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A ruthenium(III) complex formulated as [Ru(pyc)3]·H2O (where pyc is pyridine-2-carboxylate) was prepared through a one-pot reaction of pyridine-2,6-dicarboxylic acid and anhydrous ruthenium(III) chloride. Here, hydrothermal conditions led to decarboxylation from pyridine-2,6-dicarboxylic acid into pyridine-2-carboxylate. The compound was identified by spectroscopic methods and its crystal structure was determined by single-crystal X-ray diffraction. The cytotoxicity of the compounds was evaluated by MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay against three cancer cell lines containing a human melanoma (A375), a human non-small cell lung carcinoma (H1299), a human colon adenocarcinoma (HT29), and also one normal cell human foreskin fibroblast (HFF). A strong and selective inhibitory effect of the complex (IC50 = 6.50 μM, viability inhibition = 67.12%) was exhibited toward A375 cells. The apoptosis through a mitochondrial pathway was suggested via reactive oxygen species (ROS) production and mitochondria membrane potential (MMP) collapse. The cytostatic effect of the complex in the A375 3 D spheroid model was depicted.

A family of bimetallic complexes based on aurophilic interactions was synthesized, and tested for vapochromism and P–T variations. These complexes can originate cocrystals, opening the route to a new aurophilic-based crystal engineering.

Two new isomorphous metal–organic frameworks of formula [Ca(C6H12O5)2]X 2 have been synthesized and the parameters influencing their nonlinear optical response investigated., In the last few decades optical imaging techniques based on nonlinear optical properties have been of interest for biosensing applications. This work focuses on two isostructural and isomorphous sugar-derived metal–organic frameworks (MOFs) with second-harmonic generation (SHG) properties, in order to investigate their possible application as biosensors in view of their high biocompatibility. Combining 2-de­oxy-d-galactose with the metal halogenides CaX 2 (X = Br, I), two new isomorphous MOFs of formula [Ca(C6H12O5)2]X 2 were obtained and characterized through single-crystal X-ray diffraction. The first-order static hyperpolarizability and second-order susceptibility were estimated by in vacuo and in-crystal density functional theory calculations, and compared with the experimental SHG response of powdered samples. The parameters influencing the SHG response of these compounds were investigated by comparison with similar previously analysed MOFs, to understand how to design more efficient materials to be used as nanoprobes by exploiting crystal engineering techniques.

The conventional methods for the

This paper reports the synthesis of two complexes through one-pot reactions of pyridine-2,6-dicarboxylic acid (pydcH2), phenanthroline, and 2-aminopyridine, with Gd(NO3)3.6H2O and Ce (NO3)3.6H2O metal salts. The new coordination complexes C1 and C2 have been identified by spectroscopic methods. The complexes were characterized by X-ray crystallography. The nature of metal-ligand interactions was studied theoretically using NBO and EDA-NOCV analyses. The results showed that the contribution of electrostatic interactions in both complexes is considerably larger than orbital. However, the contribution of orbital interactions in [CeL3]2–, is more than that in [GdL3]3– (28.8% vs. 21.8%). In following, the cytotoxic effect of synthetic complexes was investigated in vitro using oxaliplatin as a standard against three cancer cell lines including human breast cancer (MCF7), human colon adenocarcinoma (HT29), and human lymphocyte (HL60). The most significant inhibition activity was observed by both C1 (IC50=80.7 μM, Viability inhibition=83.41%) and C2 (IC50=98.3 μM, Viability inhibition=77.19%) toward the MCF7 cell line.

Two new coordination complexes were synthesized using the reaction of two organic salts with gallium(III) nitrate octahydrate. The salts were prepared and used as ligand from the reaction of 2-aminobenzimidazole with pyridine-2,6-dicarboxylic acid and 4-hydroxypyridine-2,6-dicarboxylic acid, respectively. All compounds were identified by spectroscopic methods and their crystal structures determined by single crystal X-ray diffraction. The investigations showed that the two complexes were isostructural. Moreover, thermal analysis was carried out to study the decomposition steps of the complexes. The inhibition properties of the compounds were studied in vitro using oxaliplatin as a standard against five cell lines including a human breast cancer, a prostate cancer, a human liver hepatocellular carcinoma, a colorectal carcinoma and a human foreskin fibroblast. The anti-proliferative activity of the complexes was found to be similar in the majority of cell lines except for the prostate cancer cells. The most remarkable cytotoxicity effect of both complexes appeared on the human breast cancer cells. Determination of mitochondrial membrane potential and reactive oxygen species in this cell line suggested that apoptosis may be the main pathway for the death of the cells.

