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Euryoxic organisms are able to withstand hypoxic conditions until the restoration of normal O2 levels, when the re-introduction of oxygen causes a decisive burst in reactive oxygen species (ROS). The consequent oxidative damage is countered by defence systems constituted by antioxidant enzymes, such as SOD, CAT, Se-GPx and G6PDH. Specimens of Scapharca inaequivalvis were exposed to anoxia for 3, 6 and 24 hours and subsequent reoxygenation for 1, 3, 5 and 24 hours. It has been investigated SOD, CAT, Se-GPx and G6PDH activity and MnSOD and CuZnSOD expression in the digestive gland. The results showed SODs activity to be high during both anoxia and reoxygenation. CAT and Se-GPx increase significantly overall during recovery. Only CuZnSOD expression was greater after 6 and 24 hours of anoxia. The presence of high levels of antioxidant enzymes during anozia suggests that the response of S. inaequivalvis is typical of euryoxic animals and represents an interesting model for studying the processes of ischaemia/reperfusion in mammals.

Brazed molybdenum/graphite joints are frequently adopted for plasma facing components in fusion experiments. In particular, the RFX (Reversed Field Pinch Experiment) first wall tiles are fastened onto the vacuum vessel by molybdenum retaining keys having a graphite cap brazed onto the top. The possibility of testing graphite-molybdenum brazed joints by means of radiographic examination has been demonstrated by means of a comparison with the results of destructive methods (metallographies and mechanical tests). The good correlation that was obtained among the three different methods allowed the adoption of this test procedure for the final quality control of approximately 3000 brazed pieces to be exposed to the plasma in the RFX experiment; the tests proceeded very quickly and 100% of the pieces were accepted. The installation of the tiles with their clamps inside the vacuum vessel was then accomplished in four weeks without any major difficulty. >

The oxidative addition of PhSeX (X = Cl, Br, I) to Pt0 complexes of formula [Pt(N,N-chelate)(olefin)] is described. The reaction quantitatively affords the trigonal-bipyramidal products [PtX(SePh)(N,N-chelate)(olefin)] with the X and SePh fragments in the axial positions. NMR spectroscopic data have allowed us to gain insights into the geometrical isomerism of some of these complexes. The reactivity of the axial ligands towards electrophilic reagents is also investigated, and the molecular structures of [PtX(SePh)(dmphen)(dimethyl fumarate)] (X = Br, I) are compared. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

The site selective synthesis of functionalized indoles is presented under environmentally convenient tetrabutylammonium fluoride catalysis. The metal-free approach exploits the combined efficiency of Bu4N+ and F− ions in performing a cascade sequence involving intramolecular hydroamination of the C–C triple bond, cleavage of silyl-protecting groups and site-selective sigmatropic aza-Cope-type [3,3]-rearrangement. A range of C(3)-allenyl-(1H)-indoles (2) is obtained in an efficient manner (yield up to 93%) providing a valuable synthetic alternative to noble metal-based protocols.

Preparation of piperidine-2-one scaffolds by the hetero-Diels-Alder (HAD) reaction, assisted by microwaves, is described. The versatility of this new approach has been demonstrated by the synthesis of racemic (+/-)-2-phenylpiperidine. Theoretical calculations have allowed us to clarify the factors that govern ring closure to form four-membered rings, arising from a Staudinger-type electrocyclization, and/or six-membered rings through a classical [4+2] HAD cyclization. This competition may be lowered by increasing the electronic demand of the dienophile, as anticipated by the computational studies.

The reactions of 1-(2-haloethyl)pyrrole-2-carbaldehydes with (1S)-1-phenylglycinol or (1S)-valinol gave the corresponding fused tricyclic oxazolidines as single diastereomers from which 1,2-disubstituted 1,2,3,4-tetrahydropyrrole[1,2-a]pyrazines were obtained by addition of organometallic reagents. The diastereoselectivity was dependent on the nature of both the chiral auxiliary and the organometallic reagent. The best diastereoselectivity (dr ≤ 98:2) was obtained by using Grignard reagents with the oxazolidine derived from (1S)-phenylglycinol. (+)-1-Methyl- and (+)-1-ethyl-1,2,3,4-tetrahydropyrrole[1,2-a]pyrazines were obtained by reductive removal of the N2-substituent.

Intertidal area is characterized by several fluctuations in natural agents and anthropogenic factors (oxygen levels, temperature, salinity, B[a]P presence) that cause a noticeable increase in the expression rate of heat shock protein 70 (HSP70). HSPs acting as molecular chaperones and their induction represent a specific cellular defence mechanism in response to several stress. Chamelea gallina specimens from the North Adriatic coast were exposed to different experimental conditions: varying oxygen levels (48 h of anoxia followed by 24 h of normoxic recovery), temperatures (20, 25, 30 °C for 7 days), salinity (28, 34, 40‰ for 7 days) and B[a]P concentrations (0.5 mg/L for 24 h, 7 and 12 days). Following the extraction of the digestive gland and gills, HSP70 levels were identified in the cytosolic fraction by immunoblotting using primary monoclonal antibodies. An increase in the rate of HSP70 expression under anoxic conditions in the digestive gland was observed at high temperatures, at low salinity and in the presence of B[a]P. The protein was overexpressed in the absence of oxygen and after 12 days of B[a]P exposure, while it was underexpressed in hyposaline conditions in the gills. HSP70 induction can be considered an adaptation mechanism associated with changes in environmental parameters, but also with xenobiotic presence. The overexpression of HSP70 is therefore induced by protein damage due to stressogenic factors. HSP recruitment renders them available for the processes of folding and refolding of denatured proteins or for their transport to a degradation system. The evident sensitivity of HSP70 to natural and anthropogenic stressogenic agents was examined in the present research. The results of this research revealed an interesting response of heat shock protein 70 in C. gallina, underlining the sensitivity of this important commercial species to natural and anthropogenic stress agents. © 2010 Elsevier B.V. All rights reserved.

