Artículos de revistas: "Pyrene"

1

Babu, Srinivasarao Arulananda y Arup Dalal. "Pd(II)-Catalyzed Directing-Group-Aided C–H Arylation and Alkylation of Pyrene Core: Synthesis of C1,C2- and C1,C10-Disubstituted Pyrene Motifs". Synthesis 53, n.º 18 (31 de marzo de 2021): 3307–24. http://dx.doi.org/10.1055/a-1472-0881.

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AbstractWe report the application of the Pd(II)-catalyzed, directing-group-aided C–H arylation/alkylation tactics to functionalize the pyrene core, especially, the relatively inaccessible C2 and K-region C10 positions of the pyrene core and augmentation of the library of pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene motifs. The Pd(II)-catalyzed β-C–H arylation/alkylation of the C2-position of pyrene-1-carboxamide possessing an 8-aminoquinoline directing group yielded various C1,C2-disubstituted pyrenes. Similarly, the Pd(II)-catalyzed selective γ-C–H arylation/alkylation of the C10-position of N-(pyren-1-yl)picolinamide, possessing a picolinamide directing group, yielded various C1,C10-disubstituted pyrenes. Examples of C(9)–H arylation of pyrene-1-carboxamide and the removal of the directing group after the C–H arylation/alkylation reactions were also shown. The structures of representative pyrene derivatives were confirmed by the X-ray structure analysis. Given the importance of the pyrene derivatives in various fields of chemical sciences, this report is a contribution towards augmentation of the library of pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene amide motifs.

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2

Silva, Beatriz E. Ruiz, Edward K. Koepf, Leslie D. Burtnick y Nicholas J. Turro. "Monomer and excimer fluorescence of horse plasma gelsolin labelled with N-(1-pyrenyl)iodoacetamide". Biochemistry and Cell Biology 70, n.º 7 (1 de julio de 1992): 573–78. http://dx.doi.org/10.1139/o92-088.

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Horse plasma gelsolin was labelled with the sulfhydryl-specific fluorescent reagent N-(1-pyrenyl)iodoacetamide. The level of incorporation of probe was 1.6 ± 0.3 mol pyrene/mol gelsolin. The circular dichroism spectrum of pyrenyl-gelsolin and its ability to interact with muscle actin were not different from that found for unmodified gelsolin. The emission from pyrenyl-gelsolin was dominated by a broad emission band centred near 483 nm, characteristic of the presence of pyrene excimers. Analysis of excitation spectra for the monomer and excimer-type fluorescence suggested that ground-state interactions may occur between adjacent pyrenes in the gelsolin structure. In the case either of excimer formation or of ground-state pyrene–pyrene interactions in doubly labelled gelsolin molecules, the modified Cys residues must be in close proximity in the folded protein structure. Thermal denaturation of gelsolin could be monitored by observing the decrease in excimer emission that accompanied heating and unfolding of the tertiary structure. While heat treatment alone did not eliminate excimer fluorescence, digestion of gelsolin with chymotrypsin completely abolished such emission. Also, pyrenyl-gelsolin prepared and studied in 6 M guanidine-HCl exhibited fluorescence characteristic of pyrene monomers exclusively.Key words: gelsolin, pyrene excimer fluorescence, fluorescence lifetime, thermal denaturation.

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3

Ashley, David L., Elizabeth R. Barnhart, Donald G. Patterson y Robert H. Hill. "Identification of Polychlorinated Pyrenes and Pyrene-Addition Products Using Proton Nuclear Magnetic Resonance Techniques". Applied Spectroscopy 41, n.º 7 (septiembre de 1987): 1194–99. http://dx.doi.org/10.1366/0003702874447428.

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Nuclear magnetic resonance (NMR) techniques are used to determine the chlorination pattern on a number of chlorinated pyrenes and pyrene-addition products. Determining chemical shifts, couplings, and longitudinal relaxation rates makes the unequivocal assignment of these molecules possible. Chlorination under the conditions described here were found to follow the normal orientation rules for pyrene. Spectral parameters obtained from these molecules are consistent enough to allow further application to unknown compounds. This should simplify assigning NMR spectra to other chlorinated pyrene standards.

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4

Orehovec, Iva, Marija Matković, Isabela Pehar, Dragomira Majhen y Ivo Piantanida. "Bis-Pyrene Photo-Switch Open- and Closed-Form Differently Bind to ds-DNA, ds-RNA and Serum Albumin and Reveal Light-Induced Bioactivity". International Journal of Molecular Sciences 22, n.º 9 (6 de mayo de 2021): 4916. http://dx.doi.org/10.3390/ijms22094916.

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Newly designed and synthesized diarylethene (DAE) derivatives with aliphatic amine sidearms and one with two pyrenes, revealed excellent photo-switching property of central DAE core in MeOH and water. The only exception was bis-pyrene analogue, its DAE core very readily photochemically closed, but reversible opening completely hampered by aromatic stacking interaction of pyrene(s) with cyclic DAE. In this process, pyrene fluorescence showed to be a reliable monitoring method, an open form characterized by strong emission at 480 nm (typical for pyrene-aggregate), while closed form emitted weakly at 400 nm (typical for pyrene-DAE quenching). Only open DAE-bis-pyrene form interacted measurably with ds-DNA/RNA by flexible insertion in polynucleotide grooves, while self-stacked closed form did not bind to DNA/RNA. For the same steric reasons, flexible open DAE-bis-pyrene form was bound to at least three different binding sites at bovine serum albumin (BSA), while rigid, self-stacked closed form interacted dominantly with only one BSA site. Preliminary screening of antiproliferative activity against human lung carcinoma cell line A549 revealed that all DAE-derivatives are non-toxic. However, bis-pyrene analogue efficiently entered cells and located in the cytoplasm, whereby irradiation by light (315–400 nm) resulted in a strong, photo-induced cytotoxic effect, typical for pyrene-related singlet oxygen species production.

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5

Launen, Loren, Linda Pinto, Christine Wiebe, Eberhard Kiehlmann y Margo Moore. "The oxidation of pyrene and benzo[a]pyrene by nonbasidiomycete soil fungi". Canadian Journal of Microbiology 41, n.º 6 (1 de junio de 1995): 477–88. http://dx.doi.org/10.1139/m95-064.

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The purpose of this study was to determine the ability of nonbasidiomycete soil fungi to oxidize pyrene (four rings) and benzo[a]pyrene (BaP) (five rings). Fungi were isolated from five different soils in which the polycyclic aromatic hydrocarbon content ranged from 0.8 to 80 μg/g dry soil. Approximately 50% of the isolates in all sites were able to oxidize pyrene. The pyrene-oxidizing species belonged to all fungal divisions except basidiomycetes. The most common were Penicillium spp. of the subgenus Furcatum and these dominated the more contaminated soils. Penicillium janthinellum and Syncephalastrum racemosum exhibited the most rapid rates of pyrene oxidation. The major pyrene metabolites were identified by proton NMR and mass spectrometry as 1-pyrenol, 1,6- and 1,8-pyrenediol, and the 1,6- and 1,8-pyrenequinones. A high correlation was found between the ability to oxidize pyrene and BaP. As with pyrene, approximately 50% of the fungal isolates tested oxidized BaP to 9-hydroxy-BaP. Eighty percent of the pyrene-oxidizing strains were also able to metabolize BaP.Key words: fungi, polycyclic aromatic hydrocarbons, biotransformation, bioremediation, cytochrome P-450.