In this work, we synthetized and characterized new crystalline materials with theranostic properties, i.e., they can be used both as bio-sensors and for &ldquo, drug delivery&rdquo, The two solid crystalline compounds studied are Metal Organic Frameworks and have formulas Li[(C6H12O6)2B]&middot, 2H2O and Li[(C4H2O6)2B]&middot, 5.5H2O. They can be synthetized both with natural isotopes of Li and B or with 6Li and 10B isotopes, that can be explored for Neutron Capture Therapy (NCT) for anti-cancer treatment. The presence of chiral organic molecules, such as mannitol and tartaric acid, provides the NLO property to the crystals and thus their capability to generate the Second Harmonic, which is useful for applications as bio-sensors. The two compounds were characterized with X-ray Diffraction and the Second Harmonic Generation (SHG) responses were estimated by theoretical calculations, and the results were compared with experimental measurements of powdered samples. In order to test the behavior of such compounds under thermal neutron irradiation, we preliminary exposed one of the two compounds in the e_LiBANS facility at the Torino Physics Department. Preliminary results are reported.

This paper reports the synthesis of two complexes through one-pot reactions of pyridine-2,6-dicarboxylic acid (pydcH2), phenanthroline, and 2-aminopyridine, with Gd(NO3)3·6H2O and Ce (NO3)3·6H2O metal salts. The new coordination complexes C1 and C2 were identified by spectroscopic methods. The complexes were characterized by X-ray crystallography. The nature of metal–ligand interactions was studied theoretically using NBO and EDA-NOCV analyses. The results showed that the contribution of electrostatic interactions in both complexes is considerably larger than that of orbital. However, the contribution of orbital interactions in [CeL3]2−, is more than that in [GdL3]3− (28.8% vs. 21.8%). In following, the cytotoxic effect of synthetic complexes was investigated in vitro using oxaliplatin as a standard against three cancer cell lines including human breast cancer (MCF7), human colon adenocarcinoma (HT29), human lymphocyte (HL60) and also one normal cell, human foreskin fibroblast (HFF). The most significant inhibition activity was observed by both C1 (IC50 = 80.7 μM, Viability inhibition = 83.41%) and C2 (IC50 = 98.3 μM, Viability inhibition = 77.19%) toward the MCF7 cell line.

Abatract A zinc(II) complex formulated as (4-apyH)2[Zn(pydc)(pydcH)]2.(pydcH2)2.10H2O was prepared through a one-pot reaction of pyridine-2,6- dicarboxylic acid, 4-aminopyridine, and zinc chloride anhydrous metal salt. In all the steps, only distilled water was used as the solvent. The compound was fully characterized by single-crystal X-ray diffraction and disordered octahedral geometry was recognized for it. The cytotoxicity of the complex and its ligands was evaluated by MTT method against A375, LN229, DLD1, HT29, and HFF cell lines. The strongest anti-proliferative effect of the complex was exhibited toward HT29 (IC50=10 µM, Viability inhibition =78.23%) cells. The apoptosis was proposed as the main pathway for the death of the cells according to the product of ROS high value and reduction of MMP. The antibacterial effect of compounds was studied against two Gram-positive bacteria namely Staphylococcus aureus, and Staphylococcus epidermidis, and also three Gram-negative bacteria namely Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris. The established antibacterial tests were including the broth microdilution method and the agar well diffusion method. S. aureus (MIC=16 µg/mL, IZD=30 mm) and S. epidermidis (MIC=32 µg/mL, IZD=22 mm) were considered as the most susceptible bacteria following treatment of the complex.

