Structure of a novel form of carbon: dehydropolycondensed adamantane?

Abstract

The paper presents synchrotron X-ray diffraction and complementary transmission IR spectroscopy data on a series of products of adamantane in an attempt to elucidate the detailed nature of their structure. Although qualitative similarities between this work and earlier studies have been identified, the X-ray diffraction measurements, when coupled with IR absorption analysis, argue for a very different interpretation of the structural changes associated with the chemical processes involved in generating this suite of materials. It is clear that 1,3,5,7-tetrabromoadamantane has indeed been formed from the adamantane precursor, but that there are some Br sites that are occupied by carbon atoms. ‘Polymerisation’ of these units into an amorphous network with no residual long-range ordering may then be induced through chemical processes; the C10carbon units are broken up to form an amorphous network (or ‘patchwork’) of unit fragments. The corroborating presence of short hydrocarbon chains is also revealed. Once the material is heat treated it begins to revert to a graphitic structure, with the hydrocarbon chains being eliminated.