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6

Babu, B. Ravindra, Mads D. Sørensen, Patrick J. Hrdlicka, Smriti Trikha, Ashok K. Prasad, Virinder S. Parmar y Jesper Wengel. "Novel nucleic acid architectures involving locked nucleic acid (LNA) and pyrene residues: Results from an Indo-Danish collaboration". Pure and Applied Chemistry 77, n.º 1 (1 de enero de 2005): 319–26. http://dx.doi.org/10.1351/pac200577010319.

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We report herein our results for locked nucleic acid (LNA)-type oligonucleotides containing pyrene residues. Pyrene has a large hydrophobic and planar surface area and is therefore a potential intercalating unit; furthermore, it is interesting as a fluorescent tag when covalently bound to DNA. Synthesis and hybridization of conformationally locked universal base surrogates are described together with efficient interstrand communication as shown by the formation of pyrene excimer bands for duplexes containing 2'-N-(pyren-1-yl)methyl-2'-amino-LNA monomers positioned in a zipper-like manner within a DNA duplex.

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7

Mimura, Yuki, Tomoki Nishikawa, Ryo Fuchino, Shiho Nakai, Nobuo Tajima, Mizuki Kitamatsu, Michiya Fujiki y Yoshitane Imai. "Circularly polarised luminescence of pyrenyl di- and tri-peptides with mixed d- and l-amino acid residues". Organic & Biomolecular Chemistry 15, n.º 21 (2017): 4548–53. http://dx.doi.org/10.1039/c7ob00503b.

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8

Winnik, Françoise M., Alexander Adronov y Hiromi Kitano. "Pyrene-labeled amphiphilic poly-(N-isopropylacrylamides) prepared by using a lipophilic radical initiator: synthesis, solution properties in water, and interactions with liposomes". Canadian Journal of Chemistry 73, n.º 11 (1 de noviembre de 1995): 2030–40. http://dx.doi.org/10.1139/v95-251.

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Fluorescently labeled amphiphilic poly-(N-isopropylacrylamides) (PNIPAM) substituted with a N-[4-(1-pyrenyl)butyl]-N-n-octadecyl group at the chain end were prepared by free-radical polymerization in dioxane of N-isopropylacrylamide (NIPAM) using 4,4′-azobis{4-cyano-N,N-[4-(1-pyrenyl)butyl]-n-octadecyl}pentanamide as the initiator. The solution properties of the polymers in water were studied as a function of polymer concentration and temperature. Quasi-elastic light-scattering measurements and fluorescence experiments monitoring the pyrene excimer and pyrene monomer emissions revealed the presence of multimolecular polymeric micelles below the lower critical solution temperature (LCST) of PNIPAM. These underwent partial, reversible reorganization as they were heated above the LCST. The interactions of the pyrene-labeled amphiphilic PNIPAM with dimyristoylphosphatidylcholine (DMPC) liposomes have been examined in water at 25 °C. From fluorescence experiments it was established that the polymeric micelles are disrupted irreversibly upon contact with the liposomes. The anchoring of the polymer chains occurs by insertion of their hydrophobic tail within the phospholipidic bilayer, as evidenced from a large decrease of the pyrene excimer emission relative to pyrene monomer emission. The copolymers remained anchored within the bilayer as the temperature of the copolymer–liposome suspension was raised above the LCST of PNIPAM. Keywords: liposome, poly-(N-isopropylacrylamide), fluorescence, micelles.

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9

Ruiu, Andrea, Mireille Vonlanthen, Sandra M. Rojas-Montoya, Israel González-Méndez y Ernesto Rivera. "Unusual Fluorescence Behavior of Pyrene-Amine Containing Dendrimers". Molecules 24, n.º 22 (12 de noviembre de 2019): 4083. http://dx.doi.org/10.3390/molecules24224083.

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A new class of pyrene-based dendrimers, characterized by the presence of a 1,4,7,10-Tetraazacyclododecane (cyclen) unit as the core, was studied by SSF (steady-state fluorescence) and SPC (single-photon counting fluorescence). The photophysical behavior of these dendrimers was studied in THF, DMF and DMSO solution. The typical signals for pyrene-labeled molecules were recorded in each solvent, showing the representative fluorescence spectra: the corresponding emissions of monomer and excimer of the pyrene chromophore are observed. Unexpectedly, the typical quenching of tertiary amine on the pyrene emission was not observed in these dendrimers. Quenching studies were performed by adding up to 3 equivalents of trifluoroacetic acid (TFA). To our knowledge, this is the first report of pyrene’s unquenching behavior by a tertiary amine.

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10

de Robillard, Guillaume, Oumayma Makni, Hélène Cattey, Jacques Andrieu y Charles H. Devillers. "Towards sustainable synthesis of pyren-1-yl azoliums via electrochemical oxidative C–N coupling". Green Chemistry 17, n.º 9 (2015): 4669–79. http://dx.doi.org/10.1039/c5gc01142f.

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11

Oohora, Koji, Shota Hirayama, Tsuyoshi Mashima y Takashi Hayashi. "Supramolecular dimerization of a hexameric hemoprotein via multiple pyrene-pyrene interactions". Journal of Porphyrins and Phthalocyanines 24, n.º 01n03 (enero de 2020): 259–67. http://dx.doi.org/10.1142/s1088424619500949.

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Protein assemblies are being investigated as a new-class of biomaterials. A supramolecular assembly of a mutant hexameric tyrosine coordinated hemoprotein (HTHP) modified with a pyrene derivative is described. Cysteine was first introduced as a site-specific reaction point at position V44 which is located at the bottom surface of the cylindrical structure of HTHP. [Formula: see text]-(1-pyrenyl)maleimide was then reacted with the mutant. The modification was confirmed by MALDI-TOF mass spectrometry and UV-vis absorption spectroscopy, indicating that approximately 90% cysteine residues are attached via the pyrene derivative. Size exclusion chromatography (SEC) measurements for pyrene-attached HTHP include a single peak which elutes earlier than the unmodified HTHP. Further investigation by SEC and dynamic light scattering (DLS) measurements indicate the desired size corresponding to the dimer of the hemoprotein hexamers. The multivalent effect of pyrene–pyrene interactions including hydrophobic and [Formula: see text]–[Formula: see text] stacking interactions appears to be responsible for including formation of the stable dimer of the hexamers. Interestingly, the assembly dissociates to the hexamer by removal of heme. In the case of the apo-form of pyrene-attached HTHP, the pyrene moiety appears to be incorporated into the heme pocket because the modification point is located at the adjacent residue of the Tyr45 coordinating to heme in the holo-form of HTHP. Subsequent addition of heme into the apo-form of pyrene-attached HTHP regenerates the dimer of the hexamers. The present study demonstrates a unique heme-dependent system in which HTHP is assembled to form a dimer of hexamers in the presence of heme and disassembled by removal of heme.

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12

Thoma, Janine L., Stuart A. McNelles, Alex Adronov y Jean Duhamel. "Direct Measure of the Local Concentration of Pyrenyl Groups in Pyrene-Labeled Dendrons Derived from the Rate of Fluorescence Collisional Quenching". Polymers 12, n.º 12 (5 de diciembre de 2020): 2919. http://dx.doi.org/10.3390/polym12122919.

