Surface-Confined Friedel-Crafts Alkylation Reaction of 2,4-Dialkoxylbenzyl Alcohols: An STM Study

The Friedel-Crafts (F-C) alkylation reaction on highly oriented pyrolytic graphite (HOPG) has been studied by scanning tunneling microscopy (STM) in an ambient environment. The self-assemblies of surface-confined F-C alkylation reaction products of 2,4-dialkoxybenzyl alcohol derivatives manifest an interesting reaction selectivity. The precursor 2,4-dimethoxybenzyl alcohol forms a self-assembly of methylene coupled cyclic tetramers and the precursor 2,4-bis(decyloxy)phenyl methanol forms a self-assembly of methylene coupled dimers. The formation of ordered assemblies of the oligomers is attributed to the surface confinement effect on the growth and alignment of products on the HOPG surface. The mass spectroscopy results suggest that the solution-synthesized products are polydisperse and have a higher degree of polymerization, which is apparently different from the results of the surface-confined F-C alkylation reaction.