Spectra of dimers of anthracene and its derivatives. I. Sandwich dimers

1973 ◽  
Vol 26 (1) ◽  
pp. 91 ◽  
Author(s):  
J Ferguson ◽  
AWH Mau ◽  
JM Morris
Keyword(s):  
Absorption Spectra ◽  
Glass Matrix ◽  
Fluorescence Spectra ◽  
The Other ◽  
Fluorescence Properties ◽  
Fluorescence Lifetimes ◽  
Excimer Emission ◽  
Photochemical Cleavage ◽  
Broad Structure ◽  
Related Compounds

Sandwich dimers are obtained by photochemical cleavage of dianthracene and related compounds in a rigid glass matrix at 77 K. Detailed studies of the absorption spectra, fluorescence spectra, and fluorescence lifetimes of symmetric dimers of anthracene and 9-substituted anthracenes (both molecules the same) and dissimilar dimers (one molecule anthracene, the other 9- or 9,10-substituted anthracene) have been made. Particular attention has been paid to these properties during dissociation of the dimers as the glass is allowed to soften. The fluorescence properties show a discontinuity during this dissociation. The excimer emission maxima (lifetimes about 200 ns) move a little to higher energy (lifetimes decrease to about 100 ns) then broad structure is observed in the spectra and lifetimes drop to about 5 ns. The fluorescence spectra of the dissimilar dimers are of the excimer type with lifetimes of about 100 ns. These values do not appear to be compatible with existing theories of the excimer state.

TRYPTAMINES, CARBOLINES, AND RELATED COMPOUNDS: PART IX. THE CYCLIZATION OF SOME NITRO- AND AZIDO-PHENYLPYRIDINES. PYRIDO[1,2-b]INDAZOLE

1961 ◽  
Vol 39 (12) ◽  
pp. 2516-2528 ◽  
Author(s):  
R. A. Abramovitch ◽  
K. A. H. Adams
Keyword(s):  
Absorption Spectra ◽  
Catalytic Reduction ◽  
Nitro Compounds ◽  
Ultraviolet Absorption ◽  
The Other ◽  
Azo Compounds ◽  
Minute Amount ◽  
Ferrous Oxalate ◽  
Related Compounds ◽  
General Method

Heating 2-o-nitrophenylpyridine with ferrous oxalate gives rise to pyrido[1,2-b]indazole (III). The evidence for the structure of this compound is discussed. Similarly, heating 2-o-nitrophenylpyridine methiodide and N-oxide with ferrous oxalate gives (III), in each case, demethylation and deoxygenation preceding the cyclization. In the latter case a minute amount of δ-carboline is also formed. Heating pyridine-N-oxides with ferrous oxalate is a potentially general method of effecting deoxygenations of these compounds. Contrary to the results of Smith and Boyer (11), it is found that heating 2-o-azidophenylpyridine also gives rise to (III). On the other hand, the action of heat on 2-o-azidophenyIpyridine-N-oxide gives a mixture of δ-carboline and δ-carboline-py-N-oxide in low yield. The mechanism of the cyclization of the azides and of the reaction taking place on heating nitro-compounds with ferrous oxalate is discussed briefly; the formation of a nitrene intermediate is favored.The catalytic reduction of 2-o-nitrophenylpyridine-N-oxide giving rise to the azoxy-, azo-, and hydrazo-derivatives is described and the ultraviolet absorption spectra of these compounds are discussed. It is concluded the steric inhibition of coplanarity exists in the azoxy- and azo-compounds leading to the lack of effective conjugation across the N=N bond.

Synthesis and fluorescence properties of dioxa-, dithia-, and diselena-[3.3](1,3)pyrenophanes

2017 ◽  
Vol 16 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Hajime Maeda ◽  
Masato Hironishi ◽  
Rikiya Ishibashi ◽  
Kazuhiko Mizuno ◽  
Masahito Segi
Keyword(s):  
Fluorescence Spectra ◽  
Solvent Polarity ◽  
Fluorescence Properties ◽  
Excimer Emission ◽  
Intramolecular Excimer

The fluorescence spectra of [3.3](1,3)pyrenophanes in solution contain both monomer and intramolecular excimer emission bands. The ratio of the intensities is controlled by solvent polarity and temperature.

