ga-2), (MFM = Manchester Framework Material replacing NOTT designation), by solvothermal reaction of Ga(NO3)(3) and H4L in a mixture of DMF, THF, and water containing HCl for 3 days. MFM-300(Ga-2) crystallizes in the tetragonal space group I4(1)22, a = b = 15.0174(7) angstrom and c = 11.9111(11) angstrom and is isostructural with the Al(III) analogue MFM-300(Al-2) with pores decorated with -OH groups bridging Ga(III) centers. The isostructural Fe-doped material [Ga1.87Fe0.13(OH)(2)(L)], MFM-300(Ga1.87Fe0.13), can be prepared under similar conditions to MFM-300(Ga-2) via reaction of a homogeneous mixture of Fe(NO3)(3) and Ga(NO3)(3) with biphenyl-3,3',5,5'-tetracarboxylic acid. An Fe(III)-based material [Fe3O1.5(OH)(HL)(L)(0.5)(H2O)(3.5)], MFM-310(Fe), was synthesized with Fe(NO3)(3) and the same ligand via hydrothermal methods. [MFM-310(Fe)] crystallizes in the orthorhombic space group Pmn2(1) with a = 10.560(4) angstrom, b = 19.451(8) angstrom, and c = 11.773(5) angstrom and incorporates mu(3)-oxo-centered trinuclear iron cluster nodes connected by ligands to give a 3D nonporous framework that has a different structure to the MFM-300 series. Thus, Fe-doping can be used to monitor the effects of the heteroatom center within a parent Ga(III) framework without the requirement of synthesizing the isostructural Fe(III) analogue [Fe-2(OH)(2)(L)], MFM-300(Fe-2), which we have thus far been unable to prepare. Fe-doping of MFM-300(Ga-2) affords positive effects on gas adsorption capacities, particularly for CO2 adsorption, whereby MFM-300(Ga1.87Fe0.13) shows a 49% enhancement of CO2 adsorption capacity in comparison to the homometallic parent material. We thus report herein the highest CO2 uptake (2.86 mmol g(-1) at 273 K at 1 bar) for a Ga-based MOF. The single-crystal X-ray structures of MFM-300(Ga-2)-solv, MFM-300(Ga-2), MFM-300(Ga-2)center dot 2.35CO(2), MFM-300(Ga1.87Fe0.13)-solv, MFM-300(Ga1.87Fe0.13), and MFM-300(Ga1.87Fe0.13)center dot 2.0CO(2) have been determined. Most notably, in situ single-crystal diffraction studies of gas-loaded materials have revealed that Fe-doping has a significant impact on the molecular details for CO2 binding in the pore, with the bridging M-OH hydroxyl groups being preferred binding sites for CO2 within these framework materials. In situ synchrotron IR spectroscopic measurements on CO2 binding with respect to the -OH groups in the pore are consistent with the above structural analyses. In addition, we found that, compared to MFM-300(Ga-2), Fe-doped MFM-300(Ga1.87Fe0.13) shows improved catalytic properties for the ring-opening reaction of styrene oxide, but similar activity for the room-temperature acetylation of benzaldehyde by methanol. The role of Fe-doping in these systems is discussed as a mechanism for enhancing porosity and the structural integrity of the parent material., We thank the Universities of Nottingham and Manchester for support. M.S. acknowledges receipt of an ERC Advanced Grant and EPSRC Programme Grant. We also thank EPSRC for funding of X-ray equipment. We acknowledge the use of instrumentation within the Nottingham Nanotechnology and Nanoscience Centre, and thank Dr. Christopher Parmenter for assistance. We thank Conacyt, Mexico, for funding to C.P.K. We are especially grateful to Diamond Light Source for access to Beamlines Ill (EE8943), 119 (MT7548, MT8448, MT8937), and B22 (SM11279).

Diazoalkane complexes [Fe(eta(5)-C5H5)(N(2)CAr1Ar2)(P-P)]BPh4 (1, 2) [P-P = Ph2PCH2CH2PPh2 (dppe) (1), Ph2PCH2CH2CH2PPh2 (dppp) (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c)] were prepared by allowing chloro compounds FeCl(eta(5)-C5H5)(P-P) to react with diazoalkane in the presence of NaBPh4. Phosphine complex [Fe(eta(5)-C5H5)(dppe)(kappa(1)-PPh2CH2CH2PPh2)]BPh4 (3) was also prepared. Treatment of diazoalkane complexes 1, 2 with acrylonitrile afforded 3H-pyrazole derivatives [Fe(eta(5)- C5H5)-{N=NC(Ar1Ar2)(CH(CN)CH2}(P-P)]BPh4 (4, 5), as well as a small amount of nitrile complex [Fe(eta(5)-C5H5)(kappa(1)-NCC(H)]= CH2)(P-P)]BPh4 (6). The complexes were characterised spectroscopically (IR, NMR) and by X-ray crystal structure determination of [Fe(eta(5)-C5H5){N2C(C12H8)}(dppe)]BPh4 (1c).

