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Photochemistry and Photobiology Nov 2021An overview of the history, mechanistic aspects and applications is provided for p-hydroxyphenacyl (pHP) and benzoin photoremovable protecting groups, which release... (Review)
Review
An overview of the history, mechanistic aspects and applications is provided for p-hydroxyphenacyl (pHP) and benzoin photoremovable protecting groups, which release biologically important leaving groups upon photolysis with UV light. Also discussed is (7-diethylaminocoumarin-4-yl)methyl (DEACM), a photoremovable protecting group that absorbs visible light. These are followed by the α-keto amides and naphtho- and benzothiophene-2-carboxanilides as caging groups, which eliminate leaving groups via photochemically produced zwitterionic intermediates. Also covered are amino-1,4-benzoquinones, which upon exposure to green and red wavelengths of light photorearrange to an unstable photoproduct that subsequently eliminates leaving groups in aqueous media. Selected examples are given that use these photoremovable protecting (caging) groups for the light-activated release of biologically important substrates under physiological conditions in cells and tissue as practical applications in biology, biochemistry and physiology. These caging groups have found significant applications because their photochemistry is efficient and a single coproduct is formed in addition to the photoreleased substrate.
Topics: Photochemistry; Photolysis; Ultraviolet Rays
PubMed: 34101860
DOI: 10.1111/php.13462 -
Chemical Reviews Jan 2017Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are... (Review)
Review
Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making of covalent bonds, and excited-state proton transfer (ESPT). Many of these transformations are initiated by electron transfer (ET). The quantum yields of these processes vary significantly, from nearly 1 for ESPT to 10-10 for ET. Importantly, even when quantum yields are relatively small, at the conditions of repeated illumination the overall effect is significant. Depending on the task at hand, fluorescent protein photochemistry is regarded either as an asset facilitating new applications or as a nuisance leading to the loss of optical output. The phenomena arising due to phototransformations include (i) large Stokes shifts, (ii) photoconversions, photoactivation, and photoswitching, (iii) phototoxicity, (iv) blinking, (v) permanent bleaching, and (vi) formation of long-lived intermediates. The focus of this review is on the most recent experimental and theoretical work on photoinduced transformations in fluorescent proteins. We also provide an overview of the photophysics of fluorescent proteins, highlighting the interplay between photochemistry and other channels (fluorescence, radiationless relaxation, and intersystem crossing). The similarities and differences with photochemical processes in other biological systems and in dyes are also discussed.
Topics: Electrons; Isomerism; Luminescent Proteins; Photochemistry; Protons
PubMed: 27754659
DOI: 10.1021/acs.chemrev.6b00238 -
Physical Chemistry Chemical Physics :... Jul 2016Solar radiation was overwhelmingly the largest source of energy on the early Earth. Energy provided by the Sun has the potential to access different chemistries than... (Review)
Review
Solar radiation was overwhelmingly the largest source of energy on the early Earth. Energy provided by the Sun has the potential to access different chemistries than energy provided by other sources, such as hydrothermal vents, because of the unique characteristics of photochemistry that differentiate it from conventional thermal chemistry. This review considers how sunlight-driven reactions can abiotically generate prebiotic molecules necessary for the evolution of life. We discuss briefly the characteristics of the early Sun and the likely environmental conditions on the early Earth because photochemistry is both environment- and molecule-specific. An overview of the fundamental principles of photophysics and photochemistry is followed by discussion of a selection of prebiotically-relevant examples of photochemical reactions, focusing on syntheses that lead to the production of cellular components (e.g. sugars, lipids, and biopolymer precursors). The role of photostability as an evolutionary driving force is also considered. These examples highlight the ability of simple organic molecules to harness solar energy and convert it into high-energy chemical bonds, generating molecular complexity.
Topics: Origin of Life; Photochemistry; Solar Energy; Sunlight
PubMed: 27193698
DOI: 10.1039/c6cp00980h -
International Journal of Molecular... Dec 2022In this research, the synthesis, photochemistry, and computational study of new - and -isomers of amino-thienostilbenes is performed to test the efficiency of their...
