Linear atomic carbon chains in theory possess two different structures: the cumulenic one, characterized by a perfect sequence of double bonds and the polyynic one, which present an alternation of single and triple bonds. This thesis is based on the creation of films and crystals starting from powders constituted by two different molecules (tetraphenyl[n]cumulenes). In scientific literature, few results (theoretical and experimental) have been found concerning the properties of the examined molecules: some thermocyclization reactions and photoelectron spectroscopy. Generally, investigations regarding cumulenic or polyynic systems are mostly theoretical. Besides, they refer to single molecules modelized in different conditions. So, these studies are not comparable between each other and they cannot be applied to films and crystals fabricated during this work. Few Raman analyses have been executed on these systems, but in this thesis the vibrational properties of the single molecules have been computed theorically, then compared with the experimental results related to both films and crystals. After the creation of films and crystals it has been proceeded with the characterization of these systems, to understand their structural, morphological and electrical properties.
Le catene lineari di atomi di carbonio in teoria possiedono due strutture differenti: quella cumulenica, caratterizzata da una perfetta sequenza di legami doppi e quella poliinica, che presenta una alternanza di legami singoli e tripli. Questa tesi è basata sulla creazione di film e cristalli, partendo da polveri costituite da due molecule diverse (tetrafenil[n]cumuleni). Nella letteratura scientifica sono stati trovati pochi risultati (teorici e sperimentali) riguardanti le proprietà delle molecole esaminate: alcune reazioni di termociclizzazione e spettroscopia fotoelettronica. In generale le indagini relative alle proprietà di sistemi cumulenici o poliinici sono principalmente teoriche, inoltre si riferiscono a singole molecole modellizzate in condizioni diverse. Pertanto questi studi non sono confrontabili tra loro e non si possono applicare ai film e ai cristalli prodotti in questo lavoro. Poche analisi Raman sono state eseguite su questi sistemi, ma in questa tesi le proprietà vibrazionali delle singole molecole sono state calcolate teoricamente, poi confrontate con i risultati sperimentali riguardanti i film e i cristalli. Dopo la creazione di film e cristalli si è proceduto con la caratterizzazione di questi sistemi, per comprendere le loro proprietà strutturali, morfologiche e elettriche.
Fabrication and characterization of films and crystals from powders containing cumulenes
PENSOTTI, YURI IGOR
2016/2017
Abstract
Linear atomic carbon chains in theory possess two different structures: the cumulenic one, characterized by a perfect sequence of double bonds and the polyynic one, which present an alternation of single and triple bonds. This thesis is based on the creation of films and crystals starting from powders constituted by two different molecules (tetraphenyl[n]cumulenes). In scientific literature, few results (theoretical and experimental) have been found concerning the properties of the examined molecules: some thermocyclization reactions and photoelectron spectroscopy. Generally, investigations regarding cumulenic or polyynic systems are mostly theoretical. Besides, they refer to single molecules modelized in different conditions. So, these studies are not comparable between each other and they cannot be applied to films and crystals fabricated during this work. Few Raman analyses have been executed on these systems, but in this thesis the vibrational properties of the single molecules have been computed theorically, then compared with the experimental results related to both films and crystals. After the creation of films and crystals it has been proceeded with the characterization of these systems, to understand their structural, morphological and electrical properties.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/135614