Synthesis of water soluble axially disubstituted silicon (IV) phthalocyanines with alkyne & azide functionality

Abstract

Phthalocyanines (Pcs) are a class of photosensitizers (PSs) with a strong tendency to aggregate in aqueous solutions, which has a negative influence on their photosensitizing ability for photodynamic therapy. Four new axially disubstituted, non-aggregated silicon phthalocyanines (SiPcs), containing azide or alkyne functional groups have been synthesized and characterized. The method of synthesis is based on the reaction of silicon phthalocyanine dichloride with variable length poly(ethylene glycol) (PEG) chains in the presence of NaH. All synthesized dyes are highly soluble in alcohols, THF, CH 2Cl2, acetone, DMF and other common polar organic solvents, with the PEGylated silicon phthalocyanines (SiPcs) also being soluble in water. Photophysical and electrochemical properties of the dyes have been investigated. The presence of alkyne or azide groups in the phthalocyanine dyes, coupled with their high aqueous solubility, make these compounds useful as building blocks in copper catalyzed Huigsen azide-alkyne cycloaddition reactions (i.e. click chemistry).

Synthesis of a poly(ethylene glycol) galloyl sensitizer tip for an ’all‐in‐one' photodynamic device

“…Short chain PEG groups, such as [–O(CH 2 CH 2 O) 3 ⋅ CH 3 ] when bonded to sensitizers can reduce self‐aggregation , and retain some propensity to localize in cell membranes compared to unsubstituted sensitizers . Therefore, we surmised that a galloyl unit carrying three PEG groups could be bonded to pheophorbide silica end‐tips of a pointsource PDT device.…”

Mini-review: fluorescence imaging in cancer cells using dye-doped nanoparticles

“…In 2015, Bandera and colleagues synthesized novel silicon phthalocyanine derivatives equipped with azide or alkyne functionality to be able to use the dyes in "click" chemistry, which allows the dyes to be used in an engineered nanodevice for cancer theranostics. 87 In 2013, a water soluble porphyrin (THPP), with zinc metal as the central atom was developed and it showed an increase in in vitro photodynamic therapy activity by 2-3 times when compared to photofrin. 88 Photodynamic therapy relies on the ability of the fluorophore, when excited at the appropriate wavelength of light, to generate a reactive oxygen species (singlet oxygen) from molecular oxygen through an intersystem crossing.…”

From chemical curiosity to versatile building blocks: unmasking the hidden potential of main-group phthalocyanines in organic field-effect transistors

“…In the case of (HO) 2 -SiPc, it can also be prepared directly from DIII. As well, the two axial positions of the tetravalent metal centres can be displaced by various substituents such as phenyl, 132 phenoxy, 25,126,128,131 siloxy, 121,126,131,133 alkynyl, 134 diethylaminophenoxyethoxy, 135 1benzylpiperidin-4-oxy, 136 and even graphene 137 or benzyl ester dendrimers. 138 For this reason, a number of symmetrically and asymmetrically substituted X 2 -SiPc and X 2 -GePc derivatives have been developed over the years.…”