Patricia Remón

Small dyes are indispensable tools for probing biological processes. Among them, Nile Red (NR) is widely used for imaging lipid‐rich environments. However, the structural diversification of its phenoxazine core remains limited. Herein, we exploit B─N/C─C isosterism to connect the western and eastern fragments of NR through a B─N linkage, enabling the design of NR‐inspired boronic acid‐derived salicylidenehydrazone (NR‐BASHY) dyes with enhanced structural and functional versatility. This strategy allows the modular one‐pot synthesis of NR‐BASHY dyes, which exhibit promising photophysical properties. These include intense absorption ( ε up to 50,800 M ^–1 cm ^–1 ) and high brightness ( ε × Φ _f up to 17,000 M ^–1 cm ^–1 ) and a pronounced solvatofluorochromism with emission spanning the red to near‐infrared spectral region. In strong contrast to NR, NR‐BASHY can act as photosensitizers, featuring efficient singlet‐oxygen generation ( Φ _Δ up to 0.8) and photoinduced cytotoxicity against the U87 glioblastoma cell line in the submicromolar range (IC ₅₀ ca. 0.5 μM), while maintaining low dark toxicity (>100 μM). Moreover, the modular architecture of NR‐BASHY dyes enables click‐reaction mediated bioconjugation with the GV1001 peptide, highlighting the potential of this platform for targeted bioimaging applications.

A photoactive supramolecular five-component system mimics essential features of the natural vision process.

All-photonic and reversible switching of the composition of a supramolecular network is enabled by employing a dithienylethene guest.

In this Minireview conceptual approaches towards the communication between (supra)molecular species are illustrated. The reviewed mechanisms include photophysical communication through energy transfer and communication mediated by chemical species that are released from precursors upon application of an external stimulus. The focus is on the stimulation by (reversible) photoreactions. Special attention has been given to supramolecular systems that illustrate the idea of chemical communication and information transfer in a very descriptive manner.

A new fluorescent acrylamide-type monomer bearing a hydrogen bonding- and polarity-sensitive benzocoumarin fluorophore was synthesized. The absorption spectra, fluorescence spectra, and fluorescence lifetime of a model compound were measured in ten solvents with different hydrogen-bonding abilities and polarities to investigate the sensitivity of the fluorophore to the surrounding environment. These spectroscopic studies demonstrated that the fluorophore emits stronger fluorescence in more protic, polar environments. A fluorescent polymeric thermometer was prepared from N-isopropylacrylamide and the new fluorescent monomer, and it showed good functionality in aqueous solution (e.g., high sensitivity to temperature changes and high chemical stability), indicating the applicability of the herein developed fluorescent monomer for use in functional sensors.

A molecular triode that is operated by pH and light can be implemented with spiropyrans.

We show that FRET between Pacific Blue (PB) and Alexa488 (A488) covalently attached to a DNA scaffold can be reversibly controlled by photochromic switching of a spiropyran derivative. With the spiropyran in the closed spiro isomeric form, FRET occurs freely between PB and A488. UV-induced isomerization to the open merocyanine form shuts down the FRET process by efficient quenching of the PB excited state. The process is reversed by exposure to visible light, triggering the isomerization to the spiro isomer.

A new approach towards the rapid identification of quality binders to cucurbiturils—those that combine high affinity with high selectivity for a particular homologue—was developed. The assay exploits macrocycle‐specific optical fingerprints (colorimetric or fluorimetric) of carefully selected indicators dyes. The screening of a guest library revealed known (e.g., adamantane derivatives) and new (e.g., terpenes) quality binders. The predictive power of the assay was underpinned by the modeling of the involved thermodynamic equilibria.

Aminonaphthalimide–BODIPY energy transfer cassettes were found to show very fast (k_EET≈10¹⁰–10¹¹ s⁻¹) and efficient BODIPY fluorescence sensitization. This was observed upon one‐ and two‐photon excitation, which extends the application range of the investigated bichromophoric dyads in terms of accessible excitation wavelengths. In comparison with the direct excitation of the BODIPY chromophore, the two‐photon absorption cross‐section δ of the dyads is significantly incremented by the presence of the aminonaphthalimide donor [δ≈10 GM for the BODIPY versus 19–26 GM in the dyad at λ_exc=840 nm; 1 GM (Goeppert–Mayer unit)=10⁻⁵⁰ cm⁴ s molecule⁻¹ photon⁻¹]. The electronic decoupling of the donor and acceptor, which is a precondition for the energy transfer cassette concept, was demonstrated by time‐dependent density functional theory calculations. The applicability of the new probes in the one‐ and two‐photon excitation mode was demonstrated in a proof‐of‐principle approach in the fluorescence imaging of HeLa cells. To the best of our knowledge, this is the first demonstration of the merging of multiphoton excitation with the energy transfer cassette concept for a BODIPY‐containing dyad.