Synthesis and comparison of photodynamic activity of alkylheteroatom substituted azaphthalocyanines

Tetra(pyrazino[2,3-b]pyrazino)porphyrazines: Synthesis, absorption, photophysical and electrochemical properties of strongly electron-deficient macrocycles

“…Position of the Q-band of TPyzPyzPzs (Table 2) in pyridine reflected well the expected extension of the conjugated system by peripheral substituents and was fully in accordance with previously discovered relationships for the lower TPyzPz homologs. Thus, alkylsulfanyl 6a (l max = 705 nm) and dialkylamino 6c (l max = 693 nm) were considerably red shifted when compared to the aryloxy TPyzPyzPz 6b (l max = 682 nm) similarly as reported for analogous TPyzPzs [15]. Even larger extension of the conjugated system can be achieved for hetaryl substituted derivatives 6d (l max = 720 nm) and 6f (l max = 739 nm), again in line with previous observations made for TPyzPzs [8].…”

“…When 4a was cyclotetramerized in magnesium or lithium butoxide, TPyzPyzPz core was also formed but the product contained mix of butoxy and tert-butylsulfanyl substituents (according to MALDI MS analysis) as a consequence of the nucleophilic attack of butoxide to carbons in positions 6 and 7. Keeping in mind that the aryloxy substituents are even more prone to such exchange [14,15], the butoxide initiated cyclotetramerization reaction was not even tested for 4b. No cyclotetramerization product was observed when the above mentioned reactions were performed with compound 5.…”

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

“…[21,26,27] The ether linkages in 7 and 12 are not stable under conditions of the general method described above, as the carbon atoms in the 2-and 3-positions of the quinoxaline (7) and in the 5-and 6-positions of the pyrazine ring (12) are strongly electron deficient and are attacked by the alkoxide used as the initiator. Recently, Makhseed et al described a successful method for the cyclotetramerization of 7 into TPP5 by employing zinc acetate in dry quinoline, [25] but our attempts to repeat their procedure failed.…”

“…[20] However, a heteroatom connecting the peripheral chain is known to alter substantially the behaviour of the whole macrocycle. [21] Recently, we developed a synthetic method to alkylamino 6,7-TQP derivatives. [22] In the presented work, we show a synthetic route to the series of 6,7-TQPs bearing peripheral chains connected through the S and O heteroatoms as well as through the C-C bond.…”

Synthesis and spectral properties of tetrapyrazinoporphyrazinato metal complexes derived from sterically hindered phenol

“…4 Analogues of phthalocyanine in which nitrogen replaces some of the carbons within the four fused benzo-substituents of the phthalocyanine, possess significantly different physical properties including color, oxidation potential and stability, which may be beneficial for some of these applications. 5,6 Hence, 1,4,8,11,15,18,22,, often termed tetrapyrazinoporphyrazine in the literature, and its substituted derivatives have been investigated extensively for applications as photodynamic therapeutics, [7][8][9] colorants, 10 catalysts, 11 liquid crystals, [12][13][14] non-linear optical materials 15 and as a red fluorophore. 10,16,17 This latter application is of particular interest as the major phthalocyanine fluorescence band falls in the Near-IR region and is largely invisible to the human eye whereas AzaPc has a very strong fluorescence band in the visible spectrum.…”