Reaction of the arylchlorosilylene-NHC adduct ArSi(NHC) Cl [Ar= 2,6-Trip(2)C(6)H(3); NHC=(MeC)(2)(NMe)(2)C:] 1 with one molar equiv of lithium diphenylphosphanide affords the first stable NHC-stabilized acyclic phosphinosilylene adduct 2 (ArSi(NHC)PPh2), which could be structurally characterized. Compound 2, when reacted with one molar equiv selenium and sulfur, affords the silanechalcogenones 4a and 4b (ArSi(NHC)(= E)PPh2, 4a: E= Se, 4b: E= S), respectively. Conversion of 2 with an excess of Se and S, through additional insertion of one chalcogen atom into the Si - P bond, leads to 3a and 3b (ArSi(NHC)(= E)-E-P(= E)Ph-2, 3a: E= Se, 3b: E= S), respectively. Additionally, the exposure of 2 to N2O or CO2 yielded the isolable NHC-stabilized silanone 4c, Ar(NHC)(Ph2P) Si=O.

The oxidation reactions and transition metal complexes of cis-bisphenylalkynyl cyclodiphosphazane [cis-(PhCCP)(2)(mu-(NBu)-Bu-t)(2)] (1) is described. The reaction of 1 with aq. H2O2 and elemental selenium afforded bischalcogenides [cis-(PhC CPO)(2)(mu-NtBu)(2)] (3) and [cis-(PhC CPSe)(2)(mu-NtBu)(2)] (4). Treatment of 1 with [Ru(eta(6)-p-cymene)Cl-2](2) and [{Pd(eta(3)-C3H5)Cl}(2)] yielded dinuclear complexes [{Ru(p-cymene)Cl-2}(2){cis-(PhC CP)(2)(mu-(NBu)-Bu-t)(2)11 (5) and [{PdCl(eta(3)-C3H5)}(2){cis-(PhCCP)(2)(mu-(NBu)-Bu-t)(2)}] (6). Mixed ligand complexes [{(2,2'-bPY)CuI}(2){cis-(PhC CP)(2)(mu-(NBu)-Bu-t)(2)}] (7) and [{(1,10-phen)cul}(2)[cis-(PhC CP)(2)(mu-(NBu)-Bu-t)(2)}] (8) were obtained by reacting 1 with CuI followed by the addition of 2,2'-bipyridine and 1,10-phenanthroline, respectively. Treatment of 1 and [trans-(PhCCP)(2)(mu-(NBu)-Bu-t)(2)] (2) with [AuCl(SMe2)] afforded dinuclear complexes [(AuCI)(2)[cis-(PhCCP)(2)(mu-(NBu)-Bu-t)(2)}] (9) and [(AuCl)(2)[trans-(PhC CP)(2)(mu-(NBu)-Bu-t)(2)}] (10), respectively, in good yields. Both the complexes 9 and 10 exhibit intermolecular aurophilic interactions. The Xray analysis showed dimeric structure for 9, whereas 10 consists of a 1D-polymeric structure, due to aurophilic interactions. The crystal structures of 5, 9 and 10 were established by X-ray diffraction analysis. (C) 2015 Elsevier B.V. All rights reserved.

A series of [24 pi] dithia meta-benzisapphyrins and [22 pi] dithia para-benzisapphyrins were synthesized by 3 + 2 condensation of appropriate benzitripyrrane with bithiophene diol under mild acid catalyzed conditions. The dithia m-benzisapphyrins and dithia p-benzisapphyrins were thoroughly characterized by HR-MS, 1D and 2D NMR, absorption, and electrochemical techniques. Our studies showed that dithia m-benzisapphyrins are nonaromatic, whereas the dithia p-benzisapphyrins are aromatic in nature. Thus, we demonstrated here that the dithiabenzisapphyrins can be made aromatic by replacing the m-phenylene moiety of the benzisapphyrin macrocycle with a p-phenylene unit. Furthermore, the studies also indicated that the aromaticity of the dithia p-benzisapphyrins was relatively more compared to the reported heterosapphyrins. The structural and spectral characteristics including aromaticity of the m-benzisapphyrins and p-benzisapphyrins were also discussed with the help of DFT, NICS, and TD-DFT studies.

International audience; Unequally functionalized ferrocenes give access to valuable hemilabile reactivity in catalytic reaction. We address the synthesis of hybrid (P, N)-ferrocenyl compounds for which recent catalytic breakthrough applications have been reported, transversely in late transition metals chemistry. Palladium, nickel, rhodium, iridium, and emerging iron and gold catalysis are illustrated from selected examples, which include CC bond formation from cross-coupling and polymerization, allylic substitution, cyanation, hydroformylation, CH arylation and silylation and hydrogenation reactions.