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The model-free analysis (MFA) was applied to measure the average rate constant (<k>) for pyrene excimer formation (PEF) in a series of pyrene-labeled dendrons referred to as Pyx-G(N), where x (= 2N) is the number of pyrenyl labels born by a dendron of generation N ranging from 1 to 6. <k> was measured in four different solvents, namely tetrahydrofuran (THF), toluene, N,N-dimethylformamide (DMF), and dimethylsulfoxide (DMSO). <k> was found to increase linearly with increasing local pyrene concentration ([Py]loc), where [Py]loc had been determined mathematically for the Pyx-G(N) dendrons. The slope of each straight line changed with the nature of the solvent and represented kdiff, the bimolecular rate constant for PEF. kdiff depended on the solvent viscosity (η) and the probability (p) for PEF upon encounter between an excited and a ground-state pyrene. In a same solvent, kdiff for the Pyx-G(N) dendrons was about 360 ± 30 times smaller than kdiff obtained for ethyl 4-(1-pyrene)butyrate (PyBE), a pyrene model compound similar to the pyrene derivative used to label the dendrons. The massive decrease in kdiff observed for the Pyx-G(N) samples reflected the massive loss in mobility experienced by the pyrenyl labels after being covalently attached onto a macromolecule compared to freely diffusing PyBE. Interestingly, the kdiff values obtained for the Pyx-G(N) dendrons and the PyBE model compound followed similar trends as a function of solvent, indicating that the difference in behavior between the kdiff values obtained in different solvents were merely due to the changes in the η and p values between the solvents. Normalizing the <k> values obtained with the Pyx-G(N) dendrons by the kdiff values obtained for PyBE in the same solvents accounted for changes in η and p, resulting in a master curve upon plotting <k>/(fdiff × kdiff) as a function of [Py]loc, where fdiff was introduced to account for some pyrene aggregation in the higher generation dendron (Py64-G(6)). This result demonstrates that <k> represents a direct measure of [Py]loc in pyrene-labeled macromolecules.

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13

Hill, Jonathan P., Katsuhiko Ariga, Amy Lea Schumacher, Paul A. Karr y Francis D'Souza. "Pyren-1-ylmethyl N-substituted oxoporphyrinogens". Journal of Porphyrins and Phthalocyanines 11, n.º 05 (mayo de 2007): 390–96. http://dx.doi.org/10.1142/s1088424607000448.

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5,10,15,20-tetrakis(3,5-di-tert-butyl-4-oxocyclohexadien-2,5-yl)porphyrinogen was alkylated at its macrocyclic nitrogen atoms with pyren-1-ylmethyl groups and the effect of increasing N-substitution on the spectroscopic and electrochemical properties was investigated. Both pyrene and oxoporphyrinogen chromophores exhibit fluorescence and there is little interaction between them except in the higher N-substituted compounds. Intra- or intermolecular excimer formation by pyrene is precluded by attachment to the bulky oxoporphyrinogen. Electrochemical measurements revealed reversible redox behavior.

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14

Kim, Hyunji, A.-Rong Kim y Jong S. Park. "Synthesis and Property of Pyrene-Naphthalene Diimide-Pyrene Triad". Textile Coloration and Finishing 26, n.º 4 (27 de diciembre de 2014): 305–10. http://dx.doi.org/10.5764/tcf.2014.26.4.305.

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15

Huang, Hong-Jui, Sonai Seenithurai y Jeng-Da Chai. "TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes". Nanomaterials 10, n.º 6 (25 de junio de 2020): 1236. http://dx.doi.org/10.3390/nano10061236.

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At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes.

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16

Yamaji, Minoru, Hajime Maeda, Yasuaki Nanai y Kazuhiko Mizuno. "Substitution Effects of C-C Triple Bonds on Deactivation Processes from the Fluorescent State of Pyrene Studied by Emission and Transient Absorption Measurements". ISRN Physical Chemistry 2012 (14 de octubre de 2012): 1–7. http://dx.doi.org/10.5402/2012/103817.

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Pyrenes substituted with tert-butylethynyl, trimethylsilylethynyl, and trimethylsilylbutadiynyl groups were prepared, and the fluorescence yields (Φf), lifetimes, and triplet-triplet absorption were measured in cyclohexane. Upon introduction of the groups possessing triple bond(s) to the pyrene skeleton, the fluorescence rate (kf) increased. The variation of the terminating groups did not appreciably affect the Φf and kf values. Increasing the number of the triple bond, the kf values increased by the magnitude of order whereas the Φf were not varied. The effect of the ethynyl groups on the kf values was rationalized by the Strickler-Berg equation considering an increase of the 1La transition moment. Triplet-triplet absorption spectra of pyrene derivatives were obtained. The intersystem crossing rates (kisc) increased upon increasing the number of triple bonds terminated with the trimethylsilyl group whereas those between ethynylpyrenes were independent of the terminating groups. Heavy atom effect failed to rationalize the enhancement of the kisc values upon adding the triple bond to the pyrene moiety.

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17

Jiang, Chuang, Ling-Ling Li y Xiao-Qi Yu. "A pyrene-based fast-responsive fluorescent probe for G-quadruplexes". Analytical Methods 9, n.º 16 (2017): 2397–400. http://dx.doi.org/10.1039/c7ay00556c.

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A novel pyrene-based fluorescent probe (3-methyl-2-(pyren-1-yl)benzo[d]thiazol-3-ium iodide) (PBT) was found to be a fast-responsive and highly selective towards G-quadruplexes. PBT exhibited an opposite fluorescent variation tendency on binding with G-quadruplexes and ds-DNAs.

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18

Herbstein, Frank H. "Correction of the space group of [Ni(bipy)2(ONO2)2]·2(pyrene)". Acta Crystallographica Section B Structural Science 57, n.º 4 (24 de julio de 2001): 517–19. http://dx.doi.org/10.1107/s0108768101007807.

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The crystal structure of [Ni(bipy)2(ONO2)2]·2(pyrene), poly[[[bis(nitrato-O)nickel(II)]bis(μ-4,4′-bipyridyl-N,N′] bis(pyrene)], was originally reported in space group Pn [Biradha et al. (1999). Chem. Commun. pp. 1327–1328]. Reasons are given for changing the space group to P21/n. Consequently, incorrect descriptions of the title compound in the literature must be altered. In particular, the structure is not polar. It is further contended that description in terms of `complementary, interpenetrating covalent and noncovalent two-dimensional networks' is misleading as the `noncovalent network' (of pyrenes) has geometrical but not physical significance. The title compound is a typical host–guest inclusion complex.

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19

LUSA, Sari, Kimmo TANHUANPÄÄ, Titta EZRA y Pentti SOMERHARJU. "Direct observation of lipoprotein cholesterol ester degradation in lysosomes". Biochemical Journal 332, n.º 2 (1 de junio de 1998): 451–57. http://dx.doi.org/10.1042/bj3320451.

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We have investigated whether pyrene-labelled cholesterol esters (PyrnCEs) (n indicates the number of aliphatic carbons in the pyrene-chain) can be used to observe the degradation of low-density lipoprotein (LDL)-derived cholesterol esters (CEs) in the lysosomes of living cells. To select the optimal substrates, hydrolysis of the PyrnCE species by lysosomal acid lipase (LAL) in detergent/phospholipid micelles was compared. The rate of hydrolysis varied markedly depending on the length of the pyrenyl chain. Pyr10CE was clearly the best substrate, while Pyr4CE was practically unhydrolysed. Pyr10CE and [3H]cholesteryl linoleate, the major CE species in LDL, were hydrolysed equally by LAL when incorporated together into reconstituted LDL (rLDL) particles, thus indicating that Pyr10CE is a reliable reporter of the lysosomal degradation of native CEs. When rLDL particles containing Pyr4CE or Pyr10CE were incubated with fibroblasts, the accumulation of bright intracellular vesicular fluorescence was observed with the former fluorescent derivative, but not with the latter. However, when the cells were treated with chloroquine, an inhibitor of lysosomal hydrolysis, or when cells with defective LAL were employed, Pyr10CE also accumulated in vesicular structures. HPLC analysis of cellular lipid extracts fully supported these imaging results. It is concluded that PyrnCEs can be used to observe degradation of CEs directly in living cells. This should be particularly useful when exploring the mechanisms responsible for the accumulation of lipoprotein-derived CEs in complex systems such as the arterial intima.