In this research, the synthesis, photochemistry, and computational study of new - and -isomers of amino-thienostilbenes is performed to test the efficiency of their production and acid resistance, and to investigate their electronic structure, photoreactivity, photophysical characteristics, and potential biological activity. The electronic structure and conformations of synthesized thienostilbene amines and their photocyclization products are examined computationally, along with molecular modeling of amines possessing two thiophene rings that showed inhibitory potential toward cholinesterases. New amino-styryl thiophenes, with favorable photophysical properties and proven acid resistance, represent model compounds for their water-soluble ammonium salts as potential styryl optical dyes. The comparison with organic dyes possessing a -aminostilbene subunit as the scaffold shows that the newly synthesized -aminostilbenes have very similar absorbance wavelengths. Furthermore, their functionalized -isomers and photocyclization products are good candidates for cholinesterase inhibitors because of the structural similarity of the molecular skeleton to some already proven bioactive derivatives.
Topics: Photochemistry; Thiophenes; Benzylamines; Models, Molecular; Coloring Agents
PubMed: 36614053
DOI: 10.3390/ijms24010610 -
Photochemistry and Photobiology Jan 2022The figure presented here illuminates the large number of variables that are necessary to adequately describe phototesting protocols. Each of these characteristics can...
The figure presented here illuminates the large number of variables that are necessary to adequately describe phototesting protocols. Each of these characteristics can be critical in understanding results presented in the photomedicine community as well as the broader photobiology and photochemistry communities. The inclusion of all of these variables within each phototesting publication will aid in discourse and further scientific discovery within our field.
Topics: Photobiology; Photochemistry
PubMed: 34312877
DOI: 10.1111/php.13493 -
Spectrochimica Acta. Part A, Molecular... Nov 2021The synthesis, photoreactivity, and spectroscopic characterization of novel 1,2,3-triazole di-heterostilbenes bearing various aliphatic and aromatic substituents on the...
The synthesis, photoreactivity, and spectroscopic characterization of novel 1,2,3-triazole di-heterostilbenes bearing various aliphatic and aromatic substituents on the triazole rings were thoroughly explored. By introducing triazole rings into the o-divinylbenzene moiety, compared with the 2-furyl and 2-thienyl heteroanalogues, these compounds did not show any photochemical reactivity toward intramolecular cycloaddition reactions or electrocyclization processes. The research is further extended to the more in-depth examination of photochemical and photophysical characteristics of the investigated triazolo-stilbenes to explain the lack of reactivity in intramolecular photochemical cyclizations by configuration and substituent effects. Conformations of synthetically obtained novel triazoles are examined by Density Functional Theory (DFT). The time dependent-DFT approach was employed to obtain additional insight into the properties observed with UV/Vis spectroscopy. The frontier orbital energy was computationally investigated to determine the influence of cis-trans isomerism and the nature of substituents on the spectroscopic properties of the triazoles. Along with our previous studies of similar compounds containing furan and thiophene, respectively, this study shows that introducing various heteroaromatic rings induces diverse photochemistry and photophysics due to the conformational changes and change in electronic distribution within the molecular system.
Topics: Cyclization; Molecular Conformation; Photochemistry; Spectrum Analysis; Triazoles
PubMed: 34146829
DOI: 10.1016/j.saa.2021.120056 -
BioTechniques Jan 2019Photo-crosslinkable hydrogels have recently attracted significant scientific interest. Their properties can be manipulated in a spatiotemporal manner through exposure to... (Review)
Review
Photo-crosslinkable hydrogels have recently attracted significant scientific interest. Their properties can be manipulated in a spatiotemporal manner through exposure to light to achieve the desirable functionality for various biomedical applications. This review article discusses the recent advances of the most common photo-crosslinkable hydrogels, including poly(ethylene glycol) diacrylate, gelatin methacryloyl and methacrylated hyaluronic acid, for various biomedical applications. We first highlight the advantages of photopolymerization and discuss diverse photosensitive systems used for the synthesis of photo-crosslinkable hydrogels. We then introduce their synthesis methods and review their latest state of development in biomedical applications, including tissue engineering and regenerative medicine, drug delivery, cancer therapies and biosensing. Lastly, the existing challenges and future perspectives of engineering photo-crosslinkable hydrogels for biomedical applications are briefly discussed.
