Described here is the first application of plasma-enhanced chemical vapor deposition (PE-CVD) to thesynthesis of catalytically active materials, prepared by covering Merrifield resin beads with an oxygen-containing fluorocarbon thin film deposited in a hexafluoropropene-O2plasma. Such modified resinscatalyze both the selective epoxidation of trans--methylstyrene and its double oxidative cleavage tobenzaldeyde in organic-water biphasic media at room temperature, using potassium monoperoxysulfate(KHSO5) as the terminal oxidant. Interestingly, the epoxide/benzaldehyde product ratio strictly dependson the conditions adopted for catalyst generation. This, coupled with evidence for the presence of carbonylgroups on the surface of treated resins, point to dioxirane and singlet oxygen (1O2)-mediated oxidations;1O2being produced in the decomposition of KHSO5. Compared to traditional synthetic procedures toobtain similar catalytic active materials, the application of PE-CVD is eco-sustainable and less expensive.Also, the activity of catalysts can be fully restored upon iterative re-treatment of the exhausted resin.

In an explorative study of the opportunities for synthesis provided by oxidation of natural aminoacidic compound with methyl-(trifluoromethyl)dioxirane, we noticed that oxidation of the cyclic compound, when successful, leads to the ?-hydroxy compound, notwithstanding the presence of the isopropyl groups that are usually easy targets for this reaction, as verified with the homologous acyclic compound. We therefore initiated an ab-initio study of the reactions aimed at determining the role of the ring and explaining the reactivity differences of the cis and trans configurations. Consistently with recent literature, we confirm the fundamental role of an adduct configuration in which the dioxirane O-O bond is largely divaricated and electron pairing is broken, often denoted in the literature as diradicaloid.

Following our pioneering studies on the direct and efficient introduction of derivatizable hydroxyl handles into the valinomycin (VLM, 1) structure, a K+-ionophore with potent antitumor activity, the ensuing conjugable analogues (HyVLMs 2, 3, and 4) have herein been compared to the parent macrocycle for their potential antiproliferative effects on a panel of cancer cell lines, namely, human MCF-7, A2780, and HepG2, as well as rat C6 cells. On the basis of IC50 values, we find that hydroxyl analogues 3 and 4 are only moderately less active than 1, while analogue 2 experiences a heavily diminished activity. Cytofluorimetric analyses of MCF-7 cells treated with HyVLMs suggest that the latter depolarize mitochondria, thus retaining the typical VLM behavior. It is likely that C6 cells, for which the exceptionally potent cytotoxicity of VLM has never reported previously, follow the same fate, as evidenced by alteration of mitochondrial morphology upon incubation with each ionophore.

Silicon nanowires (SiNWs) decorated by pulsed laser ablation with gold or copper nanoparticles (labeled as AuNPs@SiNWs and CuNPs@SiNWs) were investigated for their catalytic properties. Results demonstrated high catalytic performances in the Caryl-N couplings and subsequent carbonylations for gold and copper catalysts, respectively, that have no precedents in the literature. The excellent activity, attested by the very high turn over number (TON) values, was due both to the uniform coverage along the NW length and to the absence of the chemical shell surrounding the metal nanoparticles (MeNPs). A high recyclability was also observed and can be ascribed to the strong covalent interaction at the Me-Si interface by virtue of metal "silicides" formation

We have synthesized 1-aza-adamantan-4-one (C9H13NO) starting from commercial 1,4-cyclohexanedionemonoethylene acetal and tosylmethylisocianide, following a procedure already described in the literature. The high degree of sample purity was demonstrated by gas chromatography and mass spectrometric measurements and its structure evidenced by 1H and 13C NMR spectroscopy. Among numerous interests in physical chemistry, this target molecule is of high relevance for mechanistic evaluation and the synthesis of novel pharmaceutical compounds. We present a thorough spectroscopic study of this molecule by gas phase vibrational and rotational spectroscopy. Accurate vibrational frequencies have been determined from infrared and far-infrared spectra. The pure rotational spectrum of the molecule has been recorded both by cavity-based Fourier transform microwave spectroscopy in the 2-20 GHz region by supersonically expanding the vapor pressure of the warm sample and by room-temperature absorption spectroscopy in the 140-220 GHz range. Accurate sets of rotational and centrifugal distortion parameters of 1-aza-adamantan-4-one in its ground state and in five vibrationally excited states have been derived from these measurements and compared to accurate quantum chemical calculations. The hyperfine parameters have been discussed in terms of molecular structure around the nitrogen quadrupole nucleus.