In this work four metal–organic framework isomorphs, based on fructose and alkali-earth halogenides, were investigated to better understand the effect of the size of the cation and the different polarizability of the anion on the calculated hyperpolarizability and optical susceptibility, which are correlated to non-linear optical properties. The compounds were characterized by X-ray diffraction and the first hyperpolarizability and the second-order susceptibility were obtained from theoretical calculations. Furthermore, a new method to measure the second-harmonic (SH) efficiency on a small quantity of powder at different wavelengths of excitation was optimized and an attempt was made to assess the reduction of the SH intensity for small quantities of nano-crystals, in order to ascertain the possibility of applications in biological systems. The results of this work show that both the intrinsic nature of the anion and the induced dissociation of cations and anions by fructose play a role in the second-harmonic generating properties of such compounds.

A number of oxidovanadium(IV) complexes have been reported to display anticancer activity. A theranostic approach, based on the simultaneous observation of both the effect of oxidovanadium(IV) complexes on cell viability and the disclosure of their intracellular fate, is possible by using oxidovanadium(IV) complexes functionalized with fluorescent ligands. In the present study we accomplished the characterization of six oxidovanadium(IV) complexes in conditions close to those employed for in vitro administration. In particular, we investigated the light harvesting properties of such complexes in the presence of a dimethylsulphoxide/aqueous buffer mixture, and we found that one complex exhibits a quantum yield suitable for confocal microscopy investigations. EPR investigations in the same conditions provide information about the presence of ligands' substitution processes. Finally, the electrochemical properties of all complexes were determined by cyclic voltammetry. The overall results show that these complexes exhibit an average stability in solution; EPR data confirm that DMSO enter the first coordination sphere of oxidovanadium(IV) and suggest the occurrence of partial ligand substitution in the dimethylsulphoxide/aqueous buffer mixture.

A representative library of 3-(α-aryl)alkenylindoles has been prepared via a Bronsted-acid catalysed dehydrative coupling reaction between alkyl aryl ketones and some indoles. An interesting diastereoselectivity has been observed and has been explained from a mechanistic point of view.

In this paper, we report on the unexplored reaction mechanisms of bimolecular homolytic substitution (SH2) between GeH3 radicals and the nitrogen atom of NF3. The SH2 reactions are studied both experimentally and theoretically with ab initio and density functional theory (DFT) calculations. The experimental results of X-ray irradiation of mixtures of GeH4 and NF3 show the formation of GeH3–NF2 and GeH3–F. The trend of product yields as a function of the increase in GeH4 partial pressure in the irradiated mixtures evidences the predominant role of GeH3 radicals. Particularly, the SH2 mechanism can be hypothesized for the reaction between GeH3 radicals and NF3 molecules leading to GeH3–NF2. This mechanism is further confirmed by the increase in GeH3–NF2 yield observed if O2 is added, as a radical scavenger, to the reaction mixture. In agreement with the experimental data, from the calculations performed at the CCSD(T) and G3B3 levels of theory, we observe that the GeH3–NF2 product actually occurs from a bimolecular homolytic substitution by the GeH3 radical, which attacks the N atom of NF3, and this reaction is in competition with the fluorine abstraction reaction leading to GeH3F, even if other mechanisms may be involved in the formation of this product.

Isolated, bench-stable, non-symmetric diarylmethylium salts have been reacted with cyclic silyl enol ethers. Products have been easily obtained in a prevalent diastereoselectivity irrespective of salt counter-anion, aromatic ring substitution and silyl enol ether ring size. X-ray analyses on two purified diastereomers have been performed; the observed diastereoselectivity has been confirmed and rationalised using DFT calculations.

Paracetamol has been one of the most commonly used and prescribed analgesic drugs for more than a hundred years. Despite being generally well tolerated, it can result in high liver toxicity when administered in specific conditions, such as overdose, or in vulnerable individuals. We have synthesized and characterized a paracetamol galactosylated prodrug (PARgal) with the aim of improving both the pharmacodynamic and pharmacological profile of paracetamol. PARgal shows a range of physicochemical properties, solubility, lipophilicity, and chemical stability at differing physiological pH values and in human serum. PARgal could still be preclinically detected 2 h after administration, meaning that it displays reduced hepatic metabolism compared to paracetamol. In overdose conditions, PARgal has not shown any cytotoxic effect in in vitro analyses performed on human liver cells. Furthermore, when tested in an animal pain model, PARgal demonstrated a sustained analgesic effect up to the 12th hour after oral administration. These findings support the use of galactose as a suitable carrier in the development of prodrugs for analgesic treatment.