Studies Directed Towards the Total Synthesis of Anticapsin and Related Compounds. IV. Competitive Reaction of Amino and Carboxy Substituents in the Halohydrination of 2-Aminobicyclo[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives

1994 ◽  
Vol 47 (12) ◽  
pp. 2221 ◽  
Author(s):  
MJ Crossley ◽  
SR Davies ◽  
TW Hambley
Keyword(s):  
Total Synthesis ◽  
The Other ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
Competitive Reaction ◽  
Trimethylsilyl Group ◽  
X Ray ◽  
Tricyclic Compounds ◽  
Tricyclic Compound ◽  
Related Compounds

Bromohydrination of benzyl (1RS,2SR,4SR)-2-benzyloxycarbonylamino-1-trimethylsilyloxy-bicyclo[2.2.2]oct-5-ene-2-carboxylate (6a) and the (1RS,2RS,4SR)- diastereomer (6b) with N- bromoacetamide in aqueous dioxan has been investigated. These reactions are highly regio-and stereo-selective and give the corresponding bromohydrins (9a) and (9b), but in moderate to low yield. These bromohydrins have the necessary stereochemistry for conversion into anticapsin. The other products from the reaction are tricyclic compounds formed by capture of the anti- bromonium cation intermediates or resultant bromohydrins by interaction with the proximal protected carboxy and amino groups within the molecules. Thus the carbolactone (11) is formed from the endo -adduct (6a), and the carbonimidic acid derivative (12) and the cyclic urethane (13) are formed from the exo-adduct (6b). Cleavage of the trimethylsilyl group from the tricyclic compound (12) gives benzyl (1RS,2RS,3RS,7RS,8RS)-5-benzyloxy-2-bromo-8-hydroxy-4-oxa-6-azatricyclo[5.3.1.03,8]undec-5-ene-7-carboxylate(14), the structure of which was determined by X-ray diffraction methods and refined to a residual of 0.035 for 1549 independent observed reflections. The crystals of (14) are monoclinic, P21/c, a 12.954(3), b 6.197(3), c 26.784(7) Ǻ, β 95.33(2)°, Z 4. Reactions attempting to generate iodohydrins from the alkenes (6) were also highly regioselective and gave detrimethylsilylated iodo analogues of (11) and (13).

The Synthesis and Electroluminescence Properties of 4-Benzofuranyl-1,8-Naphthalimide Derivatives

2012 ◽  
Vol 557-559 ◽  
pp. 1031-1036 ◽  
Author(s):  
Jian Xin Yang ◽  
Xiang Hui Wang
Keyword(s):  
Absorption Spectra ◽  
Fluorescence Spectra ◽  
Cycloaddition Reaction ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Maximum Brightness ◽  
Maximum Emission ◽  
Mild Conditions

A series of fluorescence compounds, 4-benzofuranyl-1,8-naphthalimides, were prepared through cycloaddition reaction from 4-ethynyl-1,8-naphthalimides and o-iodophenols which catalyzed by a Pd(PPh3)2Cl2 / CuI system under mild conditions. The intermediate material, 4-ethynyl-1,8- naphthalimide, was synthesized from 4-bromo-1,8- naphthalimide and trimethylsilyl- acetylene. The absorption and fluorescence spectra of 4-benzofuranyl-1,8- naphthalimides were studied and the quantum yields were measured. The maximum UV/vis absorption spectra were in the range of 375-400 nm and the maximum emission spectra were in the range of 470-510 nm. The electro- luminescent properties were also mensurated through a doped electroluminescent device which contains 1% 1,8-naphthalimides and 99% CBP (4,4'-N,N'-dicarbazole-biphenyl), It’s shown the maximum brightness reached 3700 cd/ m2 at 22.5V.

