Tesi etd-05122007-194220 |
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Tipo di tesi
Tesi di dottorato di ricerca
Autore
Borsacchi, Silvia
URN
etd-05122007-194220
Titolo
Structure, dynamics and interfaces of organic-inorganic multicomponent materials by means of solid-state NMR spectroscopy
Settore scientifico disciplinare
CHIM/02
Corso di studi
SCIENZE CHIMICHE
Relatori
Relatore Prof. Veracini, Carlo Alberto
Parole chiave
- broad-line
- clays
- composites
- dynamics
- lanthanum sulphates
- MAS
- metal nanoparticles
- nanocomposites
- organic-inorganic
- polymer
- polyphosphazenes
- quadrupolar
- relaxation times
- silica
- solid-state NMR
- stationary chromatographic phases
- structure
Data inizio appello
16/02/2007
Consultabilità
Completa
Riassunto
Questa tesi ha avuto come obiettivo la messa a punto e l’applicazione di un approccio metodologico per lo studio di materiali complessi multicomponente organici-inorganici mediante Spettroscopia di Risonanza Magnetica Nucleare allo Stato Solido. Tali materiali costituiscono una categoria molto ampia di sistemi di grande interesse attuale, alla cui caratterizzazione la Spettroscopia NMR a Stato Solido, una delle tecniche attualmente più potenti per lo studio di sistemi solidi e tuttavia ancora relativamente poco applicata allo studio di sistemi organici-inorganici, puo’ dare un contributo importante. In questa tesi mediante la messa a punto e l’applicazione di un approccio multinucleare, comprendente l’uso combinato di diverse tecniche e metodologie di Spettroscopia NMR a Stato Solido, è stato possibile investigare le proprietà strutturali, dinamiche e di interfaccia di diversi sistemi multicomponente organici-inorganici. La tesi è strutturata in otto capitoli: i primi due, di carattere più generale, sono dedicati, il primo, alla descrizione dei principi teorici alla base della Spettroscopia NMR a stato solido, il secondo alla descrizione dell’approccio impiegato e delle metodologie utilizzate in questa tesi. Ciascuno dei successivi sei capitoli sperimentali è invece dedicato ad uno specifico gruppo di sistemi investigati: nel capitolo 3 è riportato lo studio di due fasi stazionarie diastereoisomeriche usate in cromatografia HPLC enantioselettiva e dei rispettivi modelli solubili, essenzialmente condotta mediante tecniche in alta risoluzione per lo studio dei nuclei 13C e 1H e in bassa risoluzione per lo studio dei nuclei 1H; i capitoli 4, 5 e 6 sono dedicati allo studio di tre diversi materiali inorganici, variamente sottoposti a modifiche organiche, tutti impiegati come filler per matrici polimeriche (solfato di bario, silice e laponite, un magnesio-silicato di origine sintetica): le proprietà strutturali e dinamiche delle diverse componenti dei filler, nonché delle interfacce organiche-inorganiche in essi presenti, sono state investigate e caratterizzate mediante la combinazione di tecniche in alta risoluzione per lo studio dei nuclei 13C, 29Si e 1H in alta e bassa risoluzione; nel caso dei filler a base di silice sono stati inoltre analizzati film compositi costituiti da filler e polietilene. Nel capitolo 7 è riportato lo studio di un catalizzatore a base di nanoparticelle di palladio supportate su un poliorganofosfazene, basato sull’osservazione dei nuclei 13C, 31P e 15N. Infine il capitolo 8, dedicato allo studio, mediante spettroscopia NMR a Stato Solido del nucleo quadrupolare 139La, del processo di disidratazione del solfato di lantanio, rappresenta un esempio delle potenzialità di analisi di un problema complesso, come quello della disidratazione di un sistema inorganico anche relativamente semplice, mediante osservazione e studio di un nucleo quadrupolare allo stato solido. Nelle conclusioni vengono infine tracciate le considerazioni finali sul lavoro svolto, nonchè i possibili sviluppi futuri.
