No abstract

No abstract

No abstract

State-of-the-art computational tools were used to investigate the photophysical properties of polyfluorinated phthalocyanines (Pc) to predict their potential use as photosensitizers in photodynamic therapy. The main factors, such as the identity of the metal ion, the effect of substituents, the environment, and solvent effects that enhance the efficiency of phthalocyanines as photosensitizers, were considered, particularly taking into account their influence on the triplet-state energy and intersystem crossing probability. The population of the triplet state ultimately determines the phthalocyanine's propensity to activate singlet oxygen, which is responsible for inducing death of the cancer cell. Time-dependent density functional theory was used to elucidate the photophysical properties of pentafluorobenzyloxysubstituted phthalocyanines (R 2 Pc) as well as their unsubstituted analogues. Vibrational and dynamic effects influencing the absorption and emission spectra were included by sampling the potential energy surfaces via the Wigner distribution approach. Furthermore, the intersystem crossing pathways were analyzed by using the singlet−triplet band gap and the spin−orbit coupling constant. Finally, the singlet oxygen generation capability was experimentally verified for the R 2 −ZnPc complex both in DMSO and in different ratios of DMSO/water mixtures. The singlet oxygen quantum yield of R 2 -ZnPc in DMSO was also evaluated and compared with that of the unsubstituted ZnPc.

No abstract

An unsymmetrical zinc phthalocyanine with ferrocenylcarborane linked to the phthalocyanine ring through a phenylethynyl spacer was designed for organic field-effect transistor (OFET). The unsymmetrical phthalocyanine derivatives were characterized using a wide range of spectroscopic and electrochemical methods. In particular, the ferrocenylcarborane structure was unambiguously revealed based on the single-crystal X-ray diffraction analysis. In-depth investigations of the electrochemical properties demonstrated that the ferrocenylcarborane insertion extended the electrochemical character of ferrocenylcarborane-substituted phthalocyanine (7). Moreover, in the anodic potential scans, the oxidative electropolymerization of etynylphthalocyanine (6) and 7 was recorded. To clarify the effect of the insertion of ferrocenylcarborane (2) on the field-effect mobility, solution-processed films of 2, 6, and 7 were used as an active layer to fabricate the bottom-gate top-contact OFET devices. An analysis of the output and transfer characteristics of the fabricated devices indicated that the phthalocyanine derivative functionalized with ferrocenylcarborane moiety has great potential in the production of high-mobility OFET.

The synthesis and properties of ‘3:1’ phthalocyanines, in which three of the benzenoid rings are similarly substituted whereas the fourth is differently substituted or is replaced by a heteroaromatic ring, are overviewed with an emphasis on contributions from the group at the University of East Anglia. The synthesis of novel hepta-alkylated tribenzo-imidazolo[4,5]porphyrazines as metal-free derivatives by cross-condensation of 3,6-dialkylphthalonitrile and 1-alkyl-4,5-dicyanoimidazole is described. The compounds show Q band absorption at 701 and 660 nm. The Q band is thus hypsochromically shifted relative to the Q band absorption of the corresponding metal-free octa-alkylphthalocyanines and the metal-free hexa-alkylated derivatives of tribenzo-pyridino[3,4]porphyrazines, tribenzo-thiopheno[2,3]porphyrazines and tribenzo-thiopheno[3,4]porphyrazines. Examples of the tribenzo-imidazolo[4,5]porphyrazines have been deposited as smooth, even and transparent spin-coated films with broad-band absorption in the region 600-750 nm.

No abstract