STUDIES ON THE BACTERIAL OXIDATION OF 2,3-BUTANEDIOL AND RELATED COMPOUNDS

1944 ◽  
Vol 22b (5) ◽  
pp. 140-153 ◽  
Author(s):  
R. Y. Stanier ◽  
Sybil B. Fratkin
Keyword(s):  
Carbon Dioxide ◽  
Aeromonas Hydrophila ◽  
The Other ◽  
Bacterial Oxidation ◽  
Aerobacter Aerogenes ◽  
Aerobic Conditions ◽  
Related Compounds

Aerobacter aerogenes, Aerobacillus polymyxa, and Aeromonas hydrophila, representatives of the three genera characterized by a butanediol fermentation, can all oxidize 2,3-butanediol under aerobic conditions. The configuration of the 2,3-butanediol has considerable bearing on its decomposability: Aerobacter aerogenes is inactive on the l-isomer, but attacks both meso- and d-isomers; Aeromonas hydrophila attacks the meso-isomer but not the l- and probably not the d-isomer; Aerobacillus polymyxa can oxidize both l- and meso-2,3-butanediol, but the rate with the former is many times greater than with the latter. Aerobacter aerogenes oxidizes both 2,3-butanediol and acetoin to carbon dioxide and water, a large part of the substrate being simultaneously assimilated. The other two organisms oxidize 2,3-butanediol to acetoin, but can further oxidize the acetoin thus formed only very slowly, if at all. Both Aerobacter aerogenes and Aerobacillus polymyxa are unable to attack 1,3-butanediol, 2-methyl-1,2-propanediol and 1,2-ethancdiol. However they can oxidize 1,2-propanediol to acetol.

The Absorption Spectra of Protoheme and Heme a Complexes with Amino Acids and Related Compounds

1965 ◽  
Vol 58 (4) ◽  
pp. 334-347 ◽  
Author(s):  
MIHOKO YOSHIDA ◽  
TADATOSHI KINOSHITA ◽  
SHIGEO HORIE ◽  
NORIO SHIMAZONO
Keyword(s):  
Amino Acids ◽  
Absorption Spectra ◽  
Related Compounds

Fluorescence Enhancement of Europium(III) Perchlorate by 2,2′-Dipyridyl on Bis(benzylsulfinyl)methane Complex

2013 ◽  
Vol 634-638 ◽  
pp. 2462-2465
Author(s):  
Wen Xian Li ◽  
Bo Yang Ao ◽  
Jing Zhang
Keyword(s):  
Rare Earth ◽  
Ternary Complex ◽  
Fluorescence Enhancement ◽  
Fluorescence Emission ◽  
Europium Complex ◽  
New Method ◽  
Rare Earth Complexes ◽  
Fluorescence Properties ◽  
Binary Complex ◽  
Fluorescence Lifetimes

A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane L, was synthesized by a new method. Its novel ternary complex, has been synthesized [using L as the first ligand, and dipyridyl L' as the second ligand]. In order to study the effect of the second ligand on the fluorescence properties of rare-earth sulfoxide complex, a novel binary europium complex has been synthesized. Photoluminescent measurement showed that the first ligand L could efficiently transfer the energy to Eu (III) ions in the complex. Furthermore, the detailed luminescence analyses on the rare earth complexes indicated that the ternary Eu (III) complex manifested stronger fluorescence intensities, longer lifetimes, and higher fluorescence quantum efficiencies than the binary Eu (III) materials. The fluorescence emission intensities and fluorescence lifetimes of the ternary complex enhanced more obviously than the binary complex.

scholarly journals THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1938 ◽  
Vol 21 (4) ◽  
pp. 411-430 ◽  
Author(s):  
Aurin M. Chase ◽  
Charles Haig
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Light Transmission ◽  
Low Ph ◽  
The Other ◽  
Distilled Water ◽  
Color Purity ◽  
Chemical Combination ◽  
Ph Range ◽  
Sensitive Group

The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole.

An Introduction to Time-Resolved Pump/Probe Spectroscopy

1985 ◽  
Vol 39 (3) ◽  
pp. 444-451 ◽  
Author(s):  
F. E. Lytle ◽  
R. M. Parrish ◽  
W. T. Barnes
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
Fluorescence Spectra ◽  
Excited State Absorption ◽  
Time Dependent ◽  
Triplet Excited State ◽  
Ground State Absorption ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Spectroscopy

The construction and operating principles of a two-color pump/probe spectrometer are described. This instrument is capable of obtaining ground-state absorption spectra, both singlet-singlet and triplet-triplet excited-state absorption spectra, photoproduct spectra, and stimulated fluorescence spectra. In addition, time-dependent measurements can be made with an impulse response of 250 ps and a free temporal range of 13 ns.

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