1530-12-7Relevant articles and documents
Stabilization of Carbanions by Polarization of Alkyl Groups on Nonadjacent Atoms
Bordwell, Frederick G.,Drucker, George E.,McCollum, Gregory J.
, p. 2504 - 2510 (1982)
Equilibrium acidities in dimethyl sulfoxide solution have been found to increase along the series Me, Et, i-Pr, t-Bu for 9-substituted fluorenes when the alkyl group, R, is separated from the fluorene ring by a CH2, S, or SO2 moiety.This is a reversal of
A Kinetic Study on Reduction of 9,9'-Bifluorenylidene by Sodium Isopropoxide
Kajigaeshi, Shoji,Fujisaki, Shizuo,Nakashige, Yasuhiko,Murakami, Sadaaki
, p. 833 - 837 (1982)
The kinetics and mechanism of reduction of 9,9'-bifluorenylidene (1) by sodium isopropoxide (2) in isopropyl alcohol to yield 9,9'-bifluorenyl (3) were investigated spectrophotometrically.The kinetic data suggest that the reduction proceeds autocatalytically, the reduction product 3 acting as the catalyst.It was found that (1) (2) Reactions 1 and 2 are of the first order with respect to 1, but that the former is of the third order with respect to 2, whereas the latter is of the first.The fourth- and third-order rate constants, k1 and k2 for Reactions 1 and 2 were determined to be 3.0 * 10-5 dm9 mol-3 s-1 and 1.1 * 103 dm6 mol-2 s-1, respectively, at 130 deg C.Probable mechanisms for Reactions 1 and 2 have been offered on the basis of the reaction order for each molecular species involved.
PHOTOCHEMICAL GENERATION OF RADICAL ANIONS. AN ACCESS TO NOVEL STRUCTURES
Huber, W.
, p. 181 - 184 (1985)
The preparation of the radical anions of tetrabenzocyclooctatetraene (TBCOT) and fluorene (FLH) by photochemical methods leads to the observation of novel structures.
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Suzuki,K.,Kajigaeshi,S.
, p. 408 - 412 (1962)
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Suzuki,Minabe
, p. 1541 (1974)
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Sprinzak
, p. 466,468 (1956)
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Bavin,P.M.G.
, p. 882 - 889 (1960)
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Tucker
, p. 2182,2185 (1949)
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Ion Pair Acidities of 9,9'-Bifluorenyl in THF: pK2 Is Lower than pK1
Stratakis, Manolis,Streitwieser, Andrew
, p. 1989 - 1990 (1993)
The second pK's in THF for lithium and cesium salts of 9,9'-bifluorenyl are 0.4 and 2.0 pK units, respectively, lower than the first pK's.
A facile synthesis of dithieno[3,2-b:6,7-b]fluorenes via a tandem annulation-reduction
Xiong, Xiaoli,Liu, Qiancai,Zhang, Jun,Zhu, Min,Wang, Yanmei,Deng, Shiming
, p. 17707 - 17711 (2013)
A concise and facile synthesis of 2,8-disubstituted dithieno[3,2-b:6,7-b] fluorenes starting from 2,7-dihydroxyfluorenone is reported. The key step involved is the tandem annulation-reduction of a 3,6-dichloro-2,7-di(alkynyl) fluorenone using Na2S·9H2O as a sulfur surrogate and reductant. The final dithiophene-fused fluorenes are obtained in reasonable yields (23-43%). The Royal Society of Chemistry.
Ogata,Y. et al.
, p. 1721 - 1722 (1976)
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Pinck,Hilbert
, p. 2739,2740 (1946)
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A Kinetic Study of the Photosolvolysis of 9-Fluorenol
Gaillard, Elizabeth,Fox, Marye Anne,Wan, Peter
, p. 2180 - 2186 (1989)
Excitation of 9-fluorenol in methanol and methanol-water mixtures leads to both heterolytic and homolytic cleavage via the singlet excited state.The partitioning between homolysis and heterolysis is controlled by solvent composition, the rate constant for cation formation being a function of the solvent dielectric constant.The rate constants of intersystem crossing, fluorescence, and singlet-derived radical formation are linear functions of the mole fraction of water.
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Pinck,Hilbert
, (1946)
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Evidence for the Generation of Aromatic Cationic Systems in the Excited State. Photochemical Solvolysis of Fluoren-9-ol
Wan, Peter,Krogh, Erik
, p. 1207 - 1208 (1985)
Photolysis of fluoren-9-ol (1) in aqueous methanol solution results in efficient formation of 9-methoxyfluorene (2); the driving force for the photosolvolysis is believed to be the formation of an aromatic 4? cationic system in the excited-state.
