Oligothiophenes—-Yet Longer? Synthesis, Characterization, and Scanning Tunneling Microscopy Images of Homologous, Tsomerically Pure Oligo(alkylthiophene)s

摘要

The synthesis of structurally defined conjugated oiigomers with dimensions on the nanometer scale have recently awakened interest not only because of the possibility of investigating uans-port behavior along the "molecular wire". Interestingly, the lengths of the molecules achieved so far in the series of oligo(tetraethynylethene)s, up to 50 Q, oligo (Thienylenethynylene)s, up to 100 A, and oligo (phenylenethynylene)s, up to 128 A, have reached the size of the smallest achievable structural dimensions of lithographic nanostructures. Although members of the first series can be charged, preferably by reduction, and are suitable as molecular conductors owing to delocalization, these properties have not yet been established for oligomers linked by alkyne units.