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20

Techajaroonjit, Thanachart, Supawadee Namuangruk, Narid Prachumrak, Vinich Promarak, Mongkol Sukwattanasinitt y Paitoon Rashatasakhon. "Synthesis, characterization, and hole-transporting properties of pyrenyl N-substituted triazatruxenes". RSC Advances 6, n.º 61 (2016): 56392–98. http://dx.doi.org/10.1039/c6ra09688c.

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21

Zhang, Ran, Yun Zhao, Guoling Li, Daisheng Yang y Zhonghai Ni. "A new series of pyrenyl-based triarylamines: syntheses, structures, optical properties, electrochemistry and electroluminescence". RSC Advances 6, n.º 11 (2016): 9037–48. http://dx.doi.org/10.1039/c5ra26017e.

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A new series of pyrenyl-based triarylamines (2a–2e and 3py) were designed and synthesized. These pyrene-based triarylamines exhibit excellent photoelectric properties and are potentially functional materials for devices.

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Stacey, Oliver J., Benjamin D. Ward, Simon J. Coles, Peter N. Horton y Simon J. A. Pope. "Chromophore-labelled, luminescent platinum complexes: syntheses, structures, and spectroscopic properties". Dalton Transactions 45, n.º 25 (2016): 10297–307. http://dx.doi.org/10.1039/c6dt01335j.

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Ligands based upon 4-carboxamide-2-phenylquinoline have been functionalised with naphthyl, anthracenyl and pyrenyl chromophores. The pyrene appended Pt(ii) complex shows excited state equilibration and a long emission lifetime.

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23

Liao, Junqiu, Shenglan Liu, Yongjie Yuan y Hailiang Zhang. "Steric hindrance effect on the thermo- and photo-responsive properties of pyrene-based polymers". New Journal of Chemistry 42, n.º 8 (2018): 5698–708. http://dx.doi.org/10.1039/c8nj00136g.

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We synthesized a novel series of pyrene-based thermo- and photo-dual responsive polymers named poly(pyren-1-yl-o(m,p)-vinylbenzoate) (P(Py-o(m,p)-VB)). And the influence of the steric hindrance effect on LCST-type phase behaviors and photocleavage properties has been studied.

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24

Flamholc, Rafał, Damian Plażuk, Janusz Zakrzewski, Rémi Métivier, Keitaro Nakatani, Anna Makal y Krzysztof Woźniak. "A new class of pyrenyl solid-state emitters: 1-pyrenyl ynones. Synthesis via the Friedel–Crafts route, molecular and electronic structure and photophysical properties". RSC Adv. 4, n.º 60 (2014): 31594–601. http://dx.doi.org/10.1039/c4ra03961k.

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Friedel-Crafts acylation of pyrene with alkynoic acids in the presence of trifluoroacetic anhydride and triflic acid constitutes a direct and efficient route to 1-pyrenyl ynones fluorescent in solution and in the solid state.

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25

Zych, Dawid y Aneta Slodek. "The Impact of a 1,2,3-Triazole Motif on the Photophysical Behavior of Non-K Tetrasubstituted Pyrene with a Substitution Pattern Providing the Long Axial Symmetry". Molecules 27, n.º 13 (5 de julio de 2022): 4314. http://dx.doi.org/10.3390/molecules27134314.

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1,3,6,8-Tetrasubstituted pyrene derivatives with two types of substituents (4-(2,2-dimethylpropyloxy)pyridine, 1-decyl-1,2,3-triazole, 1-benzyl-1,2,3-triazole, and pyrazole), substituted in such a way that provides the long axial symmetry, are prepared and characterized in the present study. To the best of our knowledge, the pyrene derivative containing the same heteroaryl motif (triazole) but substituted by two various alkyls, straight decyl and benzyl-based side chains (C), is reported for the first time. For comparison, compounds with one kind of triazole motif and substituted pyridine or pyrazole groups were prepared (A and B). The photophysical properties of all molecules were evaluated by thermogravimetric analysis (TGA) and UV-Vis spectroscopy (absorption and emission spectra, quantum yields, and fluorescence lifetimes). The obtained results were compared to analogues substituted at the 1,3,6,8 positions by one kind of substituent and also with all the 1,3,6,8-tetrasubstituted pyrenes reported in the literature substituted by two kinds of substituents with a substitution pattern that provides long axial symmetry. In addition, theoretical studies based on DFT and TD-DFT were performed that supported the interpretation of the experimental results. The photophysical properties of tetrasubstituted pyrene derivatives having triazole units at the 1,8-positions, respectively, and other identical substituents at the 3,6 positions show the dominance of triazole units in the pyrene framework; the dominance is even higher in the case of the substitution of 1,3,6,8 positions by triazoles, but containing two various alkyls.

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Vila, Joaquim y Magdalena Grifoll. "Actions of Mycobacterium sp. Strain AP1 on the Saturated- and Aromatic-Hydrocarbon Fractions of Fuel Oil in a Marine Medium". Applied and Environmental Microbiology 75, n.º 19 (7 de agosto de 2009): 6232–39. http://dx.doi.org/10.1128/aem.02726-08.

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ABSTRACT The pyrene-degrading Mycobacterium sp. strain AP1 grew in nutrient-supplemented artificial seawater with a heavy fuel oil as the sole carbon source, causing the complete removal of all linear (C12 to C40) and branched alkanes from the aliphatic fraction, as well as an extensive degradation of the three- and four-ring polycyclic aromatic hydrocarbons (PAHs) phenanthrene (95%), anthracene (80%), fluoranthene (80%), pyrene (75%), and benzo(a)anthracene (30%). Alkylated PAHs, which are more abundant in crude oils than the nonsubstituted compounds, were selectively attacked at extents that varied from more than 90% for dimethylnaphthalenes, methylphenanthrenes, methylfluorenes, and methyldibenzothiophenes to about 30% for monomethylated fluoranthenes/pyrenes and trimethylated phenanthrenes and dibenzothiophenes. Identification of key metabolites indicated the utilization of phenanthrene, pyrene, and fluoranthene by known assimilatory metabolic routes, while other components were cooxidized. Detection of mono- and dimethylated phthalic acids demonstrated ring cleavage and further oxidation of alkyl PAHs. The extensive degradation of the alkanes, the two-, three-, and four-ring PAHs, and their 1-, 2-, and 3-methyl derivatives from a complex mixture of hydrocarbons by Mycobacterium sp. strain AP1 illustrates the great substrate versatility of alkane- and PAH-degrading mycobacteria.

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27

Zych, Dawid. "1,3-Di(hetero)aryl-7-substituted Pyrenes—An Undiscovered Area of Important Pyrene Derivatives". Proceedings 41, n.º 1 (14 de noviembre de 2019): 28. http://dx.doi.org/10.3390/ecsoc-23-06470.

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In this work, the necessity of synthesis of 1,3-di(hetero)aryl-7-substituted pyrenes is presented based on the results of theoretical calculations by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) by using Gaussian 09 program with B3LYP exchange-correlation functional and 6-31G** basis set. What is more, the synthetic routes with feasible reagents and conditions are presented. The subject of theoretical considerations are two pyrene derivatives which contain at position 1 and 3 pyrazolyl substituents and at position 7 amine (1) or boron (2) derivative. The theoretical calculations were also performed for the osmium complexes with mentioned ligands (3 and 4). The influence of electron-donating/accepting character of the substituent at position 7 of pyrene on the properties of molecules has been established.

