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RNA binding proteins have emerged as critical oncogenic factors and potential targets in cancer therapy. In this study, we evaluated Musashi1 (Msi1) targeting as a strategy to treat glioblastoma (GBM); the most aggressive brain tumor type. Msi1 expression levels are often high in GBMs and other tumor types and correlate with poor clinical outcome. Moreover, Msi1 has been implicated in chemo- and radio-resistance. Msi1 modulates a range of cancer relevant processes and pathways and regulates the expression of stem cell markers and oncogenic factors via mRNA translation/stability. To identify Msi1 inhibitors capable of blocking its RNA binding function, we performed a ~ 25,000 compound fluorescence polarization screen. NMR and LSPR were used to confirm direct interaction between Msi1 and luteolin, the leading compound. Luteolin displayed strong interaction with Msi1 RNA binding domain 1 (RBD1). As a likely consequence of this interaction, we observed via western and luciferase assays that luteolin treatment diminished Msi1 positive impact on the expression of pro-oncogenic target genes. We tested the effect of luteolin treatment on GBM cells and showed that it reduced proliferation, cell viability, colony formation, migration and invasion of U251 and U343 GBM cells. Luteolin also decreased the proliferation of patient-derived glioma initiating cells (GICs) and tumor-organoids but did not affect normal astrocytes. Finally, we demonstrated the value of combined treatments with luteolin and olaparib (PARP inhibitor) or ionizing radiation (IR). Our results show that luteolin functions as an inhibitor of Msi1 and demonstrates its potential use in GBM therapy.

The stereoselective access to stereotriads as important polyketide building blocks is reported on the basis of the Krische-type hydrogen-mediated syn-crotylation. The products were obtained with an extremely high diastereoselectivity (dr >99:1), and the newly formed syn stereocenters were controlled solely by the chiral catalyst. The stereochemistry was assigned by crystallography and HPLC for both product manifolds. This extension of the burgeoning transfer hydrogen methodology gives divergent asymmetric access to anti,syn and syn,syn polyketide stereotriads from the same α-chiral starting material and avoids potentially epimerizable aldehyde intermediates.

Macrocyclic β-peptides were efficiently prepared using a thiadiazole-forming cyclization reaction between an α-ketoacid and a thiohydrazide. The linear β-peptide precursors were assembled from isoxazolidine monomers by α-ketoacid-hydroxylamine (KAHA) ligations with a bifunctional initiator – a process we have termed ‘synthetic fermentation’ due to the analogy of producing natural product-like molecules from simpler building blocks. The linear synthetic fermentation products underwent Boc-deprotection/thiadiazole-forming macrocyclization under aqueous, acidic conditions to provide the cyclic products in a one-pot process. This reaction sequence proceeds from easily accessed initiator and monomer building blocks without the need for additional catalysts or reagents, enabling facile production of macrocyclic β-peptides, a relatively underexplored structural class., Chemical Science, 9 (8), ISSN:2041-6520, ISSN:2041-6539

A convergent synthetic route to the sesterterpenoid framework of the bioactive phorbaketal and alotaketal natural product families has been established. The synthetic approach hinges on a Hosomi-Sakurai coupling of complex acetal and allylsilane coupling partners, followed by DDQ-promoted oxidative cyclization of highly unsaturated advanced intermediates. This robust synthetic approach enables further investigations into the members of these natural product families and readily provides access to analogues for biological testing.

Drowning in sea water is an unusual cause of severe hypernatremia. We report the case of a 3.5-year-old boy who died 11h after drowning in sea water, with a serum sodium level of 178 mmoL/L. In this case, hypernatremia was aggravated by diarrhea and hyperglycemia with glycosuria. Usually, correction of acute hypernatremia must be quick and early, aiming at a reduction of serum sodium concentration of up to 1-2 mmoL per liter per hour.

Metabolic dysregulation promotes cancer growth through not only energy production, but also epigenetic reprogramming. Here, we report that a critical node in methyl donor metabolism, nicotinamide N-methyltransferase (NNMT), ranked among the most consistently overexpressed metabolism genes in glioblastoma relative to normal brain. NNMT was preferentially expressed by mesenchymal glioblastoma stem cells (GSCs). NNMT depletes S-adenosyl methionine (SAM), a methyl donor generated from methionine. GSCs contained lower levels of methionine, SAM, and nicotinamide, but they contained higher levels of oxidized nicotinamide adenine dinucleotide (NAD+) than differentiated tumor cells. In concordance with the poor prognosis associated with DNA hypomethylation in glioblastoma, depletion of methionine, a key upstream methyl group donor, shifted tumors toward a mesenchymal phenotype and accelerated tumor growth. Targeting NNMT expression reduced cellular proliferation, self-renewal, and in vivo tumor growth of mesenchymal GSCs. Supporting a mechanistic link between NNMT and DNA methylation, targeting NNMT reduced methyl donor availability, methionine levels, and unmethylated cytosine, with increased levels of DNA methyltransferases, DNMT1 and DNMT3A. Supporting the clinical significance of these findings, NNMT portended poor prognosis for glioblastoma patients. Collectively, our findings support NNMT as a GSC-specific therapeutic target in glioblastoma by disrupting oncogenic DNA hypomethylation.

Metabolic dysregulation drives tumor initiation in a subset of glioblastomas harboring isocitrate dehydrogenase (IDH) mutations, but metabolic alterations in glioblastomas with wild-type IDH are poorly understood. MYC promotes metabolic reprogramming in cancer, but targeting MYC has proven notoriously challenging. Here, we link metabolic dysregulation in patient-derived brain tumor–initiating cells (BTIC) to a nexus between MYC and mevalonate signaling, which can be inhibited by statin or 6-fluoromevalonate treatment. BTICs preferentially express mevalonate pathway enzymes, which we find regulated by novel MYC-binding sites, validating an additional transcriptional activation role of MYC in cancer metabolism. Targeting mevalonate activity attenuated RAS-ERK–dependent BTIC growth and self-renewal. In turn, mevalonate created a positive feed-forward loop to activate MYC signaling via induction of miR-33b. Collectively, our results argue that MYC mediates its oncogenic effects in part by altering mevalonate metabolism in glioma cells, suggesting a therapeutic strategy in this setting. Cancer Res; 77(18); 4947–60. ©2017 AACR.

