The synthesis, crystal structure, and electronic properties of perfluoro-isopropyl-substituted perfluorophthalocyanine bearing a copper atom in the central cavity (F(64)PcCu) are reported. While most halogenated phthalocyanines do not exhibit long-term order sufficient to form large single crystals, this is not the case for F(64)PcCu. Its crystal structure was determined by X-ray analysis and linked to the electronic properties determined by electron paramagnetic resonance (EPR). The findings are corroborated by density functional theory (DFT) computations, which agree well with the experiment. X-band continuous-wave EPR spectra of undiluted F(64)PcCu powder, indicate the existence of isolated metal centers. The electron-withdrawing effect of the perfluoroalkyl (R(f)) groups significantly enhances the complexes solubility in organic solvents like alcohols, including via their axial coordination. This coordination is confirmed by X-band (1)H HYSCORE experiments and is also seen in the solid state via the X-ray structure. Detailed X-band CW-EPR, X-band Davies and Mims ENDOR, and W-band electron spin-echo-detected EPR studies of F(64)PcCu in ethanol allow the determination of the principal g values and the hyperfine couplings of the metal, nitrogen, and fluorine nuclei. Comparison of the g and metal hyperfine values of F(64)PcCu and other PcCu complexes in different matrices reveals a dominant effect of the matrix on these EPR parameters, while variations in the ring substituents have only a secondary effect. The relatively strong axial coordination occurs despite the diminished covalency of the C-N bonds and potentially weakening Jahn-Teller effects. Surprisingly, natural abundance (13)C HYSCORE signals could be observed for a frozen ethanol solution of F(64)PcCu. The (13)C nuclei contributing to the HYSCORE spectra could be identified as the pyrrole carbons by means of DFT. Finally, (19)F ENDOR and easily observable paramagnetic NMR were found to relate well to the DFT computations, revealing negligible isotropic hyperfine (Fermi contact) contributions. The single-site isolation in solution and solid state and the relatively strong coordination of axial ligands, both attributed to the introduction of R(f) groups, are features important for materials and catalyst design.

Electron-withdrawing perfluoroalkyl peripheral substituents enhance the photosensitizing properties of metal phthalocyanines while increasing their solubility, thus providing opportunities for advanced characterization of their catalytically-relevant excited states. Optical absorption and electron paramagnetic resonance (EPR) spectroscopy experiments reveal that red light induces the reduction of perfluoroisopropyl-substituted zinc(ii) phthalocyanine (F64PcZn) dissolved in ethanol. A similar photoreduction does not occur in toluene. Furthermore, intense UV irradiation causes the photodegradation of F64PcZn in ethanol, but low power UV illumination favours the formation of the triplet excited state, a prerequisite for new photocatalytic applications. The UV-induced triplet state of F64PcZn is characterized using a combination of transient EPR experiments and DFT computations.

We report on the synthesis of new thermally cross-linkable all-conjugated diblock copolymers composed of a poly(3-hexylthiophene) (P3HT) block and an acrylatefunctionalized polythiophene block. These copolymers are then used in bulk heterojunction (BHJ) solar cells with [6,6]phenyl C61-butyric acid methyl ester (PCBM), and their photovoltaic performances are compared with standard P3HT/PCBM devices. Thermal cross-linking of the functional copolymers/PCBM blends is performed to improve the thermal stability of the active layer. BHJ photovoltaic cells with cross-linkable copolymers and PCBM show initial power conversion efficiencies slightly lower than that of P3HT devices. However, solar cells with cross-linkable copolymers retain more than 85% of their initial power efficiency value after 165 h of thermal annealing (accelerated aging test), whereas the same devices with P3HT retain less than 65% of their initial power efficiency. This improvement of the thermal stability of BHJ photovoltaic cells is the result of the polymer network that hampers PCBM diffusion and phase separation, as confirmed with TEM and AFM analysis of the microscopic morphology. Such an improvement is mostly observed when using a cross-linkable P3HT with a short spacer between the acrylate group and the polythiophene backbone.

A lot of effort has been put into the synthesis of copper complexes with superoxide-dismutase (SOD) activity because of their potential pharmaceutical applications. In this work, we study a model for these so-called SOD mimics (SODm), namely a copper complex of 6-(2-hydroxy-benzaldehyde) hydrazono-as-triazine-3,5-dione, which shows an extremely high SOD-like activity in solution. X-Ray diffraction reveals that the complex adopts a di-copper structure in the solid state. However, in solution, the chloride bridges are broken, forming a mono-copper center as follows from UV/Vis absorption and electron paramagnetic resonance (EPR) experiments. Using pulsed EPR techniques in combination with DFT (density functional theory) computations, the electronic structure of the complex in solution is analyzed in detail and related to its high SOD activity. The structure-activity analysis serves to orient further synthetic efforts to obtain the optimum geometry around the metal essential for SOD-like activity.