pH-Sensitive subphthalocyanines and subazaphthalocyanines

Abstract

Novel pH sensitive fluorophores have been synthesized and studied by electrochemistry, UV-vis and fluorescence spectroscopy in solution and microemulsions.

Subphthalocyanines as Efficient Photosensitizers with Nanomolar Photodynamic Activity against Cancer Cells

“…The obtained Φ Δ and Φ F values for a particular compound in both solvents correspond well to each other, which supports the correctness of the measured values. Φ F values of 1-Tyr and 1-CE were similar to the values published for unsubstituted SubPc­(OPh) (0.18 in acetonitrile) and alkyl-substituted SubPc­(Cl) (0.18 in MeOH); however, this cannot be taken absolutely because different solvents and methods were employed. Determined Φ Δ and Φ F values obeyed the heavy atom rule; thus, strong enhancement of a spin-forbidden process induced by the presence of an atom with a high atomic number was observed for triiodinated SubPcs ( 2-Cl , 2-CE , 2-Tyr , and 2-TyrBoc ), which possessed very low Φ F values not exceeding 0.04 and high Φ Δ values in the range of 0.49–0.86.…”

“…On the contrary, peripheral groups shifted the Q-band to the red. In particular, the EtS- derivatives exhibited the most remarkable bathochromic shift of their Q-band of approximately 10 and 15 nm, compared to those of halogen-substituted SubPcs and unsubstituted SubPc, respectively.…”

“… a Log P ( n -octanol/PBS, pH 7.4), absorption maximum (λ A ), extinction coefficient in THF (ε), emission maximum (λ F ), fluorescence quantum yield (Φ F ), fluorescence lifetime (τ F ), singlet oxygen quantum yield (Φ Δ ), not soluble (ns). Fluorescence lifetimes (τ F ) were determined using an HPL laser (506 nm). b Determined by the absolute method using an integrating sphere. c Determined by the reference method using rose bengal (Φ Δ = 0.68 in EtOH) and zinc phthalocyanine (Φ Δ = 0.53 in THF) as references. d Data from ref . e Data from ref . f No compound detected in the water phase. g Larger experimental error due to the weak fluorescence signal. h Decomposition observed. …”

“…As a result, SubPcs are less likely to aggregate, , which is a common undesirable property of Pcs and porphyrins . Aggregation is responsible for quenching of excited states and loss of photophysical properties. , Because of their 14 π-delocalized electrons, SubPcs possess interesting spectral and photophysical properties that are being investigated for many applications such as organic photovoltaics, organic light-emitting diodes, and fluorescent dyes. ,, These versatile tunable molecules enable attachment of different substituents to both peripheral and axial positions. This advantage together with their straightforward synthesis makes them a good alternative for other intensively studied PSs such as, e.g., BODIPY dyes. , Few recent literature reports have suggested the possibility of using SubPcs in PDT to kill bacteria , or for treatment of cancer. ,− Theranostic SubPcs combining a therapeutic (photodynamic) effect with diagnostics (cell imaging) have also been described .…”

“…15,16 Because of their 14 π-delocalized electrons, SubPcs possess interesting spectral and photophysical properties that are being investigated for many applications such as organic photovoltaics, organic light-emitting diodes, and fluorescent dyes. 11,17,18 These versatile tunable molecules enable attach- ment of different substituents to both peripheral and axial positions. This advantage together with their straightforward synthesis makes them a good alternative for other intensively studied PSs such as, e.g., BODIPY dyes.…”