Reversible martensitic transitions in molecular crystals are an unusual phenomenon, and most of the cases reported in the literature occur at relatively low temperatures. The title compound, 2-(5-(benzo[d]thiazol-2-yl)-1,3,4-oxadiazol-2-yl)-5-(diethylamino)phenol (DBOX), reveals an interesting and rich polymorphism, characterized by a reversible single-crystal-to-single-crystal transition occurring at 185 degrees C. The transition can be repeated several times on a single crystal without degradation and/or damage. The crystal structure of this high-temperature phase (II) and two low-temperature polymorphs (I and III) are solved by single-crystal X-ray analysis to fully elucidate the mechanism of the reversible I -> II transition. Changes in the molecular packing are preceded by anomalous thermal expansion and evolve as slipping/rotation motions of molecular dimers, activated by steric disengagement along the anomalous expansion direction and resulting in the reversible contraction of the long crystal axis and lateral expansion. Uncommon panchromatic- and white-emitting fluorescence properties of the reported compound are also described.

In the context of personalized medicine, there is a growing interest in materials bearing at the same time diagnostic and therapy functions. This article reports a cheap and easily reproducible procedure to obtain materials with a high potential for these applications. Three new strontium iodide–fructose-based metal–organic frameworks with formulae [Sr(C6H12O6)2]I2, [Sr2(C6H12O6)3(H2O)3]I4·0.5H2O and [Sr(C6H12O6)(H2O)3I]I differing in stoichiometry, symmetry and crystal packing, were obtained and characterized by X-ray diffraction. Bulk quantum simulations show that both the ions and the sugar are crucial in determining the predicted nonlinear response; also, the relative arrangement of various functional groups in the unit cell plays a role in the computed optical properties. Small fragments of the three compounds were selected for in vacuo calculations, proving that the reduced dimensions of the particles have a great influence on the nonlinear optical response. Despite the similar chemical composition of the three compounds, second harmonic generation measurements and in crystal and in vacuo theoretical calculations agree that one of the compounds is a much more efficient second harmonic emitter than the other two, and is thus a suitable candidate for bio-sensor applications.

In the context of personalized medicine, there is a growing interest in materials bearing at the same time diagnostic and therapy functions. This article reports a cheap and easily reproducible procedure to obtain materials with a high potential for these applications. Three new strontium iodide-fructose-based metal-organic frameworks with formulae [Sr(C

A novel thorium(IV) metal–organic framework (MOF), Th(2,6-naphtalenedicarboxylate)2, has been synthesized via solvothermal reaction of thorium nitrate and 2,6-naphtalendicarboxilyc acid. This compound shows a new structural arrangement with an interesting topology and an excellent thermal resistance, as the framework is stable in air up to 450 °C. Most notably, this MOF, combining the radioactivity of its metal center and the scintillation property of the ligand, has been proven capable of spontaneous photon emission.

Aceclofenac is a popular analgesic, antipyretic, and nonsteroidal anti-inflammatory drug (NSAID) used for prolonged treatment (at least three months) in musculoskeletal disorders. It is characterized by several limitations such as poor water solubility and low oral bioavailability. The main side-effect of aceclofenac, as well as all NSAIDs, is the gastrotoxicity; among other adverse effects, there is the risk of bleeding since aceclofenac reversibly inhibits platelet aggregation. With the aim to reduce these drawbacks, we have designed, synthesized, and characterized, both in vitro and in vivo, an orally administrable pro-drug of aceclofenac (ACEgal). ACEgal was obtained by conjugating carboxyl group with the 6-OH group of d-galactose; its structure was confirmed by X-ray powder diffractometry. The pro-drug was shown to be stable at 37 °C in simulated gastric fluid (SGF-without pepsin, pH = 1.2) and moderately stable in phosphate buffered saline (PBS, pH = 7.4). However, it hydrolyzed in human serum with a half-life ( t1/2) of 36 min, producing aceclofenac. Furthermore, if compared to its parent drug, ACEgal was four-times more soluble in SGF. To predict human intestinal absorption, cell permeability in a Caco-2 model of aceclofenac and ACEgal was determined. Anti-inflammatory, analgesic, and ulcerogenic activities have been investigated in vivo. In addition, oxidative stress parameters (thiobarbituric acid reactive substances, TBARS, and glutathione, GSH) and platelet antiaggregatory activity both of parent drug and pro-drug were evaluated. Results clearly showed that the conjugation of aceclofenac to a galactose molecule improves physicochemical, toxicological (at gastric and blood level), and pharmacological profile of aceclofenac itself without changing intestinal permeability and antiplatelet activity (in spite the new sugar moiety).