Vanadium Pyridonate Catalysts: Isolation of Intermediates in the Reductive Coupling of Alcohols
Griffin, Samuel E.,Schafer, Laurel L.
supporting information, (2020/04/15)
The reductive coupling of alcohols using vanadium pyridonate catalysts is reported. This attractive approach for C(sp3)-C(sp3) bond formation uses an oxophilic, earth-abundant metal for a catalytic deoxygenation reaction. Several pyridonate complexes of vanadium were synthesized, giving insight into the coordination chemistry of this understudied class of compounds. Isolated intermediates provide experimental mechanistic evidence that complements reported computational mechanistic proposals for the reductive coupling of alcohols. In contrast to previous mononuclear vanadium(V)/vanadium(III)/vanadium(IV) cycles, this pyridonate catalyst system is proposed to proceed by a vanadium(III)/vanadium(IV) cycle involving bimetallic intermediates.
Oxo-Free Hydrocarbon Oxidation by an Iron(III)-Isoporphyrin Complex
Doyle, Lorna M.,Farquhar, Erik R.,Gericke, Robert,Mcdonald, Aidan R.
supporting information, p. 13952 - 13961 (2020/10/09)
Metal-halides that perform proton coupled electron-transfer (PCET) oxidation are an important new class of high-valent oxidant. In investigating metal-dihalides, we reacted [FeIII(Cl)(T(OMe)PP)] (1, T(OMe)PP = meso-tetra(4-methoxyphenyl)porphyrinyl) with (dichloroiodo)benzene. An FeIII-meso-chloro-isoporphyrin complex [FeIII(Cl)2(T(OMe)PP-Cl)] (2) was obtained. 2 was characterized by electronic absorption, 1H NMR, EPR, and X-ray absorption spectroscopies and mass spectrometry with support from computational analyses. 2 was reacted with a series of hydrocarbon substrates. The measured kinetic data exhibited a nonlinear behavior, whereby the oxidation followed a hydrogen-atom-transfer (HAT) PCET mechanism. The meso-chlorine atom was identified as the HAT agent. In one case, a halogenated product was identified by mass spectrometry. Our findings demonstrate that oxo-free hydrocarbon oxidation with heme systems is possible and show the potential for iron-dihalides in oxidative hydrocarbon halogenation.
Mechanistic Features of the Oxidation-Reductive Coupling of Alcohols Catalyzed by Oxo-Vanadium Complexes
Steffensmeier, Eric,Swann, Matthew T.,Nicholas, Kenneth M.
supporting information, p. 844 - 854 (2019/01/04)
The oxo-vanadium-catalyzed redox disproportionation of activated alcohols (oxidation-reductive coupling, Ox-RC) produces carbonyl compounds and hydrocarbon dimers. A mechanistic study of this novel reaction is reported herein. Following our initial disclosure, new findings include the following: (1) The [(salimin)VO2]--catalyzed Ox-RC of Ph2CHOH in the presence of fluorene affords the products of H-atom abstraction and all possible hydrocarbon dimers. (2) Electronic substituent effects on the relative rates of Ox-RC with respect to 4-X-BnOH reactants and Bu4N[(Y-salimin)VO2] catalysts (1a-c) reveal (a) a correlation of the oxidation rate of X-BnOH reactants with the radical σ parameter and (b) correlation of the oxidation rate for (Y-salimin)VO2- with the standard Hammett σ parameter. (3) The ease of electrochemical reduction of 1a-c is Y = NO2 > OMe > H. (4) Ambient 1H NMR studies of the interaction of 1 with alcohols suggest only a weak equilibrium association. (5) Density functional theory computational modeling of the Ox-RC reaction supports a ping-pong-type catalytic pathway, beginning with alcohol oxidation by (salimin)VO2-, preferably by stepwise-H-atom transfer from the alcohol to 1, affording the carbonyl product and the reduced (salimin)V(III)(OH)2-. The reduction half-reaction likely begins with condensation of the latter species with R2CHOH to give the alkoxide complex (salimin)V(OR)OH- homolysis of the R···OV(III)(salimin) bond affords (salimin)V(IV)OH(O)- and the R-radical; the latter dimerizes and the former can disproportionate via H-transfer to reform catalyst (salimin)VO2- (1) and (salimin)V(OH)2-.
