Fluorescence Quenching of Anthracene by N,N-Diethylaniline in the Sodium Dodecyl Sulfate/Benzyl Alcohol/Water System

Photoinduced electron-transfer reaction of anthracene with N,N-diethylaniline (DEA) was studied in the SDS (sodium dodecyl sulfate)/BA (benzyl alcohol)/H₂O system. In an oil/water microemulsion, only the excited anthracene located at the interface can be quenched by DEA. In a water/oil microemulsion, this quenching reaction occurs in the BA continuous phase. Besides being the quencher of the excited anthracene, DEA could also change the system's structure.     

Deprotonated 2,3:5,6-Dibenzo-7- aza bicyclo[2.2.1]hepta-2,5-diene as a Nitrido Nitrogen Source by Anthracene Elimination: Synthesis of an Iodide(nitride)chromium(VI) Complex

Instead of azides, which can be explosive and poorly soluble in nonpolar solvents, azabicycloheptadienes can be used to synthesize nitrides. The reaction of diiodide 1 with the lithium amide 3 provides the red nitride 2 in 60 % yield with loss of lithium iodide and anthracene. The remaining iodo ligand in 2 can undergo an exchange reaction with lithium amide 3 , but no more anthracene is released.     

Diels-Alder ribozyme catalysis: a computational approach

A computational comparison of the Diels-Alder reaction of a maleimide and an anthracene in water and the active site of the ribozyme Diels-Alderase is reported. During the course of the catalyzed reaction, the maleimide is held in the hydrophobic pocket while the anthracene approaches to the maleimide through the back passage of the active site. The active site is so narrow that the anthracene has to adopt a tilted approach angle toward maleimide. The conformation of the active site changes marginally at different states of the reaction. Active site dynamics contribution to catalysis has been ruled out. The active site stabilizes the product more than the transition state (TS). The reaction coordinates of the ribozyme reaction in TS, RC1-CD1 and RC4-CD2, are 2.35 and 2.33 A, respectively, compared to 2.37 and 2.36 A in water. The approach angle of anthracene toward maleimide is twisted by 18 degrees in the TS structure of ribozyme reaction while no twisted angle is found in TS of the reaction in water. The free energy barriers for reactions in both ribozyme and water were obtained by umbrella sampling combined with SCCDFTB/MM. The calculated free energy barriers for the ribozyme and water reactions are in good agreement with the experimental values. As expected, Mulliken charges of the atoms involved in the ribozyme reaction change in a similar manner as that of the reaction in water. The proficiency of the Diels-Alder ribozyme reaction originates from the active site holding the two reactants in reactive conformations, in which the reacting atoms are brought together in van der Waals distances and reactants approach to each other at an appropriate angle.     

REVERSIBLE PHOTODIMERIZATION OF ANTHRACENE AND TETRACENE

Abstract— Dianthracene is efficiently photodissociated, forming anthracene with a quantum yield of about 0.63. Like anthracene, tetracene undergoes a reversible photochemical reaction, the product of which appears to be di-tetracene. In dilute, deoxygenated solutions the of quantum yeild for the formation of di-tetracene is directly proportional to the concentration of the monomer ødim = 2.2 (). The quantum yield for the reverse reaction is approximately 0.74
When dilute deaerated solutions of anthracene are irradiated with the unfiltered radiation from a quartz-mercury arc, a degradation product is formed. Unlike the dimer, this product cannot be converted into anthracene either by heating it to 200C or by irradiating it in solution with light of 254 nm. This degradation product appears to be the compound or compounds which Birks et al. believed to be dianthracene. Irradiation of deaerated solutions of anthracene (or tetracene) with light of wavelenghts longer than 300 nm produces only the dimer, which has an absorption spectrum similar to that reported by Coulson et al.     

