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Angewandte Chemie (International Ed. in... Dec 2022Enzymes have several advantages over conventional catalysts for organic synthesis. Over the last two decades, much effort has been made to further extend the scope of... (Review)
Review
Enzymes have several advantages over conventional catalysts for organic synthesis. Over the last two decades, much effort has been made to further extend the scope of biocatalytic reactions available to synthetic chemists, particularly by expanding the repertoire of enzymes for abiological transformations. In this regard, exciting new developments in the area of photobiocatalysis enable now the introduction of non-natural reactivity in enzymes to solve long-standing synthetic challenges. A recently described example from the Hyster group demonstrates in an unprecedented way how the combination of photochemistry with enzyme catalysis empowers the catalytic asymmetric construction of Csp -Csp bonds with high chemo- and enantioselectivity.
Topics: Stereoisomerism; Catalysis; Biocatalysis; Chemistry Techniques, Synthetic; Photochemistry; Enzymes
PubMed: 36239986
DOI: 10.1002/anie.202214313 -
Molecules (Basel, Switzerland) Feb 2023One of the challenges in developing practical CO photoconversion catalysts is the design of materials with a low cost, high activity and good stability. In this paper,... (Review)
Review
One of the challenges in developing practical CO photoconversion catalysts is the design of materials with a low cost, high activity and good stability. In this paper, excellent photocatalysts based on TiO, WO, ZnO, CuO and CeO metal oxide materials, which are cost-effective, long-lasting, and easy to fabricate, are evaluated. The characteristics of the nanohybrid catalysts depend greatly on their architecture and design. Thus, we focus on outstanding materials that offer effective and practical solutions. Strategies to improve CO conversion efficiency are summarized, including heterojunction, ion doping, defects, sensitization and morphology control, which can inspire the future improvement in photochemistry. The capacity of CO adsorption is also pivotal, which varies with the morphological and electronic structures. Forms of 0D, 1D, 2D and 3DOM (zero/one/two-dimensional- and three-dimensional-ordered macroporous, respectively) are involved. Particularly, the several advantages of the 3DOM material make it an excellent candidate material for CO conversion. Hence, we explain its preparation method. Based on the discussion, new insights and prospects for designing high-efficient metallic oxide photocatalysts to reduce CO emissions are presented.
Topics: Carbon Dioxide; Adsorption; Electronics; Oxides; Photochemistry
PubMed: 36838641
DOI: 10.3390/molecules28041653 -
Molecules (Basel, Switzerland) Nov 2016Anthocyanins are identified by the respective flavylium cation, which is only one species of a multistate of different molecules reversibly interconverted by external...
Anthocyanins are identified by the respective flavylium cation, which is only one species of a multistate of different molecules reversibly interconverted by external inputs such as pH, light and temperature. The flavylium cation (acidic form) is involved in an apparent acid-base reaction, where the basic species is the sum of quinoidal base, hemiketal and - and -chalcones, their relative fraction depending on the substitution pattern of the flavylium cation. The full comprehension of this complex system requires a thermodynamic and kinetic approach. The first consists in drawing an energy level diagram where the relative positions of the different species are represented as a function of pH. On the other hand, the kinetic approach allows measuring the rates of the reactions that interconnect reversibly the multistate species. The kinetics is greatly dependent on the existence or not of a high - isomerization barrier. In this work, the procedure to obtain the energy level diagram and the rates of inter-conversion in the multistate in both cases (low or high isomerization barrier) are described. Practical examples of this approach are presented to illustrate the theory, and recently reported applications based on host-guest complexes are reviewed.
Topics: Algorithms; Anthocyanins; Hydrogen-Ion Concentration; Isomerism; Models, Chemical; Photochemistry; Thermodynamics
PubMed: 27834931
DOI: 10.3390/molecules21111502 -
Journal of Quantitative Spectroscopy &... Sep 2020The "science-softCon UV/Vis Photochemistry Database" (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV-Vis-NIR spectral data and other...