With use of methyl(trifluoromethyl)dioxirane (TFDO), the oxidn. of some tripeptide esters protected at the N-terminus with carbamate or amide groups could be achieved efficiently under mild conditions with no loss of configuration at the chiral centers. Expanding on preliminary investigations, it is found that, while peptides protected with amide groups (PG = Ac, Tfa, Piv) undergo exclusive hydroxylation at the side chain, their analogs bearing a carbamate group [PG = Cbz, Moc, Boc, TcBoc; Moc = COOMe; TcBoc = COOC(Me)2CCl3] give competitive and/or concurrent hydroxylation at the terminal NH moiety. Valuable nitro derivs. are also formed as a result of oxidative deprotection of the carbamate group with excess dioxirane. A rationale is proposed to explain the dependence of the selectivity upon the nature of the protecting group.

A new hybrid material (3) consisting of trifluoromethyl ketone (TFMK) moieties, immobilized on silica through an appropriate spacer, was synthesized and characterized. Lacking easily oxidizable functionalities in the spacer chain, this material proved to be an excellent catalyst in heterogeneous epoxidations with potassium caroate (KHSO 5), surpassing other reported catalysts in performance and stability. The efficiency of silica-supported catalyst 3 could be assessed upon carrying out the selective dioxirane-mediated epoxidation of representative alkenes in high yields. The solid catalyst could then be recovered and reused in a number of consecutive oxidation cycles. The synthesis of a new hybrid, which presents trifluoromethyl ketone moieties anchored on silica gel through a short spacer, is reported. Lacking easily oxidizable functionalities in the linker chain, this solid material is an efficient catalyst in dioxirane-mediated heterogeneous epoxidations using potassium caroate.

A remarkable example of the progress in metal-free oxidation is the development of oxidation with dioxiranes. The reactivity of these peroxides seems to be due to the tendency for easy electrophilic O-atom transfer to nucleophilic substrates. This has been applied in order to achieve high regio- and stereoselective epoxidation and oxyfunctionalizations of target molecules. This review addresses a new approach consisting of the application of homogeneous and heterogeneous dioxiranes isolated and generate in situ.This method has shown promise to contribute to resolving a well-recognized general problem in the organic synthesis to achieve efficient synthetic methods that take into account the fundamental principles of green chemistry.

This work addresses a new approach developed in our laboratory, consisting in the application of isolated dimethyldioxirane (DDO, 1a) labelled with O-18 for synthesis of epoxidized glyceryl linoleate (Gly-LLL, 2). We expect that this work could contribute in improving analytical methods for the determination of epoxidized soybean oil (ESBO) in complex food matrices by adopting an O-18-labelled-epoxidized triacylglycerol as an internal standard.

Methyl(trifluoromethyl)dioxirane (TFDO) can be used for the oxyfunctionalization of SWCNTs filled with NaI and LuCl3 under mild conditions. The chosen metal halides are of interest for theranostics, both for imaging and therapy when in their radioactive form. The applied functionalization methodology does not require metal catalyst, preserves the integrity of the nanotubes during treatment, avoiding the release of the filling material. In this way, epoxidation can be considered as an efficient methodology for the functionalization of carbon nanocapsules, where the traditional harsh oxidation conditions by acids are not applicable.

Even though many functionalization methodologies for covalent modification of carbon nanotubes (CNTs) have been proposed, mild but effective approaches are still needed. Here we describe the epoxidation of multi-walled carbon nanotubes (MWCNTs) with dioxirane for an environmentally friendly oxidation process with an organocatalyst. Thank to the choice of dioxiranes (accessible and easy to handle and to store), multiple oxidation cycles could be performed on the same sample, thus allowing for a final improvement in the degree of oxidation at the CNT sidewall. The obtained derivatives were then used as electrophilic platforms for successive modification with an amine, with a high degree of functionalization (about 750 ?mol?g^-1 from TGA analysis) being obtained. An efficient method for the epoxidation of multi-walled carbon nanotubes (MWCNTs) is proposed. It leads to the production of materials that can be easily further functionalized by nucleophiles. Complete chemical (TGA, FTIR, XPS, Raman) and morphological (TEM) characterization of the materials has revealed a high degree of functionalization.

