Insights into extended coupled polymethines through the investigation of dual UV-to-NIR acidochromic switches based on heptamethine-oxonol dyes.

A series of heptamethine-oxonol dyes featuring different heterocyclic end groups were designed with the aim to explore structure-property relationships in π-extended coupled polymethines. These dyes can be stabilised under three different protonation states, affording dicationic derivatives with an aromatic core, cationic heptamethines, and zwitterionic bis-cyanine forms. The variation of the end groups directly impacts the absorption and emission properties and mostly controls reaching either a colourless neutral dispirocyclic species or near-infrared zwitterions.

Micellar catalysis: a green solution to enable undirected and mild C-H activation of (oligo)thiophenes at the challenging β-position.

The unexpected potential of micellar medium to achieve challenging β-selective direct arylation of (oligo)thiophenes is reported. Thanks to the use of a water/surfactant solution in combination with natural feedstock-derived undecanoic acid as an additive, this high-yielding C-H coupling could be performed regioselectively at room temperature.

A Strategy to Design Substituted Tetraamino-Phenazine Dyes and Access to an NIR-Absorbing Benzoquinonediimine-Fused Quinoxaline.

The straightforward access to N- or C-substituted dinitro-tetraamino-phenazines () is enabled in oxidative conditions via formation of two intermolecular C-N bonds from accessible 5-nitrobenzene-1,2,4-triamine precursors. The photophysical studies revealed green absorbing and orange-red emitting dyes, with enhanced fluorescence in the solid state. Further reduction of the nitro functions led to the isolation of a benzoquinonediimine-fused quinoxaline (), which undergoes diprotonation to form a dicationic coupled trimethine dye absorbing beyond 800 nm.

Lysosomes Targeting pH Activable Imaging-Guided Photodynamic Agents.

Photodynamic therapy (PDT) is a photochemistry-based medical treatment combining light at a specific wavelength and a photosensitizer (PS) in the presence of oxygen. Application of PDT as a conventional treatment is limited and clearly the approval in clinics of new PS is challenging. The selective accumulation of the PS in the targeted malignant cells is of paramount importance to reduce the side effects that are typical of the current worldwide approved PS.