Synthesis and photophysical properties of covalent conjugates of aqua platinum(II) and octacarboxy-substituted zinc phthalocyanine

Abstract

New covalent conjugates of aqua platinum(II) and octacarboxy-substituted zinc phthalocyanine, bearing one, two, three and four aqua platinum moieties on the periphery of the Pc ligand have been synthesized and characterized. The effect of the stepwise introduction of the aqua platinums on the photophysical and photochemical properties of these compounds has been investigated in dimethylsulfoxide solution. It has been found that aqua platinum moieties have only a limited effect on the dynamics of the singlet and triplet excited states, on the ability to sensitize singlet oxygen formation and on the photostability. Each conjugate has a high singlet oxygen quantum yield (ΦΔ 0.51–0.62) and thus retains potential for use as a dual action anticancer drugs by acting as a sensitizer for PDT in addition to the likely chemotherapeutic effects of the Pt(II) complexes.

Synthesis and selected properties of metallo and metal-free 2,3,9,10,16,17,23,24 –octacarboxyphthalocyanines

“…Such a combination of photodynamic activity of phthalocyanine macro-ring and high efficiency of platinum complexes can lead to creation of new effective anticancer drugs. 85,86 Covalent conjugates of aqua platinum(II) and octacarboxy-substituted ZnPc bearing one, two, three and four aqua platinum fragments have been studied for their potential of being used as sensitizers for PDT. The obtained conjugates show higher photostability in DMSO.…”

“…The obtained conjugates show higher photostability in DMSO. 85 From the chosen photophysical parameters for (OH)AlPcOC(Pt) 3 and (OH)AlPcOC(Pt) 4 complexes and zinc octacarboxyphthalocyanine conjugated with platinum it is clear that they are better photosensitizers because of their higher triplet quantum yields than the complexes without platinum. 71,85 In photodynamic therapy PDT a selective accumulation of the photosensitizer in neoplastic cells is required.…”

“…85 From the chosen photophysical parameters for (OH)AlPcOC(Pt) 3 and (OH)AlPcOC(Pt) 4 complexes and zinc octacarboxyphthalocyanine conjugated with platinum it is clear that they are better photosensitizers because of their higher triplet quantum yields than the complexes without platinum. 71,85 In photodynamic therapy PDT a selective accumulation of the photosensitizer in neoplastic cells is required. Many phthalocyanines which for example contain aluminum and zinc as central metals show a high fluorescence quantum yield and due to it the location and distribution of these complexes can be studied with the use of fluorescence imaging methods.…”

Covalent Conjugates of Ammine and Diamine Platinum(II) with Zinc(II) Octacarboxyphthalocyanine

“…As was discussed in our previously reported publication [1] the covalent conjugates (CCs) of cytotoxic Pt II complexes and porphyrinoids are promising candidates for the development of novel dual action anticancer drugs, which can act as photosensitizers and chemotherapeutics.…”

“…[6] As stated in our previously reported paper, [1] its covalent conjugates with aqua platinum(II), bearing one, two, three and four aqua platinum fragments, efficiently sensitize singlet oxygen formation and thus show potential as dual action anticancer drugs. However, strong aggregation of conjugates with aqua platinum impedes their application in aqueous and biological media.…”