Graphitic molecule

The remarkable stability of onion-like particles[15] suggests that single-shell graphitic molecules (giant fullerenes) containing thousands of atoms are unstable and would collapse to form multi-layer particles in this way the system is stabilized by the energy gain from the van der Waals interaction between shells [15,26,27],... 

The early prediction of hollow graphite molecules suggested that they should be supercritical under ambient conditions. This is not true of C60, but might still be true of higher fullerenes and graphite nanotubes of large diameter. 

Carbon, of course, is the ideal element for simple-minded chemists. Obey a few elementary valency rules, and almost any organic structure you can doodle would exist, if you could make it. And this is perhaps the justification for my own simple-minded contribution to the story of C60. For many years I have maintained a scientific alter ego, Daedalus, whose musings used to appear in New Scientist but now appear in Nature. Daedalus launches scientific proposals which are intended to fall in that uneasy no-man s-land between the clearly feasible and the clearly fantastic. His aim is inevitably rather erratic, and many of the attempts land on one side or the other. An account of some of Daedalus s chemical proposals has appeared in Chemistry in Britain (Jones 1987). His greatest moment came late in 1966, when he proposed the hollow-shell graphite molecule (Jones 1966). 

C.D. Simpson, J. Wu, M.D. Watson, K. Mullen, From graphite molecules to columnar superstructures-an exercise in nanoscience. J. Mater. Chem. 14, 494-504 (2004)... 

Besides the shape, another important factor that affects the electronic properties and chemical reactivity of PAHs is the nature of the periphery. According to Clar s classification, the graphitic molecules with armchair and cove peripheries shown in Fig. 3.14 (A and B) are all-benzenoid PAHs. In addition to these linear topologies, Stein and Brown considered two other peripheral structures, i.e. acene-like (C) and quinoidaT (D) structures, which lie in a higher energy state and thus show higher chemical reactivity [62]. 

For the acene and phene series, the UV-vis and fluorescence spectra shift dramatically when the number of the phenyl rings increases. In contrast, the shifts for all-benzenoid PAHs with either armchair or cove -type edges are small and they show a high chemical stability. Very recently, graphitic molecules with partial zig-zag periphery such as 68a, 68b and 73 (Scheme 3.19) were synthesized. It was found that the introduction of two or six extra re-centers onto the all-benzenoid graphitic molecules dramatically influences their electronic properties, chemical reactivity and two- and three-dimensional self-assembly [64]. 

Synthesis of hexa-peri-hexabenzocoronene 10 by Cu(ii)-mediated oxidative cyclodehydrogenation - a general procedure to prepare unsubstituted graphitic molecules [35]... 

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