The aim of this thesis has been the set-up and application of a possibile methodological approach for the study of organic-inorganic multicomponent materials by means of solid-state NMR Spectroscopy. This spectroscopy, one of the most powerful technique at present available for the study of solid materials, has been so far only scarcely applied to the characterization of organic-inorganic systems. In this thesis, by means of the set-up and application of a multinuclear approach, involving the combination of several solid-state NMR techinques and methodologies, it has been possibile to investigate the structural, dynamic and interface properties of several organic-inorganic multicomponent materials. The thesis is organized in eight chapters: the first and the second, more general, are dedicated, respectively, to the theoretical solid-state NMR basics, and to a description of the approach and methodologies here employed. Each of the subsequent six chapters are dedicated to a specific group of systems investigated: in chapter 3 the study of two diastereoisomeric chiral stationary phases for HPLC and of their solubile models is reported, mainly performed by means of high-resolution 13C and 1H high- and low-resolution techniques; chapters 4, 5 and 6 are dedicated to the study of three inorganic materials, subject to various organic modifications, all employed as fillers for polymeric matrices (barium sulphate, silica and laponite, a synthetic magnesium-silicate): the structural and dynamic properties of the different filler components as well as of the organic-inorganic interfaces have been investigated and characterized by means of high-resolution techniques for the observation of 13C, 29Si, and high- and low-resolution techniques for the observation of 1H nuclei; as far as the silica filler is concerned, also filler/polyethylene composite films have been analyzed. In chapter 7 the study of a catalyst constituted by palladium nanoparticles supported on a polyorganophospazene is reported, based on the observation of 13C, 31P and 15N nuclei. At last, chapter 8, which is dedicated to the study of the dehydration process of lanthanum sulphate by means of 139La solid-state NMR, is an example of the potentialities provided by the study of quadrupolar nuclei by means of solid-state NMR for the analysis of a complex problem, as the dehydration process of a relatively simple inorganic system. In the Conclusions the final considerations of the thesis and its possibile future developments are reported.
The aim of this thesis has been the set-up and application of a possibile methodological approach for the study of organic-inorganic multicomponent materials by means of solid-state NMR Spectroscopy. This spectroscopy, one of the most powerful technique at present available for the study of solid materials, has been so far only scarcely applied to the characterization of organic-inorganic systems. In this thesis, by means of the set-up and application of a multinuclear approach, involving the combination of several solid-state NMR techinques and methodologies, it has been possibile to investigate the structural, dynamic and interface properties of several organic-inorganic multicomponent materials. The thesis is organized in eight chapters: the first and the second, more general, are dedicated, respectively, to the theoretical solid-state NMR basics, and to a description of the approach and methodologies here employed. Each of the subsequent six chapters are dedicated to a specific group of systems investigated: in chapter 3 the study of two diastereoisomeric chiral stationary phases for HPLC and of their solubile models is reported, mainly performed by means of high-resolution 13C and 1H high- and low-resolution techniques; chapters 4, 5 and 6 are dedicated to the study of three inorganic materials, subject to various organic modifications, all employed as fillers for polymeric matrices (barium sulphate, silica and laponite, a synthetic magnesium-silicate): the structural and dynamic properties of the different filler components as well as of the organic-inorganic interfaces have been investigated and characterized by means of high-resolution techniques for the observation of 13C, 29Si, and high- and low-resolution techniques for the observation of 1H nuclei; as far as the silica filler is concerned, also filler/polyethylene composite films have been analyzed. In chapter 7 the study of a catalyst constituted by palladium nanoparticles supported on a polyorganophospazene is reported, based on the observation of 13C, 31P and 15N nuclei. At last, chapter 8, which is dedicated to the study of the dehydration process of lanthanum sulphate by means of 139La solid-state NMR, is an example of the potentialities provided by the study of quadrupolar nuclei by means of solid-state NMR for the analysis of a complex problem, as the dehydration process of a relatively simple inorganic system. In the Conclusions the final considerations of the thesis and its possibile future developments are reported.
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