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

Scandium(III)-catalyzed oxidation of meso-meso-linked zinc(II)-porphyrin ar rays (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-bet a -linked zinc(II)-oligoiporphyrins with 62 to 91% yields, These fused tape -shaped porphyrin arrays display extremely red-shifted absorption bands tha t reflect extensively pi -conjugated electronic systems and a low excitatio n gap. The lowest electronic absorption bands become increasingly intensifi ed and red-shifted upon the increase in the number of porphyrins and eventu ally reach a peak electronic excitation for the dodecamer at similar to 350 0 wavenumber. The one-electron oxidation potentials also decreased progress ively upon the,increase in the number of porphyrins. These properties in Lo ng and rigid molecular shapes suggest their potential use as molecular wire s.