ON PHOTOREACTIONS OF ANTHRACENE IN SOLID MATRIX—I. PHOTODIMERIZATION

Abstract— The influence of a surrounding transparent matrix on the photochemical behavior of an absorbing solute has been investigated on the particular case of anthracene in KBr , KCl and in HBO₂ and B₂O₃ glasses. In KBr compressed powders, dianthracene formation occurs with a high yield, whereas it is forbidden or negligible for pure crystalline anthracene.
Experiments show that the anthracene molecules are associated in microcrystals and suggest that the dimerization reaction occurs at the interface between KBr and anthracene crystals.
Such an influence of the heterogeneity of the irradiated medium may have implications in photobiology where heterogeneous structures are the general rule.     

Solvent Influence on the Diels‐Alder Reaction Rates of 9‐(Hydroxymethyl)anthracene and 9,10‐Bis(hydroxymethyl)anthracene with Two Maleimides

The rates of the Diels–Alder reaction of 9‐(hydroxymethyl)anthracene and 9,10‐bis(hydroxymethyl)anthracene with maleic anhydride and two maleimides, N‐ethyl‐ and N‐phenylmaleimide, have been studied at various temperatures and pressures in different solvent media. A rate acceleration in water in comparison with organic solvents is observed. Thermodynamic functions of activation for the reaction of 9,10‐bis(hydroxymethyl)anthracene with N‐ethylmaleimide in binary 1,4‐dioxane–water mixtures are determined. From the observed tendencies, it can be concluded that acceleration of the Diels–Alder reactions in water is linked with an energetically favorable dehydration of the reaction centers of the reactants on the way to the activated complex. Addition of an organic cosolvent makes the desolvation of these centers less favorable.     

Catalytic Self-Hydrogenation of Anthracene in the Presence of a Magnesium–Anthracene Adduct

The catalytic properties of cluster magnesium derivatives were studied using the self-hydrogenation reaction of unsaturated compounds as an example. In the presence of a cluster magnesium–anthracene adduct at 150–298 K, the self-hydrogenation of anthracene occurred with yields of up to 40 molecules per atom of magnesium.     

A new tandem reaction of benzyne: one-pot synthesis of aryl amines containing anthracene

[reaction: see text] The reaction of benzyne with N-substituted imidazoles affords a novel way to prepare arylamines containing anthracene under very mild conditions. This transformation is assumed to proceed via a tandem reaction involving a Diels-Alder reaction and an intermolecular nucleophilic coupling reaction.     

Zipping up: cooperativity drives the synthesis of graphene nanoribbons

We investigate the cooperative effects controlling the synthesis of a graphene nanoribbon on the Au(111) surface starting from an anthracene polymer using density functional calculations including van der Waals interactions. We focus on the high-temperature cyclodehydrogenation step of the reaction and find that the reaction proceeds by simultaneously transferring two H-atoms from the anthracene units to the Au surface, leaving behind a C-C bond in the process. This step is significantly more favorable than the three other potential reaction paths. Moreover, we find that successive dehydrogenations proceed from one end of the polyanthracene and propagate step-by-step through the polymer in a domino-like fashion.     

Hydrogen transfer from 9,10-dihydrophenanthrene to anthracene

Kinetic studies of the transfer of hydrogen from 9,10-dihydrophenanthrene to anthracene were done at 350°C in the liquid phase. Principal products were phenanthrene and 9,10-dihydroanthracene. Autocatalysis occurred at low extents of reaction, where H-transfer from 9,10-dihydroanthracene to anthracene caused an increase in free radical concentrations. At higher extents of reaction, 9,10-dihydroanthracene inhibited rates by diverting intermediate 9-hydrophenanthryl radicals back to reactants. A quantitative kinetic model based on literature rate and thermodynamic data fits the observations well. A key net reaction is the transfer of an H-atom from a radical (9-hydrophenanthryl) to a molecule (anthracene). It is shown that this process does not involve a free H-atom intermediate. The derived rate constant for this exothermic process (7.5 × 10³ M^?1 s^?1) is considerably greater than that for the related, but thermoneutral H-transfer between anthracene moieties (120 M^?1 s^?1).     