Background Glioblastoma (GBM) is one of the most lethal tumor types. Hypercellular regions, named pseudopalisades, are characteristic in these tumors and have been hypothesized to be waves of migrating glioblastoma cells. These "waves" of cells are thought to be induced by oxygen and nutrient depletion caused by tumor-induced blood vessel occlusion. Although the universal presence of these structures in GBM tumors suggests that they may play an instrumental role in GBM's spread and invasion, the recreation of these structures in vitro has remained challenging. Methods Here we present a new microfluidic model of GBM that mimics the dynamics of pseudopalisade formation. To do this, we embedded U-251 MG cells within a collagen hydrogel in a custom-designed microfluidic device. By controlling the medium flow through lateral microchannels, we can mimic and control blood-vessel obstruction events associated with this disease. Results Through the use of this new system, we show that nutrient and oxygen starvation triggers a strong migratory process leading to pseudopalisade generation in vitro. These results validate the hypothesis of pseudopalisade formation and show an excellent agreement with a systems-biology model based on a hypoxia-driven phenomenon. Conclusions This paper shows the potential of microfluidic devices as advanced artificial systems capable of modeling in vivo nutrient and oxygen gradients during tumor evolution.

The synthesis of both mono and bisbenzannulated spiroketals using an oxidative radical cyclization approach is investigated. Although unsuccessful in uncovering a novel route toward bisbenzannulated spiroketals, the oxidative radical cyclization does facilitate a new approach to monobenzannulated spiroketals such as those found in berkelic acid and in the chaetoquadrins.

Experimental analysis and manipulation of protein–DNA interactions pose unique biophysical challenges arising from the structural and chemical homogeneity of DNA polymers. We report the use of yeast surface display for analytical and selection-based applications for the interaction between a LAGLIDADG homing endonuclease and its DNA target. Quantitative flow cytometry using oligonucleotide substrates facilitated a complete profiling of specificity, both for DNA-binding and catalysis, with single base pair resolution. These analyses revealed a comprehensive segregation of binding specificity and affinity to one half of the pseudo-dimeric interaction, while the entire interface contributed specificity at the level of catalysis. A single round of targeted mutagenesis with tandem affinity and catalytic selection steps provided mechanistic insights to the origins of binding and catalytic specificity. These methods represent a dynamic new approach for interrogating specificity in protein–DNA interactions.

The reactivity of an oolitic limestone in contact with CO 2 was investigated on core samples in a 2 l batch reactor. Three types of experiments were conducted on wet samples at 150 bar of gas pressure and 80 °C in the presence of 1) supercritical CO 2 and pre-equilibrated saline solution, 2) supercritical CO 2 without aqueous solution and 3) N 2 and pre-equilibrated saline solution. Microscopic observations using optical and electronic microscopy showed little evidence of transformations although some dissolution/precipitation patterns were suspected in all experiments. Similarly, results from Hg porosity measurements, mechanical behaviour and velocity of ultrasonic waves were also slightly modified after experiments. Statistical image analysis of interoolite porosity measurements recorded by confocal scanning laser microscopy showed slight modifications of the pore distribution, connectivity and roughness in the case of the first experiment carried out with aqueous solution and CO 2 . Such observations are in good agreement with water analyses and thermodynamic simulations which predict high limestone stability with calcite dissolution of 2 pressure and pH exert opposing effects on calcite stability. The low impact of dry supercritical CO 2 on calcite dissolution was also demonstrated.

In order to obtain a better anhydrous precursor for various applications in materials science and catalysis, thermal dehydration reactions of Y(TFA)3(H2O)3 (TFA = trifluoroacetate) (A) were investigated. Thermal treatment of A at different temperatures under vacuum (5 × 10−2 mm) for several hours failed to give totally anhydrous yttrium trifluoroacetate (as indicated by IR). Two different complexes, a partially dehydrated [Y(μ,η1:η1-TFA)3(THF)(H2O)]1∞·THF (1) and a partially hydrolyzed [Y4(μ3-OH)4(μ,η1:η1-TFA)6(η1-TFA)(η2-TFA)(THF)3(DMSO)(H2O)] · 6THF (2), were obtained with good and moderate yield, respectively, by crystallization of two different thermally treated batches of A from THF (or THF + DMSO) at room temperature. More efficient dehydration of A could be achieved at 200 °C in a furnace, the obtained anhydrous yttrium tris-trifluoroacetate giving Y(TFA)3(THF)2 (3) on crystallization from THF. All the products were characterized by elemental analyses, FT-IR and 1H NMR spectroscopy as well as thermo-gravimetric analysis. In addition, single crystal X-ray structures are reported for 1 and 2, which show either a terminal (η1 and η2) or bridging (μ,η1:η1) bonding behavior of the TFA ligand.

Mesoporous iron tetrasulfophthalocyanine/TiO2 nanoparticles were prepared by a one-pot hydrolytic process starting from modified titanium alkoxide. The material has been characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction powder (XDR), transmission electronic microscopy (TEM), nitrogen absorption-desorption isotherm (BET), diffuse reflectance UV-visible spectrocopy and x-ray photoelectron spectroscopy (XPS). It contains anatase as the main crystalline phase (85%) along with brookite. Average crystallites size gave around 10 and 12 nm, for anatase and brookite, respectively. Diffuse reflectance UV-visible spectroscopy confirmed the presence of intact iron tetrasulfophtahlocyanine (FePcS), predominantly in dimeric form. The chemical interaction of the FePcS with the TiO2 nanoparticles was studied by using FTIR and XPS techniques which indicated that FePcS is covalently bonded onto TiO2 nanoparticles, leading to a stable hybrid system. Careful attention to binding energies of O 1s and S 2p elements in the nanohybrid material and in FePcS complex helps to shed light on this point.