Viscosity of cereal beta-glucan during digestion is considered to be a vital factor for its health effects. Thus, studies on solution properties and gelation are essential for understanding the mechanisms of the beta-glucan functionality. The aim of this study was to investigate the effect of the dissolution temperature on gelation of cereal beta-glucan at low concentrations that are relevant for food products. The rheological properties of oat and barley beta-glucans (OBG and BBG) using three dissolution temperatures (37 degrees C, 57 degrees C and 85 degrees C) at low concentration (1.5% and 1%, respectively) were studied for 7 days. Additionally, the beta-glucans were oxidised with 70 mM H2O2 and 1 mM FeSO4 x 7H(2)O as a catalyst, to evaluate the consequence of oxidative degradation on the gelation properties. The study showed that dissolution at 85 degrees C did not result in gelation. The optimal dissolution temperature for gelation of OBG was 37 degrees C and for gelation of BBG 57 degrees C. At these temperatures, also the oxidised OBG and BBG gelled, although the gel strength was somewhat lower than in the non-oxidised ones. Gelation was suggested to require partial dissolution of beta-glucan, which depended on the molar mass and aggregation state of the beta-glucan molecule. Therefore, the state of beta-glucan in solution and its thermal treatment history may affect its technological and physiological functionality. (C) 2017 Elsevier Ltd. All rights reserved.

The new complexes [MoBr(eta(3)-C3H5)(CO)(2)(L)(2)] (C1) and [MX2(CO)(3)(L)(2)] (M = Mo(II), X = I (C-2); M = Mo(II), X = Br (C-3); M = W(II), X = I (C-4); M = W(II), X = Br (C5)) were synthesized by reaction of 2-amino-1,3,4-thiadiazole (L) with [MoBr(eta(3)-C3H5)(CO)(2)(NCCH3)(2)] (1), [MoI2(CO)(3)(CH3CN)(2)](M = Mo (2); M = W (4)), or [MoBr2(CO)(3)(CH3CN)(2)](M = Mo (3); M = W (5)) in 2:1 ratio. The five complexes were immobilized in MCM-41, yielding the materials MCM-Cn (n = 1-5), and C1 was also immobilized in silica gel (Silica-C1) and in a polyhedral oligomeric silsesquioxane (Cube-C1). Complexes and materials were fully characterized by spectroscopic techniques and elemental analysis. DFT calculations showed that several C1 isomers should coexist. The as synthesized and supported complexes were tested as catalysts on the oxidation of geraniol, cis-hex-3-en-1-ol, trans-hex-3-en-1-ol, (S)-limonene, and 1-octene. The conversions and TOF significantly depend on the complex and the nature of the substrate. The general conclusions are (i) complex C1 has the highest activity; (ii) tungsten complexes C4 and C5 are more active than the molybdenum analogues; (iii) the immobilization of the catalysts improves the performance; and (iv) silica gel and the polyhedral oligomeric silsesquioxane supports modify the selectivity, leading to products different from the one obtained with MCM for specific substrates.

A family of exceptionally thermally stable [Ni-8] cages is reported, each being templated by a rare eta(3):eta(3):mu(6)-O-2(2-) species produced by dioxygen activation, where the reducing agent for the O-2 reduction appears to be the ligand used in the reaction mixtures, which was found within the nickel cages in its oxidized form.

[Image: see text] Diphosphatidyltrehalose (diPT) is an immunogenic glycolipid, recently isolated from Salmonella Typhi. Despite rigorous structure elucidation, the sn-position of the acyl chains on the glycerol backbone had not been unequivocally established. A stereoselective synthesis of diPT and its regioisomer is reported herein. Using a hybrid MS(3) approach combining collisional dissociation and ultraviolet photodissociation mass spectrometry for analysis of the regioisomers and natural diPT, the regiochemistry of the acyl chains of this abundant immunostimulatory glycolipid was established.

The chemical composition and the structural features of macromolecular components from red grape skins (variety Touriga Nacional) have been evaluated. The results of chemical analyses revealed the following contents of the main constituents: cellulose (20.8%), hemicelluloses (12.5%), proteins (18.8%), tannins (13.8%), extractives soluble in dichloromethane (5.0%) and ash (7.8%). Cellulose of grape skins is typical cellulose I polymorph with a degree of crystallinity of 66.1% as assessed by X-ray scattering. The hemicelluloses were analyzed by neutral sugars analysis, methylation analysis and 1D/2D H-1 NMR. The water-soluble compounds (26.4%) are composed mainly of monomeric sugars (glucose and fructose) and a complex mixture of hemicelluloses, the most abundant being pectin and acetylated glucomannan. The major part of structural polysaccharides (cellulose, xylan, xyloglucan, etc.) is embedded in cuticular layer and is poorly accessible to the acid hydrolysis. The cuticular substances contributed to ca. 8.5% of grape skins and their chemical structure has been evaluated by methanolysis. The possibility of comprehensive utilization of grape skins has been discussed. (C) 2012 Elsevier B.V. All rights reserved.

