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Chemical Reviews Jun 2021The merging of click chemistry with discrete photochemical processes has led to the creation of a new class of click reactions, collectively known as photoclick... (Review)
Review
The merging of click chemistry with discrete photochemical processes has led to the creation of a new class of click reactions, collectively known as photoclick chemistry. These light-triggered click reactions allow the synthesis of diverse organic structures in a rapid and precise manner under mild conditions. Because light offers unparalleled spatiotemporal control over the generation of the reactive intermediates, photoclick chemistry has become an indispensable tool for a wide range of spatially addressable applications including surface functionalization, polymer conjugation and cross-linking, and biomolecular labeling in the native cellular environment. Over the past decade, a growing number of photoclick reactions have been developed, especially those based on the 1,3-dipolar cycloadditions and Diels-Alder reactions owing to their excellent reaction kinetics, selectivity, and biocompatibility. This review summarizes the recent advances in the development of photoclick reactions and their applications in chemical biology and materials science. A particular emphasis is placed on the historical contexts and mechanistic insights into each of the selected reactions. The in-depth discussion presented here should stimulate further development of the field, including the design of new photoactivation modalities, the continuous expansion of λ-orthogonal tandem photoclick chemistry, and the innovative use of these unique tools in bioconjugation and nanomaterial synthesis.
Topics: Click Chemistry; Cycloaddition Reaction; Imines; Nitriles; Photochemistry; Tetrazoles
PubMed: 33104332
DOI: 10.1021/acs.chemrev.0c00799 -
Angewandte Chemie (International Ed. in... Jun 2022The application of photochemistry in polymer synthesis is of interest due to the unique possibilities offered compared to thermochemistry, including topological and... (Review)
Review
The application of photochemistry in polymer synthesis is of interest due to the unique possibilities offered compared to thermochemistry, including topological and temporal control, rapid polymerization, sustainable low-energy processes, and environmentally benign features leading to established and emerging applications in adhesives, coatings, adaptive manufacturing, etc. In particular, the utilization of photochemistry in controlled/living polymerizations often offers the capability for precise control over the macromolecular structure and chain length in addition to the associated advantages of photochemistry. Herein, the latest developments in photocontrolled living radical and cationic polymerizations and their combinations for application in polymer syntheses are discussed. This Review summarizes and highlights recent studies in the emerging area of photoinduced controlled/living polymerizations. A discussion of mechanistic details highlights differences as well as parallels between different systems for different polymerization methods and monomer applicability.
Topics: Molecular Structure; Photochemistry; Polymerization; Polymers
PubMed: 35128771
DOI: 10.1002/anie.202117377 -
Protein Science : a Publication of the... Aug 2021Cryptochromes (CRYs) function as blue light photoreceptors in diverse physiological processes in nearly all kingdoms of life. Over the past several decades, they have... (Review)
Review
Cryptochromes (CRYs) function as blue light photoreceptors in diverse physiological processes in nearly all kingdoms of life. Over the past several decades, they have emerged as the most likely candidates for light-dependent magnetoreception in animals, however, a long history of conflicts between in vitro photochemistry and in vivo behavioral data complicate validation of CRYs as a magnetosensor. In this review, we highlight the origins of conflicts regarding CRY photochemistry and signal transduction, and identify recent data that provides clarity on potential mechanisms of signal transduction in magnetoreception. The review primarily focuses on examining differences in photochemistry and signal transduction in plant and animal CRYs, and identifies potential modes of convergent evolution within these independent lineages that may identify conserved signaling pathways.
Topics: Animals; Cryptochromes; Magnetic Phenomena; Models, Molecular; Photobiology; Photochemistry; Plants; Signal Transduction
PubMed: 33993574
DOI: 10.1002/pro.4124 -
Chemical Society Reviews Aug 2015Catalysis is key to the effective and efficient transformation of readily available building blocks into high value functional molecules and materials. For many years... (Review)
Review
Catalysis is key to the effective and efficient transformation of readily available building blocks into high value functional molecules and materials. For many years research in this field has largely focussed on the invention of new catalysts and the optimization of their performance to achieve high conversions and/or selectivities. However, inspired by Nature, chemists are beginning to turn their attention to the development of catalysts whose activity in different chemical processes can be switched by an external stimulus. Potential applications include using the states of multiple switchable catalysts to control sequences of transformations, producing different products from a pool of building blocks according to the order and type of stimuli applied. Here we outline the state-of-art in artificial switchable catalysis, classifying systems according to the trigger used to achieve control over the catalytic activity and stereochemical or other structural outcomes of the reaction.
Topics: Catalysis; Coordination Complexes; Enzymes; Models, Molecular; Photochemistry
PubMed: 25962337
DOI: 10.1039/c5cs00096c -
The Journal of Physical Chemistry. B May 2022Flavins are highly versatile redox-active and colored cofactors in a large variety of proteins. These do include photoenzymes and photoreceptors, although the vast... (Review)
Review
Flavins are highly versatile redox-active and colored cofactors in a large variety of proteins. These do include photoenzymes and photoreceptors, although the vast majority performs non-light-driven physiological functions. Nevertheless, electron transfer between flavins and specific nearby amino acid residues (in particular tyrosine, tryptophan, and presumably histidine and arginine) takes place upon excitation of flavin in many flavoproteins. For oxidized flavoproteins these reactions potentially have a photoprotective role. In this Perspective, we outline work on the characterization of early reaction intermediates not only in the relatively well-studied resting oxidized forms but also in the fully reduced and the intrinsically unstable semireduced forms, where ultrafast photooxidation of flavin was recently demonstrated. Along different lines, flavoprotein-based novel photocatalysts for biotechnological applications are presently emerging, employing both substrate photooxidation and photoreduction strategies. Deep insight into the fundamental flavin photochemical reactions may help in guiding and optimizing their development and in the exploration of novel photocatalytic approaches.