In situ amino acid surface-modified TiO2 nanoparticle syntheses were performed by a simple one-pot hydrolysis of heteroleptic titanium alkoxide [Ti(OiPr)3(O2CC6H4NH2)]m in water with NnBu4Br. This process allowed precise control of the surface grafting rate by varying the amount of precursors and provided highly functionalized nanomaterials. Their compositions and microstructures were determined by C, H and N elemental analyses, TGA-MS, 13C CP-MAS NMR, XRD, TEM, BET, Raleigh diffusion, FTIR, Raman, XPS and UV/Vis experiments. The results indicated that (i) the aggregation rate increased with an increase in the loading of the organic substrate and (ii) the amino acid is chemisorbed as a carboxylate group onto the TiO2 nanoparticles, which leads to a strong interaction between the amino acid and the TiO2 nanoparticle and good stability of these hybrids. Applications of low-aggregated nanomaterials were demonstrated as efficient protection additive against UVA + UVB radiations.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The reactions between [Y(TFA) 3 (H 2 0) 3 ] and either [Cu(TFA) 2 -(MeOH)] or [Ba(TFA) 2 ]∞ in the presence of excess N-methyldiethanolamine (mdeaH 2 ) have been investigated in relation with their use as precursors for high Tc superconductors. They afford the heterometallic Y 3 Cu complex [CuY 3 (μ 3 -OH]-(μ-η 3 :η 1 -mdeaH) 3 (μ 3 η 3 :η 1 :η 1 -mdeaH) 2 (η 2 -TFA)(μ,η 2 -TEA)2] (TFA) 2 (H 2 0) (1) and the homometallic Ba-TFA ID polymer (TFA)2(H2O) (1) and the homometallic Ba-TFA 1D polymer [Ba 3 (η 3 -mdeaH2)2(μ-η 3 :η 1 -mdeaH2)2(η 1 -TFA)2(η 2 -TFA)2(μ 3 -η 2 :η 2 :η 1 -TFA) 2 ] 1 ∞, (2), respectively, in high yield. These compounds were characterised by X-ray diffraction and FT-IR, ESR (for 1) and NMR (for 2) spectroscopy. Single-crystal X-ray diffraction studies show the versatile bonding modes of the trifluoroacetate and N-methyldiethanolamine ligands, with the former acting not only as a terminal (η 1 and η 2 ) or bridging-chelating (μ,η2 and μ 3 -η 2 :η 2 :η 1 ) ligand but also as a counterion, whereas the latter, either protonated or partially deprotonated, binds the metal centres in a chelating (η 3 ) or bridging-chelating (μ,η3:η1 and μ 3 -η 3 :η 1 :η 1 ) manner. The triangular Y 3 unit [3.480(6)-3.550(6) A] in the cation of 1 consists of one nine-coordinate and two eight-coordinate Y atoms, the former of which are quite scarce in alkoxide chemistry. The unique feature of the 1D polymeric structure of 2 is the secondary F...cation bond, which has not been observed so far for TFA ligands. In addition, it is the only example where the Ba atom is linked to monodentate, bidentate and bridging trifluoroacetate ligands simultaneously.

An ionic heterometallic species [Y(DMF)8][Cu4(µ3-I)2(µ-I)3I2] (1) was isolated from a solution of CuI, NH4I and YI3(PriOH)4 in DMF–isopropoxyethanol, and was converted in a confined environment by progressive substitution of the DMF ligands with water molecules first into a 1D zig-zag structure [Y(DMF)6(H2O)2][Cu7(µ4-I)3(µ3-I)2(µ-I)4(I)]1∞ (2) and finally into a 2D sheet [Y(DMF)6(H2O)3][CuI7CuII2(µ3-I)8(µ-I)6]2∞ (3) by H-bond templating.

The reaction between BaI2 · 2H2O and NaHFIP [HFIP = OCH(CF3)2] in a 1:1 stoichiometry gave the heterometallic compound NaBaI2(HFIP)(H2O)(THF)0.5 (1). Attempts to recrystallize 1 in the presence of N- or O-donor ligands lead to redistribution reactions. Barium iodide adducts such as BaI2(DME)3 (2), trans-BaI2(DME)(triglyme) (3) and cis-BaI2(DME)(tetraglyme) (4) were isolated with DME as solvent. A similar behavior was observed for the reaction between BaI2 · 2H2O and NaTFA (TFA = O2CCF3) in a 1:1 stoichiometry in THF, and [Ba(tetraglyme)2]I2 · C7H8 (6) was isolated in the presence of excess tetraglyme. All compounds have been characterized by elemental analysis, IR and 1H NMR as well as single crystal X-ray studies for 3, 4 and 6. Compounds 3 and 4 are covalent adducts with eight- and nine-coordinate barium, respectively. Compound 6 is an ionic compound where two tetraglyme ligands wrap the 10-coordinate barium cation in a helical fashion. The presence of DME actually allows the coordination number of barium in the mixed-ligand adducts 3 and 4 to be tuned. The average Ba–O bond lengths (2.80 for 3 to 2.87 A for 6) reflect the coordination number of the metal. The same observation is valid for the average Ba–I bond distance, 3.442 for 3 vs. 3.536 A for 4.

A robust synthetic approach to cis-γ-hydroxycarvone derivatives has been developed, enabling efficient access to synthetic building blocks for the growing family of bioactive sesterterpenoid natural products. Using this approach, an allyl bromide carvone derivative was used as the key building block for the total synthesis of the natural product phorbin A. This synthetic sequence also demonstrates the utility of benozyl enol ethers as an effective means of masking a β-ketophosphonate and their subsequent application in a one-pot benzoyl transfer–intramolecular Horner–Wadsworth–Emmons reaction.