The "science-softCon UV/Vis Photochemistry Database" (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV-Vis-NIR spectral data and other photochemical information assembled from published peer-reviewed papers. The database contains photochemical data including absorption, fluorescence, photoelectron, and circular and linear dichroism spectra, as well as quantum yields and photolysis related data that are critically needed in many scientific disciplines. This manuscript gives an outline regarding the structure and content of the "science-softCon UV/Vis Photochemistry Database". The accurate and reliable molecular level information provided in this database is fundamental in nature and helps in proceeding further to understand photon, electron and ion induced chemistry of molecules of interest not only in spectroscopy, astrochemistry, astrophysics, Earth and planetary sciences, environmental chemistry, plasma physics, combustion chemistry but also in applied fields such as medical diagnostics, pharmaceutical sciences, biochemistry, agriculture, and catalysis. In order to illustrate this, we illustrate the use of the UV/Vis Photochemistry Database in four different fields of scientific endeavor.
PubMed: 34121770
DOI: 10.1016/j.jqsrt.2020.107056 -
Chemical Reviews Jan 2022Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic... (Review)
Review
Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic chemists. However, performing a photochemical transformation can be quite a challenge because of various issues related to the delivery of photons. These challenges have barred the widespread adoption of photochemical steps in the chemical industry. However, in the past decade, several technological innovations have led to more reproducible, selective, and scalable photoinduced reactions. Herein, we provide a comprehensive overview of these exciting technological advances, including flow chemistry, high-throughput experimentation, reactor design and scale-up, and the combination of photo- and electro-chemistry.
Topics: Inventions; Photochemistry
PubMed: 34375082
DOI: 10.1021/acs.chemrev.1c00332 -
Nature Communications Jun 2022Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical...
Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical applications. For the past half century, organic and metal-complex PPGs were considered mutually exclusive classes, each of which provided unique sets of physical and chemical properties thanks to their distinctive structures. Here, we introduce the meso-methylporphyrin group as a prototype hybrid-class PPG that unites traditionally exclusive elements of organic and metal-complex PPGs within a single structure. We show that the porphyrin scaffold allows extensive modularity by functional separation of the metal-binding chromophore and up to four sites of leaving group release. The insertion of metal ions can be used to tune their spectroscopic, photochemical, and biological properties. We provide a detailed description of the photoreaction mechanism studied by steady-state and transient absorption spectroscopies and quantum-chemical calculations. Our approach applied herein could facilitate access to a hitherto untapped chemical space of potential PPG scaffolds.
Topics: Ions; Light; Metals; Photochemistry; Porphyrins
PubMed: 35750661
DOI: 10.1038/s41467-022-31288-2 -
Molecules (Basel, Switzerland) May 2021In order to improve their bioapplications, inorganic nanoparticles (NPs) are usually functionalized with specific biomolecules. Peptides with short amino acid sequences... (Review)
Review
In order to improve their bioapplications, inorganic nanoparticles (NPs) are usually functionalized with specific biomolecules. Peptides with short amino acid sequences have attracted great attention in the NP functionalization since they are easy to be synthesized on a large scale by the automatic synthesizer and can integrate various functionalities including specific biorecognition and therapeutic function into one sequence. Conjugation of peptides with NPs can generate novel theranostic/drug delivery nanosystems with active tumor targeting ability and efficient nanosensing platforms for sensitive detection of various analytes, such as heavy metallic ions and biomarkers. Massive studies demonstrate that applications of the peptide-NP bioconjugates can help to achieve the precise diagnosis and therapy of diseases. In particular, the peptide-NP bioconjugates show tremendous potential for development of effective anti-tumor nanomedicines. This review provides an overview of the effects of properties of peptide functionalized NPs on precise diagnostics and therapy of cancers through summarizing the recent publications on the applications of peptide-NP bioconjugates for biomarkers (antigens and enzymes) and carcinogens (e.g., heavy metallic ions) detection, drug delivery, and imaging-guided therapy. The current challenges and future prospects of the subject are also discussed.
Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Biomarkers; Biosensing Techniques; Cell Line, Tumor; Chemistry, Inorganic; Colorimetry; Drug Carriers; Drug Delivery Systems; Humans; Ions; Ligands; Matrix Metalloproteinase 7; Metals, Heavy; Nanomedicine; Nanoparticles; Neoplasms; Peptides; Photochemistry; Precision Medicine; Spectrophotometry, Ultraviolet; Tumor Microenvironment
PubMed: 34072160
DOI: 10.3390/molecules26113228 -
Organic Letters Jan 2024Photooxygenation of flavonoids leads to the release of carbon monoxide (CO). Our structure-photoreactivity study, employing several structurally different flavonoids,...
