TY - JOUR
T1 - Self-assembled monolayers of alkoxy-substituted octadehydrodibenzo[12] annulenes on a graphite surface
T2 - Attempts at peri-benzopolyacene formation by on-surface polymerization
AU - Tahara, Kazukuni
AU - Inukai, Koji
AU - Hara, Noritaka
AU - Johnson, Charles A.
AU - Haley, Michael M.
AU - Tobe, Yoshito
PY - 2010/7/26
Y1 - 2010/7/26
N2 - Self-assembled monolayers of a series of tetraalkoxy-substituted octadehydrodibenzo[12]annulene (DBA) derivatives 1c-g possessing butadiyne linkages were studied at the 1, 2, 4-trichlorobenzene (TCB) or 1-phenyloctane/graphite interface by scanning tunneling microscopy (STM). The purpose of this research is not only to investigate the structural variation of two-dimensional (2D) monolayers, but also to assess a possibility for peri-benzopolyacene formation by two-dimensionally controlled polymerization on a surface. As a result, the formation of three structures, porous, linear, and lamella structures, were observed by changing the alkyl chain length and the solute concentration. The formation of multilayers of the lamella structure was often observed for all compounds. The selection of molecular networks is basically ascribed to intermolecular and molecule-substrate interactions per unit area and network density. The selective appearance of the linear structure of Id is attributed to favorable epitaxial registry matching between the substrate lattice and the overlayer lattice. Even though the closest inter-atomic distance between the diacetylenic units of the DBAs in the lamella structure (≈0.6nm) is slightly larger compared to the typical distances necessary for topochemical polymerization, the reactivity toward external stimuli (electronic-pulse irradiation from an STM tip and UV irradiation) was investigated. Unfortunately, no evidence for polymerization of the DBAs on the surface was observed. The present results indicate the necessity for further designing a suitable system for the on-surface construction of structurally novel conjugated polymers, which are otherwise difficult to prepare.
AB - Self-assembled monolayers of a series of tetraalkoxy-substituted octadehydrodibenzo[12]annulene (DBA) derivatives 1c-g possessing butadiyne linkages were studied at the 1, 2, 4-trichlorobenzene (TCB) or 1-phenyloctane/graphite interface by scanning tunneling microscopy (STM). The purpose of this research is not only to investigate the structural variation of two-dimensional (2D) monolayers, but also to assess a possibility for peri-benzopolyacene formation by two-dimensionally controlled polymerization on a surface. As a result, the formation of three structures, porous, linear, and lamella structures, were observed by changing the alkyl chain length and the solute concentration. The formation of multilayers of the lamella structure was often observed for all compounds. The selection of molecular networks is basically ascribed to intermolecular and molecule-substrate interactions per unit area and network density. The selective appearance of the linear structure of Id is attributed to favorable epitaxial registry matching between the substrate lattice and the overlayer lattice. Even though the closest inter-atomic distance between the diacetylenic units of the DBAs in the lamella structure (≈0.6nm) is slightly larger compared to the typical distances necessary for topochemical polymerization, the reactivity toward external stimuli (electronic-pulse irradiation from an STM tip and UV irradiation) was investigated. Unfortunately, no evidence for polymerization of the DBAs on the surface was observed. The present results indicate the necessity for further designing a suitable system for the on-surface construction of structurally novel conjugated polymers, which are otherwise difficult to prepare.
KW - Dehydrobenzoannulene
KW - Interfaces
KW - Monolayers
KW - Scanning probe microscopy
KW - Self-assembly
UR - http://www.scopus.com/inward/record.url?scp=77954853086&partnerID=8YFLogxK
U2 - 10.1002/chem.201000711
DO - 10.1002/chem.201000711
M3 - Article
C2 - 20593443
AN - SCOPUS:77954853086
VL - 16
SP - 8319
EP - 8328
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 28
ER -