Abstract
Structural transformations occurring spontaneously in a single molecule of sashlike polydiacetylene (PD) -atomic sash (AS)-, obtained by the tip-induced polymerization of a column of 17,19-hexatriacontadiyne (HTDY) molecules laid flat on a graphite (0001) surface, were observed by scanning tunneling microscopy (STM) at room temperature. In the STM images, the AS molecules at first displayed bright contrast due to PD chains lifted-up with twisted alkyl chains at α- and β- methylenes. Soon after the polymerization, paled regions appeared in the AS molecules. The PD chains of these regions seemed snaking and the interval of the alkyl chains was shortened compared with that of the rest of the molecule. The structural change was occasionally accompanied with the alteration of the direction of the PD chains and the rearrangement of the monomer columns around the AS molecules. [DOI: 10.1380/ejssnt.2005.470]