Cordyceps militaris dried fruiting bodies were extracted with 5% KOH solution. The extract was purified by freeze-thawing treatment, and dialysis (100 kDa), giving rise to a homogeneous polysaccharide (M-w 23,000 Da). Its monosaccharide composition was mannose (56.7%), galactose (34.5%), and glucose (8.8%). The anomeric configurations were determined by their coupling constants. A complex polysaccharide was identified by NMR and methylation analysis. The HSQC spectrum showed signals at delta 107.7/5.06 and 106.1/5.14; 105.9/5.12 relative to beta-D-Galf, and O-2-substituted beta-D-Galf units, respectively. The sign at delta 104.4/5.21 corresponded to alpha-D-Galf. Other signals corresponded to alpha-D-Manp O-6- and O-2-substituted (delta 100.2/4.94; 100.5/5.27; 100.6/5.23; 100.7/5.16), and alpha-D-Manp 2,6-di-O-substituted (from delta 99.3 to 99.9). The main linkages, confirmed by methylation analysis, showed the derivatives: 2,3,4-Me-3-Manp (11.9%) and 3,4,6-Me-3-Manp (28.6%). The branches were (1 -> 6)-linked-alpha-D-Manp or (1 -> 2)-linked-beta-D-Galf, terminating with beta-D-Galf, alpha-D-Galf, alpha-D-Galp, or alpha-D-Manp. 42.7% of the partially hydrolyzed product consisted of 3,4,6-Me-3-Manp, suggesting a (1 -> 2)-linked backbone. (C) 2013 Elsevier Ltd. All rights reserved.

Recent accumulating evidence has supported the notion that tumors have hierarchically organized heterogeneous cell populations and a small subpopulation of cells, termed cancer stem cells (CSCs), are responsible for tumor initiation, maintenance as well as drug resistance. Therefore, targeting the CSCs along with the other cancer cells has been the most important topic during the last decade. In the present study, we evaluated the cytotoxic activity of trans-[PtCl2(2-hepy) 2] [2-hepy = 2-(2-hydroxyethyl) pyridine] complex and the mechanism of cell death in breast CSCs. Stemness markers, Oct-4 and Sox2, were determined in mammospheres by western blotting. Cytotoxicity was assessed using the ATP viability assay. Cell death was fluorescently visualized and further confirmed by flow cytometry as well as gene expression analysis. The Pt(II) complex significantly reduced the cell viability, prevented mammosphere formation and disrupted mammosphere structures in a dose-dependent manner (0100 lM). The mode of cell death was apoptosis and it was shown by the presence of caspase 3/7 activity, Annexin V-FITC positivity, decreased mitochondrial membrane potential and increased expressions of pro-apoptotic genes (TNFRSF10A and HRK). Interestingly, necroptosis was also observed by the evidence of increased MLKL expression. In conclusion, the Pt(II) complex seems to be a highly promising anticancer compound due to its promising cytotoxic activity on CSCs. Therefore, it deserves in vivo further studies for the proof-of-concept. (C) 2016 Elsevier Ltd. All rights reserved. TUBITAK (The Scientific and Technological Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112T726] This work was supported by the Research Fund of TUBITAK (The Scientific and Technological Research Council of Turkey) for the project that is numbered 112T726. The authors are grateful to Dr. Veysel T. Yilmaz (Uludag University, Turkey) for providing us the Pt(II) complex and Dr. Raffaella Villa (Fondazione IRCCS Istituto Nazionale dei Tumori, Italy) for the interpretation the data. WOS:000397052800029 27839660 Q2

