21,23-Dithia-3,13-diazaporphycenes − Novel Aromatic Porphycene Analogues Incorporating Thiazole

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

“…Extension of the porphycene core, as in 22π and 26π acetylene-cumulene porphycenes, also shows a clear red-shift pattern, consistent with the increased size of the conjugation pathway from 18 to 22 and 26 π electrons, respectively [78,179]. Finally, red shifts can also be induced by introduction of heteroatoms in the porphycene core [92,110,[115][116][117][118][119][120].…”

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

“…Extension of the porphycene core, as in 22π and 26π acetylene-cumulene porphycenes, also shows a clear red-shift pattern, consistent with the increased size of the conjugation pathway from 18 to 22 and 26 π electrons, respectively [78,179]. Finally, red shifts can also be induced by introduction of heteroatoms in the porphycene core [92,110,[115][116][117][118][119][120].…”

Untitled

“…The 1 H-NMR spectrum of 13, e.g., shows 1s at 6.92 ppm for the olefinic protons and 1s at 1.39 ppm for the t Bu groups, indicative of a symmetrical structure without an obvious ring current. The UV/VIS spectrum of 13, which shows no absorption maximum over 400 nm, exhibits only modest conjugation between the bithiazole units, as expected for a non-planar conformer [5] [14]. The spectroscopic properties of the aza[30]annulene 14 are very similar to those of 13.…”

2,7,12,17‐Tetra(p‐butylphenyl)‐3,6,13,16‐tetraazaporphycene: The First Example of a Straightforward Synthetic Approach to a New Class of Photosensitizing Macrocycles

“…Specifically, this group reported the synthesis of the aromatic 21,23-dithia-3,13-diazaporphycenes (where two pyrrole rings of porphycene have been substituted by thiazoles, i.e., two external nitrogen atoms). [16] More significant for our work, the same group also described a macrocycle derived from 2,2Ј-bithiazole (i.e. containing four external nitrogen atoms) which, interestingly, could not be rendered aromatic.…”

“…Bearing in mind that the incorporation of nitrogen atoms to a conjugated macrocycle produces a bathochromic shift of the lowest energy band (often termed Q-band) [16] we investigated, by means of computational techniques, the effect of aza substitution on the position of the lowest-energy absorption band for 23 porphycene-like systems (2Ϫ24). Specifically, we calculated the Q-band shift ∆λ max relative to porphycene 1a (G ϭ H, Po) ( Figure 1).…”

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

“…Extension of the porphycene core, as in 22π and 26π acetylene-cumulene porphycenes, also shows a clear red-shift pattern, consistent with the increased size of the conjugation pathway from 18 to 22 and 26 π electrons, respectively [78,179]. Finally, red shifts can also be induced by introduction of heteroatoms in the porphycene core [92,110,[115][116][117][118][119][120].…”

Untitled

“…The 1 H-NMR spectrum of 13, e.g., shows 1s at 6.92 ppm for the olefinic protons and 1s at 1.39 ppm for the t Bu groups, indicative of a symmetrical structure without an obvious ring current. The UV/VIS spectrum of 13, which shows no absorption maximum over 400 nm, exhibits only modest conjugation between the bithiazole units, as expected for a non-planar conformer [5] [14]. The spectroscopic properties of the aza[30]annulene 14 are very similar to those of 13.…”

2,7,12,17‐Tetra(p‐butylphenyl)‐3,6,13,16‐tetraazaporphycene: The First Example of a Straightforward Synthetic Approach to a New Class of Photosensitizing Macrocycles

“…Specifically, this group reported the synthesis of the aromatic 21,23-dithia-3,13-diazaporphycenes (where two pyrrole rings of porphycene have been substituted by thiazoles, i.e., two external nitrogen atoms). [16] More significant for our work, the same group also described a macrocycle derived from 2,2Ј-bithiazole (i.e. containing four external nitrogen atoms) which, interestingly, could not be rendered aromatic.…”

“…Bearing in mind that the incorporation of nitrogen atoms to a conjugated macrocycle produces a bathochromic shift of the lowest energy band (often termed Q-band) [16] we investigated, by means of computational techniques, the effect of aza substitution on the position of the lowest-energy absorption band for 23 porphycene-like systems (2Ϫ24). Specifically, we calculated the Q-band shift ∆λ max relative to porphycene 1a (G ϭ H, Po) ( Figure 1).…”

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

“…Extension of the porphycene core, as in 22π and 26π acetylene-cumulene porphycenes, also shows a clear red-shift pattern, consistent with the increased size of the conjugation pathway from 18 to 22 and 26 π electrons, respectively [78,179]. Finally, red shifts can also be induced by introduction of heteroatoms in the porphycene core [92,110,[115][116][117][118][119][120].…”

Untitled

“…The 1 H-NMR spectrum of 13, e.g., shows 1s at 6.92 ppm for the olefinic protons and 1s at 1.39 ppm for the t Bu groups, indicative of a symmetrical structure without an obvious ring current. The UV/VIS spectrum of 13, which shows no absorption maximum over 400 nm, exhibits only modest conjugation between the bithiazole units, as expected for a non-planar conformer [5] [14]. The spectroscopic properties of the aza[30]annulene 14 are very similar to those of 13.…”

2,7,12,17‐Tetra(p‐butylphenyl)‐3,6,13,16‐tetraazaporphycene: The First Example of a Straightforward Synthetic Approach to a New Class of Photosensitizing Macrocycles

“…Specifically, this group reported the synthesis of the aromatic 21,23-dithia-3,13-diazaporphycenes (where two pyrrole rings of porphycene have been substituted by thiazoles, i.e., two external nitrogen atoms). [16] More significant for our work, the same group also described a macrocycle derived from 2,2Ј-bithiazole (i.e. containing four external nitrogen atoms) which, interestingly, could not be rendered aromatic.…”

“…Bearing in mind that the incorporation of nitrogen atoms to a conjugated macrocycle produces a bathochromic shift of the lowest energy band (often termed Q-band) [16] we investigated, by means of computational techniques, the effect of aza substitution on the position of the lowest-energy absorption band for 23 porphycene-like systems (2Ϫ24). Specifically, we calculated the Q-band shift ∆λ max relative to porphycene 1a (G ϭ H, Po) ( Figure 1).…”