The recent booming of gold catalysis has demonstrated that unprecedented transformations can be realized in a highly selective manner. Moreover, due to the growing availability of chiral organic ligands, gold-catalysis can be considered as one of most dynamic hot spots in asymmetric synthesis. However, in this context, the use of non-activated olefinic C–C double bonds is still largely unexplored due to the intrinsic inertness of C C (respect to allenes and alkynes) in taking part in nucleophilic additions assisted by π-electrophilic activations. Allylic alcohols have been demonstrated to be feasible “surrogates” of non-activated alkenes for the enantioselective allylic alkylation of indoles catalyzed by chiral gold(I) complexes. In this investigation, a full account addressing efficiency and substrate scope of such a process is presented.

The double addition of organometallic reagents to fused oxazino-oxazines prepared from glyoxal and ( S )-phenylglycinol afforded C 2 - or C 1 -symmetric 1,2-ethylenebis(β-aminoalcohols), depending on the nature of the organometallic reagent. This route was modified by the use of ( S )-valinol and phenylglyoxal as starting materials, and by reduction of the oxazino-oxazines by diborane. Cyclization of the β-aminoalcohol moieties gave 1,2-ethylenediaziridines bearing one substituent/stereocenter on the ring carbon and one, two or no substituents/stereocenters in the ethylene tether. These bis(aziridines) were used as ligands in the Pd-catalyzed allylic alkylation of dimethyl malonate. It was established that the substituent(s) in the carbon tether and the configuration of the corresponding stereocenters have limited influence on the enantioselectivity.

A series of oligomers of the type Boc-(L-Phe-D-Oxd)(n)-OBn (Boc = tert-butoxycarbonyl; Oxd = 4-methyl-5-carboxy oxazolidin-2-one; Bn = benzyl) were prepared for n = 2-5. The shortest oligomer, Boc-(L-Phe-D-Oxd)(2)-OBn, aggregates and forms a fiber-like material with an anti-parallel beta-sheet structure in which the oligopeptide units are connected to each other by only one intermolecular hydrogen bond. The longer oligomers exhibit structural heterogeneity. They start to organize into secondary structures by the formation of intramolecular hydrogen bonds at the pentamer level. Microscopy and diffraction of the oligomers indicated a crystalline character for only the shorter ones.E’ stata sintetizzata la serie di oligomeri Boc-(L-Phe-D-Oxd)

The dipeptide Boc-L-Phe-D-Oxd-OBn spontaneously forms fibers consisting of parallel infinite linear chains arising from single intermolecular N-H…O=C hydrogen bonds, as demonstrated by IR spectroscopy, X-ray diffraction, and solid-state NMR. SEM observations show that the thickness and the width of the filamentous material are almost constant. This is the absolute borderline case of a parallel beta-sheet structure.

A combined catalytic and crystallographic investigation on the effectiveness of chiral diamino-bithiophene (2) and the corresponding diimino molecules (1) as chiral ligands for Pd(II) catalyzed transformations is presented. In particular, a systematic X-ray characterization of the [Pd]-pre-catalytic species provided valuable rationales for the different behavior of the two classes of ligands, underlining the key role played by sterical as well as electronic factors in controlling the oxidative addition of the starting racemic allylcarbonate to the chiral Pd(0) intermediate. Moreover, the versatility of the synthetic strategy for the preparation of enantiopure oligothienyl systems allowed us to synthesize a new type of mixed thiophene/pyridine ligands (2d) that have been effectively employed in asymmetric allylic alkylations (AAA).

The effects of high temperatures on the clam, Chamelea gallina, generally recognised as a low tolerant bivalve species, were studied by evaluating some functional responses of the haemocytes. The animals were kept for 7days at 20, 25 and 30 degrees C and total haemocyte count (THC), phagocytosis, lysozyme activity (in both haemocyte lysate and cell-free haemolymph), activity and expression of the antioxidant enzyme superoxide dismutase (SOD) (in both haemocyte lysate and cell-free haemolymph) were chosen as biomarkers of exposure to high temperatures. The survival-in-air test was also performed. During the experiment, the clams showed differing burrowing behaviour: the animals kept at 20 and 25 degrees C burrowed completely, whereas at 30 degrees C the clams progressively emerged from the sediment and then remained on the surface. The highest temperature significantly increased THC, whereas it decreased the phagocytic activity of haemocytes. The haemocyte size frequency distribution in clams kept at 30 degrees C showed that the cell population of about 8-10microm was markedly reduced compared to clams kept at 20 and 25 degrees C. In clams maintained at 25 degrees C, lysozyme activity was significantly increased in haemocyte lysate, whereas it was markedly decreased in cell-free haemolymph. Total SOD activity significantly decreased in haemocytes from clams held at 30 degrees C whereas it increased in cell-free haemolymph from clams held at 25 degrees C and 30 degrees C. A significant decrease in haemocyte Mn-SOD and Cu/Zn-SOD activities was found with increasing temperature. In cell-free haemolymph, the highest Mn-SOD activity was recorded at 30 degrees C, whereas the Cu/Zn-SOD activity showed no significant changes in clams maintained at different temperatures. SOD isoform expression exhibited different patterns in haemocyte lysate and cell-free haemolymph. The resistance to air exposure of clams kept at 30 degrees C was shown to decrease significantly, LT(50) values fell from 6days in clams kept at 20 degrees C and 25 degrees C to 4days in those kept at 30 degrees C.