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28

Cheng, Yaping, Geoffrey Gontard, Abderrahim Khatyr, Michael Knorr y Hani Amouri. "N-Heterocyclic Carbene Copper (I) Complexes Incorporating Pyrene Chromophore: Synthesis, Crystal Structure, and Luminescent Properties". Molecules 28, n.º 10 (11 de mayo de 2023): 4025. http://dx.doi.org/10.3390/molecules28104025.

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Luminescent N-heterocyclic carbene chloride copper (I) complexes incorporating pyrene chromophore (1-Pyrenyl-NHC-R)-Cu-Cl, (3, 4) have been prepared and fully characterized. Two complexes were prepared with R = methyl (3) and R = naphthyl groups (4) at the nitrogen center of the carbene unit to tune their electronic properties. The molecular structures of 3 and 4 have been elucidated by X-ray diffraction and confirm the formation of the target compounds. Preliminary results reveal that all compounds including the imidazole-pyrenyl ligand 1 are emissive in the blue region at room temperature in solution and in solid-state. All complexes display quantum yields comparable or higher when compared to the parent pyrene molecule. Interestingly replacement of the methyl by naphthyl group increases the quantum yield by almost two-folds. These compounds might show promise for applications as optical displays.

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29

Liang, Yanna, Dale R. Gardner, Charles D. Miller, Dong Chen, Anne J. Anderson, Bart C. Weimer y Ronald C. Sims. "Study of Biochemical Pathways and Enzymes Involved in Pyrene Degradation by Mycobacterium sp. Strain KMS". Applied and Environmental Microbiology 72, n.º 12 (13 de octubre de 2006): 7821–28. http://dx.doi.org/10.1128/aem.01274-06.

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ABSTRACT Pyrene degradation is known in bacteria. In this study, Mycobacterium sp. strain KMS was used to study the metabolites produced during, and enzymes involved in, pyrene degradation. Several key metabolites, including pyrene-4,5-dione, cis-4,5-pyrene-dihydrodiol, phenanthrene-4,5-dicarboxylic acid, and 4-phenanthroic acid, were identified during pyrene degradation. Pyrene-4,5-dione, which accumulates as an end product in some gram-negative bacterial cultures, was further utilized and degraded by Mycobacterium sp. strain KMS. Enzymes involved in pyrene degradation by Mycobacterium sp. strain KMS were studied, using 2-D gel electrophoresis. The first protein in the catabolic pathway, aromatic-ring-hydroxylating dioxygenase, which oxidizes pyrene to cis-4,5-pyrene-dihydrodiol, was induced with the addition of pyrene and pyrene-4,5-dione to the cultures. The subcomponents of dioxygenase, including the alpha and beta subunits, 4Fe-4S ferredoxin, and the Rieske (2Fe-2S) region, were all induced. Other proteins responsible for further pyrene degradation, such as dihydrodiol dehydrogenase, oxidoreductase, and epoxide hydrolase, were also found to be significantly induced by the presence of pyrene and pyrene-4,5-dione. Several nonpathway-related proteins, including sterol-binding protein and cytochrome P450, were induced. A pyrene degradation pathway for Mycobacterium sp. strain KMS was proposed and confirmed by proteomic study by identifying almost all the enzymes required during the initial steps of pyrene degradation.

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30

Jurković, Marta, Marijana Radić Stojković, Ksenija Božinović, Davor Nestić, Dragomira Majhen, Estefanía Delgado-Pinar, Mario Inclán, Enrique García-España y Ivo Piantanida. "Novel Tripodal Polyamine Tris-Pyrene: DNA/RNA Binding and Photodynamic Antiproliferative Activity". Pharmaceutics 15, n.º 9 (25 de agosto de 2023): 2197. http://dx.doi.org/10.3390/pharmaceutics15092197.

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A novel tri-pyrene polyamine (TAL3PYR) bearing net five positive charges at biorelevant conditions revealed strong intramolecular interactions in aqueous medium between pyrenes, characterised by pronounced excimer fluorescence. A novel compound revealed strong binding to ds-DNA and ds-RNA, along with pronounced thermal stabilisation of DNA/RNA and extensive changes in DNA/RNA structure, as evidenced by circular dichroism. New dye caused pronounced ds-DNA or ds-RNA condensation, which was attributed to a combination of electrostatic interactions between 5+ charge of dye and negatively charged polynucleotide backbone, accompanied by aromatic and hydrophobic interactions of pyrenes within polynucleotide grooves. New dye also showed intriguing antiproliferative activity, strongly enhanced upon photo-induced activation of pyrenes, and is thus a promising lead compound for theranostic applications on ds-RNA or ds-DNA targets, applicable as a new strategy in cancer and gene therapy.

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31

Hu, Jie, Dong Zhang y Frank W. Harris. "Ruthenium(III) Chloride Catalyzed Oxidation of Pyrene and 2,7-Disubstitued Pyrenes: An Efficient, One-Step Synthesis of Pyrene-4,5-diones and Pyrene-4,5,9,10-tetraones". Journal of Organic Chemistry 70, n.º 2 (enero de 2005): 707–8. http://dx.doi.org/10.1021/jo048509q.

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32

Rubiyatno, Zee Chuang Teh, Diah Velentina Lestari, Arma Yulisa, Muthah Musa, Tse-Wei Chen, Noura M. Darwish, Bandar M. AlMunqedhi y Tony Hadibarata. "Tolerance of earthworms in soil contaminated with polycyclic aromatic hydrocarbon". Industrial and Domestic Waste Management 2, n.º 1 (5 de abril de 2022): 9–16. http://dx.doi.org/10.53623/idwm.v2i1.62.

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Pyrene is a very resistant polycyclic aromatic hydrocarbon (PAH) with four benzene rings that survives in the environment. This study was aimed at investigating the tolerance of earthworms in soil contaminated with pyrene. The studies were performed by employing earthworms gathered from shady regions adjacent to sewage ponds as pyrene degraders to eradicate pyrene from the soil. Numerous factors affecting pyrene degradation efficiency were explored, including the effects of contaminant concentration, earthworm and soil ration, and soil condition. The highest pyrene removal (31.2%) was shown by earthworms in the condition of soil mixed with cow dung. Pyrene decomposition was inhibited during soil sterilization due to the absence of soil microorganisms and indigenous pyrene-degrading bacteria. Nonetheless, earthworms are suitable for use as pyrene degraders in contaminated soil.

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33

Dong, Sun, Chen, Yang, Li, Wang y Luo. "Influence of Cyclodextrins on Thermosensitive and Fluorescent Properties of Pyrenyl-Containing PDMAA". Polymers 11, n.º 10 (26 de septiembre de 2019): 1569. http://dx.doi.org/10.3390/polym11101569.

