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A multi-methodological approach for bio-recognition studyDe Simone, Angela <1981> 15 April 2010 (has links)
No description available.
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Innovative methods for the generation and synthetic applications of organic free-radicalsLanza, Tommaso <1979> 04 June 2010 (has links)
No description available.
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New organocatalytic asymmetric strategies: simply catalysts for complex moleculesGalzerano, Patrizia <1982> 03 June 2010 (has links)
No description available.
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Chemical information and intramolecular dynamics by rotational spectroscopyEvangelisti, Luca <1981> 19 April 2011 (has links)
No description available.
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Advanced lithium and lithium-ion rechargeable batteries for automotive applicationsDamen, Libero <1980> 19 April 2011 (has links)
The worldwide demand for a clean and low-fuel-consuming transport promotes the
development of safe, high energy and power electrochemical storage and conversion
systems. Lithium-ion batteries (LIBs) are considered today the best technology for this
application as demonstrated by the recent interest of automotive industry in hybrid (HEV)
and electric vehicles (EV) based on LIBs. This thesis work, starting from the synthesis and
characterization of electrode materials and the use of non-conventional electrolytes,
demonstrates that LIBs with novel and safe electrolytes and electrode materials meet the
targets of specific energy and power established by U.S.A. Department of Energy (DOE)
for automotive application in HEV and EV.
In chapter 2 is reported the origin of all chemicals used, the description of the
instruments used for synthesis and chemical-physical characterizations, the electrodes
preparation, the batteries configuration and the electrochemical characterization procedure
of electrodes and batteries.
Since the electrolyte is the main critical point of a battery, in particular in large-
format modules, in chapter 3 we focused on the characterization of innovative and safe
electrolytes based on ionic liquids (characterized by high boiling/decomposition points,
thermal and electrochemical stability and appreciable conductivity) and mixtures of ionic
liquid with conventional electrolyte.
In chapter 4 is discussed the microwave accelerated sol–gel synthesis of the carbon-
coated lithium iron phosphate (LiFePO 4 -C), an excellent cathode material for LIBs thanks
to its intrinsic safety and tolerance to abusive conditions, which showed excellent
electrochemical performance in terms of specific capacity and stability.
In chapter 5 are presented the chemical-physical and electrochemical
characterizations of graphite and titanium-based anode materials in different electrolytes.
We also characterized a new anodic material, amorphous SnCo alloy, synthetized with a
nanowire morphology that showed to strongly enhance the electrochemical stability of the
material during galvanostatic full charge/discharge cycling.
Finally, in chapter 6, are reported different types of batteries, assembled using the
LiFePO 4 -C cathode material, different anode materials and electrolytes, characterized by
deep galvanostatic charge/discharge cycles at different C-rates and by test procedures of the DOE protocol for evaluating pulse power capability and available energy. First, we
tested a battery with the innovative cathode material LiFePO 4 -C and conventional graphite
anode and carbonate-based electrolyte (EC DMC LiPF 6 1M) that demonstrated to surpass
easily the target for power-assist HEV application. Given that the big concern of
conventional lithium-ion batteries is the flammability of highly volatile organic carbonate-
based electrolytes, we made safe batteries with electrolytes based on ionic liquid (IL). In
order to use graphite anode in IL electrolyte we added to the IL 10% w/w of vinylene
carbonate (VC) that produces a stable SEI (solid electrolyte interphase) and prevents the
graphite exfoliation phenomenon. Then we assembled batteries with LiFePO 4 -C cathode,
graphite anode and PYR 14 TFSI 0.4m LiTFSI with 10% w/w of VC that overcame the DOE
targets for HEV application and were stable for over 275 cycles. We also assembled and
characterized ―high safety‖ batteries with electrolytes based on pure IL, PYR 14 TFSI with
0.4m LiTFSI as lithium salt, and on mixture of this IL and standard electrolyte
(PYR 14 TFSI 50% w/w and EC DMC LiPF 6 50% w/w), using titanium-based anodes (TiO 2
and Li 4 Ti 5 O 12 ) that are commonly considered safer than graphite in abusive conditions.
The batteries bearing the pure ionic liquid did not satisfy the targets for HEV application,
but the batteries with Li 4 Ti 5 O 12 anode and 50-50 mixture electrolyte were able to surpass
the targets. We also assembled and characterized a lithium battery (with lithium metal
anode) with a polymeric electrolyte based on poly-ethilenoxide (PEO 20 –
LiCF 3 SO 3 +10%ZrO 2 ), which satisfied the targets for EV application and showed a very
impressive cycling stability.
