Fluorescence exclusively occurs from the lowest excited state of a given multiplicity according to Kasha's rule. However, this rule is not obeyed by handful anti-Kasha fluorophores whose underlying mechanism still understood merely on phenomenological basis. This lack understanding prevents rational design and property-tuning fluorophores. Here, we propose model explaining photophysical properties an archetypal fluorophore, azulene, based its ground- excited-state (anti)aromaticity. We...

A comprehensive investigation of the photophysical properties and photochemistry rose bengal provided detailed information about kinetics optical all major intermediates involved.

Reactive intermediates formed upon irradiation of chromophoric dissolved organic matter (CDOM) contribute to the degradation various contaminants in surface waters. Besides well-studied "short-lived" photooxidants, such as triplet state CDOM (3CDOM*) or singlet oxygen, CDOM-derived "long-lived" photooxidants (LLPO) have been suggested key players transformation electron-rich contaminants. LLPO were hypothesized mainly consist phenoxyl radicals derived from phenolic moieties CDOM. To test...

Methyl viologen hexafluorophosphate (MV2+·2PF6–) and dodecamethylbambus[6]uril (BU6) form crystals in which the layers of dications alternate with those a 1:2 supramolecular complex BU6 PF6–. This arrangement allows for one-electron reduction MV2+ ions upon UV irradiation to MV+• radical cations within crystal structure half-lives several hours air. The mechanism this photoinduced electron transfer solid state origin long-lived charge-separated were studied by steady-state transient...

Abstract Here we present a method to reduce the photobleaching of fluorescent proteins and associated phototoxicity. It exploits photophysical process known as reverse intersystem crossing, which induce by near-infrared co-illumination during fluorophore excitation. This dual illumination reduces effects 1.5–9.2-fold, can be easily implemented on commercial microscopes is effective in eukaryotic prokaryotic cells with wide range proteins.

Precise control over excited‐state multiplicity is a powerful strategy for controlling photochemical reactivity, particularly in multimodal systems where different multiplicities lead to distinct reaction products. Here, we present multiplicity‐sensitive, multimodal, fulgimide‐based system capable of three‐state photoswitching both solution and solid state. With the aim suppressing singlet‐state sensitization, rationally designed an intramolecularly sensitized that enables triplet‐exclusive...

Photochemical generation of dibenzosilacyclohept-4-yne 3 from the corresponding cyclopropenone 1 and its copper-free click reactions are reported. Steady-state irradiation, kinetic, transient absorption spectroscopy studies revealed that strained alkyne is rapidly (<5 ns) efficiently (Φ = 0.58–0.71) photoreleased undergoes remarkably fast, selective, high-yielding 1,3-dipolar cycloaddition with benzyl azide (∼20 M–1 s–1) or [4 + 2] inverse-electron-demand Diels–Alder reaction...

Aromatic amines are relevant aquatic organic contaminants whose photochemical transformation is affected by dissolved matter (DOM). The goal of this study to elucidate the underlying mechanism inhibitory effect DOM on such reactions. selected model aromatic amine, 4-(dimethylamino)benzonitrile (DMABN), was subjected laser flash photolysis in presence and absence various photosensitizers. produced radical cation (DMABN•+) observed react with several phenols different types a time scale ∼100...

Abstract N ‐Trifluoromethylated organics may be applied in drug design, agrochemical synthesis, and materials science, among other areas. Yet, despite recent advances the synthesis of aliphatic, cyclic heterocyclic ‐trifluoromethyl compounds, no strategy based on trifluoromethyl nitrene has hitherto been explored. Here we describe formation triplet from azidotrifluoromethane, a stable safe‐to‐use precursor, by visible light photocatalysis. The addition CF 3 to alkenes via biradical...

Catalyst recovery is an integral part of photoredox catalysis. It often solved by adding another component-a sacrificial agent-whose role to convert the catalyst back into its original oxidation state. However, additive may cause a side reaction thus decreasing selectivity and overall efficiency. Herein, we present novel approach towards chemoselective photooxidation reactions based on suitable solvent-acetonitrile acting simultaneously as electron acceptor for recovery, anaerobic...

Protected 5-(hydroxymethyl)uracil nucleotides bearing photocleavable groups as building blocks for polymerase synthesis of photocaged DNA.

