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(Arene)Ruthenium(II) Coordination Chemistry with Chelating and Tripodal Oxygen- and Nitrogen-Donor Ligands: Synthesis, Characterization, Reactivity and Application\ud
No full textSituated in the middle of the second row of the transition-metal series, ruthenium lies at the heart of the Periodic Table. This central location bestows upon ruthenium properties that are common to both its early- and late-transition-metal cousins. Harnessing the best of both world,\ud
ruthenium benefits from a confluence of desirable properties, amounting to a winning combination for catalysis. Borrowing the high reactivity of elements to its left and the less oxophilic and Lewis acidic nature of those to its right, it results in a special array of properties, which led to refer to ruthenium as an element for the connoisseur.\ud
Of all the elements of the Periodic Table, ruthenium has the widest scope of oxidation states (from –2 in Ru(CO)4\ud
2– to +8 in RuO4), and various coordination geometries in each electron configuration, which is in contrast to the narrow scope of oxidation states and simple square\ud
planar structure of palladium. For instance, in the principal lower oxidation states of 0, II, and III, ruthenium complexes normally prefer trigonal-bipyramidal and octahedral structures, respectively. Such a variety of ruthenium complexes has great potential for the exploitation of novel catalytic reactions and synthetic methods; however, as a consequence of the difficulties of\ud
matching the catalysts and substrates, ruthenium chemistry has lagged behind palladium chemistry by almost decade. Indeed, until the 1980s the reported useful synthetic methods using ruthenium catalysts were limited to a few reactions which include oxidations with RuO4,\ud
hydrogenation reactions, and hydrogen transfer reactions. As the coordination chemistry of ruthenium complexes has progressed, specific characters of ruthenium have been made clear. Ruthenium is relatively inexpensive in comparison with the other Group 8 transition metals such as rhodium, and a wide variety of ruthenium complexes have been prepared. RuCl3·nH2O is frequently used as the starting material in the preparation of most of ruthenium complexes. The ruthenium complexes can be roughly divided into five groups according to their supporting ligands: carbonyl, tertiary phosphines, cyclopentadienyl, arene/dienes, and carbenes. These ligands have proven to serve effectively as the activating factors such as generation of coordinatively unsaturated species by the liberation of ligands, and stabilization of reactive intermediates. It has been understood that the precise control of coordination sites and redox sequences of the intermediacies are especially important in the case of ruthenium to design specific organic transformations. Moreover, ruthenium complexes also demonstrate a variety of useful characteristics, which include low redox potential, high electron transfer ability, high coordination ability to heteroatoms, Lewis acid acidity, unique reactivity of metallic species and\ud
intermediates such as oxo-metals, metallacycles, and metal carbene complexes. Therefore, a large number of novel, useful reactions have begun to be developed using catalytic amounts of ruthenium complexes. The great influence of ruthenium chemistry on organic synthesis in recent years has now elevated the metal’s importance to the same level as palladium, or even higher.\ud
Indeed, some ruthenium-catalyzed reactions have become industrial processes, with typical examples including a combination of the ruthenium-catalyzed asymmetric hydrogenation of 2-benzamidomethyl-3-oxobutanate via kinetic resolution and the ruthenium-catalyzed oxidation\ud
of (1R',3S)-3-[1'-(tert-butyldimethylsilyloxy)ethyl]azetidin-2-one. The latter process provides an important industrial scheme for the synthesis of 4-cetoxyazetidinone, which is a versatile and key intermediate in the synthesis of carbapenem antibiotics. Grubb’s ruthenium carbene\ud
complexes [...] have also been used for industrial ring-opening metathesis polymerization (ROMP).\ud
Recent progress in the ruthenium carbine complex-catalyzed carbon-carbon double bond formation for organic synthesis is outstanding, and has become extremely important. The\ud
ruthenium catalysts involve hydrogenation, oxidation, various carbon–carbon bond formations, C–H activation, carbonylation, isomerization, bond cleavage reaction, metathesis reaction, and miscellaneous nucleophilic and electrophilic reactions.\ud
The organometallic chemistry of half-sandwich n6-arene-ruthenium(II) complexes has been widely developed in the last few years, due to their wide range of potential applications as catalyst precursors for hydrogen transfer, alkene polymerization, ring opening metathesis\ud
polymerization and olefin oxidation. Arene ruthenium have been also extensively investigated for their potent antibacterial and anticancer activity. Moreover arene ruthenium compounds belong to a well-established family of robust metal-organic molecules (metal = Ru(II), Rh(III)\ud