Vanadium compounds are known to display a number of therapeutic effects, namely insulin-mimetic and cardiovascular effects. Evidence of the antiproliferative and proapoptotic activity of a number of vanadyl complexes, together with their low toxicity, establishes these metal compounds as promising antitumoral therapeutic agents. In the present work, we describe the synthesis and full characterization of six new vanadyl complexes with acetylacetonate derivatives bearing asymmetric substitutions on the β-dicarbonyl moiety: the complexes were characterized in the solid state as well as in solution. Our results show that all complexes are in square pyramidal geometry; cis isomers in the equatorial plane are favored in the presence of strongly coordinating solvents. EPR evidence suggests that all complexes are in the bis-chelate form, although in two cases the mono-chelated complex seems to be present as well. Preliminary tests carried out on non-tumor and tumor cell lines show that these complexes are effective in suppressing cell viability and elicit a distinct response of tumor and non-tumor cells.

We report about the X-ray powder diffraction characterization of crystalline materials used to produce genuine and counterfeit banknotes, performed with a single-crystal diffractometer that permits fast and nondestructive measurements in different 0.5-mm sized areas; 20-euro denomination genuine banknotes were analyzed, and results were compared with counterfeit banknotes. The analysis shows that the papers used to print real banknotes are composed, as expected, of cotton-based cellulose and titanium dioxide as crystalline additive, but different polymorphs of TiO2 for different emission countries are evidenced. The counterfeit banknotes are composed of cellulose based on wood pulp; moreover, an unexpected significant quantity of TiO2 was found to be mixed with calcite, indicating that the paper employed by forgers is not simply a common low-cost type. The crystalline index and intensity ratios between the peaks attributable to cellulose and fillers can provide additional information to trace back paper suppliers for forensic purposes.

The charge density of the hydrated cupric acetate Cu2(μ-OOCCH3)4·2H2O has been studied experimentally at 100 K and by DFT calculations on the isolated molecule using the Quantum Theory of Atoms In Molecules (QTAIMs). The bimetallic moiety is bridged by four equivalent acetate groups each other perpendicular and forming penta-atomic rings. The QTAIM parameters of charge density, its Laplacian, potential and kinetic energy density, delocalization indexes, static deformation density have been used to describe all intra- and intermolecular interactions. The topological analysis of the charge density maps shows the expected bond critical points with the corresponding bond paths, Cu–Cu bonding included. The data obtained using the different parameters and functions are consistent for all types of interatomic interactions, i.e. covalent, dative and intermetallic. The unpaired electrons responsible of the magnetic properties of d9 Cu(II) ions occupy the orbitals pointing towards the acetate groups. The valence shell orbital populations of Cu(II) are consistent with the distortion of the octahedral coordination due to the Jahn–Teller effect.

The synthesis of organometal complexes from chromium hexacarbonyl with 1-methyl-naphthalene ligand is reported. Two arene-chromium-tricarbonyl isomers are formed at competitive yields, featured with the metal fragment coordinated to both the methylated and the benzenic aromatic ring. A single-crystal X-ray diffraction measurement has been performed on the [( η 6 -5,6,7,8,9,10-C 11 H 10 )Cr(CO) 3 ] isomer, which presents the metal carbonyl moiety attached to the benzenic arene ligand. The products of reaction have been studied by UV–VIS–NIR, fluorescence and 1 H NMR spectroscopies. A detailed vibrational characterisation by mean of experimental FT-IR and Raman spectroscopy and DFT calculations is reported. The electron ligand donation to the metal carbonyl system, determined by FT-IR spectroscopy, has been related to the actual decrease of resonance energy of the aromatic hydrocarbon in the complex and compared with other chromium tricarbonyl complexes of different polycyclic aromatic hydrocarbons provided with the naphthalenic moiety.

