Light-Driven Molecular Dynamics in Perylenes with Medium-Controlled Emission

Increasing the Orthogonality of 4-Pyridiniophenols: An NMR Study of Their Solvatomagnetism

The 1H- and 13C-NMR spectra of three substituted N-(4-hydroxyphenyl)pyridinium perchlorates, precursors of solvatochromic 4-pyridiniophenolate betaines, were recorded in deuterated acetone, dimethylsulfoxide, and acetonitrile, and their spectral behavior in these solvents was analyzed as evidence of the solute-solvent interactions present in solution. The effect of the increasing orthogonality between the phenolic and pyridinium fragments was clearly evident from the obtained spectra, thus shedding light on the ground-state structures of their deprotonated solvatochromic derivatives and their interactions with the solvent.

One-Step Cascade Synthesis of ortho-bay-Imidazolo-Extended Perylene Biscarboximides (OBISIM) and Their Application as Broad-Spectrum Fluorescent Dyes

A one-step synthesis of perylene dyes with lateral extension by condensed imidazoles in a cascade reaction of sodium amide and benzonitrile is described in which multiple extensions can be controlled by the reaction conditions. The extensions lead to bathochromic shifts in absorption and fluorescence while maintaining high fluorescence quantum yields. The condensed imidazole units cause additional absorption bands in the hypsochromic visible region, resulting in broad-band absorbers. Multiple extensions of the aromatic system enable the NIR spectral approach of the spectra. Energy transfer (fluorescence resonance energy transfer, FRET) of dyads with perylene biscarboximides is very efficient and achieves quantum yields close to unity regardless of the lengths and orientation of the spacer. Applications as broad-band-absorbing fluorescent dyes, such as in solar collectors, are discussed.

Dibenzopleiadiene-embeded polyaromatics via [4 + 3] annulative decarbonylation/decarboxylation

A novel and efficient sequential cross-coupling/annulation strategy is developed to construct structurally and optoelectronically diverse class of dibezopleiadiene-embeded polyaromatics.

Fluorescence and fluorescent dyes

The handling and control of light is becoming more and more attractive in science and technology such as data processing and requires functional chromophores. As a consequence, fluorescent materials are of special importance because they allow the processing of light energy. Thus, basics of fluorescence are reported as prerequisites for planning complex functional structures. Various fluorescent systems are presented beginning with historic observations followed by a detailed discussion of light absorption and emission indicating fluorescent chromophores as molecular resonators; molecular dynamics and intermolecular interactions are leading to complex functional materials.