11 páginas.-- 5 figuras.-- 1 tabla.-- 47 referencias.-- The following supplemental materials are available in the https://doi.org/10.1104/pp.16.02012, Lignin is an abundant aromatic plant cell wall polymer consisting of phenylpropanoid units in which the aromatic rings display various degrees of methoxylation. Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one], a flavone, was recently established as a true monomer in grass lignins. To elucidate the incorporation pathways of tricin into grass lignin, the metabolites of maize (Zea mays) were extracted from lignifying tissues and profiled using the recently developed ‘candidate substrate product pair’ algorithm applied to ultra-high-performance liquid chromatography and Fourier transform-ion cyclotron resonance-mass spectrometry. Twelve tricin-containing products (each with up to eight isomers), including those derived from the various monolignol acetate and p-coumarate conjugates, were observed and authenticated by comparisons with a set of synthetic tricin-oligolignol dimeric and trimeric compounds. The identification of such compounds helps establish that tricin is an important monomer in the lignification of monocots, acting as a nucleation site for starting lignin chains. The array of tricin-containing products provides further evidence for the combinatorial coupling model of general lignification and supports evolving paradigms for the unique nature of lignification in monocots. Lignin is one of the major components in plant cell walls and is deposited predominantly in the walls of secondarily thickened cells. It is a complex phenylpropanoid polymer composed primarily of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units derived from the monolignols p-coumaryl 2h, coniferyl 2g, and sinapyl 2s alcohols, respectively (Fig. 1; Freudenberg and Neish, 1968). These monolignols are biosynthesized in the cytoplasm and translocated to the cell wall, where they are oxidized by laccases and peroxidases to monolignol radicals (Boerjan et al., 2003; Dixon and Reddy, 2003; Ralph et al., 2004b; Vanholme et al., 2008, 2010; Bonawitz and Chapple, 2010; Mottiar et al., 2016). The polymer can be started by radical coupling between two monolignol radicals to form a dehydrodimer from which the chain extends by endwise polymerization with additional monolignols, producing β-O-4-, β-5-, β-1-, and β-β-linked units in the lignin. Two growing oligomers also may radically couple to increase the polymer size, producing 4-O-5- and 5-5-linked units. During such radical coupling reactions, therefore, the monomer-derived units are linked together via various C-C and C-O bonds with different frequencies depending primarily on the monomer distribution and supply (Ralph et al., 2004b)., This work was supported by the Department of Energy Great Lakes Bioenergy Research Center (grant no. DE–FC02–07ER64494 to W.L., F.L., and J.R.), by Stanford University’s Global Climate and Energy Program (to J.R., K.M., and W.B.), by the Institute for the Promotion of Innovation through Science and Technology in Flanders via the SBO project Bioleum (to W.B. and K.M.), by the China Scholarship Council's State Education Department for his Ph.D. work in the Department of Biological System Engineering, University of Wisconsin, Madison (to W.L.).

The application field of dichloridodioxidomolybdenum (VI) chelate complexes, which have been intensively investigated as catalysts for liquid-phase olefin epoxidation, is broadened to encompass acid catalysis, in particular, alcoholysis and acetalisation reactions. Complex [MoO2Cl2(L)] (1) with L = 4,4'-di-tert-butyl-2,2'-bipyridine was chosen as (pre)catalyst. Depending on the reaction conditions, 1 either remained structurally intact or was transformed into different metal species, the structures of which were determined on the basis of single-crystal X-ray diffraction, spectroscopic techniques (FT-IR and H-1 NMR), and elemental analysis. The first example of a mixed-ligand complex of the type [MoO2X(OR)(L)] (X = halide) is disclosed. This complex is one of only a handful of complexes known to date that exhibit an all-cis configuration instead of the usual cis-oxido, trans-X, cis-L configuration (X = anionic ligand). Mechanistic considerations of the formation of the metal species are made.

Facile synthesis of mono- and di-functionalised arylimido hexamolybdates, (nBu(4)N)(2)[Mo6O18(L1)1 (1), ((Bu4N)-Bu-n)(2)[Mo6O17(L1)(2)] (2) and ((Bu4N)-Bu-n)(2)[Mo6O1.8(L2)] (3) (L1 = 4-bromo-2,6-diisopropylaniline, L2 = 2,2',6,6'tetraisopropylbenzidine), has been achieved through the reaction of parent ((Bu4N)-Bu-n)(2)[Mo6O19] (4) with a series of aniline derivatives. The arylimido derivatives 1-3 have been characterised by both analytical and spectroscopic studies (1H NMR, IR, UV-Vis and mass spectral studies), apart from structural elucidation of all the three compounds by single crystal X-ray diffraction studies. Steric hindrance at the ortho-positions of the arylamine seems to strengthen and effectively protect the newly formed Mo equivalent to N bonds. The surface modification of the hexamolybdate by aryl amines results in the transformation of otherwise inactive parent compound 4 into useful catalysts 1-3, which effectively catalyse the oxidation of cyclohexene to cyclohexene epoxide and benzyl alcohol to benzaldehyde and benzoic acid.

The reactivity of cyclodiphosphazanes towards various transition metal derivatives has been studied. The products obtained showed simple monomeric to di-, tetra-, or pentameric structures. The interactions between cyclodiphosphazanes and copper halides resulted in the formation of several one-dimensional (1D), 2D, or 3D coordination polymers having adamantanoid, diamondoid, or sodalite structures, which are rare among homoleptic soft metal-soft ligand combinations.

