Fully conjugated porphyrin tapes with electronic absorption bands that reach into infrared

Scandium(III)-catalyzed oxidation of meso-meso-linked zinc(II)-porphyrin arrays (up to dodecamers) with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) led to efficient formation of triply meso-meso-, beta-beta-, and beta-beta -linked zinc(II)-oligoiporphyrins with 62 to 91% yields, These fused tape-shaped porphyrin arrays display extremely red-shifted absorption bands that reflect extensively pi -conjugated electronic systems and a low excitation gap. The lowest electronic absorption bands become increasingly intensified and red-shifted upon the increase in the number of porphyrins and eventually reach a peak electronic excitation for the dodecamer at similar to 3500 wavenumber. The one-electron oxidation potentials also decreased progressively upon the,increase in the number of porphyrins. These properties in Long and rigid molecular shapes suggest their potential use as molecular wires.