Synthesis and Reactions of Aminoporphyrazines with Annulated Five- and Seven-Membered Rings

Abstract

The novel five- and seven-membered ring appended aminoporphyrazines 3 and 12 have been prepared via mixed Linstead macrocyclization. The structures of both have been unequivocally established by X-ray crystallographic studies. Reductive deselenation of selenadiazole 3 in the presence of 9,10-phenanthrenequinone or 2,3-butanedione results in the formation of pyrazines 6a,b, whereas oxidation of porphyrazine 12 gave the corresponding seco derivative 14. seco-Porphyrazine 14 mediates the generation of singlet oxygen with a quantum yield of 0.74.

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

“…Alternatively, the Mg II , Cu II and Zn II complexes could be obtained by template cyclotetramerization of the dinitrile precursor in the presence of the metal alkoxide (Mg II ), the acetate (Cu II , Zn II ) or powdered metal (Cu) [123,204]. The Mg II macrocycle appears always formulated with one water molecule axially ligated to the central metal, in line with previous findings for the similarly formulated phthalocyanine and porphyrazine Mg II analogs [71,[214][215][216]. The Pd II and Pt II metal complexes, [TPyz42PzPd] and [TPyz42PzPt], were obtained by external demetallation of their respective pentanuclear species [207,210] (see below).…”

“…Vicinally substituted aminoporphyrazines are unstable to oxidation due to rupture of the C β =C β double bonds in pyrrole rings constituting macrocycle with formation of seco-porphyrazine derivatives involved in further side reactions [68,69]. As a result only few examples were reported about the built-up of pyrazine rings on the basis of amino substituted porphyrazine macrocycles [67,70,71] and application of this approach (Tf Pz1 + Tf Pyz2) to TPyzPzs synthesis has more academic than preparative significance.…”

Novel peripherally functionalized seco-porphyrazines: synthesis, characterization and spectroscopic evaluation

“…However, it should be noted that the most efficient seco-pz sensitizer for the production of singlet oxygen reported so far, a secoporphyrazine with an annulated seven-membered ring (F D ¼0.74), was recently reported by our group. 12 2. Results and discussion…”

Serendipitous synthesis of trimetallic porphyrazine triads

“…There is also an additional peak between 573 and 588 nm, which has been assigned to n-p * type transitions previously. 38 Although it is possible that the peaks around 620 nm and 720 nm are the result of a split Q-band due to the decrease in symmetry of the system, 39 it is more likely that they arise from two separate transitions; one from the fully conjugated, planar porphyrazine-pyrazine-porphyrazine unit and the other from the orthogonal, perpendicular porphyrazine ring. Previously, a dramatic red-shift of the Q-band has been observed for benzo-fused porphyrazine dimers.…”