Reaction of the tris(3-phenylpyrazolyl)methane sulfonate species (Tpms Ph )Li with the copper(I) complex [Cu(MeCN) 4 ][PF 6 ] affords [Cu(Tpms Ph )(MeCN)] 1 . The latter, upon reaction with equimolar amounts of cyclohexyl- (CyNC) or 2,6-dimethylphenyl (XylNC) isocyanides, or excess CO, furnishes the corresponding Cu(I) complexes [Cu(Tpms Ph )(CNR)] (R = Cy 2 , Xyl 3 ) or [Cu(Tpms Ph )(CO)] 4 . The ligated isocyanide in 2 or 3 (or the acetonitrile ligand in 1 ) is displaced by 3-iminoisoindolin-1-one to afford 5 , the first copper(I) complex containing an 3-iminoisoindolin-1-one ligand. The ligated acetonitrile in 1 undergoes nucleophilic attack by methylamine to give the amidine complex [Cu(Tpms Ph ){MeC(NH)NHMe}] 6 , whereas only the starting materials were recovered from the attempted corresponding reactions of 2 and 3 with methylamine. Complexes 1 or 6 form the trinuclear hydroxo-copper(II) species [(μ-Cu){Cu(μ-OH) 2 (Tpms Ph )} 2 ] 7 upon air oxidation in moist methanol. In all the complexes the scorpionate ligand facially caps the metal in the N , N , O -coordination mode.

The reactivity of bulky tris(trimethylsilyl) methyl group substituted aluminum trialkyl [(Me(3)Si)(3)CAlMe(2)center dot THF] (1) with a series of substituted benzoic acid derivatives has been investigated. An equimolar reaction of 4-methyl benzoic acid or 4-tert-butyl benzoic acid with 1 in toluene at 50 degrees C leads to the formation of cyclic dimeric aluminum carboxylates [(Me(3)Si)(3)CAl(Me)(mu-O(2)CC(6)H(4)R)](2) (R = Me 2; (t)Bu 3). Reaction of 3,5-di-iso- propylsalicylic acid (H(2)dipsa) with 1 leads to the exclusive isolation of a trimeric organoaluminum carboxylate [(Me(3)Si)(3)CAl(mu-ipsa)](3) (4), in which each aluminum is bound to two carboxylates, a phenoxide, and an alkyl group and produce a 12-membered macrocycle. Deliberate, but controlled, introduction of water in the form of 3,5-di-tert-butyl salicylic acid monohydrate (H(2)dtbsa center dot H(2)O) in the reaction with 1 in toluene leads to the isolation of carboxylate [(Me(3)Si)(3)CAl(mu-O)(mu-Hdtbsa)}(2)] (5) with a bicyclic structure. Compound 5 represents a rare example of an organoalumoxane carboxylate that simultaneously possesses alkyl, oxo, and carboxylate moieties on aluminum. (C) 2011 Elsevier B.V. All rights reserved.

A series of mono-functionalized core-modified expanded porphyrin building blocks such as thiasapphyrin, thiarubyrin, oxasmaragdyrin, and BF(2)-oxasmaragdyrin have been synthesized by simple condensation of readily available precursors. The mono-functionalized core-modified expanded porphyrin building blocks were used to synthesize the first three examples of covalently linked diphenylethyne-bridged dyads containing two different expanded porphyrin macrocycles, namely thaisapphyrin-BF(2)-oxasmaragdyrin, thiarubyrin-BF(2)-oxasmaragdyrin, and thiasapphyrin-thiarubyrin, by coupling appropriate mono-functionalized expanded porphyrin building blocks under mild Pd(0) coupling reaction conditions. The three dyads were freely soluble in common organic solvents and characterized by MS, NMR, absorption, electrochemical, and fluorescence techniques. The NMR, absorption, and electrochemical studies indicated that the two macrocycles in the dyads interact weakly with each other and maintain their independent characteristic features. The steady-state fluorescence studies of the dyads showed that the thiasapphyrin and thiarubyrin units are nonfluorescent but fluorescence was observed from the BF(2)-oxasmaragdyrin unit. However, the quantum yield of the BF(2)-oxasmaragdyrin unit in the dyads was less than that of monomeric BF(2)-oxasmaragdyrin because of an enhancement of nonradiative decay channels operating in the dyads. The potential use of two of the three dyads containing the BF(2)-smaragdyrin subunit as fluorescent sensors for anions was explored. The studies showed that the binding of the anion at the protonated sapphyrin and rubyrin sites in the respective dyads can be followed by the clear changes in the fluorescence band of the BF(2)-oxasmaragdyrin unit, which indicates that these dyads can be used as fluorescent anion sensors.

This review summarizes the rapid developments in the chemistry of phosphonium-stabilized group 1 and 2 methandiides, i.e. that of alkali and alkaline-earth metal bis(iminophosphorane)methandiide and bis(thiophosphorane)methandiide complexes. Apart from syntheses, structures and reactivities, also a critical discussion on bonding is given. The group 2 complexes of this type can truly be seen as polar metal carbene compounds with a formally polar double metal-carbon bond. (C) 2010 Elsevier B.V. All rights reserved.