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A series of pyrenyl-containing PDMAA copolymers were prepared by free radical copolymerization of dimethylacrylamide (DMAA) with pyrenebutanoyloxy ethyl methacrylate (PyBEMA). The structure of as-prepared copolymers was characterized by UV, FT-IR and 1H NMR spectroscopy. The effect of cyclodextrins (α-CD, β-CD and γ-CD) on the thermosensitivity and fluorescence of the copolymers in aqueous solutions were investigated. It was found that the as-prepared copolymers exhibit lower critical solution temperature (LCST)-type thermosensitivity. Cloud point (Tcp) decreases with the increasing molar content of PyBEMA unit in the copolymers. Tcp of the copolymers increases after the CD is added from half molar to equivalent amount relative to pyrenyl moiety, and that further adding twice equivalent CD results in a slight decrease in Tcp. The copolymers exhibit a pyrene emission located at 377 nm and a broad excimer emission centered at 470 nm. The copolymers in water present a stronger excimer emission (Intensity IE) relative to monomer emission (Intensity IM) than that in ethanol. The IE/IM values decrease after the addition of equivalent α-CD, β-CD and γ-CD into the copolymers in aqueous solution, respectively. The IE/IM values abruptly increase as the copolymers’ concentration is over 0.2 mg/L whether in ethanol solution or aqueous solution with or without CD, from which can probably be inferred that intra-polymeric pyrene aggregates dominate for solution concentration below 0.2 mg/L and inter-polymeric pyrene aggregates dominate over 0.2 mg/L. Furthermore, the formation of the CD pseudopolyrotaxanes makes it possible to form pyrene aggregates. For high concentration of 5 g/L, the copolymers and their inclusion complexes completely exhibit an excimer emission. The IE values abruptly increased as the temperature went up to Tcp, which indicates that the IE values can be used to research phase separation of polymers.

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34

Košćak, Marta, Isabela Pehar, Ksenija Božinović, Goutam Kumar Kole, Sandra Sobočanec, Iva I. Podgorski, Marija Pinterić et al. "Para-N-Methylpyridinium Pyrenes: Impact of Positive Charge on ds-DNA/RNA and Protein Recognition, Photo-Induced Bioactivity, and Intracellular Localisation". Pharmaceutics 14, n.º 11 (17 de noviembre de 2022): 2499. http://dx.doi.org/10.3390/pharmaceutics14112499.

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The 2- and 2,7- substituted para-N-methylpyridinium pyrene cations show high-affinity intercalation into ds-DNAs, whereas their non-methylated analogues interacted with ds-DNA/RNA only in the protonated form (at pH 5), but not at physiological conditions (pH 7). The fluorescence from non-methylated analogues was strongly dependent on the protonation of the pyridines; consequently, they act as fluorescence ratiometric probes for simultaneous detection of both ds-DNA and BSA at pH 5, relying on the ratio between intensities at 420 nm (BSA specific) and 520 nm (DNA specific), whereby exclusively ds-DNA sensing could be switched-off by adjustment to pH 7. Only methylated, permanently charged pyrenes show photoinduced cleavage of circular DNA, attributed to pyrene-mediated irradiation-induced production of singlet oxygen. Consequently, the moderate toxicity of these cations against human cell lines is strongly increased upon irradiation. Detailed studies revealed increased total ROS production in cells treated by the compounds studied, accompanied by cell swelling and augmentation of cellular complexity. The most photo-active 2-para-N-methylpyridinium pyrene showed significant localization at mitochondria, its photo-bioactivity likely due to mitochondrial DNA damage. Other derivatives were mostly non-selectively distributed between various cytoplasmic organelles, thus being less photoactive.

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35

Moody, Joanna D., James P. Freeman, Peter P. Fu y Carl E. Cerniglia. "Degradation of Benzo[a]pyrene by Mycobacterium vanbaalenii PYR-1". Applied and Environmental Microbiology 70, n.º 1 (enero de 2004): 340–45. http://dx.doi.org/10.1128/aem.70.1.340-345.2004.

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ABSTRACT Metabolism of the environmental pollutant benzo[a]pyrene in the bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized benzo[a]pyrene with dioxygenases and monooxygenases at C-4,5, C-9,10, and C-11,12. The metabolites were separated by reversed-phase high-performance liquid chromatography (HPLC) and characterized by UV-visible, mass, nuclear magnetic resonance, and circular dichroism spectral analyses. The major intermediates of benzo[a]pyrene metabolism that had accumulated in the culture media after 96 h of incubation were cis-4,5-dihydro-4,5-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-4,5-dihydrodiol), cis-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-11,12-dihydrodiol), trans-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene trans-11,12-dihydrodiol), 10-oxabenzo[def]chrysen-9-one, and hydroxymethoxy and dimethoxy derivatives of benzo[a]pyrene. The ortho-ring fission products 4-formylchrysene-5-carboxylic acid and 4,5-chrysene-dicarboxylic acid and a monocarboxylated chrysene product were formed when replacement culture experiments were conducted with benzo[a]pyrene cis-4,5-dihydrodiol. Chiral stationary-phase HPLC analysis of the dihydrodiols indicated that benzo[a]pyrene cis-4,5-dihydrodiol had 30% 4S,5R and 70% 4R,5S absolute stereochemistry. Benzo[a]pyrene cis-11,12-dihydrodiol adopted an 11S,12R conformation with 100% optical purity. The enantiomeric composition of benzo[a]pyrene trans-11,12-dihydrodiol was an equal mixture of 11S,12S and 11R,12R molecules. The results of this study, in conjunction with those of previously reported studies, extend the pathways proposed for the bacterial metabolism of benzo[a]pyrene. Our study also provides evidence of the stereo- and regioselectivity of the oxygenases that catalyze the metabolism of benzo[a]pyrene in M. vanbaalenii PYR-1.

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36

Sharma, Ashutosh y Otto S. Wolfbeis. "Fiberoptic Oxygen Sensor Based on Fluorescence Quenching and Energy Transfer". Applied Spectroscopy 42, n.º 6 (agosto de 1988): 1009–11. http://dx.doi.org/10.1366/0003702884430470.

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A new type of oxygen sensor is described that is based on electronic energy transfer from a donor (whose fluorescence is efficiently quenched by molecular oxygen) to an acceptor (which is less affected by oxygen). We use pyrene as the donor and perylene as the acceptor. The fluorescence emission band of the donor shows good overlap with the absorption band of the acceptor. When excited at 320 nm, the two-fluorophore system shows strong fluorescence at 476 nm, where pyrene itself is nonfluorescent. Although perylene is not efficiently quenched by oxygen, the system strongly responds to oxygen because fluorescence is quenched with an efficiency that by far exceeds the quenching efficiency for pyrene or pyrelene alone. The principle has been applied in order to devise a fiberoptic oxygen sensor by incorporating the two dyes in a polymer matrix that has been attached to the end of an optical fiber. Oxygen can be detected in the 0–150 kPa range with ±0.3 kPa precision. The detection limit is 60 Pa oxygen.

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37

Milzani, Aldo, Isabella DalleDonne y Roberto Colombo. "N-Ethylmaleimide-modified actin filaments do not bundle in the presence of α-actinin". Biochemistry and Cell Biology 73, n.º 1-2 (1 de enero de 1995): 116–22. http://dx.doi.org/10.1139/o95-014.

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We show that the modification of actin subdomain 1 by N-ethylmaleimide (NEM), which binds Cys-374 close to the C-terminus of the molecule, inhibits the α-actinin-induced bundling of actin filaments. This effect is not merely related to the block of Cys-374, since N-(1-pyrenyl)iodoacetamide (pyrene-IA) is unable to prevent bundling. Considering that NEM (but not pyrene-IA) influences actin assembly, we suggest that the inhibition of the actin – α-actinin interaction is due to the chemical modification of actin Cys-374 which, by inducing a marked spatial reorganization of actin monomers, is able to modify both the intra- and inter-molecular interactions of this protein. Finally, NEM-modified actin filaments form bundles in the presence of polyethylene glycol 6000 since, in this case, the side by side association of actin filaments does not depend on the accessibility of binding sites nor on the formation of chemical bonds.Key words: chemically modified actin, N-ethylmaleimide, pyrene-IA, Cys-374, actin bundles, α-actinin.