The first total synthesis of (R)-convolutamydine A has been achieved by the organocatalytic addition of acetone to 4,6-dibromoisatin. The absolute configuration was determined by single crystal X-ray diffraction. DFT studies were used to model the transition states for the aldol reaction and equilibrium geometries of the post-aldol reaction intermediates. The DFT study revealed that the aldol bond forming reaction was considerably endothermic.

C 2 -Symmetrical, enantiopure 2,6-di[1-(1-aziridinyl)alkyl]pyridines (DIAZAPs) were prepared by a high-yielding, three-step sequence starting from 2,6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield and up to 99% enantiomeric excess were obtained in the reactions of the enolates derived from malonate, phenyl- and benzylmalonate dimethyl esters with 1,3-diphenyl-2-propenyl ethyl carbonate.

The vinyliminium complexes [Fe2{μ-η1:η3-C(R′) C(R′)C N(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = Me, R′ = Et, 1a; R = Me, R′ = Ph, 1b; R = R′ = Me, 1c; R = Xyl, R′ = Me, 1d; R = Xyl, R′ = Et, 1e; R = Xyl, R′ = Ph, 1f; Xyl = 2,6-Me2C6H3), react with MeLi affording the corresponding μ-vinylalkylidene complexes [Fe2{μ-η1:η3-C(R′)C(R′) CHN(Me)(R)}(μ-CO)(CO)(Cp){C5H4(Me)}] (2a–f). The formation of 2a–f is believed to proceed via nucleophilic attack at the Cp ligand, followed by hydrogen migration from the resulting cyclopentadiene to the iminium carbon. Similarly, the complex [Fe2{μ-η1:η3-C(Ph) C(Ph)C N(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] reacts with PhLi to give [Fe2{μ-η1:η3-C(Ph)C(Ph) CHN(Me)(Xyl)}(μ-CO)(CO)(Cp){C5H4(Ph)}] (4). Treatment of 2a with CF3SO3CH3 results in methylation of the nitrogen, yielding the complex [Fe2{μ-η1:η3-C(Et)C(Et)CH(NMe3)}(μ-CO)(CO)(Cp){C5H4(Me)}][CF3SO3] (5). Analogously, the μ-vinylalkylidene complexes [Fe2{μ-η1:η3-C(R′)C(R″) CHN(Me)(R)}(μ-CO)(CO)(Cp)2], (R = Me, R′ = Tol, R″ = H, 3a; R = Me, R′ = SiMe3, R″ = H, 3b; R = Me, R′ = R″ = Et, 3c; R = Me, R′ = R″ = Ph, 3d; R = Bz, R′ = Tol, R″ = H, 3e; R = Bz, R′ = SiMe3, R″ = H, 3f; R = Bz, R′ = COOMe, R″ = H, 3g; R = Bz, R′ = R″ = COOMe, 3h; R = Bz, R′ = R″ = Me, 3i; Bz = CH2Ph), react with CF3SO3CH3 to give the corresponding ammonium-functionalized μ-allylidene complexes [Fe2{μ-η1:η3-C(R′)C(R″)CH(NMe2R)}(μ-CO)(CO)(Cp)2][CF3SO3] (6a–i). The molecular structures of 5 and 6c have been elucidated by X-ray diffraction studies. Finally, protonation of [Fe2{μ-η1:η3-C(Et)C(Et) CH(NMe2)}(μ-CO)(CO)(Cp)2] (3c), with HBF4, affords the complex [Fe2{μ-η1:η3-C(Et)C(Et)CH(NHMe2)}(μ-CO)(CO)(Cp)2]][BF4] (7).

A new class of chiral C 2 -symmetrical diamino-oligothiophenes is described to be effective in catalyzing Pd-mediated asymmetric allylic alkylations in a highly enantioselective manner. The combination of experimental as well as crystallographic evidence revealed the key role played by sulfur-based heteroaromatic rings in the stereodiscriminating step of the procedure. In particular, unprecedented non-covalent secondary interactions between the inner thiophene and the metal center proved to be essential to create the stereochemical environment necessary in order to guarantee excellent levels of chemical and optical yields.

Reaction of a wide variety of aldehydes with the easily prepared 2-azadienes, in the presence of BF3 etherate, furnishes the corresponding hetero Diels–Alder adducts which have been converted, mainly, to cis epoxides via N-Boc protection followed by one-pot two-step ring opening and nucleophilic displacement of the halogen atom, resulting in final formation of an oxirane ring.