Photooxygenation of flavonoids leads to the release of carbon monoxide (CO). Our structure-photoreactivity study, employing several structurally different flavonoids, including their C-labeled analogs, revealed that CO can be produced via two completely orthogonal pathways, depending on their hydroxy group substitution pattern and the reaction conditions. While photooxygenation of the enol 3-OH group has previously been established as the CO liberation channel, we show that the catechol-type hydroxy groups of ring B can predominantly participate in photodecarbonylation.
Topics: Carbon Monoxide; Flavonoids; Photochemistry
PubMed: 38227978
DOI: 10.1021/acs.orglett.3c04141 -
Free Radical Biology & Medicine Sep 2019Phototoxic effects of 6,8 dihalogenated quinolones confers to this type of molecules a potential property as photochemotherapeutic agents. Two photodehalogenation...
Phototoxic effects of 6,8 dihalogenated quinolones confers to this type of molecules a potential property as photochemotherapeutic agents. Two photodehalogenation processes seem to be involved in the remarkable photoinduced cellular damage. In this context, a new 6,8 dihalogenated quinolone 1 (1-methyl-6,8-difluoro-4-oxo-7-aminodimethyl-1,4-dihydroquinoline-3-carboxylic acid) was synthetized looking for improving the phototoxic properties of fluoroquinolones (FQ) and to determine the role of the photodegradation pathways in the FQ phototoxicity. With this purpose, fluorescence emissions, laser flash photolysis experiments and photodegradation studies were performed with compound 1 using 1-ethyl-6,8-difluoro-4-oxo-7-aminodimethyl-1,4-dihidroquinoline-3-carboxylic acid (2) and lomefloxacin (LFX) as reference compounds. The shortening of alkyl chain of the N(1) of the quinolone ring revealed a lifetime increase of the reactive aryl cation generated from photolysis of the three FQ and a significant reduction of the FQ photodegradation quantum yield. The fact that these differences were smaller when the same study was done using a hydrogen donor solvent (ethanol-aqueous buffer, 50/50 v/v) evidenced the highest ability of the reactive intermediate arising from 1 to produce intermolecular alkylations. These results were correlated with in vitro 3T3 NRU phototoxicity test. Thus, when Photo-Irritation-Factor (PIF) was determined for 1, 2 and LFX using cytotoxicity profiles of BALB/c 3T3 fibroblasts treated with each compound in the presence and absence of UVA light, a PIF more higher than 30 was obtained for 1 while the values for 2 and LFX were only higher than 8 and 10, respectively. Thereby, the present study illustrates an approach to modulate the photosensitizing properties of FQ with the purpose to improve the chemotherapeutic properties of antitumor quinolones. Moreover, the results obtained in this study also evidence that the key pathway responsible for the phototoxic properties associated with dihalogenated quinolones is the aryl cation generation.
Topics: 3T3 Cells; Animals; Antineoplastic Agents; Dermatitis, Phototoxic; Drug Design; Fluoroquinolones; Halogens; Lasers; Methane; Mice; Mice, Inbred BALB C; Microscopy, Confocal; Photochemistry; Quinolones; Singlet Oxygen
PubMed: 31195085
DOI: 10.1016/j.freeradbiomed.2019.06.010 -
Current Opinion in Chemical Biology Aug 2016Light provides a uniquely powerful stimulus to help visualize and/or perturb biological systems. The use of tissue penetrant near-IR wavelengths enables in vivo... (Review)
Review
Light provides a uniquely powerful stimulus to help visualize and/or perturb biological systems. The use of tissue penetrant near-IR wavelengths enables in vivo applications, however the design of molecules that function in this range remains a substantial challenge. Heptamethine cyanine fluorophores are already important tools for near-IR optical imaging. These molecules are susceptible to photobleaching through a photooxidative cleavage reaction. This review details efforts to define the mechanism of this reaction and two emerging fields closely tied to this process. In the first, efforts that slow photooxidation enable the creation of photobleaching resistant fluorophores. In the second, cyanine photooxidation has recently been employed as the cornerstone of a near-IR uncaging strategy. This review seeks to highlight the utility of mechanistic organic chemistry insights to help tailor cyanine scaffolds for new, and previously intractable, biological applications.
Topics: Drug Delivery Systems; Fluorescent Dyes; Oxidation-Reduction; Photobleaching; Photochemistry; Spectroscopy, Near-Infrared
PubMed: 27348157
DOI: 10.1016/j.cbpa.2016.05.022