A novel rearrangement of fluorescent human thymidylate synthase inhibitor analogues in ESI tandem mass spectrometry

Cu(I) catalyzed alkyne-azide cycloaddition reaction was employed to synthesize a series of anthracene-based human thymidylate synthase (hTS) inhibitor analogues. The triazolo-anthracene derivatives were characterized by ESI-MS/MS and a novel rearrangement reaction in ESI-MS/MS was observed. The mechanism is proposed whereby the protonated triazolo-anthracene derivative forms a carbocation, and then the carbocation electrophilically attacks an anthracene moiety resulting in formation of a rearrangement ion. Moreover, the carbocation prefers to attack the γ position rather than the α or β position of the anthracene moiety by an electrophilic substitution mechanism.     

An Unprecedented Photochemical Reaction for Anthracene‐Containing Derivatives

A series of anthracene‐containing derivatives have been synthesised and characterised. The photochemical behaviour of these derivatives have been investigated by ¹H NMR spectroscopy. An unprecedented photolysis reaction for anthracene‐containing derivatives was observed in the case of anthracenes directly armed with a ‐CH₂O‐R group upon UV irradiation. The photolysis reaction process has been demonstrated to occur in three steps. Firstly, the anthracene‐containing derivatives are converted into the corresponding endoperoxide intermediate upon UV irradiation in the presence of air; then, the endoperoxide intermediate is decomposed to the corresponding starting compound and 9‐anthraldehyde; finally, 9‐anthraldehyde is further oxidised to anthraquinone. Additionally, the photolysis reaction of anthracene‐containing derivatives is significantly promoted in the presence of a thiacalix[4]arene platform.     

Polymerizable anthracene derivatives for labeling emulsion copolymers

We describe the synthesis of three anthracene–methacrylate monomers [9‐methacryloxymethyl‐10‐methyl anthracene ( 4 ), 9‐methacryloxyethyloxymethyl‐10‐methyl anthracene ( 5 ), and 9‐methacryloxy‐10‐methyl anthracene ( 6 )] as well as their emulsion copolymers containing butylacrylate. When films prepared from latex dispersions containing 4 or 5 were heated, the anthracene (An) group was cleaved from the polymer at temperatures above 120 °C. Lower temperatures induced this reaction when strong acids were present. In 4 and 5 , the polymerizable group is connected to the An ring via a 9‐CH₂O? linkage. The cleavage reaction requires more stringent conditions when the connection involves a benzylic ether ( 5 ) instead of a benzylic ester. Polymers prepared from 6 , with an An? O? bond, were stable for 1 h at 150 °C in the presence of 0.5 wt % p‐toluene sulfonic acid. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1495–1504, 2001     

The role of the triplet state in the photosensitization of cationic polymerizations by anthracene

The photosensitization mechanism for cationic polymerizations initiated by diaryliodonium salts photosensitized by anthracene was investigated using fluorescence and phosphorescence spectroscopy. In situ photosensitizer fluorescence measurements confirmed that the photosensitization reaction proceeds by an electron transfer process. Transient phosphorescence studies demonstrated that electron transfer occurred from the triplet excited state of anthracene to the initiator, with an intrinsic kinetic rate constant of 2 × 10⁸ L/mol s. Further evidence for the role of the triplet state was provided by an observed seven-fold decrease in the polymerization rate upon addition of a triplet state quencher. Finally, numerical solution of the photophysical kinetic equations indicated that the triplet state concentration was approximately three orders of magnitude higher than that of the singlet state, and that 94-96% of the active cationic centers are produced by reaction of the initiator with the triplet state. These results indicate that the electron transfer occurs primarily from the triplet state of anthracene, with the singlet state providing only a minor contribution to the photosensitization reaction. © 1995 John Wiley & Sons, Inc.     