and Ir(III)) very soluble and stable in water, with many potential advantages such as alleviation of environmental problems associated with the use of organic solvents, industrial applications with the introduction of new biphasic processes and metal-mediated organic syntheses in water.\ud
The pi-ligated arene confers great stability to Ru in +2 oxidation state, and the characteristic “piano stool” structure offers the possibility to vary the additional donors via substitution of halide(s) with a variety of sigma-donors ranging from phosphines to beta-diketones,\ud
to aliphatic as well as aromatic amines.\ud
Our work regards the synthesis and characterization of new complexes of formula [Ru(arene)(ligand)Cl], containing diverse kinds of ligands, namely 4-acyl-5-pyrazolonate ligands and scorpionate ligands (bis-, tris- and tetrakis(pyrazolyl)borates, bis-(pyrazolyl)alkanes, bis(pyrazolyl)acetates and tris(pyrazolyl)methanesulfonates) with arene on Ru being cymene, benzene or hexamethylbenzene (HMB).\ud
We have been studied the reactivity of the [Ru(cymene)(ligand)Cl] complexes toward neutral and anionic monodentate donor ligand and toward exo-bidentate ditopic donor ligands, as we were interested in evaluating the coordination modes of the employed ligands system, the\ud
nuclearity of the resulting complexes and the geometries around the metal. We have also placed special emphasis on the neglected solution properties of the complexes, together with the structural characterization at the crystalline state.\ud
We have been studied the redox properties by cyclic voltammetry and controlled potential electrolysis, which, on the basis of their measured RuII/III reversible oxidation potentials, have allowed the ordering of the ligands according to their electron-donor character. Accomplished with these studies, we have also performed some DFT calculations in order to investigate the\ud
contribution of acylpyrazolonate or scorpionate ligand orbitals to the HOMOs, with respect to the contribution of the ancillary monodentate ligands on Ru. Additionally, for selected complexes containing scorpionate ligands, we have been studied the reactivity and the interionic structure\ud
through an integrated experimental approach based on NOE and PGSE (pulsed field gradient spin-echo) NMR experiments as function of the concentration. As an extension of our studies we have also been investigated the catalytic properties of selected neutral and ionic (arene)Ru(II)\ud
bis(pyrazol-1-yl)alkane complexes with respect to oxidation of a number of olefins by dihydrogen peroxide.\u
Improved anodic materials for lithium-ion batteries: surface modification by metal deposition and electrochemical characterization of oxidized graphite and titanium dioxide electrodes
No full textThe research work presented in this thesis has been carried out during my Ph.D. study at the Chemistry Department of Camerino University (Italy) and at the “Centre for\ud
Solar Energy and Hydrogen Research Baden-Württemberg” (ZSW) in Ulm, (Germany).\ud
[...]\ud
The thesis deals with the evaluation of the electrochemical performances of metal-modified anodes for lithium-ion batteries. The results obtained by using either partially\ud
oxidized graphite or TiO2 anatase as active materials for anode fabrication are presented.\ud
The obtained results have been the subject of the following scientific publications and proceedings of congress:\ud
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F. Nobili, S. Dsoke, M. Mancini, R. Tossici, R. Marassi, “Electrochemical investigation of polarization phenomena and intercalation kinetics of oxidized graphite electrodes coated with evaporated metal layers”, Journal of Power Sources, 180 (2008) 845-851.\ud
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M. Mancini, F. Nobili, S. Dsoke, F. D’Amico, R. Tossici, F. Croce, R. Marassi, “Lithium intercalation, interfacial kinetics of composite anodes formed by oxidized graphite and\ud
copper”, Journal of Power Sources (2008), in Press, doi:10.1016/j.jpowsour.2008.10.084.\ud
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M. Mancini, P. Kubiak, J. Geserick, R. Marassi, N. Hüsing, M. Wohlfahrt-Mehrens, “Mesoporous anatase TiO2 composite electrodes: electrochemical characterization and high rate performances”, Journal of Power Sources (2008), in Press,\ud
doi:10.1016/j.jpowsour.2008.10.050.\ud
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F. Nobili, S. Dsoke, M. Mancini, R. Marassi, “Interfacial properties of copper coated graphite electrodes: coating thickness dependence”, Fuel Cells, Accepted, DOI:\ud
10.1002/fuce.200800087.\ud
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M. Mancini, P. Kubiak, J. Geserick, R. Marassi, N. Hüsing, M. Wohlfahrt-Mehrens, “Electrochemical performances of mesoporous anatase TiO2 electrodes modified by vacuum metal deposition”, 214th Meeting of the Electrochemical Society (ECS). Honolulu, Hawaii, USA, 12-17 October, 2008. Abs. 1261.\ud
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P. Kubiak, M. Mancini, J. Geserick, R. Marassi, N. Hüsing and M. Wohlfahrt-Mehrens, “Mesoporous anatase TiO2 composite electrodes: electrochemical characterization and\ud
high rate performances”, IMLB-14, The 14th International Meeting on Lithium Batteries. TEDA, Tianjin, China, 22-28 June, 2008. Abs. 142.\ud