Reaction of the cluster salt [(η5-Cp′)3Mo3S4][pts] ([1][pts], Cp′=methylcyclopentadienyl; pts=p-toluenesulfonate) with CuCl yielded a new heterobimetallic cluster, [(η5-Cp′)3Mo3S4Cu(Cl)][pts] ([2][pts]). X-ray crystal structure determination of [1][pts] and [2][pts] showed that the incorporation of CuCl into the Mo3S4 cluster core has only minor consequences on the Mo–Mo and Mo–S distances. The metal atoms in the cluster core of [2]+ form an almost regular tetrahedron. The [2]+ cation conforms to an idealized C3v symmetry ignoring the Cp′ groups since the Cu–Cl bond is almost aligned with the axis defined by the Cu–S(4) cube diagonal.

The reaction of a series of symmetric and unsymmetric triaminobenzene derivatives with proton as electrophile has been studied. The formation of both Wheland complex (C-H salt) and N-H salt in relative amount depending on the experimental conditions has been observed. In the case of the attack of the proton on the nitrogen atom, the 1H and 13C NMR spectra showed the equivalence of three aromatic protons (and related carbon atoms) of the adduct thus indicating that salification occurs on a non-defined nitrogen atom. This behavior can be explained hypothesizing motion of the proton from a nitrogen atom to another in a motion that could not permit to define the protonation site. On the contrary, X-ray diffraction analysis on crystals of the NH salts reveals that in the solid state the proton is situated in a well-defined position.

A family of cyclometalated [lr(III)] complexes containing two F(2)ppy ligands and a bis-oxazoline (box) ancillary ligand, either chiral (1) or achiral (2) has been synthesized. They exhibit photophysical and electrochemical properties quite similar to the isoelectronic and well known [lr(F(2)ppy)(2)(acac)] complex. However, an unprecedented photoreactivity has been observed. Upon UV irradiation of air-equilibrated solutions of both complexes, stable photoproducts containing an [Ir(IV)] metal center are obtained. The photoproducts exhibit highly efficient blue luminescence with good OLED performances. The same [Ir(IV)] complexes are obtained also by electrochemical oxidation.

In this paper a new family of imines [N,N′-bis(2-pyridylmethylidene)-1,2-(R,S)-cyclohexanediamine (ligand 1); N,N′-bis(2-pyridylmethylidene)-1,2-(R,S)-cyclohexanediamine (ligand 3)] and amines [N,N′-bis(2-pyridylmethylene)-1,2-(R,R + S,S)-cyclohexanediamine (ligand 2); N,N′-bis(2-pyridylmethylene)-1,2-(R,S)-cyclohexanediamine (ligand 4)] pyridine-based chiral ligands and their chiral nitrate Eu(III) complexes is presented. Combination of structural and spectroscopic evidences in the solid state, reveals that the Eu(III) ion environment is characterized by a low symmetry for all the complexes. The 5D0 → 7F0 Eu(III) emission intensity reflects the degree of distortion of the metal surroundings, that is higher in the case of cis isomer of amine-based complex. This new family of Eu(III) chiral complexes are promising candidates for applications in the sensing field as probes in solution of the nitrate anion and of chiral molecules.

A new class of neutral cyclometalated iridiumACHTUNGTRENUNG(III) complexes with enantiomerically pure C1-symmetric phenol-oxazolines (3 a,b) have been synthetized in high yields and fully characterized. Resolution of the corresponding DR and LR or DS and LS isomers was easily achieved by conventional flash chromatography. The corresponding D and L helicities have been confirmed by CD spectroscopy and Xray crystallography. Regarding the absorption and luminescence properties with unpolarized light, no significant difference between D and L isomers has been observed. A strong blue luminescence is observed for deaerated solutions of complexes 5a and 5b in CH3CN.

A reliable synthetic route to fused polycyclic indolines is documented by the development of a stereoselective gold catalyzed cascade cyclization of indole propargylic alcohols.

Some compounds containing the L-Phe-D-Oxd [L-Phe = L-phenylalanine; D-Oxd = (4R,5S)-4-carboxy-5-methyl oxazolidin-2-one] moiety have been prepared and their properties as supramolecular material have been checked. Some derivatives of the dipeptide L-Phe-L-Phe (that usually forms nanotubes) and some long chain derivatives that behave as low molecular weight gelators (LMWG) have been prepared. Simultaneously we have built the same structures replacing the D-Oxd moiety with a D-Pro (D-Pro = D-proline) moiety, to check if the presence of the Oxd moiety is essential for the existence of those materials: in contrast with the D-Oxd containing compounds, no material is ever formed with all the D-Pro containing molecules. This outcome suggests that the L-Phe-D-Oxd moiety may be defined as a “privileged scaffold” for the formation of supramolecular materials and can be introduced in more complex structures to induce some selected properties in the solid state.

The diastereomeric intramolecular nucleophilic alkoxylation of enantioenriched allylic alcohols, e.g. (I), (IV) or (V), is efficiently catalyzed by a Au(I)—Ag(I)—dppf complex to give vinylmorpholines in high yields and excellent diastereoselectivities (up to < 96% d.e.).

