The Synthesis of Arylalkyne‐Substituted Tetrapyrazinoporphyrazines and an Evaluation of Their Potential as Photosensitisers for Photodynamic Therapy

Abstract

New aryl-terminated octaalkynyl tetrapyrazinoporphyrazines were prepared in three steps starting from functionalised bisarylalkynyl 1,2-diones. While the tert-butylphenyl substituents were shown to aid solubility in organic solvents and to reduce chromophore aggregation efficiently, more hydrophilic tetrapyrazinoporphyrazines were obtained through the use of polyethylene glycol-substituted (PEGsubstituted) phenyl groups. The absorption profiles and the singlet oxygen quantum yields of the acetylenic tetrapyrazinoporphyrazines were determined with a view to assess their suitability for PDT applications. In all cases the presence of the terminal aryl moieties resulted in noticeable bathochromic and hyperchromic shifts of the lowest-energy ab-

Red‐Emitting Dyes with Photophysical and Photochemical Properties Controlled by pH

“…Similar to what was observed for fluorescence in DMF, the F D of compounds 10-14 reached very low values and the controls (15 and 16) showed values typical for ZnAzaPc. [33,34] After acidification (5 % sulfuric acid in solution), the F D values of all of the compounds were comparable due to the inhibition of the ICT in the pH sensitive derivatives (Table 1). Singlet oxygen production for the pH sensitive derivatives increased several times (by a factor of 18-110) upon changing the acidity of the solutions.…”

Tetrapyrazinoporphyrazines and their metal derivatives. Part I: Synthesis and basic structural information

“…The light harvesting properties of such styryl substituted TPyzPzs might arise from the possibility of the intramolecular charge transfer from the peripheral stilbenoid π-chromophores to the central porphyrazine π-chromophore. TPyzPzs bearing silyl and aryl substituted alkynyl groups have been synthesized from the corresponding bis(alkynyl)pyrazinedicarbonitriles Pyz22 and Pyz23a-d [111,112] for potential use as photosensitizers in PDT (Chart 7). The Zn II and Ni II complexes of the silyl substituted derivatives [TPyz22PzNi] and [TPyz22PzZn] were prepared by template cyclotetramerization of the dinitrile in quinoline in the presence of Zn(AcO) 2 or NiCl 2 (ca 30% yield) [111].…”

“…The Zn II and Ni II complexes of the silyl substituted derivatives [TPyz22PzNi] and [TPyz22PzZn] were prepared by template cyclotetramerization of the dinitrile in quinoline in the presence of Zn(AcO) 2 or NiCl 2 (ca 30% yield) [111]. The Mg II complexes (from Pyz22 and Pyz23a-d) have been prepared by Linstead template cyclotetramerization (Mg in n-BuOH, 4h, 30-40%), and converted to the Zn II complexes by successive treatment with p-TsOH and Zn(AcO) 2 in THF [111,112]. The metal free silyl substituted compound [TPyz22PzH 2 ] was also prepared by demetallation of the Mg II complex with p-TsOH.…”

The synthesis and characterization of novel unsymmetrical azaphthalocyanines containing one carboxylic group

“…One of the standard procedures for AzaPc macrocycle formation involves reaction in butanol in the presence of butoxides [28,29]. This cyclization method usually proceeds in high yields.…”

“…Magnesium complexes of AzaPc can readily be converted to metal-free compounds, and subsequently various central metals can be inserted into the centre of macrocycle [22,29]. Due to the problems described above in the preparation of magnesium complexes, we decided to use rather a direct cyclotetramerization of precursors in DMF with zinc acetate resulting in the zinc complexes 8 and 9.…”