The reaction between dysprosium chips or DY5O(OPri)(13) and 2-isopropoxyethanol afforded the title compound. It has been characterized in the solid state by X-ray diffraction and magnetic susceptibility measurements. (C) 2006 Elsevier B.V. All rights reserved.

The reactions between titanium or zirconium alkoxides namely Ti(OR)4 (R = iPr, nBu) or Zr2(OiPr)8(HOiPr)2, Zr(OnBu)4 respectively and lead 2-ethylhexanoate Pb(O2CC7H15)2 were investigated at room temperature (rt) and by heating. The various compounds were characterized by elemental analysis, FT-IR, 1H and 207Pb NMR. The mixed-metal species obtained at rt were adducts Pb4Zr4(μ-O2CR′)8(OR)16(OHR)21 and Pb2Ti4(μ-O2CR′)4(OR)162 (R′=CHCHEt(CH2)2Me, R = iPr) independently of the stoichiometry used. The structures of 1 and 2 are based on triangular M2Pb cores (M = Zr, Ti). with 6-coordinate transition metals -as required for perovskites- and 6- or 7-coordinate lead atoms. Similar observations were made with n-butoxides. Thermal and hydrolytic condensation reactions were investigated. Thermal condensation was more difficult for the n-butoxide derivatives than for the isopropoxide ones. Powders derived from the hydrolysis of the Single Source Precursor 1 in various conditions were characterized by TGA, XRD and SEM for the PZ ceramic.

Alcohol exchange reactions applied to HfAl2(OPri)10 (1) afforded heterometallic Hf–Al aminoalkoxides namely HfAl2(OPri)8(dmae)2 (dmae = N,N-dimethylaminoethoxide) (2) and HfAl2(OPri)8(dmap)2 (dmap = dimethylaminopropoxide) (3). They were characterized by elemental analysis, FT-IR, 1H NMR, mass spectrometry and TGA. The molecular structure of 2, as established by single-crystal X-ray diffraction, HfAl2(μ-OPri)2(μ,η2-OC2H4NMe2)2(OPri)6, is based on an open-shell trinuclear unit with a central 6-coordinate Hf atom and 5-coordinate Al centres. Compound 2 was tested as a single-source precursor for the deposition of hafnium aluminate films by liquid-injection MOCVD. The films growth rate, composition and morphology were studied in relation with the deposition temperature. The as-deposited at 500–800 °C films (both on sapphire and silicon) were amorphous; partial crystallization occurred after 1 h annealing at 900 °C. The bulk of the films was Al-rich (Al/Hf = 1.2–1.6) and contained small amounts of carbon (2–4%) and nitrogen (4–5%).

Hafnium β-diketonatochlorides HfCl2(thd)2 (1), HfCl(thd)3 (2) as well as β-diketonato-silylamide and/or siloxide derivatives of 1 namely Hf(thd)2[N(SiMe3)2]2 (3), Hf(thd)2(OSiMe3)2 (4) and Hf(thd)2(OSitBuMe2)2 (5) (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) were synthesized and characterized by elemental analysis, FT-IR, 1H NMR and TGA. 2 and 5 were also characterized by single-crystal X-ray diffraction. The siloxide ligands are in cis position for 5 and exert a strong trans effect. The new volatile compounds were tested as single-source precursors for the deposition of HfSixOy films by pulsed liquid injection MOCVD on Si(1 0 0) and R plane sapphire. The as-deposited at 600–800 °C films were essentially amorphous, Hf-rich (Hf/Hf + Si = 0.7–0.85) and smooth.

The preparation of lead(II) aminoalkoxides has been demonstrated from the direct reaction of aminoalcohols with lead(II) oxide. The denticity of the aminoalcohols determined the facility of the reactions, the rate increasing with the number of hydroxyls. Thus, [Pb(dmae)2], 1, [Pb(mdea)]∞, 2, and [Pb(teaH)]2, 3 (dmaeH = dimethylaminoethanol, mdeaH2 = N-methyldiethanolamine, and teaH3 = triethanolamine) have been prepared in high yields and characterized by 1H and 13C NMR. The X-ray crystal structure analyses of 2 and 3 are described.

Hydrolysis of tellurium isopropoxide, in the presence of tetraalkylammonium bromide solution, led to oriented α-TeO 2 crystals. Anisotropic growth was enhanced by adding trace amounts of titanium isopropoxides which allowed to get higher aspect ratio α-TeO 2 crystals. Higher amounts of titanium isopropoxides afforded mixtures of α-TeO 2 rods and β-TeO 2 square crystals or TiTe 3 O 8 crystalline materials after annealing at 480 °C. Those materials have been characterised by FT-IR, XRD, XPS and SEM-EDX techniques.

A new hafnium β-ketoesterate Hf(tbob)4 (tbob=tert-butyl-3-oxobutanoate or tert-butylacetoacetate) was obtained by ligand exchange reaction applied to Hf2(OiPr)8(iPrOH)2. It was characterized by elemental analysis, FT-IR, 1H NMR, mass-spectroscopy and TGA. The compound is volatile and it was tested for the growth of HfO2 films on Si(100) and R-plane sapphire substrates at 600–800 °C by pulsed liquid injection MOCVD. The films were characterized by XRD, XPS and AFM. Stoichiometric amorphous films were obtained on silicon, while those on sapphire were relatively well crystallized (00l) monoclinic. The growth was kinetically limited in all the temperature range studied (600–800°C).