The preparation and characterization of self-assembled monolayers on copper with n-alkyl and functional thiols was investigated. Well-ordered monolayers were obtained, while the copper remained oxide-free. Direct attachment of N-succinimidyl mercaptoundecanoate (NHS-MUA) onto the copper surface allowed for the successful attachment of biomolecules, such as β-d-glucosamine, the tripeptide glutathione, and biotin. Notably, the copper surfaces remained oxide-free even after two reaction steps. All monolayers were characterized by static water contact angle measurements, X-ray photoelectron spectroscopy, and infrared reflection absorption spectroscopy. In addition, the biotinylated copper surfaces were employed in the immobilization of biomolecules such as streptavidin.

Decamethylzirconocene cation [Cp*2ZrMe](+) (2) decomposes in bromobenzene-d(5) solution to generate sigma-aryl species [Cp*Zr-2(2-C6H4Br-kappa Br,C)][B(C6F5)(4)] (3). This a-bond metathesis reaction is catalyzed by tertiary amines via a two-step mechanism, in which the amine acts as a proton relay. In benzene-d(6) compound 2 decomposes via C H bond activation of one of the Cp* ligands to generate tucked-in compound [Cp*{eta(5):eta(1)-C5Me4(CH2)}Zr](+) (4). In the presence of Et3N, no formation of tucked-in compound 4 is observed, but instead an overall double C-H bond activation and C-N bond cleavage of the tertiary amine is observed, resulting in [Cp*Zr-2{C(Me)NEt-kappa C,N}](+) (6). A mechanism is proposed that nominates [Cp*2ZrNEt2](+) as an intermediate, the result of a C-H bond activation of Et3N, followed by beta-amide elimination. Attempted synthesis of this species by treatment of Cp*Zr-2(NEt2)Me with [Ph3C][B(C6F5)(4)] results, again, in formation of compound [6](+). The presence of Et3N also has an effect on the stability of THF adduct [Cp*2ZrMe(THF)](+) as the amine performs a nucleophilic THF ring-opening to generate [Cp*2ZrMe{O(CH2)(4)NEt3}](+) (7). The results show that amine coproducts, often generated in the synthesis of cationic transition-metal complexes, are not necessarily innocent.

The reaction of [Fe2(CO)6(μ-toluene-3, 4-benzenedithiolate)] 1 and bidentate diphosphine, 1, 1′-bis(diphenylphosphino)ferrocene (dppf) has been studied. New complexes obtained have been characterized by various spectroscopic techniques as bioinspired models of the iron hydrogenase active site. The crystal structure of [Fe2(CO)5(κ 1-dppfO)(μ-toluene-3, 4-benzenedithiolate)] 4 is reported.

A series of nickel complexes (1-3)b of 1,2,4-triazole derived amido-functionalized N-heterocyclic carbene ligands were synthesized and structurally characterized. In particular, the [1-(R)-4-N-(furan-2-ylmethyl) acetamido-1,2,4-triazol-5-ylidene](2)Ni [R = Et (1b), i-Pr (2b) and Bn (3b)] complexes were obtained by the direct reaction of the corresponding triazolium chloride salts (1-3) a by the treatment with NiCl2 center dot 6H(2)O in presence of K2CO3 as a base. The density functional theory studies performed on these complexes reveal highly polar character of the NHC-Ni sigma-bonding interaction with corresponding molecular orbital having a maximum contribution (59-69%) from the NHC ligand fragments while that of a minimum contribution (4%) from the central nickel atom. The (1-3)b complexes were found to be moderately active for the catalytic borylation reactions of bromoaryl derivatives by bis(pinacolato) diboron reagent (B(2)pin(2)) in the presence of Cs2CO3 as a base at 70 degrees C. (C) 2015 Elsevier B.V. All rights reserved.

The last two decades have seen a remarkable growth in the design of new hybrid materials applied to different areas, from photonics to biomaterials, together with new coating materials with self-cleaning features. Among the various systems studied, the PDMS-SiO2 system remains as a good basis for further developments by adding other compounds such as transition metals. In this work, a detailed study of the influence of titanium or zirconium in the chemical structure and final microstructure of such hybrids was made. It was concluded that, due to the lower reactivity of the titanium alkoxide during the sol-gel preparation process, titanium is preferably located on the surface of secondary particles of silica, unlike the zirconium, which being more reactive, positions on the surface of the primary particles. This difference leads to xerogels with dissimilar characteristics and morphologies. (C) 2015 Elsevier Ltd. All rights reserved.