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38

Feng, Qi, Wenhui Huan, Jiali Wang, Fang Guo, Jiadan Lu, Guowang Diao y Yaqi Shan. "Cocrystal Assembled by Pyrene Derivative and 1,4-Diiodotetrafluorobenzene via a C=O···I Halogen Bond". Crystals 8, n.º 10 (17 de octubre de 2018): 392. http://dx.doi.org/10.3390/cryst8100392.

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Cocrystal formation is a strategy used to modify the solid-state properties of a given molecule. In this study, a new cocrystal assembled by 1,4-Diiodotetrafluorobenzene (1,4-DITFB) and a pyrene derivative, 1-acetyl-3-phenyl-5-(1-pyrenyl)-pyrazoline (APPP), was synthesized. Due to the twisted structure of APPP, the crystal structure is greatly different with some large π-conjugated compounds, which exhibits edge-to-face π-stacked arrangement between 1,4-DITFB and pyrene rings, rather than the face-to-face π-stacked arrangement. Hirshfeld surface analysis and the shift of characteristic vibration band of the carbonyl group in FT-IR spectroscopy suggest the formation of a C=O···I halogen bond.

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39

Dar, Tawseef Ahmad, Amir Sohel Bulbul, Muniappan Sankar y Karl M. Kadish. "Meso-Tetrapyrenylporphyrins: Synthesis, structural, spectral, electrochemical properties and Förster energy transfer (FRET) studies". Journal of Porphyrins and Phthalocyanines 24, n.º 05n07 (mayo de 2020): 985–92. http://dx.doi.org/10.1142/s108842462050008x.

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Meso-tetrapyrenylporphyrin and its metal (Co[Formula: see text], Cu[Formula: see text], Ni[Formula: see text] and Zn[Formula: see text]) complexes were synthesized, characterized and studied for their spectral, electrochemical and energy transfer properties. DFT optimization was carried out to gain an insight into the interactions between the porphyrin [Formula: see text]-system and the pyrenyl substituents. The pyrenyl substituents and the porphyrin core remain essentially orthogonal to each other in both the free base and the metallated porphyrins. Redox potentials of the pyrenylporphyrins are marginally shifted as compared to their corresponding phenyl derivatives. Förster resonance energy transfer (FRET) studies were carried out in toluene for free-base pyrenylporphyrin and its Zn(II) complex. Since pyrene is a good donor, an efficient energy transfer from pyrene (D) to the porphyrin core (A) on the order of 80–85% was observed for these two compounds. It was observed that energy transfer occurs mainly via ”through-bond” (TB) interaction rather than ”through-space” (TS) interaction.

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40

Styler, S. A., M. E. Loiseaux y D. J. Donaldson. "Substrate effects in the photoenhanced ozonation of pyrene". Atmospheric Chemistry and Physics Discussions 10, n.º 11 (15 de noviembre de 2010): 27825–52. http://dx.doi.org/10.5194/acpd-10-27825-2010.

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Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.

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41

Styler, S. A., M. E. Loiseaux y D. J. Donaldson. "Substrate effects in the photoenhanced ozonation of pyrene". Atmospheric Chemistry and Physics 11, n.º 3 (14 de febrero de 2011): 1243–53. http://dx.doi.org/10.5194/acp-11-1243-2011.

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Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.

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42

Qutob, Mohammad, Mohd Rafatullah, Syahidah Akmal Muhammad, Abeer M. Alosaimi, Hajer S. Alorfi y Mahmoud A. Hussein. "A Review of Pyrene Bioremediation Using Mycobacterium Strains in a Different Matrix". Fermentation 8, n.º 6 (31 de mayo de 2022): 260. http://dx.doi.org/10.3390/fermentation8060260.

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Polycyclic aromatic hydrocarbons are compounds with 2 or more benzene rings, and 16 of them have been classified as priority pollutants. Among them, pyrene has been found in higher concentrations than recommended, posing a threat to the ecosystem. Many bacterial strains have been identified as pyrene degraders. Most of them belong to Gram-positive strains such as Mycobacterium sp. and Rhodococcus sp. These strains were enriched and isolated from several sites contaminated with petroleum products, such as fuel stations. The bioremediation of pyrene via Mycobacterium strains is the main objective of this review. The scattered data on the degradation efficiency, formation of pyrene metabolites, bio-toxicity of pyrene and its metabolites, and proposed degradation pathways were collected in this work. The study revealed that most of the Mycobacterium strains were capable of degrading pyrene efficiently. The main metabolites of pyrene were 4,5-dihydroxy pyrene, phenanthrene-4,5-dicarboxylate, phthalic acid, and pyrene-4,5-dihydrodiol. Some metabolites showed positive results for the Ames mutagenicity prediction test, such as 1,2-phenanthrenedicarboxylic acid, 1-hydroxypyrene, 4,5-dihydropyrene, 4-phenanthrene-carboxylic acid, 3,4-dihydroxyphenanthrene, monohydroxy pyrene, and 9,10-phenanthrenequinone. However, 4-phenanthrol showed positive results for experimental and prediction tests. This study may contribute to enhancing the bioremediation of pyrene in a different matrix.

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43

KUMARI, BEEMA y RAM CHANDRA. "A Review on Bacterial Degradation of Benzo[a]pyrene and Its Impact on Environmental Health". Journal of Experimental Biology and Agricultural Sciences 10, n.º 6 (31 de diciembre de 2022): 1253–65. http://dx.doi.org/10.18006/2022.10(6).1253.1265.

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Benzo[a]pyrene is a polycyclic aromatic hydrocarbon (PAH) having a high molecular weight. Benzo[a]pyrene and other PAHs are induces severe acute or chronic human health hazards and are extremely carcinogenic, mutagenic, immunotoxic, and teratogenic. Microorganisms play a crucial part in the degradation of benzo[a]pyrene from polluted environments. Such micro-organisms synthesize monooxygenase and di-oxygenase enzymes that proceed with the aerobic or anaerobic catabolic degradations of benzo[a]pyrene. Bioaugmentation, biomineralization, and biostimulation methods can be used for the decontamination of benzo[a]pyrene from hydrocarbon contaminated sites. In this review paper, we thoroughly explained the impacts of benzo[a]pyrene pollution on human health and the environment. Further, this study also described various pathways regarding the bio-degradation of benzo[a]pyrene and also an updated overview of future prospects of benzo[a]pyrene biodegradation.

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44

Yip, Jamie, Jean Duhamel, Xing Ping Qiu y Françoise M. Winnik. "Fluorescence studies of a series of monodisperse telechelic α,ω-dipyrenyl poly(N-isopropylacrylamide)s in ethanol and in water". Canadian Journal of Chemistry 89, n.º 2 (febrero de 2011): 163–72. http://dx.doi.org/10.1139/v10-117.