The β-ketoimine MeC(O)CHCMeNH(CH2CH2NiPr2) (HLiPr) was prepared and used for the synthesis of new calcium, strontium and barium β-ketoiminates. These were characterized by elemental analysis, FT-IR, 1H NMR, and, for the strontium bis-N,N-di(isopropyl)aminoethylamino-2-penten-4-onate, by single-crystal X-ray diffraction. Two molecular units having similar conformations are present in the asymmetric unit cell. Both molecules are linear trimers with six-coordinate strontium atoms and bond lengths spreading over the range 2.454(4)–2.511(4) A and 2.572(6)–2.635(4) A for the Sr–O and Sr–N linkages, respectively. All ketoiminate ligands are bonded in μ,η2-mode leading to an unprecedented structural motif, with the amine functionality remaining pendant, probably due to the steric hindrance of the diisopropylamino moiety.

New bulky Zr and Hf β-diketonates (2,2,8,8-tetramethyl-4,6-nonanedionates, tmnd) were synthesized and characterized by elemental analyses, 1 H NMR, FT-IR and mass spectrometry. A volatile copper compound Cu(tmnd) 2 , an intermediate product of ligand synthesis, was isolated and characterized as well. The M(tmnd) 4 (M=Zr, Hf) compounds were tested as precursors for MOCVD of ZrO 2 and HfO 2 films. Preferentially (001)/(010)/(100) textured and in-plane oriented films of monoclinic oxides have been deposited by pulsed liquid injection MOCVD on R plane sapphire. Smooth films could be grown, especially on sapphire and at low temperature (500 °C). The films on Si(100) were polycrystalline and had rougher surface. XPS study showed 3–4 and 7–8 at.% of carbon in HfO 2 and ZrO 2 films, respectively. Zr(tmnd) 4 and Hf(tmnd) 4 lead to significantly higher growth rates of ZrO 2 and HfO 2 films at low temperature than conventional Zr(thd) 4 and Hf(thd) 4 precursors (thd=2,2,6,6-tetramethyl-3,5-heptanedionate) and are attractive precursors for oxide films.

The reactions between Ti(OR)4 and allylacetatoacetate (HAAA) in 1:1 or 1:2 stoichiometry at rt gave Ti2(OR)6(AAA)2 R = Et (1), iPr (2) and Ti(OR)2(AAA)2 R = Et (3), iPr (4) species. A monosubstituted derivative Ti2(OiPr)6(AMP)2 (5) was isolated with allylmethylphenol (AMPH). 1 and 5 were characterized by single crystal X-ray diffraction. Their molecular structures consist of dimers with the polymerizable ligands in terminal positions andbridging alkoxide ligands assembling five and six-coordinated metal atoms, respectively. The Ti-O bond lengths of 1 are in the range 1.76(1) to 2.11(1) A with the variation Ti-OEt < Ti-μ-OEt < Ti-η2-O (allylacetatoacetate). All compounds were characterized by FT-IR and 1H NMR. The possibility to accede to more extended arrays either by hydrolysis or by radical initiated homo- or co-polymerization reactions was investigated for the allylacetato derivatives as well as for Ti(OiPr)2(AAEMA)2 AAEMA = [2-(methacryloyloxy)ethylacetoacetato] for the latter reactions. Synthesen und Strukturen von Titan-Derivaten mit polymerisierbaren Liganden Ti(OiPr)4 reagiert mit Allylacetoacetate (HAAA) im Verhaltnis 1:1 oder 1:2 bei Raumtemperatur zu Ti2(OR)6(AAA)2 (R = Et (1), iPr (2)) und Ti(OR)2(AAA)2 (R = Et (3), iPr (4)). Mit Allylmethylphenol (AMPH) wurde Ti2(OiPr)6(AMP)2 (5) isoliert. 1 und 5 wurden durch Einkristallstrukturanalyse charakterisiert. Ihre Molekulstruktur besteht aus Dimeren mit endstandigen, polymerisierbaren Liganden und verbruckenden Alkoxidliganden um funf- bzw. sechsfach-koordinierten Metallatomen. Die Bindungslangen Ti-O in 1 betragen 1.76(1) bis 2.11(1) A in der Reihe Ti-OEt < Ti-μ-OEt < Ti-η2-O (Allylacetoacetat). Alle Verbindungen werden durch FT-IR- und 1H NMR-Spektroskopie charakterisiert. Die Moglichkeit ausgedehntere Wirkgruppen sowohl durch Hydrolyse oder durch radikalinitiierte Homo- oder Kopolymerisation zu erhalten, wurde fur die Allylacetato-Derivate wie fur Ti(OiPr)2(AAEMA)2 (AAEMA = 2-(methacryloyloxy)ethylacetoacetato) untersucht.

The reaction between copper powder and Ba(TFA)2 (TFA = CF3CO2) in methanol under air and in the presence of an aminoalcohol, afforded Cu(II) alkoxides and subsequent formation of heterometallic species or cocrystallization depending on the functional alcohol, dimethylaminoethanol (dmeaH) or N-dimethylaminoethanol (mdeaH2), respectively. A 1D-coordination polymer [Ba3Cu2(μ,η2-TFA)6(μ,η2-OC2H4NMe2)4(MeOH)2,2MeOH]∞, based on zig–zag chains was obtained with dmeaH, whereas mdeaH2 lead to [Ba(η1-TFA)2{MeN(C2H4OH)2}2] 2a and [Cu{MeN(C2H4O)(C2H4OH)}2] (2b) which cocrystallize as two independent molecules in the asymmetric unit cell.

The reaction between hafnium tetrachloride and neopentyl alcohol in the presence of ammonia lead to hafnium oxoneopentoxide ( 1 ). 1 was characterized by FT-IR, 1 H and 13 C NMR. Single-crystal X-ray diffraction identified it as a trinuclear oxo species Hf 3 (μ 3 -O)(μ 3 -ONep)(μ-ONep) 3 (ONep) 6 . The oxoneopentoxide has been used as precursor for the growth of HfO 2 films by pulsed liquid injection MOCVD. The influence of deposition temperature (320–750°C) on film growth rate, roughness and microstructure was studied and compared with the conventional Hf(thd) 4 (thd=2,2,6,6-tetramethyl-3,5-heptanedionate) precursor. Depending on the deposition temperature, amorphous, polycrystalline or epitaxial films can be obtained on sapphire ( R -plane) substrates. The film growth rate was independent of the deposition temperature in the range 350–750°C.