The synthesis of the small pseudopeptide Boc-L-Phe-D-Imz-OBn (Imz = imidazolidin-2-one-4-carboxylate) is reported. Crystallization of this peptide from methanol, ethanol, and isopropanol leads to isostructural solvates when the solvent is methanol or ethanol with a peptide/solvent ratio of 2:1 and to an unsolvated polymorph in the case of isopropanol. The solvate peptide crystallizes forming infinite chains with the monomers in parallel orientation connected by a single hydrogen bond. The chains are arranged in antiparallel direction and cross-linked through the NH group of the imidazolidin heterocycle with formation of a stable 2D network. Crystals from isopropanol form a different 2D network. The degree of order in the crystal assembly decreases from methanol and ethanol solvates to the unsolvated pseudopeptide grown from isopropanol. Quantum chemical calculations at the HF/6-31G* level of ab initio MO theory, carried out on the two different packings, show a slight preference for the unsolvated packing.

Novel inner-core dithienothiophene S-oxide and S, S-dioxide oligomers were designed and synthesized. The controlled oxidation at the central sulfur of the dithienothiophene core allows the combined tailoring of the HOMO-LUMO energies, thermal properties, and thin film morphology. Electrochemical measurements indicate that a marked decrease in electron affinity is obtained by addition of the first oxygen at the central sulfur, while addition of the second oxygen induces only minor effects on both the oxidation and reduction potentials. The newly synthesized materials exhibit high solubility in common organic solvents together with good film forming properties when deposited on SiO2 by solution-based techniques. Similar hole field effect transistor (FET) mobility for solution-deposited and thermally-evaporated films together with FET performances independent of film morphology and molecular orientation call for non-conventional charge transport mechanisms.

Heteropolytopic oxalyl and malonyl diamide ligands, derived from 1H-pyrazole, 3,5-dimethyl-1H-pyrazole, 1H-indazole and 1H-1,2,3-benzotriazole, have been synthesised by reaction of the corresponding azole with oxalyldichloride and carbon suboxide respectively and fully characterized by elemental analyses, IR and NMR (1H, 13C). In the examined cases single crystal X-ray diffraction studies revealed important supramolecular assemblies based on H-bonds and/or π–π interactions. The reactivity behaviour toward metal salts is also described.

The two epimers Boc-l-Phe-d-Oxd-(S)-β3-hPhg-OBn (1) and Boc-l-Phe-d-Oxd-(R)-β3-hPhg-OBn (2) have been prepared by standard methods in solution, and their conformation was analyzed both in solution ...

New (arene)ruthenium(II) derivatives containing neutral HL or anionic L(-) ligands (arene = p-cymene or benzene, HL in general, in particular HL(1) = bis(pyrazol-1-yl)acetic acid and HL(2) = bis(3,5-dimethylpyrazol-1-yl)acetic acid) have been synthesized and analytically and spectrally characterized. The ligands in neutral form coordinate ruthenium in a chelating kappa(2)-N,N'-bidentate fashion affording 1:1 derivatives of formula [Ru(arene)(HL)Cl]Cl, where the inner Cl can be replaced by a phosphine. These derivatives show very high conductance values in water, due to the contribution of H(3)O(+) produced by deprotonation of the -COOH fragment in HL ligands and consequent formation of 1:2 electrolytes such as [Ru(arene)(kappa(3)-N,N',O-L)]Cl(2) species. However, the remaining derivatives contain monoanion L(-) ligands coordinating in the tripodal kappa(3)-N,N',O-tridentate fashion. The solid-state X-ray structure of the complex [Ru(eta(6)-p-cymene)(kappa(3)-N,N',O-L(1))]PF(6) confirmed such behavior. The redox properties of those compounds have been investigated by cyclic voltammetry and controlled potential electrolysis, which, on the basis of their measured Ru(II/III) oxidation potentials, have allowed for the ordering of the HL and L(-) ligands according to their electron-donor character. This is accounted for by DFT calculations, which show a relevant contribution of L ligand orbitals to the highest occupied molecular orbitals (HOMOs) when they are coordinated in the monoanionic tridentate form, while for derivatives containing neutral HL ligands, the main contribution to the HOMOs comes from orbitals of the metal and chlorine atoms, the overall contribution from the bidentate HL ligand orbitals being small. Values of the Lever electrochemical E(L) ligand parameter (a measure of the net electron donor character of a ligand) have been estimated for the above and related acylpyrazolonate ligands, as well as for the eta(6)-coordinated benzene and cymene.

A new anticancer-active platinum(II) compound [Pt(A9pyp)(dmso)(cbdca)], containing the E-1-(9-anthryl)-3-(2-pyridyl)-2-propenone ligand (abbreviated as A9pyp) has been synthesized by the replacement of the anionic chloride ligands in cis -[Pt(A9pyp)(dmso)Cl 2 ] by the dianionic chelating cyclobutanedicarboxylate ligand (abbreviated as cbdca). The in vitro relevance of the leaving group of these new platinum(II) compounds has been investigated. Measurements of the time-dependent intracellular accumulation of both compounds in human ovarian carcinoma cell lines show that the leaving group affects their cellular uptake. In addition, the leaving group also influences DNA platination, and, therefore, has an effect on the biological activity against a pair of human ovarian carcinoma cell lines, i.e. sensitive and resistant to cisplatin.

