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The n1-allyl platinum and palladium cationic complexes tridentate neutral pincer ligand [(PNP)M(n1-CH2CH=CHR1)]+ (1, PNP = 2,6-bis-diphenylphosphinomethylpyridine) undergo intermol. attack of the terminal gamma-carbon atom of the allyl system at the coordinated olefin of dicationic platinum and palladium complexes [(PNP)M(n2-CH2=CHR)]2+ (2), producing binuclear species [(PNP)M(n2:n1-CH2=CHCHR1CHRCH2)M(PNP)]3+ (4), in which the metal formerly p-coordinated becomes s-bonded, and the metal formerly s-bonded becomes p-coordinated. The reaction can be run catalytically with respect to the addn. of ethylene to a n1-allyl complex, using the dicationic ethylene complex as catalyst.

A number of 2,9-disubstituted 1,10-phenanthrolines are synthesized. These are used as ligands in different cationic (eta3-allyl)palladium and -platinum complexes. It was found that while a syn configuration was by far the most stable one with the parent 1,10-phenanthroline, 2,9-substituents such as methyl, chloro, cyano, and propynyl induced a preference for the anti configuration. Since terminal nucleophilic addition to anti-eta3-allyl complexes will yield (Z)-alkenes, this observation opens up a potentially selective route to (Z)-alkenes. Using molecular mechanics calculations these effects may be rationalized.

Platinum(II) olefin compounds [PtMe(N,N′-imino, amide)(η2-olefin)] have been found to dimerize spontaneously in solution, yielding dinuclear complexes through an oxidative coupling. The extended conjugation within the molecules produces an intense blue color, and the properties of the compounds have been investigated through NMR spectroscopy, optical measurements, and theoretical calculations. The solid-state structure of a representative compound has been solved.

New neutral carbene complexes of gold(I) [Au(Im-Me)X] (X = Cl, Au1; X = Br, Au2; X = I, Au3) have been synthesized and fully characterized by different techniques, including NMR and UV-vis absorption spectroscopy and single crystal X-ray diffraction. The carbene ligand Im-Me is decorated with a glucoside fragment via a triazole linker, obtainable through a click chemistry reaction. The compounds retain the Au-NHC fragment in aqueous solvents, and an equilibrium between the neutral halo- and the cationic di-carbene form [Au(Im-Me)2]+ is observed, whose extent follows the trend Au1 < Au2 < Au3. Cytotoxicity studies on two cancer and two non-tumorigenic cell lines reflect the solution behavior, as a certain difference among the complexes was disclosed, with the iodo complex Au3 being more active and selective. The compounds interact with both DNA and protein model systems. The X-ray structure of the adduct formed upon the reaction of Au1 with bovine pancreatic ribonuclease (RNase A) reveals Au binding at the side chain of His105 of both protein molecules A and B of the asymmetric unit. The binding of gold atoms at both the nitrogen atoms of the imidazole ring of His15 and at the N-terminal tail has been found in the adduct formed with hen egg white lysozyme.

This study describes new platinum(II) cationic five-coordinate complexes (1-R,R’) of the formula [PtR(NHC)(dmphen)(ethene)]CF3SO3 (dmphen = 2,9-dimethyl-1,10-phenanthroline), containing in their axial positions an alkyl group R (methyl or octyl) and an imidazole-based NHC-carbene ligand with a substituent R’ of variable length (methyl or octyl) on one nitrogen atom. The Pt–carbene bond is stable both in DMSO and in aqueous solvents. In DMSO, a gradual substitution of dmphen and ethene is observed, with the formation of a square planar solvated species. Octanol/water partitioning studies have revealed the order of hydrophobicity of the complexes (1-Oct,Me > 1-Oct,Oct > 1-Me,Oct > 1-Me,Me). Their biological activity was investigated against two pairs of cancer and non-cancer cell lines. The tested drugs were internalized in cancer cells and able to activate the apoptotic pathway. The reactivity of 1-Me,Me with DNA and protein model systems was also studied using UV–vis absorption spectroscopy, fluorescence, and X-ray crystallography. The compound binds DNA and interacts in various ways with the model protein lysozyme. Remarkably, structural data revealed that the complex can bind lysozyme via non-covalent interactions, retaining its five-coordinate geometry.

