Synthesis, Separation, And Reaction Of Carbon Clusters Relevant To Fullerene

The dissertation is devoted to the study of synthesis, separation, characterization and reaction of perchlorinated carbon clusters relevant to fullerene C60 While research on the chemistry of C60 has run at a furious pace, the considerable attention has given to the small carbon clusters. Firstly, although there have been a great many of achievements in the experimental and theoretical investigations of fullerenes, their formation mechanism is still a puzzle to chemist and physicists. Various schemes have been put forward to explain the formation of fullerenes, but none of them can fit nicely with all of the available experimental evidence. The further research on the formation mechanism relies on trapping and characterizing the intermediates and fragments of fullerenes. Secondly, these carbon clusters are aggregates of carbon atoms ranging in size from two to tens of thousands of monomer units, they are distinct from bulk materials. They have structures and properties that differ from anything that can be observed in the bulk due to the stability of carbon clusters with magic numbers, reactive, catalytic properties, size and quantum effect, thereby making them attractive for many new applications. In this thesis, plasma methods were developed for the synthesis of perchlorinated carbon clusters. Focusing on the separation of products from chloroform plasma reaction, special attention was paid to the reactivity of the perchlorinated carbon clusters, and the results can be summarized as follow:(1) Plasma methods were developed for the synthesis of perchlorinated carbon clusters from chloroform by liquid arc and glow discharge reaction.(2) By coupling high-performance liquid chromatography with ultraviolet absorption spectroscopy and atmospheric pressure chemical ionization mass spectrometry(HPLC-UV-MS), we attempted to analyze the perchlorinated carbon clusters and fullerenes in the products of liquid arc discharge reaction from chloroform. To optimize the HPLC conditions, we investigated the effects on different stationary phase and mobile phase. The results show that, the commercially available reversed-phase HPLC on an C18 column was found to be effective in separating perchlorinated carbon clusters and fullerenes by selecting methanol/ethanol/cyclohexane as mobile phase; The acid-treated zirconia-alumina composite, after being modified with 2,4,6-trinitrophenol, exhibits advantage in the separation of fullerenes and large size carbon clusters when selecting toluene/cyclohexane as mobile phase; Silica gel bonding with C8-C13 were suitable for the pre-separate of plasma products. We can obtain undersize perchlorinated carbon clusters or polar carbon clusters when selectingmethanol as mobile phase. Medium size perchlorinated carbon clusters can be obtained when selecting cyclohexane as mobile phase. Large scale perchlorinated carbon clusters can be obtained when selecting toluene as mobile phase.On these conditions, more than fifty compounds in the sample were isolated successfully on a C|8 column with a methanol-ethanol-cyclohexane gradient mobile phase. HPLC was coupled with both mass spectroscopy (MS) and ultraviolet absorption spectroscopy (UV) for simultaneous separation and characterization of the products from glow plasma reaction of chloroform.(3) Phosphorus pentachloride(PCl5) has been used to perchlorinate acenaphthene under moderate pressure and temperature in sealed reaction vessels. Some polychlorinated carbon clusters, including perchloracenaphthenev perchloroacenaphthylene and dimmer or trimer of them were obtained after growing single crystals, recrystallization, open column chromatography with A12O3 as stationary phase and HPLC-UV-MS analysis.(4) Perchlorinated carbon clusters can undergo nucleophilic aromatic substitution reactions with sodium 4-methoxyphenylthiolate and sodium benzenethiolate in different solvents. Products with complete or part displacement of the chlorine atoms can be obtained. Reaction of the hexachloroben...