This paper describes an expeditious and reliable method for determining the thermal effects in a static condition of commercial NOx storage catalysts (NSCs) using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM/EDS). It is worth remarking that possible changes in the morphology and in the elemental composition of the catalyst may be considered as the most important causes of the lower conversion of NOx. The information attained in this work indicates that Pt nanoparticle sintering is strongly increased by the oxygen exposure, and this can be considered a very useful preliminary investigation for the studies already present in the literature on the efficiency of NSCs.

Dioxiranes are powerful oxidants that can act via two different mechanisms: 1) homolytic (H abstraction and oxygen rebound) and 2) heterolytic (electrophilic oxidation). So far, it has been reported that the nature of the substrate dictates the reaction mode independently from the dioxirane employed. Herein, we report an unprecedented case in which the nature of the dioxirane rules the oxidation chemoselectivity. In particular, a switch from C-H to N-H oxidation is observed in the oxidation of lactams moving from dimethyl dioxirane (DDO) to methyl(trifluoromethyl)dioxirane (TFDO). A physical organic chemistry study, which combines the oxidation with two other dioxiranes methyl(fluoromethyl)dioxirane, MFDO, and methyl(difluoromethyl)dioxirane, DFDO, with computational studies, points to a diverse ability of the dioxiranes to either stabilize the homo or the heterolytic pathway.

Bio-polyols synthesized from vegetables oils are a great alternative to petrochemical polyols for polyurethanes industry. The simplest approach to bio-polyols synthesis involves epoxidation of carbon-carbon double bond of unsaturated fatty ester moieties and subsequent epoxide ring-opening by nucleophilic reagents. In order to improve the latter process by increasing both productivity and product quality, the advantages of flow chemistry were exploited, such as facile automation, reproducibility, improved safety and process reliability, investigating for the first time in the literature the methanolysis reaction of epoxidized soybean oil (ESO) in a continuous flow mode. Compared with batch reaction, flow mode allowed the cut of the reaction time from 30 min to 2 min, and the reduction of catalyst concentration by an order of magnitude, which brought significant benefits in terms of cost efficiency and eco-sustainability, rendering the method suitable for industrial applications.

An innovative and eco-friendly one-pot synthesis of bio-based polyurethanes is proposed via the epoxy-ring opening of epoxidized soybean oil (ESO) with methanol, followed by the reaction of methoxy bio-polyols intermediates with 2,6-tolyl-diisocyanate (TDI). Both synthetic steps, methanolysis and polyurethane linkage formation, are promoted by a unique catalyst, molybdenum(VI) dichloride dioxide (MoCl2O2), which makes this procedure an efficient, cost-effective, and environmentally safer method amenable to industrial scale-up

Dioxiranes are used as reagents in a myriad of synthetically useful oxidations performed in aqueous medium. To extend such an approach also to substrates that are highly hydrophobic, we propose here the use of microemulsions based on the surfactant hexadecyltrimethylammonium hydrogen sulphate (CTAHS) because of its high stability against peroxide species. In this paper, we examine the dioxirane (isolated or generated in situ) reactivity in different CTAHS microemulsions. Yield and selectivity of the oxidation of ?-methylstyrene by dimethyldioxirane (DDO) generate "in situ" and of laurolactam by isolated methyl(trifluorometyl)dioxirane (TFDO) were studied. For each microemulsion, the aggregate size and the localization of the components were determined by a combination of NMR and light scattering techniques. The hydrodynamic radius of the micelles is close to the length of the surfactant and this suggests they are spherical in shape. When acetone (the precursor of DDO) is present in the formulation, it partitions itself between the aqueous bulk and the micellar palisade so that the dioxirane eventually formed is readily available to oxidize substrates secluded in the micelle. Apolar substrates, confined within the micelles, are protected from uncontrolled oxidations, leading to an astonishing high selectivity of oxidation of laurolactam to 12-nitro-lauric acid by TFDO. This opens the way to an easy procedure (performed in water under mild conditions) to synthetize ?-nitroacids.

By taking advantage of the appreciable stability of dioxiranes in water, a safe yet efficient route to ?-nitro acids by oxidation of lactams of various ring size under mild conditions has been reported. In essentially all the cases examined, reactions proceed selectively to afford products in remarkable high yields (up to 99%) and with high purity (94-99%). Also, an interesting example of higher reaction selectivity in water than in organic solvent (acetonitrile) is discussed.

