2294-82-8Relevant articles and documents
Functionalization of azafullerene C59N. Radical reactions with 9-substituted fluorenes
Vougioukalakis, Georgios C.,Orfanopoulos, Michael
, p. 8649 - 8652 (2003)
An efficient reaction between the azafullerene dimer, (C 59N)2 and 9-substituted fluorenes leads to the formation of four new azafullerene monoadducts.
Excited-state dynamics of bis(9-fluorenyl)methane and its derivative 9-(9-ethylfluorenyl)-9′-fluorenylmethane: Steric effect on energetics and dynamics of ground- and excited-state conformations
Boo, Bong Hyun,Lee, Minyung,Jeon, Ki-Seok,Kim, Seung-Joon
, p. 2269 - 2278 (2014)
Intramolecular excimer formation of bis(9-fluorenyl)methane (BFM) and 9-(9′-ethylfluorenyl)-9-fluorenylmethane (EFFM), in which an ethyl group is substituted to a 9-H atom in BFM, was studied by means of steady-state and time-resolved fluorescence. Ab initio and DFT calculations enabled the prediction of three conformers as stable species of orthogonal, trans-gauche, and gauche-gauche. The theoretical and experimental results reveal that the substitution effect is also found to appreciably influence the energies, spectroscopy, and kinetics associated with the interconversion of various conformers of the diaryl compounds. We have not observed the rising components in the excimer fluorescence decay of BFM and EFFM in PMMA as observed in the liquid solutions probably because of the existence of the sandwich conformer responsible for the excimer fluorescence prior to the laser irradiation.
Decatungstate-Photocatalyzed Radical Addition of 9-Substituted Fluorenes to [60]Fullerene: A Mechanistic Approach
Malliaros, Nikitas G.,Orfanopoulos, Michael
supporting information, p. 4846 - 4850 (2021/09/20)
An innovative, efficient, regioselective functionalization of C60 with 9H-fluorenes has been disclosed. This efficient photochemical approach uses certain fluorenyl radicals in 9-position deriving from fluorenes through a hydrogen-atom transfer (HAT) process mediated by tetrabutylammoniumdecatungstate [(n-Bu4N)4W10O32]. The single addition of these fluorenyl radicals to C60 proceeded to produce [60]fullerene-fluorene dyads in a single step. The scope and mechanism of this new reaction have been examined. The primary kinetic isotope effect measurements signify the presence of a stepwise mechanism in which the C?H (D) bond scission is the rate-limiting step of the reaction.
Nickel-catalyzed synthesis of 9-monoalkylated fluorenes from 9-fluorenone hydrazone and alcohols
Fan, Jiang-Tao,Fan, Xin-Heng,Chen, Yong-Jie,Gao, Cai-Yan,Yang, Lian-Ming
supporting information, p. 2895 - 2902 (2019/08/12)
A practical protocol was disclosed for the nickel-catalyzed C-alkylation of 9-fluorenone hydrazone with alcohols using t-BuOK as the base, and 9-monoalkylated fluorene derivatives were obtained in good yields under the benign conditions.
Transition-metal-free intramolecular carbene aromatic substitution/Büchner reaction: Synthesis of fluorenes and [6,5,7]benzo-fused rings
Liu, Zhenxing,Tan, Haocheng,Wang, Long,Fu, Tianren,Xia, Ying,Zhang, Yan,Wang, Jianbo
supporting information, p. 3056 - 3060 (2015/03/30)
Intramolecular aromatic substitution and Büchner reaction have been established as powerful methods for the construction of polycyclic compounds. These reactions are traditionally catalyzed by RhII catalysts with a-diazocarbonyl compounds as the substrates. Herein a transition-metal-free intramolecular aromatic substitution/Büchner reaction is presented. These reactions use readily available N-tosylhydrazones as the diazo compound precursors and show wide substrate scope.
Radical reactivity of Aza[60]fullerene: Preparation of monoadducts and limitations
Vougioukalakis, Georgios C.,Roubelakis, Manolis M.,Orfanopoulos, Michael
experimental part, p. 4124 - 4130 (2010/10/02)
Six aza[60]fullerene monoadducts were synthesized by the thermal reaction between the azafullerene radical C59N· and 9-alkyl-substituted fluorenes, 9,10-dihydroanthracene, or xanthene. Unlike fluorenes, dihydroanthracene, and xanthene, the structurally related substituted diphenylmethanes, ethylbenzene, cumene, 1,2-diphenylethane, 5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene, 10,11-dihydro-5H-dibenzo[a,d] cycloheptene, 9-methylanthracene, and 9-benzylanthracene do not lead to the isolation of azafullerene monoadducts. Moreover, 1,2-dichlorobenzene, the most commonly utilized solvent for azafullerene reactions, reacts slowly with the azafullerenyl radical C59N· affording the corresponding aza[60]fullerene monoadduct.
New cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions
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Page/Page column 34, (2008/06/13)
The invention is directed to a phosphine compound represented by general formula (1) wherein R' and R" independently are selected from alkyl, cycloalkyl and 2-furyl radicals, or R' and R" are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle; the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals; Cps is a partially substituted or completely substituted cyclopentadien-1-yl group, including substitutions resulting in a fused ring system, and wherein a substitution at the 1-position of the cyclopentadien-1-yl group is mandatory when the cyclopentadien-1-yl group is not part of a fused ring system or is part of an indenyl group. Also claimed is the use of these phosphines as ligands in catalytic reactions and the preparation of these phosphines.
9-Fluorenylphosphines for the Pd-catalyzed Sonogashira, Suzuki, and Buchwald-Hartwig coupling reactions in organic solvents and water
Fleckenstein, Christoph A.,Plenio, Herbert
, p. 2701 - 2716 (2008/03/14)
The lithiation/alkylation of fluorene leads to various 9-alkyl-fluorenes (alkyl = Me. Et, /Pr, -Pr. -C18H25) in > 95% yields, for which lithiation and reaction with R2PCl (R = Cy, iPr, tBu) generates 9-alkyl, 9-PR2fluorenes which constitute electron-rich and bulky phosphine ligands. The in-situ-formed palladium-phosphinc complexes ([Na2PdCl4], phosphonium salt, base, substrates) were tested in the Sonogashira. Suzuki, and Buchwald-Hartwig reactions of aryl chlorides and aryl bromides in organic solvents. The Sonogashira coupling of aryl chlorides at 100-120°C leads to >90% yields with 1 mol % of Pd catalyst. The Suzuki coupling of aryl chlorides typically requires 0.05 mol % of Pd catalyst at 100°C in dioxane for quantitative product formation. To carry out "green" cross-coupling reactions in water, 9-ethylfluorenyldicyclohexylphosphine was reacted in sulphuric acid to generate the respective 2-sulfonated phosphonium salt. The Suzuki coupling of activated aryl chlorides by using this water-soluble catalyst requires only 0.01 mol% of Pd catalyst, while a wide range of aryl chlorides can be quantitatively converted into the respective coupling products by using 0.1-0.5 mol % of catalyst in pure water at 100°C. Difficult substrate combinations, such as naphthylboronic acid or 3-pyridylboronic acid and aryl chlorides are coupled at 100°C by using 0.1-0.5 mol % of catalyst in pure water to obtain the respective N-heterocycles in quantitative yields. The copper-free aqueous Sonogashira coupling of aryl bromides generates the respective tolane derivatives in > 95 % yield.
REACTIVITY OF CARBANIONS. XXI. KINETICS OF THE REACTION OF THE ALKALI-METAL SALTS OF CH ACIDS WITH 1-HALOGENOALKANES
Solov'yanov, A. A.,Karpyuk, A. D.,Sizov, A. Yu.,Beletskaya, I. P.,Reutov, O. A.
, p. 1461 - 1466 (2007/10/02)
The kinetics of the alkylation of the alkali-metal of triphenylmethane, fluorene, 1,3-diphenylindene, fluoradene, 9-methoxycarbonylfluorene, and 9-cyanofluorene by 1-halogenoalkanes with the general formula CH3(CH2)nX, where X = Cl, Br, and I and n varies between 0 and 5, were investigated in solvents of the ether type and in dipolar aprotic solvents.It was established that the rate constant for the alkylation of the carbanions decreases with increase in n from 0 to 2.The rate constant increases with further increase in the length of the alkyl chain.The observedextremal dependence of the reaction rate on n is due to the dynamic effects of the hydrocarbon chain.
Proton-Transfer Reactions between 9-Alkylfluorene and (9-Alkylfluorenyl)lithium in Ether
Murdoch, J. R.,Bryson, J.A.,McMillen, D.F.,Brauman, J.I.
, p. 600 - 610 (2007/10/02)
The rates of proton-transfer reactions between 9-substituted fluorenes and 9-substituted fluorenyllithium have been examined in ether at 25 and 71 deg C.A high primary isotope effect (kH/kD = 9.5) and substantial secondary kinetic (1.11 +/- 0.04) and equilibrium (1.19 +/- 0.04) isotope effects are observed for fluorene.Surprisingly, intermolecular steric effects seem to play only a minor role in spite of the fact that the alkyl groups are located directly at the carbon involved in the proton transfer.The barriers for the endergonic cross reactions (i.e., those involving different alkyl groups in the anion and hydrocarbon) are half of the sum of the barriers for the two corresponding identity reactions (i.e., those involving the same alkyl groups in the anion and hydrocarbon).This leads to Broensted slopes which vary from 0.7 for reactions of fluorenyl anion to 1.8 for reactions of 9-(tert-butyl)fluorenyl anion.The rates of the identity and cross reactions give approximate linear correlations with each other and with ΔpK and are dominated by an effect which correlates with ?*.The substituent effect correlated by ?* is inconsistent with a classical field or repulsive steric effect and may originate from solvatation effects.The thermodynamic and kinetic relationships between the identity and cross reactions show that the transition states for the cross reac tions are only responding to half of the substituent effect on the identity reactions and that the substituent effect on the equilibria appears absent from the cross-reaction transition states.The results can be consistent with Marcus' theory only if the substituent effect on the equilibria appears in steps separate from proton transfer.The results suggest that changes in solvation and proton transfer occur as discrete kinetic steps.
