Synthesis, Characterization and Protonation Behavior of Quinoxaline-Fused Porphycenes

Abstract

9,10-Quinoxaline-fused porphycenes 1a-H2 and 1b-H2 were synthesized by intramolecular McMurry coupling. As a result of the annulation of the quinoxaline moiety on the porphycene skeleton, 1a-H2 and 1b-H2 display absorption and fluorescence in the near infra-red (NIR) region. Additionally, the quinoxaline moieties of 1a-H2 and 1b-H2 act as electron-withdrawing groups, introducing lower reduction potentials than for pristine porphycene. The protonation occurred at the nitrogen atoms in the cavity of freebase porphycenes and at the quinoxaline moieties for their nickel complexes to give diprotonic species.

Gram-scale synthesis of porphycenes through acid-catalyzed oxidative macrocyclizations of E/Z-mixed 5,6-diaryldipyrroethenes

“…13,14 Various porphycenes with meso-and b-substituents and their metal complexes have been reported to have tunable functionalities, crystallinities and solubilities. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] However, the main obstacle to the widespread application of porphycenes is the lack of efficient and economical methods for their production. Therefore, porphycene chemistry has advanced more slowly than that of the parent isomer porphyrin.…”

Porphyrinoids with Vinylene Bridges

“…65 We synthesized the meso-quinoxaline-fused porphycene 57 to attain NIR absorption and fluorescence. 66…”

Synthesis of a meso‐Tetraalkylporphycene Bearing Reactive Sites: Toward Porphycene–Polydimethylsiloxane Hybrids with Enhanced Photophysical Properties

“…Because of their unique optical properties, porphycene derivatives have been investigated as potential photosensitizers for photodynamic therapy, as artificial heme components, as catalysts, as near‐infrared absorption dyes, as tautomerization,, and as various functional materials . From the viewpoint of synthetic chemistry, porphycenes can be modified with substituents at the β‐ and meso ‐positions, thereby introducing differences that affect their solubilities, electronic states, metal coordinating abilities, and intramolecular hydrogen bonding behaviors.…”