1,2,3- versus 1,2-Indeno Ring Fusions Influence Structure Property and Chirality of Corannulene Bowls

Annulated corannulenes <b>3</b>–<b>5</b> form via distinct synthetic pathways: (i) Pd-catalyzed sp³ CH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C–F activation/CH insertion. Crystal structure, redox, and photophysical studies elucidate the differing influence of 1,2,3- versus 1,2-indeno ring fusions. Mono and dianions of <b>3</b>–<b>5</b> are characterized. Resolution of <b>4</b> gives enantiopure forms, allowing assessment of the bowl-inversion barrier

1,2,3- versus 1,2-Indeno Ring Fusions Influence Structure Property and Chirality of Corannulene Bowls

Annulated corannulenes <b>3</b>–<b>5</b> form via distinct synthetic pathways: (i) Pd-catalyzed sp³ CH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C–F activation/CH insertion. Crystal structure, redox, and photophysical studies elucidate the differing influence of 1,2,3- versus 1,2-indeno ring fusions. Mono and dianions of <b>3</b>–<b>5</b> are characterized. Resolution of <b>4</b> gives enantiopure forms, allowing assessment of the bowl-inversion barrier

1,2,3- versus 1,2-Indeno Ring Fusions Influence Structure Property and Chirality of Corannulene Bowls

Annulated corannulenes <b>3</b>–<b>5</b> form via distinct synthetic pathways: (i) Pd-catalyzed sp³ CH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C–F activation/CH insertion. Crystal structure, redox, and photophysical studies elucidate the differing influence of 1,2,3- versus 1,2-indeno ring fusions. Mono and dianions of <b>3</b>–<b>5</b> are characterized. Resolution of <b>4</b> gives enantiopure forms, allowing assessment of the bowl-inversion barrier

1,2,3- versus 1,2-Indeno Ring Fusions Influence Structure Property and Chirality of Corannulene Bowls

Annulated corannulenes <b>3</b>–<b>5</b> form via distinct synthetic pathways: (i) Pd-catalyzed sp³ CH insertion, (ii) Pd-catalyzed aryl coupling, and (iii) silyl cation-promoted C–F activation/CH insertion. Crystal structure, redox, and photophysical studies elucidate the differing influence of 1,2,3- versus 1,2-indeno ring fusions. Mono and dianions of <b>3</b>–<b>5</b> are characterized. Resolution of <b>4</b> gives enantiopure forms, allowing assessment of the bowl-inversion barrier

Kinetics of the Regeneration by Iodide of Dye Sensitizers Adsorbed on Mesoporous Titania

Regeneration of dye sensitizer molecules by reducing species contained in the electrolyte is a key mechanism in liquid dye-sensitized solar cells because it competes kinetically with a detrimental charge recombination process. Kinetics of the reduction by iodide ions of the oxidized states (S⁺) of two Ru^II complex dyes and four organic π-conjugated bridged donor–acceptor sensitizers were examined as a function of the electrolyte concentration. Results show that two different cases can be distinguished. A sublinear behavior of the regeneration rate and a plateau value reached at high bulk iodide concentrations were found for N820 ruthenium dye and interpreted as being due to an associative interaction involving the formation of (S⁺, I^–)···I^– surface complexes prior to the reaction. On the other hand, feeble reaction rates at low electrolyte concentrations and a superlinear behavior are observed predominantly for the organic dyes, pointing to a repulsive interaction between the dyed surface and iodide anions. At higher iodide bulk concentration, a linear behavior is reached, providing an estimate of a second-order rate constant. A correlation of these two opposite behaviors with the structure of the dye is observed, emphasizing the role of sulfur atoms in the association of I^– anions in the dye-sensitized layer. These findings allow for a better understanding of the dye–electrolyte interaction and of the effect of the iodide concentration on the photovoltaic performances of dye-sensitized solar cells

[3+3] Cyclocondensation of Disubstituted Biphenyl Dialdehydes: Access to Inherently Luminescent and Optically Active Hexa-substituted <i>C</i>₃‑Symmetric and Asymmetric Trianglimine Macrocycles

A general synthetic route to inherently luminescent and optically active 6-fold substituted C₃-symmetric and asymmetric biphenyl-based trianglimines has been developed. The synthesis of these hexa-substituted triangular macrocycles takes advantage of a convenient method for the synthesis of symmetrically and asymmetrically difunctionalized biphenyl dialdehydes through a convergent two-step aromatic nucleophilic substitution-one-pot Suzuki-coupling reaction protocol. A modular [3+3] diamine-dialdehyde cyclocondensation reaction between both the symmetrically and asymmetrically difunctionalized-4,4′-biphenyldialdehydes with enantiomerically pure (1<i>R</i>,2<i>R</i>)-1,2-diaminocyclohexane was employed to construct the hexa-substituted triangular macrocycles. B97-D/6-311G­(2d,p) density functional theory determined structures and X-ray crystallographic analysis reveal that the six substituents appended to the biphenyl legs of the trianglimine macrocycles adopt an alternating conformation not unlike the 1,3,5-alternate conformation observed for calix[6]­arenes. Reduction of the imine bonds using NaBH₄ afforded the corresponding 6-fold substituted trianglamine without the need to alkylate the amine nitrogen atoms which could hinder their later use as metal coordination sites and without having to introduce asymmetric carbons