In conclusion, we developed three lithium-ion batteries of different chemistries that
demonstrated to be suitable for application in power-assist hybrid vehicles: graphite/EC
DMC LiPF 6 /LiFePO 4 -C, graphite/PYR 14 TFSI 0.4m LiTFSI with 10% VC/LiFePO 4 -C and
Li 4 T i5 O 12 /PYR 14 TFSI 50%-EC DMC LiPF 6 50%/LiFePO 4 -C. We also demonstrated that
an all solid-state polymer lithium battery as Li/PEO 20 –LiCF 3 SO 3 +10%ZrO 2 /LiFePO 4 -C is
suitable for application on electric vehicles. Furthermore we developed a promising anodic
material alternative to the graphite, based on SnCo amorphous alloy.
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Stereoselective synthesis of heterocycles as intermediates of biologically active compoundsMosconi, Elisa <1981> 19 April 2011 (has links)
The aim of this thesis was to investigate the synthesis of enantiomerically enriched heterocycles and dehydro-β-amino acid derivatives which can be used as scaffolds or intermediates of biologically active compounds, in particular as novel αvβ3 and α5β1 integrin ligands. The starting materials of all the compounds here synthesized are alkylideneacetoacetates. Alkylidene derivates are very usefull compounds, they are usually used as unsaturated electrophiles and they have the advantage of introducing different kind of functionality that may be further elaborated.
In chapter 1, regio- and stereoselective allylic amination of pure carbonates is presented. The reaction proceeds via uncatalyzed or palladium-catalyzed conditions and affords enantiopure dehydro-β-amino esters that are useful precursor of biologically active compounds. Chapter 2 illustrates the synthesis of substituted isoxazolidines and isoxazolines via Michael addition followed by intramolecular hemiketalisation. The investigation on the effect of the Lewis acid catalysis on the regioselectivity of the addition it also reported. Isoxazolidines and isoxazolines are interesting heterocyclic compounds that may be regarded as unusual constrained -amino acids or as furanose mimetics. The synthesis of unusual cyclic amino acids precursors, that may be envisaged as proline analogues, as scaffolds for the design of bioactive peptidomimetics is presented in chapter 3. The synthesis of 2-substituted-3,4-dehydropyrrole derivatives starting from allylic carbonates via a two step allylic amination/ring closing metathesis (RCM) protocol is carried out. The reaction was optimized by testing different Grubbs’ catalysts and carbamate nitrogen protecting groups. Moreover, in view of a future application of these dehydro-β-amino acids as central core of peptidomimetics , the malonate chain was also used to protect nitrogen prior to RCM. Finally, chapter 4 presents the synthesis of two novel different classes of integrin antagonists, one derived from dehydro-β-amino acid prepared as described in chapter 1 and the other one has isoxazolidines synthesized in chapter 2 as rigid constrained core. Since that these compounds are promising RGD mimetics for αvβ3 and α5β1 integrins, they have been submitted to biological assay. and to interpret on a molecular basis their different affinities for the αvβ3 receptor, docking studies were performed using Glide program.
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Synthesis and application of new ion-tagged ligands and organocatalystsChiarucci, Michel <1983> 19 April 2011 (has links)
We report the synthesis and application of some ion-tagged catalysts in organometallic catalysis and organocatalysis. With the installation of an ionic group on the backbone of a known catalyst, two main effects are generally obtained. i) a modification of the solubility of the catalyst: if judicious choice of the ion pair is made, the ion-tag can confer to the catalyst a solubility profile suitable for catalyst recycling. ii) the ionic group can play a non-innocent role in the process considered: if stabilizing interaction between the ionic group and the developing charges in the transition state are established, the reaction can speed up.
We describe the use of ion-tagged diphenylprolinol as Zn ligand. The chiral ligand grafted onto an ionic liquid (IL) was recycled 10 times with no loss of reactivity and selectivity, when it was employed in the first example of enantioselective addition of ZnEt2 to aldehydes in ILs. An ammonium-tagged phosphine displayed the capability to stabilize Pd catalysts for the Suzuki reaction in ILs. The ionic phase was recycled 6 times with no detectable loss of activity and very low Pd leaching in the organic phase. This catalytic system was also employed for the functionalization of the challenging substrate 5,11-dibromotetracene. In the field of organocatalysis, we prepared two ion-tagged derivatives of the McMillan imidazolidinone. The results of the asymmetric Diels-Alder reaction between trans-cinnamaldehyde and cyclopentadiene exhibited great dependence on the position and nature of the ionic group. Finally, when O-TMS-diphenylprolinol was tagged with an imidazolium ion, exploiting a silyl ether linker, an efficient catalyst for the asymmetric addition of aldehydes to nitroolefins was achieved. The catalyst displayed enhanced reactivity and the same high level of selectivity of the untagged parent catalyst and it could be employed in a wide range of reaction conditions, included use of water as solvent.