The first aim of the present study is the development of a new ruthenium(III) complex, belonging to NAMI-A class, with a potentially high cytotoxic ability. The presence of a fully protected sugar moiety as ruthenium ligand should increase the complex ability to cross cellular membranes. Furthermore, it sets this molecule in the area of biocompatible agents as tumor drug. The second, more relevant, purpose is to verify the ruthenium complexes activity after loading into liposomes. We reported the characterization and in vitro biological assays of pyridine derivatives of ruthenium complexes loaded into Egg l -α-phosphatidylcholine cholesterol/DSPE-PEG liposomes. Dynamic light scattering estimates that the sizes of all obtained liposomes are in the 100 nm range. This value is suitable for in vivo use. The loading ability and release kinetic allowed selecting the best ratio between the lipid fraction and metal to be tested in cellular experiments. The growth inhibitory effects of both liposomal and free complex in PC-3 prostate cancer cell lines demonstrate a high cytotoxic ability of the liposome entrapped ruthenium (III) complex suggesting additional role further the antimetastatic function.

Novel coordinatively saturated platinum(II) compounds bearing C-linked carbohydrates were synthesized and characterized. The complexes exhibit bipyramidal trigonal geometry with a bidentate nitrogen ligand and ethylene in the equatorial plane. The axial positions are occupied by a halide ligand X and a D-galactose or D-glucose derivative, linked either via C1 or C6. The compounds were designed for evaluation of the biological activity because they combine the steady coordinative saturation, the beneficial action of the modular sugar moiety and the organometallic nature of the Pt-sugar linkage, which is expected to be stable in the biological media, until the target is reached. The newly synthesized molecules were stable in mixed DMSO/aqueous solvents, able to bind DNA in vitro and exhibited a selective cytotoxic activity on cancer cells through apoptosis activation.

This communication describes extremely efficient homogeneous iron(III) catalysts for the synthesis of solketal from glycerol and acetone. The activities are the highest ever reported so far for this type of reaction, with TOFs up to 10 5 h − 1 at negligible catalyst loading.

Stable five-coordinate Pt(II) complexes have been highlighted as a promising and original platform for the development of new cytotoxic drugs. Their interaction with proteins has been scarcely studied. Here, the reactivity of the five-coordinate Pt(II) compound [Pt(I)(Me) (dmphen)(olefin)] (Me = methyl, dmphen = 2,9-dimethyl-1,10-phenanthroline, olefin = dimethylfumarate) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) has been investigated by X-ray crystallography and electrospray ionization mass spectrometry. The X-ray structures of the adducts of RNase A and HEWL with [Pt(I)(Me)(dmphen)(olefin)] are not of very high quality, but overall data indicate that, upon reaction with RNase A, the compound coordinates the side chain of His105 upon releasing the iodide ligand, but retains the pentacoordination. On the contrary, upon reaction with HEWL, the trigonal bi-pyramidal Pt geometry is lost, the iodide and the olefin ligands are released, and the metal center coordinates the side chain of His15 probably adopting a nearly square-planar geometry. This work underlines the importance of the combined use of crystallographic and mass spectrometry techniques to characterize, in detail, the protein&ndash, metallodrug recognition process. Our findings also suggest that five-coordinate Pt(II) complexes can act either retaining their uncommon structure or functioning as prodrugs, i.e., releasing square-planar platinum complexes as bioactive species.