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M. Mancini, F. Nobili, S. Dsoke, R. Tossici, R. Marassi, “Metal coated oxidized graphite electrodes: electrochemical investigation of polarization phenomena and intercalation kinetics”, 11th UECT Ulm Electrochemical Talks 2008. Neu-Ulm, Germany, 10-12 June, 2008. Abs. p. 48.\ud
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F. Nobili, S. Dsoke, M. Mancini, R. Tossici, R. Marassi, “Electrochemical investigation of polarization phenomena and intercalation kinetics of oxidized graphite electrodes coated with evaporated metal layers”, 3rd German-Italian-Japanese Meeting of Electrochemists. Taormina-Messina, Italy, May 25-28, 2008. Abs p.s 41-42.\ud
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M. Mancini, S. Dsoke, F. Nobili, R. Tossici, R. Marassi, “Metal-oxidized graphite composite electrodes as anodes for lithium-ion batteries”, School of the Physical\ud
Chemistry Section: “Composite Materials: from Molecular Sciences to nanotechnology”. Turin, Italy, 3-8 September, 2006. Abs. p. 94
Impact of solid state properties of sodium naproxen hydrates on their technological performance
Get PDFSodium naproxen, a member of the class of non-steroidal anti-inflammatory drugs (NSAIDs), exists in one anhydrous form and four hydrated ones: one monohydrate, two dihydrate and one tetrahydrate. Sodium naproxen (SN) forms can be summarised as follows:\ud
• the anhydrous sodium naproxen (ASN) is the commercialised form;\ud
• the monohydrated sodium naproxen (MSN), is obtained by dehydration of the dihydrated sodium naproxen (DSN), according to Kim and Rousseau (2004);\ud
• the dihydrated sodium naproxen (DSN) is obtained by exposing the ASN to 55% RH according to Di Martino et al. (2001);\ud
• the dihydrated sodium naproxen (CSN) is obtained by crystallizing sodium naproxen from water, according to Di Martino et al. (2001) and Kim and Rousseau (2004);\ud
• the tetrahydrated form (TSN) is obtained by exposing the ASN at 75% RH according to Di Martino et al. (2007).\ud
The hydration state of SN may strongly influence its physico-chemical and technological properties and consequently its bioavailability. Water exposure during\ud
storage or pharmaceutical processing can cause changes in the crystal lattice of the starting material. Therefore, a profound understanding and characterisation of SN solid\ud
state and phase transitions throughout storage or processing are important in predicting and defining its technological performance.\ud
In fact, it was observed that following wet granulation process by high-shear mixergranulator, the drug hydrated to the tetrahydrated form. Performing two different drying\ud
procedures, granules of different water content and crystallographic characteristics were obtained. This means that differences in drying procedures could lead to products of different crystallographic properties. The behaviour under compression revealed that one of the batches offered the best tabletability and compressibility. These results make it possible to state that differences in the crystallographic properties and water content of\ud
sodium naproxen are such that different hydration/drying processes can alter the drug crystal form and thus the tabletability of the resulting granules.\ud
Next, the water uptake of ASN during storage was evaluated. A correlation between water uptake by ASN at two different relative humidities and modifications in tableting and\ud
densification behaviour under hydration exists. Models for the hydration kinetics of ASN at 55% and 86%, corresponding to the formation of the dihydrated and tetrahydrated forms\ud
respectively, were evaluated assuming Eyring’s dependence on temperature. Tabletability, compressibility, compactibility and densification behaviour were determined using an instrumented single punch tablet machine.\ud
Kinetic data is consistent with a model where water molecules enter the crystal preferentially along hydrophilic tunnels existing in the crystal structure and corresponding to the propionate side chain. Water inclusion perturbs the crystallographic structure, causing slight structural changes according to the amount and associated to an increase in entropy. The interposition of water molecules between SN molecules weakens intermolecular bonds, and these sites can behave like sliding planes under compression.\ud
Such structural changes may explain the improved compression behaviour and modified densification propensity mechanism. Kinetic data describing the water hydration\ud
mechanism of ASN explains in an original way the improved tableting and densification properties under hydration.\ud
Because different hydration/dehydration processes can alter the drug crystal form, the isothermal dehydration of some of SN hydrates was observed by thermogravimetry at several temperatures. The rate of water removal from the crystal was used to determine the mechanism of dehydration in the solid state, by fitting results with selected expressions\ud
corresponding to the most common solid-state processes. The water loss was then evaluated according to Eyring’s equation, and both changes in activation enthalpy ( ÄH*)\ud
