STM observations of the self-assembled monolayers of alpha-aryl-alpha '-mercaptomethylthiophenes an Au(111)

A series of alpha'-mercaptomethylthiophenes with substituents at the alpha position were synthesized. The STM images of the SAMs of the thiophene deri vatives showed domain structures with constant row-to-row spacings of 14 an d 15 Angstrom for methyl and mesityl derivatives, respectively. However, th e anthracenyl derivative gave different structures. These results suggest t hat the substitution at the a position does not have strong effect on the r ow-to-row spacing unless the substituent is bulkier than a mesityl group.