The reaction between yttrium chips or Y5O(OPri)13 and 2-isopropoxyethanol afforded the title compound. It has been characterized in the solid state by X-ray diffraction and in solution by 1H and 89Y NMR spectroscopy.

Y 2 O 3 /Pr 3+ nanoparticulate powder has been prepared through a one-step hydrolytic sol–gel process using an yttrium praseodymium heterometallic alkoxide. The powder was characterized by TGA/TDA, XRD, TEM, XPS and photoluminescent experiments, which showed that a homogeneous and a highly crystalline material was obtained by calcination as low as 500 °C.

Cerium(IV) oxazoline derivatives Ce(Me 2 oxaz) 4 ( 1 ) [Me 2 oxazH=2-(2 ′ -hydroxyphenyl)-4-dimethyl)oxazoline] and Ce(Pr i Hoxaz) 4 ( 2 ) [Pr i HoxazH=2-(2 ′ -hydroxyphenyl)-4-isopropyl)oxazoline] were prepared in high yields by ligand exchange reactions between Ce 2 (OPr i ) 8 (Pr i OH) 2 and the corresponding 2-(2 ′ -hydroxyphenyl)-2-oxazolines. Characterisation was achieved by elemental analysis, FT-IR, 1 H NMR and mass spectroscopy (MS). 2 was also characterized by polarimetric measurement. Their thermal decomposition pathways under nitrogen were studied by TGA and coupled TGA-CG/MS experiments.

Adducts of cobalt(II) 2,4-pentanedionate (acac) and 2,2,6,6-tetramethyl-3,5-heptanedionate (thd) with TMEDA (N,N,N′,N′-tetramethyl-1,2-diaminoethane) and aminoalcohols, namely 1-dimethylamino-2-propanol (DMAPH) and 2-dimethylaminoethanol (DMAEH), have been synthesized and characterized by elemental analyses, FT-IR, 1H NMR, mass spectrometry and TGA. The molecular structures of Co(acac)2(TMEDA) (1) and [Co(acac)2(DMAPH)]2 (2) have been determined by single-crystal X-ray diffraction. 1 is monomeric while 2 is dimeric with two molecules linked by hydrogen bonds (O–H–O distance 2.708 A av.). The most volatile and stable new adducts Co(acac)2(TMEDA) and Co(thd)2(TMEDA) have been studied as precursors for cobalt oxide deposition by liquid injection MOCVD in DME on monocrystalline LaAlO3 and Si substrates. Films were characterized by XRD and XPS. These preliminary MOCVD experiments showed that epitaxial Co3O4 films can be obtained by using both new precursors.

New metalorganic compounds—adducts of cobalt(II) acetylacetonate (acac) and cobalt(II) 2,2,6,6-tetramethyl-3,5-heptanedionate (thd) with N,N,N′,N′-tetramethyl-1,2-diaminoethane have been synthesized and studied as potential precursors for liquid injection metalorganic chemical vapor deposition of Co 3 O 4 films. The properties of the films were compared with those deposited using standard [Co(acac) 2 ] 4 and Co(thd) 2 precursors. Depositions were carried out at 350–600°C on LaAlO 3 (1 0 0), sapphire (R-plane), MgO (1 0 0) and Si (1 0 0) substrates. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. Depending on substrate material, highly (1 1 0) or (1 0 0) textured Co 3 O 4 films have been deposited; moreover, films exhibited preferential in-plane orientation. No significant difference has been found in the quality of Co 3 O 4 films deposited from different precursors.

New Zr, Hf and Y 2,7,7-trimethyl-3,5-octanedionates (tod) as well as the corresponding Cu β-diketonate have been synthesized and characterized by FT-IR, elemental analyses, TGA, and 1H NMR or ESR. The molecular structure of Hf(tod)4 has been determined by single-crystal X-ray diffraction, the metal displays a square antiprismatic geometry. Zr, Hf and Y β-diketonates were investigated as precursors for MOCVD deposition of ZrO2, HfO2 and yttria-stabilized hafnia thin films. The films were characterized by XRD, XPS, EDS and AFM. Highly textured and in-plane oriented films were deposited on sapphire by pulsed liquid injection MOCVD. Zr(tod)4 and Hf(tod)4 precursors lead to higher growth rates of ZrO2 and HfO2 films at lower temperatures than conventional Zr(thd)4 and Hf(thd)4 precursors (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) and are attractive new precursors for oxide films.

The reaction between the yttrium β-diketonate complexes Y(tmhd)3(H2O)x (x=0 or 1) and 0.5 or 1 equivalent of N,N,N′,N′-tetramethylethylenediamine (tmeda=Me2NCH2CH2NMe2) in hexane at room temperature afforded [Y(tmhd)3]2(tmeda) (1) and Y(tmhd)3(tmeda) (2) derivatives, respectively. They have been characterized by FT-IR, 1H NMR spectroscopy and by single crystal X-ray diffraction for 1. Variable temperature 1H NMR experiments indicated an equilibrium between 1 and 2. Their thermal behaviors were characterized by TGA and sublimation experiments. 2 is converted into compound 1 by heating over 100 °C. These precursors were used for the growth of Y2O3 and YBa2Cu3O7 − x films by pulsed injection metal organic chemical vapor deposition (PI-MOCVD).

