Tuning the Acceptor Unit of Push-Pull Porphyrazines for Dye-Sensitized Solar Cells.

A family of four push-pull porphyrazines of AB type, where each unit A contains two peripheral propyl chains and the unit B is endowed with a carboxylic acid, were prepared. The carboxylic acid was attached to the β-position of the pyrrolic unit, either directly (Pz ), or through cyanovinyl (Pz ) and phenyl (Pz ) groups. The fourth Pz () consisted in a pyrazinoporphyrazine wherein the dinitrogenated heterocycle provided intrinsic donor-acceptor character to the macrocycle and contained a carboxyphenyl substituent.

Panchromatic Photosensitizers Based on Push-Pull, Unsymmetrically Substituted Porphyrazines.

A series of five push-pull porphyrazines of A B type, in which unit B is an isoindole 4-carboxylic acid, has been prepared. The units A have been endowed with thioether, amine, ether and alkyl functions, either directly attached to the β-position of the pyrrolic units, or connected to the porphyrazine core through p-substituted phenyl groups. Attaching the electron-donor functions to the porphyrazine periphery produces strong perturbations in the electronic and redox properties of the dyes.

Tri- and hexaferrocenyl-substituted subphthalocyanines in the quest for the optimum electron donor-acceptor distances.

Three and six ferrocenyl subunits have been attached to the periphery of subphthalocyanines (SubPcs). Unlike axially coordinated ferrocenes, peripherally-bonded ferrocenes have an impact on the electronic features of SubPcs, which show a 44 to 70 nm red-shift of their Q-bands. The unusually deep and narrow ferrocenyl-SubPc is able to host C, giving rise to atypical SubPc•C cocrystallates, through a combination of concave-convex and convex-convex π-π interactions.

Phthalocyanine-Perylenediimide Cart Wheels.

The electronic features of Zn(II) and Ru(II) phthalocyanines (Pcs) have been modulated by direct peripheral attachment of up to eight ferrocenes. The presence of peripheral ferrocenes noticeably impacts the electronic properties of the corresponding ZnPc and RuPc complexes 7, 12 and 9, 15, respectively-a notion that is supported by optical spectroscopy with bathochromic shifts of up to 8-10 nm per ferrocene unit. Cyclic voltammetry and optical spectroscopy reveal long-distance (10-11 bonds) electronic interaction between ferrocene units.

Tuning electron donor-acceptor hybrids by alkali metal complexation.

A zinc phthalocyanine endowed with four [18]-crown-6 moieties, ZnPcTeCr, has been prepared and self-assembled with either pyridyl-functionalized perylenebisimides (PDI-Py) or fullerenes (C60-Py) to afford a set of novel electron donor-acceptor hybrids. In the case of ZnPcTeCr, aggregation has been circumvented by the addition of potassium or rubidium ions to lead to the formation of monomers and cofacial dimers, respectively. From fluorescence titration experiments, which gave rise to mutual interactions between the electron donors and the acceptors in the excited state, the association constants of the respective ZnPcTeCr monomers and/or dimers with the corresponding electron acceptors were derived.

Ultrafast photoinduced processes in subphthalocyanine electron donor-acceptor conjugates linked by a single B-N bond.

We have prepared two different subphthalocyanine conjugates by linking these macrocycles either to an electron-accepting perylene diimide or to an electron-donating phenothiazine through a single B-N covalent bond. The short spacing between the two active building blocks results in ultrafast photoinduced electron-transfer reactions.

Cyclopentadienylruthenium π complexes of subphthalocyanines: a "drop-pin" approach to modifying the electronic features of aromatic macrocycles.

Facing facts: Coordination of Cp*Ru (Cp*=C(5)Me(5)) to the concave and convex π surfaces of subphthalocyanines constitutes a new approach to the functionalization of subazaporphyrins. While the convex face shows higher reactivity, coordination to the concave side produces a stronger diatropic influence on the Cp* ligand and a greater perturbation of the macrocyclic π-electronic features.