The synthesis and photophysical properties of polyether substituted phthalocyanines of potential use in photodynamic therapy
作者:Sarah Foley、Gurnos Jones、Raffaelle Liuzzi、David J. McGarvey、Martin H. Perry、T. George Truscott
DOI:10.1039/a701079f
日期:——
The synthesis, photophysical properties and singlet oxygen
yields of
a range of polyether substituted metallo and free-base phthalocyanines
are reported and discussed in the context of the potential use of these
compounds as alternatives to haematoporphyrin derivatives (HpD) in the
photodynamic therapy (PDT) of cancer. The triplet states of the
phthalocyanines have been studied in benzene and methanol using
nanosecond laser flash photolysis and pulse radiolysis. Triplet state
absorption maxima occur at ca. 510 to 525 nm and the quantum
yields of triplet formation (ϕT) lie in
the range 0.14 to 0.32. Triplet state lifetimes are in the range 26 to
155 µs. Energy transfer from the triplet state
(T1) of the phthalocyanines to ground state molecular oxygen
O23Σg-
to produce singlet oxygen O21ωg is efficient and evidence is
presented for the establishment of an equilibrium in perdeuterated
benzene, eqn. (a).Singlet oxygen quantum yields (ϕΔ),
determined by time resolved near infrared luminescence, are comparable
with the triplet yield suggesting a high proportion of quenching
encounters result in the formation of singlet oxygen.The photophysical properties of the metallophthalocyanines are
dependent on the relative atomic mass and the magnetic properties of the
central metal ion.