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Steady-state and time-resolved fluorescence measurements were performed on solutions in ethanol and in water (23 °C) of a series of poly(N-isopropylacrylamide)s labeled with a pyrenyl group at each chain end (Py2-PNIPAM) and ranging in molecular weight (Mn) from 5 900 to 44 500 g·mol−1. Water and ethanol are of similar solvent quality towards the PNIPAM chain. The pyrene labels, in contrast, are soluble in ethanol but not in water. The efficiency of excimer formation for Py2-PNIPAM samples in ethanol decreased with increasing chain length, a trend typical of pyrene end-labeled polymers in good solvents. The ratio IE/IM, where IE is the Py excimer emission intensity and IM is the Py monomer emission intensity, scaled as Mn−1.4, where Mn is the number-average molecular weight of the sample. The kinetics of excimer formation were more complex for aqueous Py2-PNIPAM solutions, as a consequence of pyrene–pyrene association prior to excitation. The excimer time-dependent profiles exhibited significantly faster rise times, compared with the situation in ethanol, and they could not be fitted with the traditional Birks scheme. The results are discussed in the context of the solution properties of telechelic amphiphilic PNIPAMs and are compared with data gathered previously in studies of dipyrenyl end-labeled poly(ethylene oxides), the only other polymers soluble in water and organic solvents subjected to similar studies in the past.

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45

Moriguchi, Tomohisa, Satomi Hida, Fumio Yoneda y Kazuo Shinozuka. "Synthesis and Spectroscopic Properties of a Novel Bifunctional Pyrene Derivative and its Incorporation into OligoDNA". Australian Journal of Chemistry 68, n.º 2 (2015): 256. http://dx.doi.org/10.1071/ch14477.

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A new pyrene derivative bearing a modifiable silyl function (electron-donating group) and cyano function (electron-withdrawing group) was synthesized as a labelling agent for biological substances. The modified pyrene exhibited a marked bathochromic shift in both absorption and fluorescence spectra. The fluorescence quantum yield of the modified pyrene was also significantly increased compared with that of the unmodified pyrene. The modified pyrene was successfully incorporated into oligoDNA.

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46

Cheng, Chih-Chia, Jyun-Jie Huang, Adem Ali Muhable, Zhi-Sheng Liao, Shan-You Huang, Shun-Chieh Lee, Chih-Wei Chiu y Duu-Jong Lee. "Supramolecular fluorescent nanoparticles functionalized with controllable physical properties and temperature-responsive release behavior". Polymer Chemistry 8, n.º 15 (2017): 2292–98. http://dx.doi.org/10.1039/c7py00276a.

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47

Stefansson, Steingrimur, Lára A. Stefansson, Suk-won Chung, Kevin Ko, Hena H. Kwon y Saeyoung Nate Ahn. "Evaluation of Aromatic Boronic Acids as Ligands for Measuring Diabetes Markers on Carbon Nanotube Field-Effect Transistors". Journal of Nanotechnology 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/371487.

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Biomolecular detections performed on carbon nanotube field-effect transistors (CNT-FETs) frequently use reactive pyrenes as an anchor to tether bioactive ligands to the hydrophobic nanotubes. In this paper, we explore the possibility of directly using bioactive aromatic compounds themselves as CNT-FET ligands. This would be an efficient way to functionalize CNT-FETs since many aromatic compounds bind avidly to nanotubes, and it would also ensure that ligand-binding molecules would be brought in close proximity to the nanotubes. Using a model system consisting of pyrene, phenanthrene, naphthalene, or phenyl boronic acids immobilized on CNT-FET wafers, we show that all are able to bind glycated human serum albumin (gHSA), which is an important diabetes marker. Pyrene boronic acid proved to bind CNTs with the greatest apparent affinity as measured by gHSA impedance. Interestingly, gHSA CNT-FET signal intensity, which is proportional to amount of protein bound, remained essentially unchanged for all the boronic acids tested.

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48

Kim, Seong-Jae, Jaekyeong Song, Ohgew Kweon, Ricky D. Holland, Dae-Wi Kim, Jongnam Kim, Li-Rong Yu y Carl E. Cerniglia. "Functional Robustness of a Polycyclic Aromatic Hydrocarbon Metabolic Network Examined in anidAAromatic Ring-Hydroxylating Oxygenase Mutant of Mycobacterium vanbaalenii PYR-1". Applied and Environmental Microbiology 78, n.º 10 (9 de marzo de 2012): 3715–23. http://dx.doi.org/10.1128/aem.07798-11.

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ABSTRACTIn this study, we obtained over 4,000 transposon mutants ofMycobacterium vanbaaleniiPYR-1 and analyzed one of the mutants, 8F7, which appeared to lose its ability to degrade pyrene while still being able to degrade fluoranthene. This mutant was identified to be defective innidA, encoding an aromatic ring-hydroxylating oxygenase (RHO), known to be involved in the initial oxidation step of pyrene degradation. When cultured with pyrene as a sole source of polycyclic aromatic hydrocarbon (PAH), high-pressure liquid chromatography analysis revealed that thenidAmutant showed a significant decrease in the rate of pyrene degradation compared to the wild-type PYR-1, although pyrene was still being degraded. However, when incubated with PAH mixtures including pyrene, phenanthrene, and fluoranthene, the pyrene degradation rate of the mutant was higher than that of the mutant previously incubated with pyrene as a sole source of PAH. There was no significant difference between wild-type PYR-1 and the mutant in the rates of phenanthrene and fluoranthene degradation. From the whole-cell proteome analysis of mutant 8F7 induced by pyrene, we identified expression of a number of RHO enzymes which are suspected to be responsible for pyrene degradation in thenidAmutant, which had no expression of NidA. Taken together, results in this study provide direct evidence for thein vivofunctional role ofnidAin pyrene degradation at the level of the ring-cleavage-process (RCP) functional module but also for the robustness of the PAH metabolic network (MN) to such a genetic perturbation.

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49

Jadhav, Sushilkumar. "Synthesis of fluorescent carboxylic acid ligands for construction of monolayers on nanostructures". Open Chemistry 10, n.º 5 (1 de octubre de 2012): 1640–46. http://dx.doi.org/10.2478/s11532-012-0078-2.

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AbstractTwo new long-chain carboxylic acids (1, 2) bearing strong fluorescent group pyrene as ligands for Self-Assembled Monolayers (SAMs) have been synthesized. The multistep targeted synthesis is accomplished by use of Pyren-1-yl methylamine hydrochloride and employing simplified synthetic protocols. Compound 2 contains a chiral center purposely introduced along the atom chain in order to make it suitable for chiro-optical studies of the resulting SAMs.

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50

Zimmermann, Domenik M., Knud Seufert, Luka Ðorđević, Tobias Hoh, Sushobhan Joshi, Tomas Marangoni, Davide Bonifazi y Willi Auwärter. "Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)". Beilstein Journal of Nanotechnology 11 (29 de septiembre de 2020): 1470–83. http://dx.doi.org/10.3762/bjnano.11.130.

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The controlled modification of electronic and photophysical properties of polycyclic aromatic hydrocarbons by chemical functionalization, adsorption on solid supports, and supramolecular organization is the key to optimize the application of these compounds in (opto)electronic devices. Here, we present a multimethod study comprehensively characterizing a family of pyridin-4-ylethynyl-functionalized pyrene derivatives in different environments. UV–vis measurements in toluene solutions revealed absorption at wavelengths consistent with density functional theory (DFT) calculations, while emission experiments showed a high fluorescence quantum yield. Scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of the pyrene derivatives adsorbed on a Cu(111)-supported hexagonal boron nitride (hBN) decoupling layer provided access to spatially and energetically resolved molecular electronic states. We demonstrate that the pyrene electronic gap is reduced with an increasing number of substituents. Furthermore, we discuss the influence of template-induced gating and supramolecular organization on the energies of distinct molecular orbitals. The selection of the number and positioning of the pyridyl termini in tetrasubstituted, trans- and cis-like-disubstituted derivatives governed the self-assembly of the pyrenyl core on the nanostructured hBN support, affording dense-packed arrays and intricate porous networks featuring a kagome lattice.

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Artículos de revistas sobre el tema "Pyrene"

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