Graphite acceptor

Blinowski, J., N. Hy Hau, C. Rigaux, J. P. Vieren, R. Toullec, G. Furdin, A. Herold, and J. Melin. 1980. Band structure model and dynamical dielectric function in lowest stages of graphite acceptor compounds. J. Phys. (Paris) 41 47-58. 

Metal chloride intercalate compounds such as graphite-FeQa, ZnCl2, BeCl2, ZrCU, NbCls, and TaCls are all Friedel-Crafts catalysts, and their action has been well described. The mechanism of formation of graphite acceptor compounds of this type is of interest in that electrons are removed from graphite to form negative ions the neutral molecules formed at the same time diffuse into the lattice. 

Figure 1. In the manner that polycyclic aromatic hydrocarbons react with oxidants to form aromatic radical cations (top), graphite reacts with oxidants to form graphite-acceptor...

For SWCNT bundles [35], ID intercalation would occur between the CNTs columns as it is the case for jxilyacetylene. Intercalation either by acceptors (Fig. 6) or donors (Fig. 7) increases the electrical conductivity as expected, however the effect is less pronounced than in bulk graphite [34]. 

Issi, J. -P., Transport properties of metal chloride acceptor graphite intercalation compounds. In Graphite Intercalation Compounds,... 

The simplest example of oxygen spillover is found in the adsorption of oxygen on carbon. The spillover oxygen migrates from the basal carbon (donor) to carbon atoms exposed at steps between layers of the graphite surface, where it reacts with the edge carbons (acceptor).71 In this case the donor and acceptor phase consist of the same material with different surface properties. 

The addition of various Kolbe radicals generated from acetic acid, monochloro-acetic acid, trichloroacetic acid, oxalic acid, methyl adipate and methyl glutarate to acceptors such as ethylene, propylene, fluoroolefins and dimethyl maleate is reported in ref. [213]. Also the influence of reaction conditions (current density, olefin-type, olefin concentration) on the product yield and product ratios is individually discussed therein. The mechanism of the addition to ethylene is deduced from the results of adsorption and rotating ring disc studies. The findings demonstrate that the Kolbe radicals react in the surface layer with adsorbed ethylene [229]. In the oxidation of acetate in the presence of 1-octene at platinum and graphite anodes, products that originate from intermediate radicals and cations are observed [230]. 

Fig. 4. The in-plane arrangement of a CgX network typical of many donor and acceptor compounds of graphite.

E3. Ebert, L. B., "Characterization of Graphite Intercalated by Electron Acceptors, Ph.D. Thesis, Stanford University, 1975, 324 pp. 

A higher conductivity might still be obtained if necessary, either by compacting the porous carbon structure or by inserting acceptor or donor molecules. Thus, in the case of pristine graphite, the perpendicular to the plane conductivity was found to increase to 2.1(P cm by insertion of potassium intercalates and as high as 8.1(T cm- by using lithium (14). 

The stabilizing influence of oxides, which cover the surface of graphite (result of heat treatment during purification and exfoliation) is usually associated with enhancement of its acceptor properties. This influence in the case of TEG was seen to produce highly stable to oxidation carbonaceous material. 

Furthermore, we believe that the stabilizing influence of boron in the structure of graphite is connected with enhancement of its acceptor properties, which manifest themselves when Boron atoms substitute carbon atoms in the crystalline structure (hexagon ring) of carbon. Such effects are mentioned in the literature for some types of carbon materials [3] and the influence of boron on TEG can be the similar. 

Fig. 25 STS curves (normalized I/V plots of LB monolayers of isomers 55 (crosses) and 56 (dots), deposited on an Au film over HOPG (highly oriented pyrolytic graphite), and scanned with a Pt/Ir nanotip. The films exhibit rectification in opposite quadrants of the plot, where the polarity is defined by the sign of the substrate electrode. Electron flow at forward bias in each case is from the acceptor to the donor [127]...

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