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Synthesis and photophysical properties of tetra- and octasubstituted phosphorous oxide triazatetrabenzcorrole photosensitizers.

Antunes EM, Nyokong T - Met Based Drugs (2008)

Bottom Line: The Q band absorption spectra of the complexes are red-shifted compared to unsubstituted PTBC.The latter complex shows a large triplet lifetime (1.7 milliseconds), higher than for MPc derivatives.The chlorinated derivatives show good triplet yields (Phi(T) approximately 0.46 and 0.36) and relatively long lifetimes (256 and 452 microseconds), respectively, for 11 and 13.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa.

ABSTRACT
The synthesis of phosphorous oxide triazatetrabenzcorroles (TBC) tetra- (9, 11) or octa- (13) substituted on the ring with halogenated functional groups is reported. The complexes are not aggregated in dimethylsulfoxide (DMSO) and show solubility in solvents such as pyridine. The Q band absorption spectra of the complexes are red-shifted compared to unsubstituted PTBC. The latter complex shows a large triplet lifetime (1.7 milliseconds), higher than for MPc derivatives. The chlorinated derivatives show good triplet yields (Phi(T) approximately 0.46 and 0.36) and relatively long lifetimes (256 and 452 microseconds), respectively, for 11 and 13.

No MeSH data available.


Synthetic procedure for the tetrasubstituted PTBC complexes.
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sch1: Synthetic procedure for the tetrasubstituted PTBC complexes.

Mentions: Triazatetrabenzcorroles(TBC) are phthalocyanine-like compounds which have lost one of the bridgingnitrogen atoms [9]. Thesynthesis of Ge, Si, Ga, and Al TBC complexes have been reported [10, 11]. Wehave recently reported on a microwave synthesis of a sulfonated SnTBC [12]. Goutermanet al. were the first to report on the synthesis and unusual electronic spectraof the PcPIII compared to PcPV [9, 13]. It became apparentthat upon complexation with the trivalent phosphorous, a bridging nitrogen waslost to form the phosphorous oxide tetrabenzcorroles (PTBC). Since then, a number of octa- andtetrasubstituted PTBC derivatives have been synthesized [14–19]. Most complexessynthesized contained alkyl chain ring substituents. High fluorescence quantumyields [18] and singlet oxygen quantum yields [15] have been reported for thecomplexes. The water-soluble tetrasulphonated PTBC showed good photodynamictherapy towards HeLa cells [19]. For applications in PDT, high tripletlifetimes and yields are desired; however there are no reports on the triplet-statebehavior of the PTBC complexes. In thiswork, we report on PTBC complexes tetra- or octasubstituted with chloride andbromide ring substituents (see Schemes 1 and 2), since the halogens are expected toenhance intersystem crossing, resulting in high triplet yields due to the heavyatom effect. A PTBC derivativecontaining a mixture of butoxy and chloro ring substituents has been reported[17], but no photophysical data has been reported for halogenated PTBCs.


Synthesis and photophysical properties of tetra- and octasubstituted phosphorous oxide triazatetrabenzcorrole photosensitizers.

Antunes EM, Nyokong T - Met Based Drugs (2008)

Synthetic procedure for the tetrasubstituted PTBC complexes.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2266970&req=5

sch1: Synthetic procedure for the tetrasubstituted PTBC complexes.
Mentions: Triazatetrabenzcorroles(TBC) are phthalocyanine-like compounds which have lost one of the bridgingnitrogen atoms [9]. Thesynthesis of Ge, Si, Ga, and Al TBC complexes have been reported [10, 11]. Wehave recently reported on a microwave synthesis of a sulfonated SnTBC [12]. Goutermanet al. were the first to report on the synthesis and unusual electronic spectraof the PcPIII compared to PcPV [9, 13]. It became apparentthat upon complexation with the trivalent phosphorous, a bridging nitrogen waslost to form the phosphorous oxide tetrabenzcorroles (PTBC). Since then, a number of octa- andtetrasubstituted PTBC derivatives have been synthesized [14–19]. Most complexessynthesized contained alkyl chain ring substituents. High fluorescence quantumyields [18] and singlet oxygen quantum yields [15] have been reported for thecomplexes. The water-soluble tetrasulphonated PTBC showed good photodynamictherapy towards HeLa cells [19]. For applications in PDT, high tripletlifetimes and yields are desired; however there are no reports on the triplet-statebehavior of the PTBC complexes. In thiswork, we report on PTBC complexes tetra- or octasubstituted with chloride andbromide ring substituents (see Schemes 1 and 2), since the halogens are expected toenhance intersystem crossing, resulting in high triplet yields due to the heavyatom effect. A PTBC derivativecontaining a mixture of butoxy and chloro ring substituents has been reported[17], but no photophysical data has been reported for halogenated PTBCs.

Bottom Line: The Q band absorption spectra of the complexes are red-shifted compared to unsubstituted PTBC.The latter complex shows a large triplet lifetime (1.7 milliseconds), higher than for MPc derivatives.The chlorinated derivatives show good triplet yields (Phi(T) approximately 0.46 and 0.36) and relatively long lifetimes (256 and 452 microseconds), respectively, for 11 and 13.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa.

ABSTRACT
The synthesis of phosphorous oxide triazatetrabenzcorroles (TBC) tetra- (9, 11) or octa- (13) substituted on the ring with halogenated functional groups is reported. The complexes are not aggregated in dimethylsulfoxide (DMSO) and show solubility in solvents such as pyridine. The Q band absorption spectra of the complexes are red-shifted compared to unsubstituted PTBC. The latter complex shows a large triplet lifetime (1.7 milliseconds), higher than for MPc derivatives. The chlorinated derivatives show good triplet yields (Phi(T) approximately 0.46 and 0.36) and relatively long lifetimes (256 and 452 microseconds), respectively, for 11 and 13.

No MeSH data available.