Composite materials prepared by loading polycrystalline TiO 2 powders with lipophilic highly branched Cu(II)- and metal-free phthalocyanines or porphyrins, which have been used in the past as photocatalysts for photodegradative processes, have been successfully tested for the efficient photoreduction of carbon dioxide in aqueous suspension affording significant amounts of formic acid. The results indicated that the presence of the sensitizers is beneficial for the photoactivity, confirming the important role of Cu(II) co-ordinated in the middle of the macrocycles. A comparison between Cu(II) phthalocyanines and Cu(II) porphyrins indicated that the Cu(II)- phthalocyanine sensitizer was more efficient in the photoreduction of CO2 to formic acid, probably due to its favorable reduction potential

Polyurethane-resin doming is currently one of the fastest growing markets in the field of industrial graphics and product identification. Semi-rigid bio-based polyurethanes were prepared deriving from soybean oil as a valuable alternative to fossil materials for digital doming and applied to digital mosaic technology. Bio-resins produced can favorably compete with the analogous fossil polymers, giving high-quality surface coatings (ascertained by SEM analyses). In addition, polyurethane synthesis was accomplished by using a mercury- and tin-free catalyst (the commercially available zinc derivative K22) bringing significant benefits in terms of cost efficiency and eco-sustainability.

The reaction of 1,3-dimethylimidazolium-2-carboxylate and dimethylcarbonate (DMC) at high temperature yielded the new compounds 2-ethyl-1,3-dimethylimidazolium methyl carbonate salt and 2-ethyl-1,3-dimethylimidazolium-4-carboxylate zwitterion which were obtained as a mixture in approximately 4:1 molar ratio. The compounds were also isolated in pure form through alternative synthetic procedures and characterized by ESI-HRMS, H-1, C-13 NMR and FTIR spectroscopy. The 1,3-dimethylimidazolium-2-carboxylate/dimethylcarbonate system was employed in the synthesis of 1,7-heptanedioic acid dimethyl ester from cyclohexanone and DMC. The target compound was obtained in 49% yield and 66% selectivity. (C) 2013 Elsevier B.V. All rights reserved.

The direct conversion of methane to methanol at low temperatures was achieved selectively using dioxiranes 1a,b either in the isolated form or generated in situ from aqueous potassium caroate and the parent ketone at a pH close to neutrality. Results suggest that the more powerful dioxirane TFDO (1b) should be the oxidant of choice.

A synthesis of representative monohydroxy derivatives of valinomycin (VLM) was achieved under mild conditions by direct hydroxylation at the side chains of the macrocyclic substrate using dioxiranes. Results demonstrate that the powerful methyl(trifluoromethyl)dioxirane 1b should be the reagent of choice to carry out these key transformations. Thus, a mixture of compounds derived from the direct dioxirane attack at the beta-(CH(3))(2)C-H alkyl chain of one Hyi residue (compound 3a) or of one Val moiety (compounds 3b and 3c) could be obtained. Following convenient mixture separation, each of the new oxyfunctionalized macrocycles became completely characterized.

Valinomycin (VLM, 1) is a K+ ionophore cyclodepsipeptide capable of depolarizing mitochondria and inducing apoptosis to several mammalian cell types, including a number of tumor cell lines. With the aim of creating VLM-based ligand-targeted anticancer drugs that may selectively convey VLM to pathological cells, we have previously introduced derivatizable hydroxyl handles into the VLM structure, allowing to access a three-entity library of monohydroxyl VLMs (HyVLMs) bearing the OH group at the isopropyl side chain of a d-Hyi, d-Val, or l-Val residue (analogs 2-4, respectively). Herein, the levels of bioactivity retained by the conjugable HyVLMs have been assessed on the basis of their ability to alter the functionality of isolated rat-liver mitochondria. Experiments run with HyVLMs in the range 1-10nM and in 20 or 125mM KCl medium show that the hydroxyl group reduces the potency of HyVLMs relative to VLM to an extent that depends upon the molecular site involved in the hydroxylation. On the other hand, estimation of the stability constants of complexes (in methanol at 25 degrees C) of each analog with Na+, K+, and Cs+ reveals that HyVLMs nicely retain the VLM binding features, except for a moderate increase in the stability of Na+ complexes. These findings, along with pertinent structural considerations, suggest that the incorporation of OH into the VLM structure might actually have altered its K+ transporting ability across mitochondrial membranes. Besides facing new aspects of VLM structure-activity relationship, these studies set the basis for the rational design of ligand-HyVLMs conjugates through derivatization of hanging OH group.

