Showing papers on "Fluorenone published in 1976"
TL;DR: In this article, the mechanism of efficient intersystem crossing of anthrone has been discussed and compared with that of benzophenene, and the rise time of fluorenone has been found to be sensitive to solvent, changing from 140 ps in cyclohexane to 12 ns in acetone.
90 citations
TL;DR: In this article, 1,3-Dipolar cycloadducts were obtained by the copper chelate-catalyzed decomposition of 1-(diazoacetyl)fluorenone in the presence of acetylenic and ethylenic dipolarophiles.
Abstract: 1,3-Dipolar cycloadducts were obtained by the copper chelate-catalyzed decomposition of 1-(diazoacetyl)fluorenone in the presence of acetylenic and ethylenic dipolarophiles. The reaction proceeded via intermediate carbonyl ylide (3), which has been generated by the carbene-carbonyl reaction of 2. The cycloaddition of 3 with ethylenic dipolarophiles was determined to proce d stereospecifically.
31 citations
TL;DR: In this paper, the authors have shown that the electrohydrodimerization mechanism of activated olefins is of the radical-radical coupling type up to the decimolar range on the particular example of p -methyl-benzylidene-malononitrile (MBM) in DMF.
23 citations
TL;DR: In this article, a series of fluorene and fluorenone diamines were polymerized with two aromatic dianhydrides, and the resulting polyamic acids were cyclodehydrated to aromatic polyimides.
Abstract: A series of fluorene and fluorenone diamines were polymerized with two aromatic dianhydrides, and the resulting polyamic acids were cyclodehydrated to aromatic polyimides. A study of the mechanical properties of the polyimide films disclosed they are among the stiffest reported to date, with an excellent retention of rigidity at elevated temperatures. Comparisons of the tensile properties and glass transition temperatures of the fluorene-derived polymer films with those from the corresponding open-chain polyimide films established that the unusual rigidity, especially at elevated temperatures, was in large part due to the contribution of the bulky, tricyclic fluorene (one) moieties in the polymer structures.
21 citations
TL;DR: In this paper, a simple algorithm is given, adaptable to a desk-top calculator, for treatment of experimental data to obtain rate constants and total product yields (or absorptions) in this situation, illustrated in the case of photoreduction of fluorenone triplet by 1,4-diazabicyclo(2.2) octane, a reaction which yields a pair of radical-ions.
12 citations
TL;DR: In this paper, the reaction of N4S4 with benzoyl-1-phenylhydrazine (1b), benzophenone- (2a) and fluorenone hydrazone (2b) was carried out in refluxing benzene or toluene.
Abstract: The reaction of N4S4 with benzoyl- (1a) and 1-methyl-1-phenylhydrazine (1b), benzophenone- (2a) and fluorenone hydrazone (2b) was carried out in refluxing benzene (1a and 1b) or toluene (2a and 2b) and N4S4 was found to behave as a N–N bond cleaving reagent for 1b, while both a N–N bond cleaving and an oxidizing reagent for 1a and 2. The reaction mechanism was briefly mentioned.
11 citations
TL;DR: In this article, the 1H n.m.r. spectra of cyclopentadithiophenones (CF3CO2H at 15°) are discussed.
Abstract: The 1H n.m.r. spectra of protonated fluorenone, cyclopentadithiophenones (FSO3H–SbF5–SO2 at –60°), and cyclopentadithiophens (CF3CO2H at –15°) are discussed. Di- and mono (carbonyl)-protonation occurred. Cyclopenta[1, 2-c : 3, 4-c′]dithiophen-7-one and fluorenone are found to be protonated first at the carbonyl group. PPP Calculations show that carbonyl protonated ketones having a cyclopentadiene carbocyclic ring are energetically less favourable than those having a cyclopentane or cyclopentene carbocyclic ring. From the values of the chemical shift of the OH protons it is concluded that the C–O bond remains largely a double bond. Three cyclopentadithiophens are easily protonated in CF3CO2H at –15° at corresponding positions in the b-annulated thiophen ring. The absorption frequencies in the electronic absorption spectra of these protonated cyclopentadithiophens are in good agreement with transition energies calculated by PPP methods.
8 citations
TL;DR: In this paper, the π,π * absorption spectra of fluorenone and 9,10-phenanthrenequinone were examined and it was found that there is an exact similarity between these two spectra up to near 250 nm.
8 citations
01 Jun 1976
4 citations
TL;DR: In this article, the rates of establishment of the acid-base equilibria for the radical anions of benzaldehyde, benzamide, benzonitrile, benzophenone, p-cyanoacetophenone and fluorenone have been studied by pulse radiolysis.
Abstract: The rates of establishment of the acid-base equilibria for the radical anions of benzaldehyde, benzamide, benzonitrile, benzophenone, p-cyanoacetophenone and fluorenone have been studied by pulse radiolysis. In each case a first order rate of reaction was observed with kobs=k′+k″[H+], the constants having values of k′=(0.3–7.8)× 104 s–1 and k″=(0.7–2.5)× 1010 dm3 mol–1 s–1. These rate constants are associated with the reaction of the radical anion with water (k′) and H+(k″). The nature of the radical ions involved is discussed.
3 citations
01 Jan 1976
Journal Article•
TL;DR: The synthesis of derivatives of fluorene, fluorenol, fluorenone, diam inobenzophenone, diaminiodiphenylmethane and benzidine, all of them with corresponding side chains, allowed to establish structural requirements for interferon inducing capability.
Abstract: Among the aminoacyl derivatives of 2,7-diaminofluoren-9-one a few compounds were found capable of inducing interferon in the mouse when administered perorally. One of them, 2,7-bis[(diethylamino)acetylamino]fluoren-9-one exhibited an inducing activity comparable to that of 2,7-bis-(2-diethylaminoethoxy)-fluoren-9-one (tilorone). The synthesis of derivatives of fluorene, fluorenol, fluorenone, diaminobenzophenone, diaminiodiphenylmethane and benzidine, all of them with corresponding side chains, allowed to establish structural requirements for interferon inducing capability.
TL;DR: In this paper, 1,3-Dipolar cycloadducts were obtained by the copper chelate-catalyzed decomposition of 1-(diazoacetyl)fluorenone in the presence of acetylenic and ethylenic dipolarophiles.
Abstract: 1,3-Dipolar cycloadducts were obtained by the copper chelate-catalyzed decomposition of 1-(diazoacetyl)fluorenone in the presence of acetylenic and ethylenic dipolarophiles. The reaction proceeded via intermediate carbonyl ylide (3), which has been generated by the carbene-carbonyl reaction of 2. The cycloaddition of 3 with ethylenic dipolarophiles was determined to proce d stereospecifically.
TL;DR: In this paper, the rates of establishment of the acid-base equilibria for the radical anions of benzaldehyde, benzamide, benzonitrile, benzophenone, p-cyanoacetophenone and fluorenone have been studied by pulse radiolysis.
Abstract: The rates of establishment of the acid-base equilibria for the radical anions of benzaldehyde, benzamide, benzonitrile, benzophenone, p-cyanoacetophenone and fluorenone have been studied by pulse radiolysis. In each case a first order rate of reaction was observed with kobs=k′+k″[H+], the constants having values of k′=(0.3–7.8)× 104 s–1 and k″=(0.7–2.5)× 1010 dm3 mol–1 s–1. These rate constants are associated with the reaction of the radical anion with water (k′) and H+(k″). The nature of the radical ions involved is discussed.