Cardoon seed oil (CO), derived from the nonedible Cynara cardunculus plant, growing in marginal and contaminated soils of Mediterranean regions, was successfully epoxidized (ECO) in a fed-batch modality. The cost-effective and environmentally friendly oils have been used as bioplasticizers of poly(lactic acid) (PLA), to improve the overall properties and broaden its industrial applications as a biodegradable packaging material. Hence, physical blends and films of PLA, containing 3% by weight of CO and ECO, were prepared by melt extrusion and compression molding, and the effect of the both bioplasticizers on structural, thermal, and mechanical properties of the obtained films was investigated. Cardoon oils induced the decreasing of glass transition temperature due to PLA free volume enhancement. This effect was particularly marked in PLA–ECO film. Thermal stability of PLA was meaningfully improved upon addition of the oils, and the mechanical properties made evident the increase of PLA ductility, particularly enhanced in the PLA–ECO system, where the polymeric matrix and the oil showed stronger physical interaction and improved phase compatibility, as also revealed by spectroscopic and morphological analyses. Therefore, the plasticization action exerted by very low concentrations of epoxidized cardoon oil efficiently overcomes PLA drawbacks, thus encouraging the feasibility of its use as a bioplastic for packaging material.

The success of platinum complexes as chemiotherapeutic drugs pushed the scientific community to design new transition metal based complexes. to fight cancer and overcome the severe side effects and the insurgence of platinum resistance [1]..Among these compound ruthenium (III) complexes have been demonstrated very powerful against metastatic tumour but very poor is their action as cytotoxic agent.[2] The first aim of the present study was the development of a new ruthenium(III) complex, belonging to NAMI-A class, bearing to pyridine ligand a fully protected sugar moiety (RuPyTri). The presence of carbohydrate in coordination sphere should increase the complex ability to cross cellular membranes and sets this molecule in the area of biocompatible agents as tumour drug. The stability of the complex was studied and compared to RuPy complex in solution at different pH following UV-VIS spectra. The second, more relevant, purpose was to verify the ruthenium complexes activity after loading into liposomes. Liposomes can induce different mechanisms of delivery, increase the ability to cross cell membrane and stabilize the complexes reducing the water exchange. The lipid composition Egg L-α-phosphatidylcholine cholesterol / DSPE-PEG liposomes was selected to reproduce analog supramolecular aggregates in clinical use to vehicle doxorubicin (Doxil). Ruthenium complexes were loaded into liposomes using the passive equilibration loading method estimating the entrapped metal amount by ICP-MS. Full drug containing liposomes were structurally characterized by dynamic light scattering (DLS). Measurements confirm that sizes of all liposomes are in the 100 nm range, suitable for in vivo use. Loading ability and release kinetic allowed to select the best ratio between the lipid fraction and the metal to be tested in cellular experiments. Stability and drug release properties of ruthenium containing liposomes were confirmed in buffer. The growth inhibitory effects of both liposomal and free complex in PC3 prostate cancer cell lines validate a high cytotoxic ability of the liposome entrapped ruthenium (III) complexes.

This article describes the synthesis and characterization of novel cationic five-coordinate Pt(II) complexes containing nitrogen sugar-based ligands. The cytotoxicity of the complexes was evaluated on different cell lines with the expectation that both the coordinative saturation and the sugar moiety cooperate to enhance their biological activity. In fact, the complexes resulted to be more active than cisplatin but still with little selectivity. They activate the apoptosis pathway. Binding of representative compounds with DNA was studied by ethidium bromide displacement assay and circular dichroism. Binding to model proteins was also investigated; the X-ray structure of the adduct formed in the reaction between a representative compound and the model protein bovine pancreatic ribonuclease was obtained. The structure discloses an unprecedented interaction between a five-coordinate Pt(II) moiety and a His side chain.

