No abstract

It is demonstrated that a cationic iridium(III) dichloride phenanthroline complex is capable of CH activation and H/D exchange. It can cleave benzylic and unactivated secondary CH bonds, but exhibits unique selectivity when compared to similar systems that have been studied in the condensed phase. Gas‐phase rate constants and kinetic isotope effects are reported for a variety of substrates and the analysis is supported by DFT calculations at the M06/QZVP level.

Starre π‐konjugierte Brücken wie die Ethinylgruppe sind geeignet, um das π‐System eines Phthalocyanins effektiv an das Leitungsband von TiO2 zu koppeln. Eine Reihe von Zinkphthalocyanin‐Photosensibilisatoren mit Carboxyethinyl‐Ankergruppen wurde synthetisiert. Solarzellen, die mit der gezeigten Verbindung sensibilisiert wurden, zeigten Wirkungsgrade von 5.5 % und 6.1 % unter 100 (1 sun) bzw. 9.5 mW cm−2.

"Green" graphene: For the first time, the covalent attachment of a light-harvesting and electron-donating phthalocyanine to the basal plane of few-layer graphene is reported. Physicochemical characterizations reveal an ultrafast charge separation from the photoexcited phthalocyanine to few-layer graphene followed by a slower charge recombination.

We describe herein the first example of highly exfoliated graphene covalently linked to electron accepting phthalocyanines. The functionalization of the nanocarbon surface with alkylsulfonyl phthalocyanines was attained by means of a "click" chemistry protocol. The new ensemble was fully characterized (thermogravimetric analysis, atomic force microscopy, transmission electron microscopy and Raman, as well as ground-state absorption) and was studied in terms of electron donor-acceptor interactions in the ground and in the excited state. In particular, a series of steady-state and time-resolved spectroscopy experiments demonstrated photoinduced electron transfer from the graphene to the electron-accepting phthalocyanines. This is the first example of an electron donor-acceptor nanoconjugate, that is, few-layer graphene/phthalocyanine, pinpointing the uncommon electron donating character of graphene.

A new phthalocyanine (Pc) bearing bulky peripheral substituents and a carboxylic anchoring group directly attached to the macrocycle has been prepared and used as a sensitizer in DSSCs, reaching 5.57% power conversion efficiency. In addition, an enhanced performance for the TT40 dye, previously reported by us, was achieved in optimized devices, obtaining a new record efficiency with Pc-sensitized cells.

Herein, we describe the synthesis of a zinc(II) alkylsulfonylphthalocyanine-pyrene conjugate, its assembly with highly exfoliated graphite, and the investigation of the photophysical properties of the resulting nanohybrid. The presence of the pyrene unit in the conjugate is decisive in terms of non-covalently immobilizing the electron accepting phthalocyanines onto the basal plane of highly exfoliated graphite.As a matter of fact, strong interactions dominate the electronic properties of the nanohybrid in both the ground and excited states. For example, femtosecond pump probe experiments assist in corroborating an ultrafast charge separation, that is, the generation of the one-electron reduced radical anion of the phthalocyanine and one-electron oxidized graphene after irradiation at 387 nm, followed by slow charge recombination.

Zinc porphyrin solar cell dyes with donor−π–acceptor architectures combine light absorber (π), electron-donor, and electron-acceptor moieties inside a single molecule with atomic precision. The donor−π–acceptor design promotes the separation of charge carriers following optical excitation. Here, we probe the excited-state electronic structure within such molecules by combining time-resolved X-ray absorption spectroscopy at the N K-edge with first-principles time-dependent density functional theory (TD-DFT) calculations. Customized Zn porphyrins with strong-donor triphenylamine groups or weak-donor tri-tert-butylbenzene groups were synthesized. Energetically well-separated N K-edge absorption features simultaneously probe the excited-state electronic structure from the perspectives of the macrocycle and triphenylamine N atoms. New absorption transitions between the macrocycle N atoms and the excited-state HOMO vacancy are observed, and the triphenylamine associated absorption feature blue-shifts, consistent with partial oxidation of the donor groups in the excited state.