Our recent molecular dynamics (MD) simulation of an insertion/duplication mutant 'L20' of bacteriophage T4 lysozyme demonstrated a solvent induced alpha ->beta transition in a loosely held duplicate helical region, while alpha-helical conformation in the parent region was relatively stabilized by its tertiary interactions with the neighboring residues. The solution NMR of the parent helical sequence, sans its protein context, showed no inherent tendency to adopt a particular secondary structure in pure water but showed alpha-helical propensity in TFE/water and SDS micelles. In this study we investigate the conformational preference of the 'parent' and 'duplicate' sequences, sans the protein context, in pure water and an apolar TFE/water solution. Apolar TFE/water solution is a model for non-polar protein context. We performed MD simulations of the two peptides, in explicit water and 80 % (v/v) TFE/water, using GROMOS 53a6 force field, at 300 K and 1 bar (under NPT conditions). We show that in TFE/water mixture, salt bridges are stabilized by apolar TFE molecules and main chain-main chain hydrogen bonds promote the alpha-helical conformation, particularly in the duplicate peptide. Solvent exposure, in pure water, resulted in an alpha ->beta transition to form a triple stranded beta-sheet structure in the 'duplicate' sequence, with a rare psi-loop topology, while a mixture of turn/bend conformations were adopted by the 'parent' sequence. Thus the differences in conformational preference of the parent and duplicate sequence sans protein context, in pure water and TFE/water, implicate the importance of the environment polarity in dictating the peptide conformation. Mechanism of folding of the observed psi-loop in the duplicate sequence gives insights into folding of this rare beta-sheet topology.

The residual lignin (LR sample) was isolated from unbleached acid sulphite pulp from Eucalyptus globulus with kappa number 18.2 by acidolysis and structurally characterized by wet chemistry and NMR techniques. The main structural features of LR were compared with lignin isolated from sulphite spent liquor (LSSL sample) and dioxane lignin (DL sample) from eucalypt wood. LR contains less sulphonic groups (4.4%) compared to LSSL (11.3%), and its molecular weight (2200 Da) is very close to that of DL (2600 Da). A part of sulphonic groups is located at the benzylic carbon in β-O-4′ and β-5′ structures. LR revealed ca. 20% lower abundance of β-O-4′ structures than DL, but ca. 40% higher abundance of these structures than LSSL. The degree of condensation of LR was higher than that of DL but lower than that of LSSL. The condensed structures in LR mainly originate from C6-linked syringyl units. The structural peculiarities of LR consisted of the relatively high proportion of syringyl units compared to DL and the strong structural association with hemicelluloses via benzyl ether linkages. The differences in the structure of residual lignins from eucalypt sulphite and kraft pulps have been discussed.

International audience; A novel Zn(II) coordination polymer of N-nicotinyl phosphoric triamide ligand, {[Zn(L)(2)(H2O)(2)]center dot(NO3)(2)}(n) C1 (L = 3-NC5H4C(O)NHP(O)(NC6H12)(2)), has been synthesized and characterized by IR and H-1, C-13, P-31 NMR spectroscopy. Crystal structure analysis of C1 demonstrates a distorted octahedral geometry for Zn(II) ions. The oxygen atom of phosphoryl group (O-phosphoryl) and the nitrogen atom of pyridine ring (N-pyridine) of ligand take part in coordination to Zn(II) centers in a bidentate bridging mode. This coordination pattern results in infinite 1D polymeric chains along c axis, which are composed of metal shared 16-membered puckered rings. Structural data show that despite binding through O-phosphoryl, the P=O bond distance unexpectedly shortens in C1 when compared to that of the ligand, conceivably due to the steric factors in the solid state. This is confirmed by comparing the structural and electronic properties of C1 and L in the gas phase by using density functional theory (DFT) calculations. Natural bond orbital (NBO) analysis reveals the metal-ligand interaction for C1 as donor-acceptor type delocalizations (charge transfer). Besides, on the basis of the quantum theory of atoms in molecules (QTAIM) analysis, the nature of Zn-O and Zn-N bondings is found to be mainly electrostatic with a small amount of covalent character. (C) 2015 Elsevier B.V. All rights reserved.

3-Arylamino-1-ferrocenylpropan-1-ones, prepared through aza-Michael addition of aromatic amines to 1-ferrocenylpropenone, were transformed into the corresponding 1,3-amino alcohols upon NaBH4-mediated carbonyl reduction. The latter amino alcohols were deployed as eligible substrates for the synthesis of a variety of ferrocene-containing heterocycles including 1,3-oxazinanes, 1,3-oxazinan-2-ones, and tetrahydropyrimidin-2-ones, which were subsequently evaluated for their antimicrobial and cytotoxic activities.

Aminopyridinato-ligand-stabilized organoyttrium cations are accessible in very good yield through alkane elimination from trialkyl yttrium complexes with sterically demanding aminopyridines, followed by abstraction of one of the two alkyl functions using ammonium borates. At 80 degrees C and in the presence of small amounts of aluminum alkyl compounds, very high ethylene polymerization activities are observed if very bulky aminopyridinato ligands are used. During these polymerizations a reversible polyethylene chain transfer is observed between the organoyttrium cations and aluminum alkyls. The chain-transfer catalyst system described here is able to produce relatively long-chain (up to 4000 g mol-1) Al-terminated polyethylene with a molecular-weight distribution