On the nature of basic sites on carbon surfaces:: An overview

The nature of basic sites on carbon surfaces is a controversial issue within Carbon Science. Traditionally, oxygen-containing groups like: T pyrone-type, chromene, diketone or quinone groups, on the one hand, and delocalized pi-electrons of the basal planes, on the other, are assumed to have a basic nature. However, there is no consensus about neither the strength as bases of these sites, nor the extent of their contribution to the overall carbon basicity. Researchers are divided between those that support basic-oxygen-containing groups as main responsible of carbon basicity and those that attribute the overall basicity of a carbon to the delocalized pi-electrons of the basal planes. In this work we will discuss the virtues and drawbacks of the different hypotheses about basic carbon sites in view of experimental and theoretical results. (C) 2004 Elsevier Ltd. All rights reserved.