Novel metallophthalocyanines with bulky 4-[3,4-bis(benzyloxy)benzylidene]aminophenoxy substituents

Abstract: Novel metallophthalocyanines substituted with four peripheral 4-[3,4-bis(benzyloxy)benzylidene]aminophenoxy groups were prepared by Schiff base condensation of 4-aminophenoxy-substituted phthalocyanines with 3,4-bis(benzyloxy)benzaldehyde. The structures were elucidated with elemental analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectrometry, and matrix assisted laser desorption ionization-time of flight spectrometry along with Ultraviolet–Visible spectrophotometry. In the studied concentration range of 1–10 × 10⁻⁶ M, no appreciable aggregation of the new species was detected. In tetrahydrofuran, the fluorescent quantum yield Φ_F value of the zinc phthalocyanine was lower than the unsubstituted ZnPc (Φ_F = 0.25) due to the peripheral [3,4-bis(benzyloxy)benzylidene]aminophenoxy substituents which surely caused fluorescence quenching. The zinc phthalocyanine showed fluorescent quenching by the addition of 1,4-benzoquinone in tetrahydrofuran with obedience to Stern–Volmer kinetics. Graphic abstract: [Figure not available: see fulltext.]