CYP1A sub-family represents the main form of cytochrome P450 involved in benzo[a]pyrene (B[a]P) detoxification, but there are no clear evidences about its presence in invertebrates. 7-Ethoxy resorufin O-deethylase (EROD) activity is strictly related to CYP1A presence, at the same time P450-dependent oxidative metabolism leads to reactive oxygen species (ROS) production, thought to be an important mechanism of pollutant-mediated toxicity in aquatic organisms. Superoxide dismutases (SODs), EROD and CYP1A activities and/or expressions were detected in haemocytes of pooled clams (Chamelea gallina) and cell-free haemolymph after 24 h, 7 and 12 days of exposure to 0.5 mg/L of B[a]P. After 24 h, B[a]P content was maximum in whole tissues. A 61 kDa band was recognized in haemocytes and cell-free haemolymph by polyclonal anti-fish CYP1A, while 53.5 and 63.8 kDa CYP1A immunopositive proteins were discriminate without differences of expression. Differently, EROD, MnSOD activity/expression and ECSOD expression decreased in haemocytes and haemolymph. C. gallina immune system presents an interesting response dose/time exposure of B[a]P and the 7 days condition highlights the major effects of xenobiotic action. The identification of basal EROD levels supports the possible presence of the CYP1A, never identified in C. gallina and more specifically never isolated in immune cells, as confirmed by CYP1A-immunopositive proteins identification.

The reactions of CuII carboxylates (valerate, 2-methylbutyrate, hexanoate, heptanoate) with pyrazole (Hpz) in EtOH or EtOH/water solutions easily afford the triangular trinuclear copper derivatives [Cu3(μ3-OH)(μ-pz)3(RCOO)2(L)x] [R = CH3(CH2)3, L = H2O, x = 1 for 5; R = CH3CH2CH(CH3), L = EtOH, x = 2 for 6; R = CH3(CH2)4, L = EtOH, x = 1 for 7; R = CH3(CH2)5, L = EtOH, x = 1 for 8] as it has been previously found for R = H, L = Hpz, x = 2, (1); R = CH3, L = Hpz, x = 1, (2); R = CH3CH2, L = EtOH, x = 1, (3) and [Cu3(μ3-OH)(μ-pz)3(CH3(CH2)2COO)2(MeOH)(H2O)], (4). The trinuclear structure common to 5–8 has been assigned on the basis of magnetic susceptibility studies, ESI MS, IR and UV/Vis spectroscopy as well as 1H NMR measurements. The room temp. magnetic susceptibilities of 5–8 almost correspond to the presence of a single unpaired electron for each trinuclear unit. The IR spectra exhibit signals due to the bridging μ3-OH in accordance with what was observed in the spectra of 1–4. Solid-state and MeOH solution UV/Vis spectra show the same features previously reported for 1–4 and 1H NMR spectra of 1–8 show almost identical low field signals that can be assigned to pz– hydrogens. A detailed investigation of the supramolecular structures of 1 and 4 and the single-crystal X-ray study of the polymeric paddlewheel Cu(2-methylbutyrate)2, A, are also reported. Electrochemical experiments show that in 1–8 the CuII ions can be reduced, in distinct steps, to CuI and Cu0. All the complexes act as catalysts or catalyst precursors for the efficient peroxidative oxidation, by aqueous hydrogen peroxide in acetonitrile and at room temp., of cycloalkanes RH (cyclohexane and cyclopentane) to the corresponding cyclic alcohols and ketones, with overall yields of up to 34 % and TONs up to 42. Radical pathways involving the formation of alkyl hydroperoxides (ROOH) are involved.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

1-Allyl-2-pyrroleimines obtained from (S)-valinol and (S)-phenylglycinol underwent highly diastereoselective addition of allylmagnesium chloride, used in excess amounts, to give the corresponding secondary amines with concomitant allyl to (Z)-1-propenyl isomerization of the 1-pyrrole substituent. Transformation of the 2-amino alcohol moiety to an oxazolidinone, or its cleavage and subsequent N-protection, followed by ring-closing metathesis of the two alkene groups gave the unsaturated bicyclic compound. Full hydrogenation of the alkene function and the aromatic rings afforded the indolizidine derivative as a mixture of two or three diastereomers with a ratio which was dependent on the nature of both the N-substituent and the catalyst. The two prevalent diastereomers were isolated, and their configuration was determined by X-ray crystallographic analysis.

The cyclopentadienide nucleophilic ring opening on the cyclopentene oxide affords diastereoselectively an efficient entry to a new polyalcoholic (1,2,4)-C5H2[CH(CH2)3CHOH]3 propeller-like, hybrid ligand CpOOO. The diastereoselective rhodium complexation gives rise almost quantitatively to a new class of racemic CpOOORh(L,L) (L,L ) nbd, cod, C2H4, CO) complexes. Thermal treatment gives predominantly the air-stable CpOOORh(nbd) rac-4a (73.5%), having SP planar chirality, as determined by X-ray diffraction studies. It has also been possible to isolate its stable atropisomer rac-4c (20.5%), while the minor kinetic isomer rac-4b, showing opposite planar chirality (∼10%), has been identified by NOESY NMR experiments. The high solubility in water and benzene, evidencing the amphiphilic character, has been measured by the n-octanol/water partition coefficient. The intermolecular H-binding, due to the hydroxy groups, plays a crucial role in selecting the rhodium coordination in the reaction mixture, whereas in the solid, it determines the supramolecular organization. DFT calculations in vacuo are in agreement with the spectroscopically identified structures.