Topics: Animals; Biosensing Techniques; Drug Delivery Systems; Gelatin; Humans; Hyaluronic Acid; Hydrogels; Neoplasms; Photochemical Processes; Photochemistry; Polyethylene Glycols; Polymerization; Tissue Engineering
PubMed: 30730212
DOI: 10.2144/btn-2018-0083 -
Molecules (Basel, Switzerland) Jun 2022The structure, tautomerization pathways, vibrational spectra, and photochemistry of 2-amino-4-methylthiazole (AMT) molecule were studied by matrix isolation FTIR...
The structure, tautomerization pathways, vibrational spectra, and photochemistry of 2-amino-4-methylthiazole (AMT) molecule were studied by matrix isolation FTIR spectroscopy and DFT calculations undertaken at the B3LYP/6-311++G(3df,3pd) level of theory. The most stable tautomer with the five-membered ring stabilized by two double C=C and C=N bonds, was detected in argon matrices after deposition. When the AMT/Ar matrices were exposed to 265 nm selective irradiation, three main photoproducts, N-(1-sulfanylprop-1-en-2-yl)carbodiimide (fp1), N-(1-thioxopropan-2-yl)carbodiimide (fp2) and N-(2-methylthiiran-2-yl)carbodiimide (fp3), were photoproduced by a cleavage of the CS-CN bond together with hydrogen atom migration. The minor photoreaction caused by the cleavage of the CS-CC bond and followed by hydrogen migration formed 2-methyl-1H-azirene-1-carbimidothioic acid (fp15). We have also found that cleavage of the CS-CN bond followed by disruption of the N-C bond produced cyanamide (fp11) and the C(CH3)=CH-S biradical that transformed into 2-methylthiirene (fp12) and further photoreactions produced 1-propyne-1-thiole (fp13) or methylthioketene (fp14). Cleavage of the CS-CC bond followed by disruption of the N-C bond produced propyne (fp22) and the S-C(NH)=N biradical that transformed into 3-aminethiazirene (fp23); further photoreactions produced N-sulfanylcarbodiimide (fp25). As a result of these transformations, several molecular complexes were identified as photoproducts besides new molecules in the AMT photolysis process.
Topics: Carbodiimides; Hydrogen; Models, Molecular; Photochemistry; Spectroscopy, Fourier Transform Infrared
PubMed: 35745029
DOI: 10.3390/molecules27123897 -
Photochemistry and Photobiology Jul 2022The direct photolysis of estrone in solvents ranging from water to cyclohexane is reported. The photodegradation is dominated by lumiestrone, an epimer of estrone...
The direct photolysis of estrone in solvents ranging from water to cyclohexane is reported. The photodegradation is dominated by lumiestrone, an epimer of estrone resulting from the inversion of the methyl group at carbon 13, regardless of solvent and photolysis wavelength in the range 254-320 nm. Solvent addition products are also observed in lesser amounts. The photodegradation rate in water is an order of magnitude slower than in nonaqueous solvents. Short wavelength excitation enhances photodegradation. Together, these results suggest complicated photophysics underlie the photochemistry with implications for the remediation of environmental estrogens.
Topics: Estrone; Photochemistry; Photolysis; Solvents; Water
PubMed: 34664279
DOI: 10.1111/php.13542 -
Molecules (Basel, Switzerland) Nov 2020Since their conception, ionic liquids (ILs) have been investigated for an extensive range of applications including in solvent chemistry, catalysis, and... (Review)
Review
Since their conception, ionic liquids (ILs) have been investigated for an extensive range of applications including in solvent chemistry, catalysis, and electrochemistry. This is due to their designation as designer solvents, whereby the physiochemical properties of an IL can be tuned for specific applications. This has led to significant research activity both by academia and industry from the 1990s, accelerating research in many fields and leading to the filing of numerous patents. However, while ILs have received great interest in the patent literature, only a limited number of processes are known to have been commercialised. This review aims to provide a perspective on the successful commercialisation of IL-based processes, to date, and the advantages and disadvantages associated with the use of ILs in industry.
Topics: Anions; Catalysis; Cations; Chlorine; Dimerization; Electrochemistry; Fluorine; Hydrogen; Industry; Ionic Liquids; Methylation; Models, Chemical; Organic Chemicals; Photochemistry; Solvents; Temperature
PubMed: 33182328
DOI: 10.3390/molecules25215207