Photocontrollable J-aggregation of a diarylethene-phthalocyanine hybrid and its aggregation-stabilized photochromic behavior

Self-assembly of azaphthalocyanine–oligodeoxynucleotide conjugates into J-dimers: towards biomolecular logic gates

Unique spatial self-assembly of azaphthalocyanine–oligonucleotide–fluorescein conjugates can be selectively dissociated by a complementary sequence or coordinating solvent and used for the development of biomolecular logic gates.

Cyclomatrix Polyphosphazene Porous Networks with J-Aggregated Multiphthalocyanine Arrays for Dual-Modality Near-Infrared Photosensitizers

Here, we have developed a kind of cyclomatrix polyphosphazene with excellent photophysical properties and pursued their potential of being organic photosensitizers for dual-modality phototherapy. Briefly, hexachlorocyclophosphazene (HCCP) with D_{3 h} symmetry is adopted as a synthon to attach Zn(II) phthalocyanine (ZnPc) to form dendritic units that are covalently expanded into a soluble porous network through the nucleophilic substitution reaction. Molecular simulation reveals that the multi-ZnPc units around HCCP can be oriented in a side-by-side manner, leading to the remarkably red-shifted and intense absorbance in the near-infrared (NIR) region. To validate the potential in bioapplication, such ZnPc-based polyphosphazenes are assembled by incorporation of polyvinylpyrrolidone (PVP) to produce the uniform nanoparticles with aqueous dispersibility and biocompatibility. From the in vitro results, the PVP-stabilized photosensitizing nanoparticles can undergo the photothermal/photodynamic processes to concurrently generate heat and singlet oxygen for efficiently killing cancer cells upon exposure to a single-bandwidth NIR laser (785 nm). Compared with the known organic photosensitizers, cyclomatrix polyphosphazene would be a promising platform to configure a diversity of reticular arrays with dense and oriented arrangement of dye molecules, leading to their largely enhanced photophysical and photochemical properties.

Evaluation of the Intramolecular Charge-Transfer Properties in Solvatochromic and Electrochromic Zinc Octa(carbazolyl)phthalocyanines

2,3,9,10,16,17,23·24-Octakis-(9H-carbazol-9-yl) phthalocyaninato zinc(II) (3) and 2,3,9,10,16,17,23·24-octakis-(3,6-di-tert-butyl-9H-carbazole) phthalocyaninato zinc(II) (4) complexes were prepared and characterized by NMR and UV-vis spectroscopies, magnetic circular dichroism (MCD), matrix-assisted laser desorption ionization mass spectrometry, and X-ray crystallography. UV-vis and MCD data are indicative of the interligand charge-transfer nature of the broad band observed in 450-500 nm range for 3 and 4. The redox properties of 3 and 4 were probed by electrochemical and spectro-electrochemical methods, which are suggestive of phthalocyanine-centered first oxidation and reduction processes. Photophysics of 3 and 4 were investigated by steady-state fluorescence and time-resolved transient absorption spectroscopy demonstrating the influence of the carbazole substituents on deactivation from the first excited state in 3 and 4. Protonation of the meso-nitrogen atoms in 3 results in much faster deactivation kinetics from the first excited state. Spectroscopic data were correlated with density functional theory (DFT) and time-dependent DFT calculations on 3 and 4.

Preparation, characterization and investigation of photo-physical properties of thiophene-substituted rare-earth bisphthalocyanines

Three bis[octakis-(2-thienyl)phthalocyaninato] rare-earth metal(III) phthalocyanine complexes (Pc[Formula: see text]Pr, Pc[Formula: see text]Sm, Pc[Formula: see text]Gd) were synthesized for the first time. The new compounds were characterized by UV-vis, NMR, FT-IR, mass spectroscopies as well as elemental analysis and electrochemistry. Production of singlet oxygen was also estimated by 9,10-dimethylanthracene method.

Synthesis and spectroscopic properties of photochromic dithienylethene-functionalized subphthalocyanine conjugate

A subphthalocyanine-dithienylethene dyad has been synthesized and characterized by 1H-, [Formula: see text]C-NMR, HR-MS, UV-visible and emission spectroscopy. The results show that photoinduced isomerization of dithienylethene moiety from close-form to opened form can be achieved under visible light using subphthalocyanine as a light-harvesting unit and the fluorescence properties of subphthalocyanine could be modulated by the isomerization state of the dithienylethene moiety.

CB[8] gated photochromism of a diarylethene derivative containing thiazole orange groups

Photochromism in a diarylethene derivative (1O) can be gated by a host–guest interaction where the thiazole orange groups are bound into the hydrophobic cavity of CB[8] in water.

Multiphotochromic molecular systems

We review molecular compounds encompassing several photochromic units with a focus on their functionalities.

Effects of position (α or β) and linker heteroatom (O or S) of substituent on the photophysicochemical behavior of poly(oxyethylene) substituted ZnPcs and assessment of J-aggregation or protonation using TD-DFT computations

A series of zinc phthalocyanines (ZnPcs) tetra-substituted with 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanol () or 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanethiol () at peripheral (β) () and non-peripheral (α) () positions have been synthesized and characterized. The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of these newly synthesized phthalocyanines have been investigated in DMSO. The effects of the position of the substituents on the phthalocyanine skeleton and the nature of the linker heteroatom on their spectroscopic, photophysical and photochemical properties have been determined. The quenching behavior of the zinc phthalocyanines by 1,4-benzoquinone has been studied in DMSO. All of the zinc(ii) Pc complexes ( and ) showed similar electronic absorption spectra in various solvents (chloroform, dichloromethane, DMF, DMSO, THF and toluene). However, complex gave an extra red-shifted band at 742 nm in chloroform and dichloromethane. DFT and TD-DFT computations were performed on the model structures (, and ) to find out the cause of the extra red-shifted Q band (J-type aggregation or protonation of the Pc ring). The computational results showed that monoprotonation of a meso nitrogen atom leads to the formation of this extra band. Photophysical and photochemical measurements indicated that these newly synthesized ZnPc derivatives are promising candidates for use as photosensitizers in the application of PDT.