A new series of compounds, structurally related to leflunomide, based on the 1,2,5-oxadiazole ring system (furazan) has been synthesised, and their ability to undergo ring scission at physiological pH to afford the corresponding cyano-oximes has been analyzed. The latter, together with the respective nitro derivatives obtained by oxidation, have been characterised as weak inhibitors of rat dihydroorotate dehydrogenase (DHODH).

The reactions of the complexes Fe3(CO)12, H2FeRu3(CO)13, H2Ru4(CO)13 and CpNiRu3(H)3(CO)9 with 2(diphenylphosphino)ethyl-triethoxysilane give considerable yields of the complexes Fe3(CO)10L2 (1), H2FeRu3(CO)10L2 (2), Ru4(CO)10L3 (3) and CpNiRu3(H)3(CO)7L2 (4) where L = Ph2PCH2CH2Si(OEt)3. The complexes (1–3) have been characterized by analytical and spectroscopic techniques. The structure of (4) has been determined by X-ray analysis. The presence of a phosphine containing the –Si(OEt)3 group has been exploited for grafting complexes (3) and (4) on the mesoporous SBA-15 and the resulting inorganic–organometallic materials have been characterized by means of ICP-MS, FT-IR, DR-UV–vis spectroscopy, XRD and textural analysis.

The complex Co2(CO)6[μ-η2-(H3CC CCH2CH2OH)] (1) with the ligand 3-pentyn-1-ol (pol) has been synthesized following established procedures. Its structure has been determined by X-ray analysis. The complex Co2(CO)6(mbo) (mbo = 2-methyl-3-butyn-2-ol, HC CC(CH3)2OH), (3), along with the already known Co2(CO)6(bud) (bud = 1,4-butyn-diol, HOCH2C CCH2OH) (2), and Co2(CO)8 were reacted with 2(diphenylphosphino)ethyl-triethoxysilane [Ph2PCH2CH2Si(OCH2CH3)3] (dpts) and tris(hydroxymethyl)phosphine [P(CH2OH)3] (thp). With dpts, mono- and di-substituted complexes were obtained: these were characterized by analytical and spectroscopic techniques. The structures of Co2(CO)6(dpts)2 (5) and of Co2(CO)4(pol)(dpts)2 (8) have been determined by X-ray analysis. Complex (1) was reacted with 3-(triethoxysilyl)propyl isocyanate [(H3CCH2O)3Si(CH2)3NCO] (tsi): the new complex Co2(CO)6[H3CC CCH2CH2OC( O)NH(CH2)3Si(OCH2CH3)3] (9) was obtained and spectroscopically characterized. The complex has also been reacted with tetraethyl orthosilicate (teos); a new inorganic–organometallic material was obtained. Complex (5) has been grafted on the mesoporous material SBA-15. The hybrid inorganic–organometallic materials obtained have been characterized by inductively coupled plasma-mass spectrometry (ICP-MS), infrared spectroscopy (FT-IR) under vacuum conditions, X-ray diffraction (XRD) and scanning electron microscopy coupled to EDS probe (SEM–EDS).

The reactions of Fe3(CO)12 with 2-methyl-3-butyn-2-ol and 3-pentyn-1-ol in CH3OH/KOH solution lead, respectively, to the binuclear complex Fe2(CO)6(μ-CO)(μ-η2-[HCC{ C(CH3)2}C( O)(OCH3)]) (as the main product) and to the closed trinuclear hydridic complex (μ-H)Fe3(CO)9(μ3-η3-[H3CCC(CH2)(CH2)CO]) (as the unique product). The oxygenated ligands of these complexes are formed, respectively, by coupling of a formerly coordinated CO with a methoxy group and by coupling of a formerly coordinated CO with a deoxygenated alkynic residual.