Topics: Electron Transport; Flavins; Flavoproteins; Oxidation-Reduction; Photochemistry
PubMed: 35442696
DOI: 10.1021/acs.jpcb.2c00969 -
Chemical Reviews Jun 2021At its basic conceptualization, photoclick chemistry embodies a collection of click reactions that are performed via the application of light. The emergence of this... (Review)
Review
At its basic conceptualization, photoclick chemistry embodies a collection of click reactions that are performed via the application of light. The emergence of this concept has had diverse impact over a broad range of chemical and biological research due to the spatiotemporal control, high selectivity, and excellent product yields afforded by the combination of light and click chemistry. While the reactions designated as "photoclick" have many important features in common, each has its own particular combination of advantages and shortcomings. A more extensive realization of the potential of this chemistry requires a broader understanding of the physical and chemical characteristics of the specific reactions. This review discusses the features of the most frequently employed photoclick reactions reported in the literature: photomediated azide-alkyne cycloadditions, other 1,3-dipolarcycloadditions, Diels-Alder and inverse electron demand Diels-Alder additions, radical alternating addition chain transfer additions, and nucleophilic additions. Applications of these reactions in a variety of chemical syntheses, materials chemistry, and biological contexts are surveyed, with particular attention paid to the respective strengths and limitations of each reaction and how that reaction benefits from its combination with light. Finally, challenges to broader employment of these reactions are discussed, along with strategies and opportunities to mitigate such obstacles.
Topics: Alkynes; Azides; Click Chemistry; Cycloaddition Reaction; Photochemistry
PubMed: 33835796
DOI: 10.1021/acs.chemrev.0c01212 -
Photosynthesis Research Feb 2022
Topics: Electrochemistry; Electron Transport; Photochemistry; Photosynthesis
PubMed: 35181868
DOI: 10.1007/s11120-022-00901-2 -
Chemical Communications (Cambridge,... Nov 2022Polyfluoroaryl compounds belong to privileged moieties and engender distinct properties in many pharmaceuticals, agrochemicals, and materials. Over the past decade,... (Review)
Review
Polyfluoroaryl compounds belong to privileged moieties and engender distinct properties in many pharmaceuticals, agrochemicals, and materials. Over the past decade, considerable seminal reports and reviews have merely paid close attention to fluoroalkylation chemistry, such as trifluoromethylation, difluoroalkylation, perfluoroalkylation, trifluoromethylthiolation or trifluoromethoxylation. Polyfluoroarylation has inevitably lagged somewhat behind its fluoroalkylation counterparts, emanating from a lack of awareness and understanding of the synthetic significance. Together with the renaissance of photochemistry, the photocatalytic polyfluoroarylation using polyfluoroarenes as an inexpensive and easy-available radical precursor has emerged as a topical interest and vibrant area of chemical research. In this review, we have endeavored to present the state-of-the-art in photocatalytic polyfluoroarylation since 2014, and the discussions cover the basic concept, reaction design, mechanistic insight, and research prospects, which are organized by the reaction types. We hope this review will provide a comprehensive overview of this topic and stimulate significant research interest.
Topics: Hydrocarbons, Fluorinated; Photochemistry
PubMed: 36349779
DOI: 10.1039/d2cc05000e -
Molecules (Basel, Switzerland) Nov 2022A series of symmetrical dibenzylidene derivatives of cyclobutanone were synthesized with the goal of studying the physicochemical properties of cross-conjugated dienones...
A series of symmetrical dibenzylidene derivatives of cyclobutanone were synthesized with the goal of studying the physicochemical properties of cross-conjugated dienones (ketocyanine dyes). The structures of the products were established and studied by X-ray diffraction and by NMR and electronic spectroscopy. All the products had ,-geometry. The oxidation and reduction potentials of the dienones were determined by cyclic voltammetry. The potentials were shown to depend on the nature, position, and number of substituents in the benzene rings. A linear correlation was found between the difference of the electrochemical oxidation and reduction potentials and the energy of the long-wavelength absorption maximum. This correlation can be employed to analyze the properties of other compounds of this type. Quantum chemistry was used to explain the observed regularities in the electrochemistry, absorption, and fluorescence of the dyes. The results are in good agreement with the experimental redox potentials and spectroscopy data.
Topics: Photochemistry; Electrochemistry; Oxidation-Reduction; Magnetic Resonance Spectroscopy; Coloring Agents
PubMed: 36364429
DOI: 10.3390/molecules27217602 -
Biochemistry. Biokhimiia Oct 2023The diversity of the retinal-containing proteins (rhodopsins) in nature is extremely large. Fundamental similarity of the structure and photochemical properties unites... (Review)
Review
The diversity of the retinal-containing proteins (rhodopsins) in nature is extremely large. Fundamental similarity of the structure and photochemical properties unites them into one family. However, there is still a debate about the origin of retinal-containing proteins: divergent or convergent evolution? In this review, based on the results of our own and literature data, a comparative analysis of the similarities and differences in the photoconversion of the rhodopsin of types I and II is carried out. The results of experimental studies of the forward and reverse photoreactions of the bacteriorhodopsin (type I) and visual rhodopsin (type II) rhodopsins in the femto- and picosecond time scale, photo-reversible reaction of the octopus rhodopsin (type II), photovoltaic reactions, as well as quantum chemical calculations of the forward photoreactions of bacteriorhodopsin and visual rhodopsin are presented. The issue of probable convergent evolution of type I and type II rhodopsins is discussed.
Topics: Rhodopsin; Bacteriorhodopsins; Photochemistry
PubMed: 38105022
DOI: 10.1134/S0006297923100097