Epoxides are essential building blocks in organic chemistry. The epoxidation of unsubstituted cyclic dienes 2-4, and triene 5 using dimethyldioxirane (DDO, 1a) and its trifluoro analog 1b (TFDO) has been investigated. The excellent yields obtained (90-98%) are accompanied by outstandingly high diastereoselectivities (90-98%). Interpretation of results based upon the early idea that polar groups can direct the dioxirane attack by dipole-dipole interaction provides a likely rationale, along with a more generalized mechanistic view.

A valuable analog of the K+-ionophore valinomycin (1), bearing a pentafluorophenyl ester moiety, has been obtained by selective reaction between the tertiary hydroxyl moiety of analog 2 (available from valinomycin hydroxylation) and the isocyanate group of pentafluorophenyl N-carbonyl glycinate (3) catalyzed by bis(N,N-dimethylformamide)dichlorodioxomolybdenum(VI). LC-HRMS studies show that analog 4 undergoes easy derivatization under mild conditions by reaction with OH- and NH2-containing compounds. Mitochondrial depolarization assays suggest that 4 acts as a K+-ionophore, provided that the glycine carboxyl group is appropriately masked.

Carbon-cage molecules have generated a considerable interest from both experimental and theoretical points of-view. We recently performed a high-resolution study of adamantane (C10H16), the smallest hydrocarbon cage belonging to the diamandoid family (Pirali, O.; et al. J. Chem. Phys. 2012, 136, 024310). There exist another family of hydrocarbon cages with additional interesting chemical properties: the so-called platonic hydrocarbons that comprise dodecahedrane (C20H20) and cubane (C8H8). Both possess C C bond angles that deviate from the tetrahedral angle (109.8 degrees) of the spa hybridized form of carbon. This generates a considerable strain in the molecule. We report a new wide-range high-resolution study of the infrared spectrum of cubane. The sample was synthesized in Bari upon decarboxylation of 1,4-cubanedicarboxylic acid thanks to the improved synthesis of literature. Several spectra have been recorded at the AILES beamline of the SOLEIL synchrotron facility. They cover the 600-3200 cm(-1) region. Besides the three infrared-active fundamentals (v(10),v(1), and v(12)), we could record many combination bands, all of them displaying a well resolved octahedral rotational structure. We present here a preliminary analysis of some of the recorded bands, performed thanks the SPVIEW and XTDS software, based on the tensorial formalism developed in the Dijon group. A comparison with ab initio calculations, allowing to identify some combination bands, is also presented.

Anatase (TiO?) and multiwalled carbon nanotubes bearing polyethylenimine (PEI) anchored on their surface were hybridized in different proportions according to a sol-gel method. The resulting nanocomposites (TiO?@PEI-MWCNTs), characterized by BET, XRD, XPS, SEM, and UV techniques, were found efficient catalysts for CO? photoreduction into formic and acetic acids in water suspension and under visible light irradiation. PEI-grafted nanotubes co-catalysts are believed to act as CO? activators by forming a carbamate intermediate allowing to accomplish the first example in the literature of polyamines/nanotubes/TiO? mediated CO? photoreduction to carboxylic acids

Organic functionalization of carbon nanotube sidewalls is a tool of primary importance in material science and nanotechnology, equally from a fundamental and an applicative pointof view. In this paper, a mild and easily tunable approach to the sidewall decoration of single-walled carbon nanotubes (SWCNTs) with epoxides and their subsequent derivatization(ring opening) upon treatment with reactive nucleophiles is presented. The treatment of HiPco purified SWCNTs with dioxirane solutions results in highly oxidized CNTs, which areused as electrophilic platforms for their successive derivatization/functionalization. As a result of the choice of accessible, easy to handle and store dioxiranes, multiple oxidationcycles could be performed on the same sample, thus allowing for a final improvement in the extent of oxidation at the CNT sidewall.

Metal-free, Cu(II)- or Zn(II) tetrakis [4-(2,4-bis-(1,1-dimethylpropyl)phenoxy)]phthalocyanines loaded over TiO2 (anatase) proved to be active in the photoreduction of CO2 to formic acid (HCO2H) in water under UV-vis light. CuPc/TiO2 is catalyst of choice, allowing to reach a maximum yield of HCO2H, unequalled by any other similar catalytic systems. Because of their low environmental impact, low potential cost, and efficient power conversion, these multipurpose materials show promise in the setup of sustainable methods for CO2 valorization. (C) 2014 Elsevier B.V. All rights reserved.