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Chemical analysis and reactivity of biomass pyrolysis products. Application to the development of carbon-neutral biofuels and chemicalsTorri, Cristian <1982> 09 May 2011 (has links)
In this dissertation the pyrolytic conversion of biomass into chemicals and fuels was investigated from the analytical point of view. The study was focused on the liquid (bio-oil) and solid (char) fractions obtainable from biomass pyrolysis.
The drawbacks of Py-GC-MS described so far were partially solved by coupling different analytical configurations (Py-GC-MS, Py-GC-MIP-AED and off-line Py-SPE and Py-SPME-GC-MS with derivatization procedures).
The application of different techniques allowed a satisfactory comparative analysis of pyrolysis products of different biomass and a high throughput screening on effect of 33 catalysts on biomass pyrolysis. As the results of the screening showed, the most interesting catalysts were those containing copper (able to reduce the high molecular weight fraction of bio-oil without large yield decrease) and H-ZSM-5 (able to entirely convert the bio-oil into “gasoline like” aromatic products).
In order to establish the noxious compounds content of the liquid product, a clean-up step was included in the Py-SPE procedure. This allowed to investigate pollutants (PAHs) generation from pyrolysis and catalytic pyrolysis of biomass. In fact, bio-oil from non-catalytic pyrolysis of biomass showed a moderate PAHs content, while the use of H-ZSM-5 catalyst for bio-oil up-grading determined an astonishing high production of PAHs (if compared to what observed in alkanes cracking), indicating an important concern in the substitution fossil fuel with bio-oil derived from biomass. Moreover, the analytical procedures developed in this thesis were directly applied for the detailed study of the most useful process scheme and up-grading route to chemical intermediates (anhydrosugars), transportation fuels or commodity chemicals (aromatic hydrocarbons). In the applied study, poplar and microalgae biomass were investigated and overall GHGs balance of pyrolysis of agricultural residues in Ravenna province was performed. A special attention was put on the comparison of the effect of bio-char different use (fuel or as soil conditioner) on the soil health and GHGs emissions.
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Bioanalytical applications of multicolour bioluminescence imaging: new tools for drug discovery and developmentMezzanotte, Laura <1982> 12 April 2011 (has links)
The subject of this thesis is multicolour bioluminescence analysis and how it can provide new tools for drug discovery and development.The mechanism of color tuning in bioluminescent reactions is not fully understood yet but it is object of intense research and several hypothesis have been generated. In the past decade key residues of the active site of the enzyme or in the surface surrounding the active site have been identified as responsible of different color emission. Anyway since bioluminescence reaction is strictly dependent from the interaction between the enzyme and its substrate D-luciferin, modification of the substrate can lead to a different emission spectrum too. In the recent years firefly luciferase and other luciferases underwent mutagenesis in order to obtain mutants with different emission characteristics. Thanks to these new discoveries in the bioluminescence field multicolour luciferases can be nowadays employed in bioanalysis for assay developments and imaging purposes. The use of multicolor bioluminescent enzymes expanded the potential of a range of application in vitro and in vivo. Multiple analysis and more information can be obtained from the same analytical session saving cost and time. This thesis focuses on several application of multicolour bioluminescence for high-throughput screening and in vivo imaging. Multicolor luciferases can be employed as new tools for drug discovery and developments and some examples are provided in the different chapters. New red codon optimized luciferase have been demonstrated to be improved tools for bioluminescence imaging in small animal and the possibility to combine red and green luciferases for BLI has been achieved even if some aspects of the methodology remain challenging and need further improvement. In vivo Bioluminescence imaging has known a rapid progress since its first application no more than 15 years ago. It is becoming an indispensable tool in pharmacological research. At the same time the development of more sensitive and implemented microscopes and low-light imager for a better visualization and quantification of multicolor signals would boost the research and the discoveries in life sciences in general and in drug discovery and development in particular.
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Liquid crystal nanodroplets and their surface wettingVanzo, Davide <1983> 20 April 2011 (has links)
No description available.
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