SYNTHESIS OF 1,2-ACEANTHRYLENEDIONE THROUGH ACYLATION OF ANTHRACENE WITH OXALYL CHLORIDE

Acylation of anthracene and oxalyl chloride in the presence of anhydrous AlCl3 was investigated. Pure 1,2-aceanthrylenedione, which is used as new functional macromolecule, was prepared by extraction and recrystallation. The structure of 1,2-aceanthrylenedione was identified by measure of melting point, GC/MS, FTIR and 1↑HNMR analyses. The influences of various parameters, such as solvent, dosage of catalyst, molar ratio of anthracene to oxalyl chloride, reaction temperature, and reaction time were studied. The anhydrous AlCl3 was found to catalyze the reaction with high yeild and good selectivity. When the reaction temperature is 303K, reaction time is 5h and molar ratio of anthracene to oxalyl chloride is 1：2, the yield and selectivity of 1,2-aceanthrylenedione is 83.8 % and 92.3% respectively.     

Über die Entstehung von Oligoanthrylen bei der milden Sulfonierung von Anthracen

The sulfonation of anthracene yields a variety of products and byproducts by different reaction paths depending on the reaction conditions. While trying to reduce the number of products formed by sulfonation under mild conditions, a new reaction was found: under certain sulfonation conditions anthracene is not sulfonated but reacts to form oligoanthrylenes. The highest average molecular weight of a fraction, insoluble in benzene, is about 3,000.     

Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework

A spin-selective tribo-chemical reaction using a dinuclear lanthanide complex is demonstrated for the first time. The dinuclear complex is composed of two Eu^III ions, hexafluoroacetylacetonato ligands, and anthracene-based phosphine oxide bridges. Single-crystal analysis revealed a face-to-face-type anthracene dimer structure in the dinuclear Eu^III complex. Mechanical stimulus on the dinuclear Eu^III complex induced selective formation of oxidized anthracene. The tribo-chemical reaction is based on a characteristic energy-transfer pathway for the selective formation of an excited triplet state.     

Photochemical ligation of DNA conjugates through anthracene cyclodimer formation and its fidelity to the template sequences

Anthracene readily forms photoadducts, anthracene dimers, and this photodimerization reaction has been well characterized. In general, however, the reaction requires close proximity and certain spatial alignment of both reaction partners. DNA could provide an ideal scaffold for accelerating the photocyclic addition. We synthesized a number of anthracene-DNA conjugates. The sequences of the conjugates, 5'AntODNn and 3'AntODNn (the length of methylene linkers: n = 3 or 6), were designed to bind adjacent sequences of the template with the anthracene units directed such that they stacked with each other. The conjugates were only dimerized in the presence of the template by light irradiation. The efficiency was affected by one-base displacement in the template sequence.     

硼掺杂还原态氧化石墨烯催化剂的制备及其蒽催化加氢性能的研究

制备了一系列硼掺杂的还原氧化态石墨烯催化剂并应用于蒽加氢反应。结果表明，随着催化剂处理温度的升高，催化剂中有序碳结构会发生变化，硼会取代材料骨架中的碳，进而影响蒽和氢气的吸附活化。经硼改性后，催化剂对蒽加氢反应表现出了很高的加氢活性，蒽的最高转化率可达97%，深度加氢产物八氢蒽的最高选择性可达19%。     

A Vinylanthracene and Vinylferrocene‐Containing Copolymer: A New Dual pH/Sulfide Sensor

A single electroactive copolymer containing both anthracene and ferrocene units has been synthesized to form a dual pH/sulfide sensor. Under cyclic voltammetric conditions the oxidation of the ferrocene moiety undergoes an electrocatalytic reaction with sulfide, producing a linear increase in the oxidative peak current over the range 0.2–2.0 mM. Furthermore, square wave voltammetry was utilized to determine the pH of the solution by measuring the variation in the anthracene oxidation potential with respect to the ferrocene oxidation wave.