New Zn-based catalysts are described that act as heterogenized or heterogeneous catalysts, with easy recovery and re-utilization with a limited or even zero Zn-leaching. For stabilizing in the heterogeneous form the catalytically active Zn centre, mixed oxides, ZIF-8 and Zn-tethered systems have been synthesized and found to sensibly reduce the leaching of Zn in solution with respect to ZnO, making possible their recovery and reuse. ZIF-8 can be used for long time of reaction, reaching high DEC yields (comparable or higher than those obtained with ZnO) without any significant loss of zinc.

The synthesis and characterization of N,N′-diethyl (L-Et,Et) and N-ethyl,N′-methyl (L-Et,Me) glyoxal-bridged cyclam ligands are described, together with the X-ray crystal structure of the complex [MnCl2(L-Et,Me)]. Bleaching of morine in the presence of hydrogen peroxide by the corresponding Mn catalysts [MnCl2(L-Et,Et)], [MnCl2(L-Et,Me)] and [MnCl2(L-Me,Me)] has been studied in aqueous solution at three different pH values (8.0, 8.75, and 9.0). The results clearly show that increasing pH has a different effect on the three catalysts, and that the dimethyl derivative is by far the most active.

It is described the simple design of a series of N,N′,O,O′-chiral ligands (elpaN-salen-H2), which represent a subset of the elpaN-type library of ligands based on β-1,2- d -glucodiamine. The corresponding Mn(III) complexes were examined in the asymmetric epoxidation of styrenes with satisfactory results, e.g. cis-β-methylstyrene was functionalised in ees up to 88%.

A homogeneous supported catalyst based on Zn(II) was prepared by anchoring complex [Zn(OAc) 2 (N,N′-chelate)] on silica, where N,N′-chelate is a suitably functionalised di-imine ligand. The complex was able to promote the esterification and transesterification of acidic vegetable oils at 160 °C within two hours. The catalyst could be also easily recovered and immediately re-cycled.

This study aimed to optimize the zinc-catalyzed trans-esterification, and pointed to assess the effect of the solvent, the catalyst, its loading and the nature of the substrate. The screening disclosed the remarkable ability of zinc(II) acetate to promote the reaction in refluxing toluene at low catalyst loading. A significant improvement ensued with respect to recently results on the same reactions, in terms of less restrictive conditions and more convenient catalyst precursors.

New zinc(II) compounds containing functionalized Schiff bases have been prepared and characterized. The complexes catalyze the transesterification of soybean oil in mild conditions, and their activity can be modulated by a fine selection of the anions and/or of the substituents on the ancillary bidentate ligand. The compounds are active in the esterification of fatty acids and could therefore also be used to produce biodiesel from waste oils.

The coordinated olefin in dicationic platinum(II) and palladium(II) complexes [M(PNP)(olefin)](SbF6)2 (M = Pt, Pd; PNP = 2,6-bis(diphenylphosphinomethyl)pyridine; olefin = ethene, propene) is electrophilic enough to react with benzene rings activated by methoxy substituents. If the proton released by the aromatic ring is trapped by a base, stable σ-alkyl derivatives of the type [M(PNP)CH2CH(R)Ar](SbF6) or [M(PNP)CH(R)CH2Ar](SbF6) (R = H, Me) are formed; otherwise the M−C σ-bond can be cleaved by the proton, setting up a catalytic cycle that leads to the alkylated aromatic compound. The molecular structure of the σ-alkyl derivative [(PNP)PtCH2CH2−C6H2(OMe)3](BF4) has been determined by X-ray diffraction analysis, and the factors affecting the mechanism and the rates of the catalytic reaction have been qualitatively investigated and rationalized, showing that the rates of C−C bond formation and M−C bond cleavage are inversely correlated.

This article describes a stereochemical study on five-coordinate complexes of PtII containing a prochiral alkene (E-R1O2CCH=CHCO2R1) and a prochiral sulfide R2SR3, of general formula [PtMe(R2SR3)(dmphen) (E-R1O2CCH=CHCO2R1)]BF4. Through mono- and two-dimensional NMR spectroscopy, it was demonstrated that there is mutual recognition between the prochiral ligands in the presence of aryl sulfides R2SAr, whose origin was also explained. The equilibrium constants of sulfide exchange were also evaluated, which are in full agreement with the σ-donor properties of the ligands.

