No abstract

We describe the preparation of a battery of chiral Zn(II) phthalocyanines with an AABB substitution pattern through cross-condensation of different chiral, binaphthyloxy-linked bisphthalonitriles and (non)functionalized single phthalonitriles. All the compounds are endowed with reactive groups (halogen and/or ethynyl moieties) that will allow us to prepare customized amphiphilic phthalocyanines. Preliminary self-assembly studies in solution have been performed by UV−vis and circular dichroism experiments.

We describe here the preparation of a series of trans‐ABAB Zn(II) phthalocyanines (ZnPcs, which combine several interesting features. First, these compounds present high solubility and hindered aggregation, due to the functionalization of two facing isoindole constituents (B) of the ZnPc with bis(trifluoromethylphenyl) units. Second, the other two isoindoles (A) bear extra‐annulated phthalimide units containing different substituents in the nitrogen positions, this feature results in a collinear arrangement of a variety of functional groups. Some of these collinearly functionalized ZnPcs are interesting building blocks for constructing either homo‐ or heteroarrays containing ZnPc units. Furthermore, the amphiphilic nature of some members of the series renders them interesting candidates for photosensitization of singlet oxygen. Photophysical studies on a model compound of the series have shown that these molecules are efficient singlet oxygen photosensitizers in both polar and apolar media, with 1O2 quantum yields (φΔ) as high as 0.74.

Non-aggregated, crosswise ZnPcs functionalized with bis(trifluoromethyl)phenyl groups in facing isoindoles have proved efficient photosensitizers for singlet oxygen generation.

Herein, the photodynamic activity of phthalocyanine (pc)‐assembled nanoparticles against bacterial strains is demonstrated. The photosensitizers (PS) studied in this work are two chiral ZnIIPcs (PS‐1 and PS‐2), with an AABB geometry (where A and B refer to differently substituted isoindole constituents). They contain differently functionalized, chiral binaphthyloxy‐linked A isoindole units, which determine the hydrophobicity of the system, and cationic methyl pyridinium moieties in the other two isoindoles to embody hydrophilicity. Both compounds have the ability to self‐assemble into nanoparticles in aqueous media and have proved efficient in the photo‐inactivation of Staphylococcus aureus and Escherichia coli, selected as models of Gram‐positive and Gram‐negative bacteria. The average size of the nanoparticles was determined by substitution at the binaphthyl core and, in turn, influences the toxicity of the PS. Thus, PS‐1, presenting a nonsubstituted binaphthyl core, forms larger nanoparticles with a larger cationic surface than the octyl‐functionalized PS‐2. Although both PSs present similar structure and photophysical features, the self‐assembled nanostructures of PS‐1 are more effective at killing both types of strain, showing an outstanding photo‐inactivation capacity with the Gram‐negative E. coli.