Tetra[6,7]quinoxalinoporphyrazines: The Effect of an Additional Benzene Ring on Photophysical and Photochemical Properties

Abstract

Synthetic methods for a series of zinc tetra[6,7]quinoxalinoporphyrazines (6,7‐TQP) with peripheral chains connected through the S, O and N heteroatoms as well as through the C–C bond were developed. Photophysical and photochemical properties of 6,7‐TQP were compared with tetrapyrazinoporphyrazines (TPP) bearing the same peripheral substituents to disclose the effect of insertion of a benzene ring between the pyrazine and porphyrazine moieties. The influence of the peripheral heteroatom in the group of 6,7‐TQP is also discussed. Prepared 6,7‐TQP have their main absorption band (Q‐band) strongly batho‐ and hyperchromically shifted (λmax = 730–770 nm in pyridine, ϵ up to 500000 dm3 mol–1cm–1) in comparison to TPP. They showed high singlet oxygen quantum yields (ΦΔ = 0.50–0.74) and relatively lowfluorescence quantum yields (ΦF < 0.08).

Systematic investigation of phthalocyanines, naphthalocyanines, and their aza-analogues. Effect of the isosteric aza-replacement in the core

“…Syntheses of precursors 1 53 and 3 54 as well as macrocycles TPyzPz, 55 6,7-TQPz, 54 and Pc 55 Synthesis of 6,7-bis(tert-butylsulfanyl)quinoxaline-2,3dicarbonitrile (6). Compound 9 (2.9 g, 7.7 mmol, for synthesis of 9 see ESI) was dissolved in DMF (80 mL), and sodium ptoluenesulfinate (1.37 g, 7.7 mmol) was added followed by KCN (poison!)…”

Peripheral substitution as a tool for tuning electron-accepting properties of phthalocyanine analogs in intramolecular charge transfer

“…The synthesis of most of the precursors (6 -11) 12,14,[17][18][19][20] (Scheme 1) was performed according to previously published protocols. The synthesis of most of the precursors (6 -11) 12,14,[17][18][19][20] (Scheme 1) was performed according to previously published protocols.…”

“…The treatment of the statistical mixture of magnesium complexes with p-toluenesulfonic acid (TsOH) in THF at room temperature afforded a mixture of metal-free complexes that typically do not tail. [17][18][19][20] Electrochemistry 12 Indeed, the conversion of the mixture of magnesium derivatives to metal-free derivatives significantly facilitated the separation, and AAAB type congeners 2H -5H were isolated in yields ranging from 9 % to 16 %.…”

“…In general, the synthesis of TPyzPzs starts from the corresponding precursors, which are substituted pyrazine-2,3dicarbonitriles. The synthesis of most of the precursors (6-11) 12,14,[17][18][19][20] (Scheme 1) was performed according to previously published protocols. Precursor 12 was obtained nearly quantitatively by nucleophilic substitution of chlorine in 11 by 2-( piperidin-4-yl)ethan-1-ol as a nucleophilic agent in the presence of K 2 CO 3 serving as a base.…”

Synthesis of Unsymmetrical Alkyloxy/Aryloxy‐azaphthalocyanines Based on a Transetherification Reaction

“…Peripheral substitution plays a crucial role in defining the properties of AzaPc and Pc derivatives. It has been shown that alkylsulfanyl‐10 and alkyloxy‐substituted11,12 AzaPcs are characterized by high singlet oxygen ( Φ Δ ) and fluorescence quantum yields ( Φ F ), which makes them ideal candidates for cancer treatment by PDT, or fluorescence detection. On the other hand, alkylamino substitution leads to values of almost zero for both Φ F and Φ Δ because of effective intramolecular charge transfer 13.…”