STRUCTURE, DYNAMICS AND INTERFACES OF ORGANIC-INORGANIC MULTICOMPONENT MATERIALS BY MEANS OF SOLID-STATE NMR SPECTROSCOPY

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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.