Reactions between lanthanum triflate adducts La(OTf) 3 (LL x ) (OTf = O 3 SCF 3 ; LL 1 = triglyme, LL 2 = tetraglyme] and 2 equiv. of LiOAr (Ar = C 6 H 3 -2,6-Me 2 ) in THF lead to La(OTf)(OC6H3-2,6-Me 2 ) 2 (LLX) [LL 1 = triglyme(1); LL 2 = tetraglyme (2)] derivatives. They were characterised by elemental analysis, FT IR and NMR ( 1 H, 1 3 C, 1 9 F). The adduct with tetraglyme (2) was also characterised by single crystal X-ray diffraction. The metal is octacoordinated, surrounded by anionic monodentate ligands including the triflate and a pentadentate glyme. The La-O bond distances spread over the range 2.225(3)-2.692(3) A with the ranking La-O(Ar) < La-O(Tf) < La-O(tetraglyme). The grafting of 1 onto silica led to an hybrid material, characterised by elemental analysis, FT IR, 1 3 C CP-MAS NMR and XPS. It was used as hydroxymethylation catalyst of silyl enol ether in mild conditions.

The development of new materials for the technological demands requires chemical routes, in the case of oxides mostly being sol–gel or CVD processing, for their elaboration. Those processes need metallic precursors with a set of ligands that are able to provide suitable properties such as solubility or volatility, clean decomposition pathways, control of stoichiometry for multimetallic arrays, to name but a few. These aspects will be illustrated on some recent examples of non-silicon systems.

TiO2 nanoparticles with a mesoporous structure have been synthesised by a one step, simple, efficient, low temperature (100 °C) and environmentally friendly sol–gel process using ammonium bromide salts as catalysts. They have been characterised by FT-IR, TGA/TDA, XRD, BET and TEM techniques. Their photocatalytic activities are compared to highly porous commercial TiO2 in liquid/solid and gas/solid systems. Deposition of a uniform crystalline TiO2 coating with high adhesivity was achieved on organic substrates such as cellulose fibers.

The structures of the cerium tetrafluoroisopropoxide adducts with TMEDA (1) and diglyme [Me(OC2H4)2OMe] (2) were established by single crystal X-ray diffraction (TMEDA=tetramethylethane-1,2-diamine). The cerium atom is hexa- and heptacoordinated for 1 and 2, respectively. The CeO(hfip) bond distances are quite short [2.115(5)–2.152(6) A] and are associated to large CeO(hfip) angles (>156°). Both complexes display a range of short F⋯C contacts, the shortest ones having values of 3.754 and 4.060 A for 1 and 2, respectively. Decomposition experiments were achieved in a cold-wall reactor. The films deposited on glass substrates were characterized by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis spectroscopy.

Functional indium [In(OR)3]m alkoxides (R = C2H4OMe, C2H4NMe2) have been obtained by alcoholysis of In[N(SiMe3)2]3 and characterised by elemental analysis, FT-IR and NMR spectroscopy. The 2-dimethylaminoethoxide was characterised by X-ray diffraction. It corresponds to the association of two InO6 octahedra giving the unsymmetrical dimer [In2(μ,η1-OR)(μ,η2-OR)(η2-OR)3(η1-OR)] (2). 2 was used as a pincer ligand toward Cu(acac)2.

New homo- and heterometallic [M(OR)3]m and [ZnM2(OR)8]m species (M = Al, Ga; R = C2H4OMe, C2H4NMe2) have been prepared and characterised by elemental analysis, electrospray mass spectrometry, FT-IR and multinuclear NMR. Hydrolyses of the heterometallic compounds were investigated and the particle sizes were determined. The thermal behaviour of the hydrolysed products was studied by TGA/DTA and the nature of the phases was analysed by powder X-ray diffraction. Various sol–gel processing parameters were studied in order to stabilise nanosized colloidal suspensions for access to thin films by spin coating. [ZnGa2(OC2H4OMe)8]2 was the best candidate for sol–gel processing, allowing crystalline ZnGa2O4 solids to be obtained at 300 °C. Films, obtained on glass and MgO substrates, were transparent (>95%) and characterised by UV-visible and X-ray photoelectron spectroscopies, tapping mode AFM, SEM, EDX and X-ray diffraction.

The reactions between lithium bis(trimethyl)phenylenediamide and niobium or tantalum pentachlorides at low temperature afforded [{4,5-Me2-C6H2(NSiMe3)2}2MCl] (M=Nb (1), Ta (2)) independently of the stoichiometry used, 1:1 or 2:1. The reaction between tantalum pentachloride and N,N′-bis(trimethylsilyl)-o-dimethylphenylene diamide o-C6H2Me2(NSiMe3)2 in Et2O–DME at −78 °C leads to a tantalum(V) imide 3. Monosubstitution with diamides was achieved on tantalum with the more rigid 1,8-diamido-naphtalene. The various compounds were characterized by elemental analysis, FT-IR and NMR. Compounds 1 and 3 were characterized also by single crystal X-ray diffraction. The metal is pentacoordinated for 1 bearing two bidentate o-phenylenediamide ligands and a chlorine in the apical position of a distorted square-tetragonal pyramid. The salient features are a disymmetrical coordination mode of the diamide ligand with two quite different Nb–N distances namely 1.981(2) and 2.053(3) A, as well as short Nb–C distances with the phenyl ring [2.495(3) and 2.471(3) A]. The diamide ligand is thus coordinated in a η4-fashion in the solid state. The salient feature of the structure of 3 is the presence in the metal coordination sphere of the functional imido ligand [Me2C6H2N(SiMe2Cl)(NSiMe3−xClx)]2− (x=1 or 0) which was generated by N–Si bond cleavage and Si–Me/Si–Cl scrambling. Tantalum is six-coordinate, linked to the bulky imido ligand, three chlorine and a bidentate dimethoxyethane. The surrounding of the metal is distorted with a TaN bond distance of 1.706(5) A and a large Ta–N(2)–C(2) angle [170.7(5)°]. The thermal behavior as well as the reactivity as soluble α-olefin polymerization catalyst were evaluated for 1.