and activation entropy ( ÄS*) were estimated from rate constant values. Experiments made it possible to distinguish different dehydration mechanisms for these hydrate forms, and in particular, to discern the dehydration behaviour of CSN and DSN dihydrate forms. These\ud
results add new evidence supporting the X-ray powder diffraction study and showing different patterns for these two forms. X-ray powder diffractometry evaluation of the phase transitions occurring during dehydration of these two dihydrate forms showed that they vary according to dehydration temperature.\ud
To finalize our study, the technological and mechanical properties of several solid forms of SN were investigated. Particular attention has been made in order to reduce\ud
differences, among the samples, in crystal habit, particle size and distribution, amount of absorbed water, so that only the hydration degree and the crystalline structure might affect the technological behaviour of powders. Thus, the compression behaviours were determined by using an instrumented single punch tablet machine and evaluated through the tabletability, compressibility and compactibility analysis. The results showed that the\ud
compression ability was influenced by the hydration degree and the crystalline form. In general, the tabletability was mainly due to the ability of particles to close up by\ud
establishing numerous bonds.\u
A Role for the Neuropeptide S System in the Mechanisms of Alcohol Addiction\ud
No full textThe present study sought to determine whether the NPS system might have a role in the regulation of alcohol related behaviours. In fact, back ground information indicates that in alcohol-prefering female rats, ICV treatment with NPS was able to decrease ethanol\ud
intake in a two bottle choice paradigm (Badia-Elder et al., 2008); in addition NPS blocked both acquisition and expression of morphine conditioned place preference in\ud
mice implanted ICV (Li W et al., 2009). In addition to this, NPSR mRNA is abundantly expressed in brain regions (i.e., amygdala, hippocampus and lateral hypothalamus) that\ud
are known to play a significant role in the regulation of alcohol drinking and reinstatement of alcohol-seeking (Heilig and Koob, 2007; Le and Shaham, 2002).\ud
Moreover, the arousing effects of NPS together with its ability to activate the HPA axis system may represent a condition that resembles the patho-physiogical state associated with excessive alcohol use or preceding relapse (Adinoff et al., 2005; Cleck and Blendy, 2008). Altogether these observations prompted us to investigate the significance of the NPS receptor system in the modulation of alcohol abuse related behaviors.\ud
In our studies we first investigated the effects of ICV NPS injection on ethanol self administration using both genetically selected alcohol-preferring rats and heterogeneous Wistars (from which the msP rats were derived). Secondly we studied the effect of NPS in the modulation of craving and relapse using several well validated animal models of relapse. Recently it has been reported that ICV injection of NPS induce Fos expression\ud
in the lateral hypothalamus (LH) hypocretinergic neurons (Niimi, 2006). Based on these findings, and in light of the significant role of the Hcrt-1/Ox-1 system in the regulation of relapse to drug seeking (Boutrel et al., 2005; Harris et al., 2005; Lawrence et al., 2006),\ud
we used the Hcrt-1/Ox-A receptor selective antagonist SB334867 to investigate the possibility that an interaction exists between the NPS and the hypocretin systems in the\ud
LH. Finally the ability of NPS to induce conditioned place preference was evaluated.\ud
[....]\ud
The present study sought to determine whether ethanol intoxication would result in changes in NPS system expression and activity in laboratory animal. Two main reasons prompted us to hypothesize the involvement of the NPS system in withdrawal subsequent ethanol intoxication. First, NPSR mRNA is abundantly expressed in brain regions (i.e. amygdala, thalamus and hypothalamic regions) that are known to be involved in anxiety and is consistent with a possible role of the NPS system in modulating behavioural\ud
response to stress (Xu et al., 2007). In addition, NPS is known to possess anxiolytic properties in rodents (Badia-Elder et al., 2008; Leonard et al., 2008; Rizzi et al., 2008; Vitale et al., 2008; Xu et al., 2004) and, as described previously, it regulates several alcohol-related behaviours.\ud
To address this hypothesis, we first investigated the variations of NPSR mRNA expression in rats exposed to 6 days of intermittent ethanol intoxication. The study was\ud
carried out on tissue samples obtained from rats killed 12 hours after intoxication, when the physical signs of withdrawal were detected and 7 days after intoxication, when only the psychological signs of withdrawal, such as anxiety, were present. Furthermore, seven days after intoxication, we tested anxiolityc-like properties of 0.3 and 1 nmole of NPS in non-dependent and post-dependent rats in two different paradigms, elevated plus maze (EPZ), and defensive burying (DB).\u
Plant diversity dynamics by an extensive chronosequencial approach in the Beech coppices in the Central Apennines (Italy).