Two μ-pyrazolate dicopper derivatives, [Cu2(μ-pz)2(Tpx)2] [Tpx = Tp, tris(pyrazol-1-yl)borate or Tp∗, tris(3,5-dimethylpyrazol-1-yl)borate], prepared either by treating the trinuclear [Cu3(μ3-OH)(μ-pz)3(RCOO)2LxL′y] species (R = H, Me, Et, Pr; L, L′ = H2O, MeOH, EtOH, Hpz; Hpz = pyrazole) with an excess of M[Tpx] (M = Na, K) or by reaction of Cu(RCOO)2 with equimolar amounts of Hpz and M[Tpx], have been characterized by IR, magnetic susceptibility measurements and single crystal XRD structural determination.

The new derivative 2-amino-4-chloro-6-pyrazolyl-[1,3,5]triazine, 1, prepared by reaction of 2-amino-4,6-dichloro-[1,3,5]triazine with an excess of pyrazole, has been characterized by 1H, 13C and 15N NMR measurements and single crystal XRD structural determination. The non-equivalence of the NH2 hydrogens evidences the iminium character of this moiety. Compound 1, exploiting strong H-bonds, self-assembles generating supramolecular linear tapes. Theoretical calculations are in good agreement with experimental solid state and solution data. Electronic properties of 1 (lowest lying excitation energies and corresponding oscillator strength) have also been determined by time dependent DFT at the PBE level.

The diiron aminocarbyne complexes [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (R = Xy1, 1a; R = Me, 1b; R = CH2Ph, 1c; Xy1 = 2,6-Me2C6H3) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe2{μ-CN(Me) (R)}(μ-CO)(CO)(X)(Cp)2] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R = CH2Ph, X = Cl, 4c; R = CH2Ph, X = Br, 4d; R = CH2Ph, X = I, 4e; R = Xy1, X = SC(S)NEt2, 5a; R = Me, X = SC(S)NEt2, 5b; R = Xy1, X = CH(CN)2, 7), in good yields. The molecular structure of 5a shows an unusual η1 coordination mode of the dithiocarbamate ligand. Similarly, treatment of [M2{μ-CN(Me) (R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (M = Fe, R = Xy1, 1a; M = Fe, R = Me, 1b; M = Ru, R = Xy1, 2a; M = Ru, R = Me, 2b) with a series of phosphanes generates the cationic complexes [M2{μ- CN(Me)(R)}(μ-CO)(CO)(P)(Cp)2][SO3CF3] (M = Fe, R = Xy1, P = PPh2H, 6a; M = Fe, R = Xy1, P = PPh3, 6b; M = Fe, R = Xy1, P = PMe3, 6c; M = Fe, R = Me, P = PMe2Ph, 6d; M = Fe, R = Me, P = PPh3, 6e; M = Fe, R = Me, P = PMePh2, 6f; M = Ru, R = Xy1, P = PPh2H, 6g; M = Ru, R = Me, P = PPh2H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(NCR′)(Cp)2][SO3CF3] [R′ = Me, 1a; R′ = tBu, 3] with PhLi and PPh2Li yield [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(Ph)(Cp)2] (8) and [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(PPh2)(Cp)2] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe2{C(Me)N(Me)(Xy1)}(μ-CO)2(CO)(Cp)2] (10). Finally, the acetone complex [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(OCMe2)(Cp)2][SO3CF3] (12) reacts with lithium acetylides to give complexes [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(C≡CR)(Cp)2] (R = p-C6H4Me, 11a; R = Ph, 11b; R = SiMe3, 11c), in high yields. Filtration through alumina of a solution of 11a in CH2Cl2 results in hydration of the acetylide group and C-Si bond cleavage, affording [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO){C(O)Me}(Cp)2] (12).

The design, synthesis and properties of liquid-crystalline semiconducting oligothiophenes containing dithienothiophene (DTT), benzothiadiazole (BTZ) and carbazole (CBZ) rigid cores are described. The effect of molecular structure (shape, size and substitution) on their thermal behaviour and electrical properties has been investigated. Polarised optical microscopy (POM) and differential scanning calorimetry (DSC) analyses have revealed highly ordered smectic mesophases for most of the newly synthesised compounds. X-ray diffraction (XRD) studies performed at various temperatures have shown that the smectic order is retained in the crystalline state upon cooling across the transition temperature, affording cast films with a more favourable morphology for FET applications.

The effects of water-borne exposure to benzo[a]pyrene (36 hrs; celite-bound 0.44 mg L-1 B[a]P) on cytochrome P450 (CYP) and superoxide dismutases (SODs) were examined in digestive gland of the blood clam, Scapharca inaequivalvis. B[a]P accumulation and elimination were rapid, with maximum whole-body concentrations of 1.78 ng g-1 wet wt. after 12 hours of treatment, followed by a progressive decline to 0.89 ng g-1 at 36 hours. The presence of B[a]P resulted in an increase in total CYP of digestive gland microsomes from 54 ± 14 to 108 ± 21 pmol mg-1 protein (mean ± SD; p

New chiral chelating C2 bis-oxazoline-amide ligands (1) exhibiting a highly flexible molecular structure have been prepared in high yield through a versatile synthetic pathway. Combined crystallographic, variable temperature (VT)-NMR, IR, and ESI-MS studies have been carried out to investigate the nature of the 1-Pd complexes that are effective tools in controlling the stereochemical outcome of Pd-catalyzed allylic alkylations (ee up to 98%).