Soluble Ni(II) alkoxides, namely the dimethylaminoisopropoxide clathrate with toluene, Ni(η2-ORN)2·C7H8 (I) and the solvent free crystalline Ni(ORN)2 (RN=CHMeCH2NMe2) species (II), obtained by sublimation of I in vacuo, were characterized by X-ray diffraction. The reaction between Ni(ORN)2 and copper carboxylates such as propionate and copper acetate hydrate in hydrocarbons afforded [CuNi2(O2CEt)3(ORN)3(RNOH)] (III) and [Ni(Ni0.25Cu0.75)2(μ3-OH)(μ-OAc)(η1-OAc)2(μ,η2-ORN)2(η2-RNOH)] (IV), respectively. The structures of I and II are based on square planar molecules of the trans isomer. The structure of IV corresponds to triangular aggregates with a M3(μ3-OH) central core. The remarkable feature is the presence of three types of coordination sphere, one metal is coordinated octahedrally and corresponds to nickel and the other two have square pyramidal and square planar coordinations, respectively, and an electronic density corresponding to Cu (75%) and Ni (25%). The monodentate behavior of the two acetato ligands is stabilized by intramolecular hydrogen bonding involving the hydroxyl functionalities of the μ3-hydroxo (2.776(9) A) and the solvated aminoalcohol ligand (2.573(6) A). Magnetic data in the 20–300 K temperature range for III and IV account for three uncoupled metal centers at high temperature whereas ferromagnetic exchange interactions are likely below 20 K.

Decomplexation of Ca3(thd)6 by mono- and bidentate N-donors [morpholine, dimorpholinoethane (DIMOE), TMEDA, bipyridine] afforded the corresponding adducts Ca(thd)2L [L=morpholine (1a), DIMOE (1b), TMEDA (2)] and {Ca(thd)2}2(bipy) (3). All complexes have been fully characterised by elemental analysis, FT-IR and 1H NMR spectroscopy. Compounds 1b and 3 have also been characterised by X-ray crystallography. The structure of 3 is based on six- and seven-coordinated Ca centres; it is the first dimeric volatile Lewis base adduct of Ca(thd)2. The thermal behaviour of all derivatives has been studied by thermal gravimetric analysis.

The reaction between barium 2,6-dimethylphenoxide (1) and copper 2,2,6,6-tetramethylheptane-3,5-dionate gave the volatile β-diketonatoaryloxide [Cu(μ-OC6H3-2,6-Me2)(thd)]2 (2). The complex was characterized by elemental analysis, IR and ESR spectroscopy as well as single-crystal X-ray diffraction. It crystallises in the space group P21 /c with a = 6.602(2), b = 24.454(5), c = 12.391(4) A, β = 95.49(2)°. TGA experiments at 1 atmosphere show that 2 is volatile and decomposes at 292°C to metallic copper by a ligand-mediated reduction.

The high coordination numbers required by large elements (Ln, Ba...) favor the formation of closo oxo aggregates by desolvation of M(OR)n(ROH)x solvates and subsequent non-hydrolytic condensation. Pentanuclear M5O cores display a remarkable stability for large elements and can associate along an edge or an apex. Heteronuclear arrays are thus accessible from these aggregates by Lewis acid-base reactions or, for a better control of stoichiometry between the metals, by reactivity of the coordinated alcohol of a solvate. Functionalisation by polymerisable O-donors such as allylacetatoacetate (HAAA) provides species which can be converted into organic-inorganic arrays by copolymerisation reactions.

Polylactide samples obtained by the ring-opening polymerization of (D,L)-lactide by using different lanthanide alkoxide initiators were examined by SEC, 13 C NMR and MALDI-TOF MS techniques. The evidence of substantial transesteriffcation was observed in the case of a polymerization initiated by lanthanum alkoxide and bimetallic aluminium-yttrium alkoxide initiators. In the case of Y and Sm alkoxide initiators, the MWD remains narrow up to high conversions for reasonable polymerization times, but the prolongation of the post-polymerization time increases the amount of ester-eschange reactions, The extent of the transesterification reactions was evaluated on the basis of the intensity of the stereosequence resonances for the methine carbon signal in the 13 C NMR spectra. MALDI-TOF MS analysis revealed the presence of add-numbered oligomers in all spectra. Thus, transesterification reactions occus from the beginning of the polymerization. Linear and cyclic oligomers were detected in some cases indicating the simultaneous occurrence of inter- and intramolecular exchange reactions. The microstructure analysis of the polymers by 13 C NMR spectroscopy indicates a preference for a syndiotactic addition during the polymerization process.

SnO 2 or doped SnO 2 thin films can be used as transparent conductors in various optoelectronic devices such as screens or solar cells. They usually present high optical transmittance, low resistivity and high chemical and mechanical stability. The synthesis and single crystal X-ray diffraction analysis of new tin (IV) modified alkoxides Sn(OEt) 2 (η 2 -acac) 2 ( 1 ) and Sn 4 (μ 3 -O) 2 (μ 2 -OEt) 4 (OEt) 6 (η 2 -acac) 2 ( 2 ) (acacH=2,4 pentanedione) are reported. 1 crystallizes in the monoclinic system (space group P 2 1 / n ) while 2 crystallizes in the triclinic system (space group P 1). The asymmetric unit of the molecular species Sn(OEt) 2 (η 2 -acac) 2 contains two monomers which are slightly different. Sn 4 (μ 3 -O) 2 (μ 2 -OEt) 4 (OEt) 6 (η 2 -acac) 2 is a tetranuclear species in which Sn atoms are connected together by two triply bridging oxo ligands and four bridging ethoxo groups. Six terminal ethoxo groups and two chelating β-diketonato ligands are completing the coordination of the metal atoms. Their behaviour towards hydrolysis–condensation reactions is discussed.