Triply Linked Porphyrinoids

Abstract

Triply linked porphyrin arrays, so called porphyrin tapes, are intriguing molecules in terms of their planar structures, far red-shifted absorption bands, multi-charge storage abilities, and high conductivities. Recently, porphyrin tape variants such as porphyrin-expanded porphyrin hybrid tapes, porphyrin arch-tapes, corrole tapes, and a subporphyrin tape have been explored as novel π-conjugated materials. These new molecules exhibit electronic and structural characteristics owing to direct triple linkages. This Minireview first discusses the fundamental properties of the parent porphyrin tapes and the peripherally functionalized porphyrin tapes. Then, a focus has been placed on the syntheses, structures, and unique properties of the recently explored porphyrin tape variants.

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

“…[197] Many p-extended porphyrins have been synthesized by inter-o ri ntramolecular oxidative coupling;h owever, they will not be described here due to space restrictions and the fact that this subject has been reviewed recently. [198,199] As reported by Tanaka, Kim, Osuka, and co-workers, similar to porphyrin analogues, meso-meso-linked corrole dimers 189 a-c bearing various aryl substituents can also be oxidatively planarized to the corresponding triply linked products 190 a-c (Scheme 28). [200] Ther eaction was accomplished using DDQ in boiling chloroform and required high dilution of the starting materials to minimize unwanted intermolecular coupling reactions.The cyclization was accompanied by overoxidation, thereby leading to the loss of one NH hydrogen atom in each corrole macrocycle,w hich as ac onsequence became non-aromatic.S imilar overoxidation also occurred in the case of the doubly linked corrole dimer 191,w hich was synthesized under similar conditions.…”

“…Many π‐extended porphyrins have been synthesized by inter‐ or intramolecular oxidative coupling; however, they will not be described here due to space restrictions and the fact that this subject has been reviewed recently …”

ELDOR-detected NMR beyond hyperfine couplings: a case study with Cu(ii)-porphyrin dimers

“…Porphyrins are suitable components for molecular wires that mediate long distance charge transport, because of their large delocalized p-systems, small HOMO-LUMO gaps, rigid frameworks, and small reorganization energies. [23][24][25][26][27] The edge-fused porphyrin tapes, pioneered by Osuka and coworkers, [28][29][30] exhibit particularly strong electronic coupling, leading to highly conductive molecular wires. 31 Here we report an EDNMR investigation of two copper porphyrin dimers: the edge-fused dimer f-CuP2 and the meso-meso singly linked dimer CuP2; see chemical structures in Fig.…”

Singly, Doubly, and Triply Linked Corrole Oligomers: Synthesis, Structures, and Linking Position Dependent Properties

“…The contrasting characters between 2‐2′,18‐18′ doubly linked corrole dimer 25 and 8‐8′,10‐10′,12‐12′ triply linked corrole dimers 28 a,c,d are worthy to note . The corresponding 2NH ‐corrole monomer is a neutral monoradical species as explained above (Figure ) .…”

“…Oligomerization, either directly or with spacer units, is an important way to study their electronic interaction between porphyrinoid units and to tune their optical, electrical, and magnetic properties . In particular, meso‐meso , β‐β, β‐β triply linked porphyrin arrays exhibit remarkably strong electronic communications between the porphyrin units and are promising in applications such as NIR dyes, NLO materials, and conductive wires –…”