This work describes two sustainable methods for production and purification of azelaic acid (AA) to replace the current process of ozonolysis of oleic acid (OA). The first proceeds in two steps, coupling smooth oxidation of OA to 9,10-dihydroxystearic acid (DSA) with subsequent oxidative cleavage by sodium hypochlorite. An alternative methodology is also proposed, using a chemocatalytic system consisting of H2O2/H2WO4 for direct oxidative cleavage of the double bond of OA at 373 K. A convenient technique for separation and purification of azelaic acid is also proposed.

The simple synthesis of new O,N,O′-tridentate ligands derived from carbohydrates is illustrated. The ligands are obtained by condensing 2-amino-α- d -glucosides or 2-amino-α- d -alloside with several 3,5-disubstituted-2-hydroxybenzaldehydes. The efficiency of the imines in the V(IV)-promoted asymmetric oxidation of thioanisole has been examined and ee's up to 60% have been achieved.

The ability of chiral diamine silver complexes to bind chiral and prochiral alkenes has been analyzed in detail. The stereoselectivity in binding of alkenes to a chiral ethanediamine silver complex has been investigated by NMR. The low-energy conformations of several small model complexes have been explored by DFT methods. By successive substitution of the computational model complexes, it has been possible to elucidate the role of each amine substituent in achieving successful discrimination of alkenes. The conformational space has been fully explored using small model systems, allowing an unbiased calculation of stereoselectivities that match well the experimental results. For a chiral allylic alcohol substrate, the correct stereoselectivity was obtained only when the structures were optimized with a continuum representation of the solvent. The discrepancy between gas phase and solution data is found to result from a competition between internal stabilization and solvation of the OH group of the substrate.

New chiral P,N-chelates o-Ph2PC6H4CHNR (R=carbohydrate residue) derived from d -glucose and d -mannose were described. The synthesis of palladium(0) and rhodium(I) complexes of respective formula [Pd(P,N-chelate)(fumarodinitrile)] and [Rh(1,5-cyclooctadiene)(P,N-chelate)]BF4 was performed. It was found that the ligands effectively discriminate between the enantioface of fumarodinitrile in the Pd(0) species, prompting up to 100% diastereomeric excess when R is a 2,3,4-tri-O-acetylated glucoside moiety linked to N through C6. The catalytic activity of the complexes towards allylic alkylation and olefin hydroboration was also examined.

Complexes of a tertiary diphosphine with cyclic core, cis - P , P ′-diphenyl-1,4-diphospha-cyclohexane (dpdpc), with metal ions of Groups 9 and 10 have been prepared and characterised. In neutral M(0) or M(II) (M=Pt, Pd) complexes the diphosphine acts as a bridge affording polynuclear products. Instead, in cationic mononuclear Pt(II) and Pd(II) species a clear preference for chelation of dpdpc is observed. Also the cation [Ni(dpdpc) 2 Cl] + contains the two dpdpc moieties as chelates. The molecular and crystal structure of [Ni(dpdpc) 2 Cl] 2 (NiCl 4 ) discloses a significantly small bite angle of the chelate and interaction of near phenyl rings pertaining to opposite dpdpc moieties. Coordination of dpdpc to cobalt prompts its oxidation to the corresponding P , P ′-dioxide.

Two classes of hydrophilic Pd0 complexes containing P,N and N,N sugar-based ligands were prepared and tested in the Suzuki–Miyaura cross-coupling reaction under environmentally friendly aqueous conditions. The best catalyst was tolerant towards different substrates, and its activity is comparable with the highest values reported so far for reactions in aqueous media [loading 0.0010 %, turnover frequency (TOF) 3.5 × 104 h–1].