Advanced Materials, Vol.14, No.1, 75-79, 2002
Discrete conjugated porphyrin tapes with an exceptionally small bandgap
An Ag-I-promoted meso-meso coupling reaction has been extended to prepare discrete 100 nm long linear arrays of porphyrins. Oxidation of the resulting phenyl end-capped meso-meso linked porphyrins using a combination of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and Sc-III(OTf)(3) directly produces fully pi-conjugated fused porphyrin arrays (porphyrin tapes) of 10 nm molecular size. This research news article presents their synthesis, X-ray crystal structures, and optical and electronic properties. Among these, the extremely small highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) optical gaps that reach into the infrared region suggest many, applications of these compounds in materials science.