The thermal reactions of 2-methyl-1-hexen-3-yne [CH3CH2C≡CC(=CH2)CH3, metey] with Fe3(CO)12 have been studied: cluster opening or fragmentation and alkyne dimerization occur. Main products are the open triangular isomers [Fe3(CO)6(μ-CO)2{CH3(=CH2)CC(Et)C(Et)C(=CH2)CH3}] (complex 3a) and [Fe3(CO)6(μ-CO)2{C(Et)CCH3(=CH2)C(Et)CCH3(=CH2)}] (complex 3b). The structure and isomerism of the complexes has been confirmed by X-ray studies. The minor products of the reaction have been characterized by spectroscopic techniques. An attempt at exploiting the reactivity of the “free” C=C bonds of the coordinated ene-yne was made: complex 3a was reacted with styrene under thermal conditions. Unexpectedly considerable yields of the closed triangular cluster [Fe3(CO)6{EtC2C(=CH2)CH3}2] (complex 5) have been obtained. This behaviour had not been previously observed. The unprecedented structure of complex 5 has been confirmed with an X-ray study.

The title complex is the main product of the reaction of Fe3(CO)12 with isopropenylacetylene in basic methanolic solution (followed by acidification); it is obtained upon carbon–carbon bond forming and dimerization of the alkyne. The same complex is also obtained by reacting Fe3(CO)12 in CH3OH/KOH solution with 2-methyl-hex-1-en-3-yne; carbon–carbon bond cleavage presumably occurs to form isopropenylacetylene, which then reacts with the iron carbonyl. The unprecedented structure of the complex has been determined with a X-ray diffraction analysis.

Strigolactones (SLs) are new plant hormones with various developmental functions. They are also soil signaling chemicals that are required for establishing beneficial mycorrhizal plant/fungus symbiosis. In addition, SLs play an essential role in inducing seed germination in root-parasitic weeds, which are one of the seven most serious biological threats to food security. There are around 20 natural SLs that are produced by plants in very low quantities. Therefore, most of the knowledge on SL signal transduction and associated molecular events is based on the application of synthetic analogues. Stereochemistry plays a crucial role in the structure-activity relationship of SLs, as compounds with an unnatural D-ring configuration may induce biological effects that are unrelated to SLs. We have synthesized a series of strigolactone analogues, whose absolute configuration has been elucidated and related with their biological activity, thus confirming the high specificity of the response. Analogues bearing the R-configured butenolide moiety showed enhanced biological activity, which highlights the importance of this stereochemical motif.

This gives exclusively the E isomers of the arylidene-hetarylium tetrafluoroborates, which can be easily reduced to the corresponding aryl-hetaryl-methanes.

A representative number of bench-stable nonsymmetric diarylcarbenium tetrafluoroborates have been isolated via the direct coupling of aryl (or heteroaryl) aldehydes and N-heteroarenes and fully characterized. They have proven to be highly stable in the presence of both EDG and EWG substituents. An (E)-iminium vinylogous substructure has been shown as the common cation scaffold by X-ray analysis and by NOE determination.

Ru3(CO)12 has been reacted with the compounds hex-1-en-3-yne [EtC≡CCH=CH2], 2-methyl-hex-1-en-3-yne [EtC≡CC(=CH2)CH3] and with 3(ethoxy-silyl)propyl isocyanate [(EtO)3Si(CH2)3NCO] and the compound tb [(EtO)3Si(CH2)3NHC(=O)OCH2C≡CCH2OC(=O)NH(CH2)3Si(OEt)3] in hydrocarbon solution. Some reactions in CH3OH/KOH solution (followed by acidification) have also been performed. The main products of the reactions with ene-ynes are the clusters Ru3(CO)6(μ-CO)2L2 (L = C6H8, C7H10) and their demolition products, the “ferrole” Ru2(CO)6L2 complexes. One of the isomers of Ru3(CO)6(μ-CO)2L2, and Ru2(CO)6L2 (L = C7H10) have been reacted with vinyl-triethoxysilane [(EtO)3SiCH=CH2]: these reactions did not afford complexes containing new carbon–carbon bonds or triethoxy-silyl groups. Only polymerization of vinyl-triethoxysilane occurred. The reactions of Ru3(CO)12 with triethoxysilyl-propyl-isocyanate and tb (in the presence of Me3NO) lead to the same products, that is the isomeric complexes (μ-H)Ru3(CO)9[C=N(H)(CH2)3Si(OEt)3] with a “perpendicular” ligand (complex 3, as proposed on the basis of spectroscopic results) and (μ-H)Ru3(CO)9[HC=N(CH2)3Si(OEt)3] with a “parallel” ligand (complex 4, as confirmed by a X-ray analysis). The reaction pathways leading to these products are discussed. Complex 4 has been reacted with tetraethyl orthosilicate and the resulting material has been characterized. These reactions are part of a study on the synthesis of inorganic-organometallic materials through sol–gel techniques.