Photosensitized cross-linking of N-acetyl derivatives tryptophan and tyrosine by rose bengal in phosphate buffer saline was studied steady-state absorption emission spectroscopy, nanosecond transient chemical analyses. These amino acids undergo to form dimeric higher oligomeric products under anoxic conditions with as a sacrificial oxidant, whereas they react predominantly singlet oxygen produced aerated solutions. This investigation provides comprehensive view into the first steps...

We will present a new method to reduce the photobleaching of fluorescent proteins and associated phototoxicity. Our exploits photophysical process known as reverse intersystem crossing, which we induce by near-infrared co-illumination during fluorophore excitation. This dual illumination typically reduces effects 4-fold, can be easily implemented on commercial microscopes is effective in eukaryotic prokaryotic cells with wide range proteins.

Three symmetrically and three unsymmetrically substituted cibalackrot (7,14-diphenyldiindolo[3,2,1-de:3',2',1'-ij][1,5]naphthyridine-6,13-dione, 1) dyes carrying two derivatized phenyl rings have been synthesized as candidates for molecular electronics especially singlet fission, a process of interest solar energy conversion. Solution measurements provided triplet excitation energies fluorescence yields lifetimes; conformational properties were analyzed computationally. The are close to...

Fluorescein, eosin Y, and rose bengal are dyes used in clinical medicine considered (photo-)chemically stable. Upon extensive irradiation with visible light aqueous solutions, we found that these compounds release carbon monoxide (CO) - a bioactive gasotransmitter 40-100% yields along the production of low-mass secondary photoproducts, such as phthalic formic acids, multistep degradation process. Such photochemistry should be applications dyes, they could also utilized visible-light...

Abstract Organic solar cells have been continuously studied and developed through the last decades. A major step in their development was introduction of fused‐ring non‐fullerene electron acceptors. Yet, beside high efficiency, they suffer from complex synthesis stability issues. Perylene‐based acceptors, contrast, can be prepared only a few steps display good photochemical thermal stability. Herein, we introduce four monomeric perylene diimide acceptors obtained three‐step synthesis. In...

The oxidizing ability of peroxodisulfate upon complexation inside the Bambusuril macrocycle cavity is inhibited. This dianionic agent can be released on demand from its stable 1:1 complex in water (log Ka =6.9 m-1 ) by addition a more strongly bound anion, such as iodide =7.1 ), which also delivered situ irradiation 4-hydroxyphenacyl derivative with spatial and temporal precision. properties ions liberated recover take part subsequent chemical transformations.

Abstract Leaving groups attached to the meso ‐methyl position of many common dyes, such as xanthene, BODIPY, or pyronin derivatives, can be liberated upon irradiation with visible light. However, course phototransformations photoactivatable systems quite complex and identification reaction intermediates even products is often neglected. This paper exemplifies photochemistry a 9‐dithianyl‐pyronin derivative, which undergoes an oxidative transformation at ‐position give 3,6‐diamino‐9 H...

This study employs a combination of spectroscopic techniques, including absorption, photoluminescence (PL), time-resolved PL kinetics, and transient absorption measurements, to elucidate the dynamics excited states oleic acid (OA)-capped colloidal PbS quantum dots (QDs) in toluene with mean size approximately 3 nm. decay profiles were properly treated employing either fitting or fitting-free models extract average lifetimes lifetime distributions. Our findings highlight profound impact...

Three series of novel deazaflavinum salts differing in their substitutions at positions 5 (R = H, phenyl or mesityl), 7 and 8 OMe, Me, H Cl) were synthesized as potential catalysts a chemoselective visible light–mediated anaerobic oxidation primary secondary alcohols to carbonyl compounds. This mild procedure uses acetonitrile solvent, which acts simultaneously sacrificial electron acceptor (in place the oxygen usually used photooxidation reactions) therefore reaction does not need any...

Three symmetrically and three unsymmetrically substituted cibalackrot (7,14-diphenyldiindolo[3,2,1-de:3',2',1'-ij][1,5]naphthyridine-6,13-dione, 1) dyes carrying two derivatized phenyl rings have been synthesized as candidates for molecular electronics especially singlet fission, a process of interest solar energy conversion. Solution measurements provided triplet excitation energies fluorescence yields lifetimes; conformational properties were analyzed computationally. The are close to...