The chiral clusters [H(4)Ru(4)(CO)(12-n)(L)(n)] (n = 1, 2; L = NMDPP), 1,1-[H(4)Ru(4)(CO)(10)(L-L)] (L-L = DUPHOS, DIPAMP), 1,2-[H(4)Ru(4)(CO)(10)(DIOP)] and [{H(4)Ru(4)(CO)(10)(DIOP)}(2)] have been synthesized by derivatizing the parent carbonyl cluster [H(4)Ru(4)(CO)(12)] with the appropriate mono- or didentate chiral phosphine ligand. The phosphine-substituted clusters were found to be able to catalyze the (asymmetric) hydrogenation of tiglic acid albeit with relatively low selectivity (enantiomeric excesses varying from 0 to 23%). It was found that the stability of the chiral ruthenium hydride clusters and the product distribution obtained in the catalytic reactions are dependent on the nature of the chiral phosphine. The crystal structures of [H(4)Ru(4)(CO)(12-n)(L)(n)] (n = 1, 2; L = NMDPP), 1,1-[H(4)Ru(4)(CO)(10)(L-L)] (L-L = DUPHOS, O-DUPHOS (partially oxygenated ligand), DIPAMP), 1,2-[H(4)Ru(4)(CO)(10)(DIOP)] and [{H(4)Ru(4)(CO)(10)(DIOP)}(2)] are presented.

The diiron vinyliminium complexes [Fe2{μ-η1:η3-C(R′) C(H)C N(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R=Me, R′ = SiMe3 (1a); R = Me, R′ = CH2OH (1b); R = CH2Ph, R′ = Tol (1c), Tol = 4-MeC6H4; R = CH2Ph, R′ = COOMe (1d); R = CH2Ph, R′ = SiMe3 (1e)) undergo regio- and stereo-selective addition by cyanide ion (from NBu 4 n CN ), affording the corresponding bridging cyano-functionalized allylidene compounds [Fe2{μ-η1:η3-C(R′)C(H)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)2] (3a–e), in good yields. Similarly, the diiron vinyliminium complexes [Fe2{μ-η1:η3-C(R′) C(R′)C N(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = R′ = Me (2a); R = Me, R′ = Ph (2b); R = CH2Ph, R′ = Me (2c); R = CH2Ph, R′ = COOMe (2d)) react with cyanide and yield [Fe2{μ-η1:η3-C(R′)C(R′)C(CN)N(Me)(R)}(μ-CO)(CO)(Cp)2] (9a–d). The reactions of the vinyliminium complex [Fe2{μ-η1:η3-C(Tol) CHC N(Me)(4-C6H4CF3)}(μ-CO)(CO)(Cp)2][SO3CF3] (4) with NaBH4 and NBu 4 n CN afford the allylidene [Fe2{μ-C(Tol)C(H) C(H)N(Me)(C6H4CF3)}(μ-CO)(CO)(Cp)2] (5) and the cyanoallylidene [Fe2{μ-C(Tol)C(H) C(CN)N(Me)(C6H4CF3)}(μ-CO)(CO)(Cp)2] (6), respectively. Analogously, the diruthenium vinyliminium complex [Ru2{μ-η1:η3-C(SiMe3) CHC N(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2][SO3CF3] (7) reacts with NBu 4 n CN to give [Ru2{μ-η1:η3-C(SiMe3)CHC(CN)N(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2] (8). Finally, cyanide addition to [Fe2{μ-η1:η3-C(COOMe) C(COOMe)C N(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2e) (Xyl = 2,6-Me2C6H3), yields the cyano-functionalized bis-alkylidene complex [Fe2{μ-η1:η2-C(COOMe)C(COOMe)(CN)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (10). The molecular structures of 3a and 9a have been elucidated by X-ray diffraction.

Three sets of oligomers containing the 4-carboxy-5-methyloxazolidin-2-one (Oxd) moiety have been synthesized with the aim of checking whether these molecules are able to fold in ordered structures: A set [Boc-(L-Ala-L-Oxd)(n)-OR], B set [Boc-(L-Ala-D-Oxd)(n)-OR], and C set [Boc-(Aib-L-Oxd)(n)-OR] preferential conformations have been analyzed with IR absorption, NMR, and CD. We have noticed that in these oligomers three stabilizing effects are active: (i) the rigid Oxd -CO-N(CH)-CO- moiety, which always tend to assume a trans conformation; (ii) the formation of Oxd C=O...H-(alpha)C intramolecolar H-bonds; (iii) the alternate formation of 1-- 4 intramolecular C=O...H-N H-bonds. Through the analysis of the experimental data, we could demonstrate that only the oligomers of the B set are able to meet all three requirements listed above. By a deeper insight into the CD spectra, we gathered that the secondary structure adopted by the B set oligomers is a beta-bend ribbon spiral, which is a subtype of the 3(10)-helix.

Gastric cancer is the second most common cancer worldwide. The involvement of reactive oxygen species (ROS) in the pathogenesis of gastric malignancies is well known. Many human tumours have shown significant changes in the activity and expression of superoxide dismutase (SOD), which might be correlated with clinical-pathological parameters for the prognosis of human carcinoma. The aim of this study is the detection of MnSOD and CuZnSOD activity and their expression in gastric adenocarcinoma and healthy tissues. Gastric samples (adenocarcinoma and healthy tissues) harvested during endoscopy or resected during surgery were used to determine MnSOD and CuZnSOD activity and expression by spectrophotometric and Western blotting assays. The total SOD activity was significantly higher (p