Today, the experimental charge density of transition metal compounds can be determined with a good degree of reliability and analyzed with the quantum theory of atoms in molecules in order to better characterize the atomic interaction. Here, we present a short summary of the main topological results obtained with this technique on Mn2(CO)10, Co2(CO)6(μ-CO)(μ-C4O2H2), KMnO4 and KClO4 compounds. To cite this article: R. Bianchi et al., C. R. Chimie 8 (2005).

The title compound has been obtained in considerable yield by reacting Ru3(CO)12 with 2-pentynal-diethyl-acetal [CH3CH2C CC(H)(OEt)2] (PDA) in hydrocarbon solvents. The X-ray analysis shows that the title complex belongs to the well known family of the flyover derivatives. Some X-ray structural studies have been reported, many years ago, on di-iron flyover complexes; in contrast only a few examples of diruthenium derivatives have been structurally characterized. The complex contains ethoxy-groups which could potentially undergo hydrolysis in the presence of tetraethyl-orthosilicate (TEOS) in the presence of catalysts. Reactions of complex Ru2(CO)6[μ-η4-{EtC2C(H)(OEt)2}CO{EtC2C(H)(OEt)2}] with TEOS in the presence of HCl or of NaF (as catalysts) have been attempted. An inorganic-organometallic sol-gel material containing the skeleton of the complex has been obtained and characterized with IR-Raman, XRD on powders and SEM microscopy.

The reactions of Fe3(CO)12 with but-2-yn-1,4-diol (BUD), 1,4-dichloro-but-2-yne (DCB), propargyl alcohol (PA) and propargyl chloride (PC) in KOH/CH3OH solutions (followed by acidification with HCl) and under thermal conditions have been examined. The complex Fe2(CO)6{H2CCCCH2} is the main product of the reactions with BUD or DCB in all conditions. The complexes Fe2(CO)6{H2CCC(H)C(OMe)O} and Fe3(CO)10{H2CCC(H)C(O)C{CH2(O)CH3}CCH2} are the main products obtained respectively in the reactions with propargyl chloride (PC) or propargyl alcohol (PA) in basic methanolic solution. The structures of the three complexes have been determined by means of X-ray analysis. Complex Fe2(CO)6{H2CCCCH2} contains a butatrienyl ligand in an uncommon structural arrangement. The formation of complex Fe2(CO)6{H2CCC(H)C(OMe)O} requires CO and methanol activation; its ferrole like structure contains a coordinated acetate group. Complex Fe3(CO)10{H2CCC(H)C(O)C{CH2(O)CH 3}CCH2} contains one Fe(CO)4 and one Fe2(CO)6 fragments linked through a carbon atom chain derived from the insertion of CO and dimerization of propargyl alcohol (with substitution of OCH3 from methanol in the place of OH). Comments on the syntheses and on the reaction pathways leading to the complexes are made.

The experimental charge density determination ( T = 120 K) of a second-row transition metal cluster and subsequent topological analysis elucidate the bonding of the Ru 3 (CO) 12 molecule. The Ru–Ru bond critical point features were found to be close to those of the first-row transition metal–metal bonds. Furthermore, the experiment reveals the presence of C⋯C interactions among the axial carbonyl ligands. They may justify the sterically hindered D 3h configuration of the molecule and the distortion of axial COs from linearity.