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Scrittori e giornalismo: sondaggi su Novecento letterario italiano (Nuova edizione).
No full textIl volume contiene i risultati di un progetto di ricerca svolto presso l’Università di Macerata. Lo scopo del progetto non era offrire un quadro d’insieme, una mappa esaustiva del rapporto fra letteratura e giornalismo in Italia; era invece proporre alcune indagini più ravvicinate e puntuali che potessero precisare, definire, forse talvolta modificare il panorama generale sull’argomento che diversi studi precedenti avevano già tratteggiato, ma solo a grandi linee. Il programma della ricerca è stato dunque quello di estendere le conoscenze specifiche riguardo alla collaborazione a giornali e riviste di alcuni significativi autori del Novecento, e di analizzare l’influenza di tale collaborazione sui loro scritti creativi. Gli scrittori analizzati nei vari saggi sono Gabriele D’Annunzio, Leo Ferrero, Cesare Pavese, Vitaliano Brancati, Carlo Levi e Tiziano Terzani; cronologicamente, si parte dagli anni Ottanta dell’Ottocento per arrivare ai primi anni del Duemila; i punti di vista con cui si è analizzato il tema, infine, sono diversi: si va dalla considerazione dell’intera esperienza di un giornalista-scrittore all’indagine sulla collaborazione di alcuni autori a singole testate, all’analisi della trasposizione romanzesca di reali esperienze giornalistiche, fino allo studio delle varianti fra testi pubblicati sia in riviste sia in volumi. Questa nuova edizione è arricchita di due testimonianze: di Vittorio Emiliani su Terzani e di Anna Proclemer su Brancati
La gestione in forma associata dei servizi sociali: valutazioni di convenienza e profili organizzativi.
No full textIl lavoro illustra i risultati di un’attività di ricerca e formazione svolta tra ottobre 2007 e giugno 2008, e finalizzata a: realizzare un percorso di apprendimento sulla gestione in forma associata dei servizi sociali; sviluppare un percorso di training on the job riguardante la valutazione di convenienza economica e l’organizzazione di gestioni associate di servizi sociali, con specifico riferimento al Comune di Fermo e agli altri Comuni dell’Ambito territoriale sociale XIX della Regione Marche; formulare proposte di forma giuridica e assetto organizzativo per la gestione associata di servizi sociali da parte dei Comuni stessi. Questo rapporto scaturisce dal lavoro svolto in termini di analisi e di formulazione di proposte ed è frutto del coordinamento, del dettaglio e della rielaborazione dei risultati prodotti studiando le gestioni associate in ordine a: profili organizzativi; distacco del personale; profili qualitativi; forme giuridiche; costi. Filo conduttore di lavoro si è avuto nella convinzione dell’importanza strategica delle gestioni associate di servizi sociali, accompagnata dalla salda consapevolezza delle difficoltà e dei nodi da sciogliere affinché si possa pervenire con successo a tali gestioni
Il contributo della Psicologia Sociale allo studio dell’adolescenza e della giovinezza: Traguardi raggiunti e nuove sfide da affrontare.
No full textQuesto volume raccoglie i contributi di studiosi e ricercatori che lavorano da anni sul tema dell’adolescenza e della giovinezza. Per la complessità dell’argomento si è voluto documentare non solo ricerche fatte, ma anche lavori in itinere e percorsi di studio, nello sforzo di riflettere su alcune criticità, sulle diversità delle realtà territoriali e quindi sulle differenti tipologie di adolescenti e giovani con cui si lavora. In questa attività di documentazione, di confronto e d’intento cooperativo sono stati chiamati studiosi di diverse università italiane e straniere: ogni gruppo di ricerca presenta sfaccettature del problema che si snodano come se un filo rosso le tenesse unite. L’ultima parte del volume fa dialogare non solo gli psicologi sociali ma anche sociologi e psicologi dello sviluppo, assumendo l’insegnamento lewiniano che auspicava nella ricerca un’apertura multidisciplinare, apertura che ha permeato tutta la sua opera