2299-68-5

Upstream product

• 1940-57-4 9H-fluoren-9-yl bromide 
• 2762-16-5 fluorenylidene 
• 75-05-8 acetonitrile 
• 832-80-4 9-diazofluorenone 
• 260-94-6 acridine 
• 86-73-7 9H-fluorene 
• 92-82-0 Phenazin 
• 6630-65-5 9-chlorofluorene 
• 2564-83-2 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical 
• 120-12-7 anthracene 
• 67-64-1 acetone 
• 1689-64-1 9-Fluorenol 

Relevant academic research and scientific papers

INDIRECT OBSERVATION OF SPIN POLARIZATION IN TRIPLET FLUORENYLIDENE AT ROOM TEMPRTATURE

The spin polarization of triplet fluorenylidene has been observed indirectly at room temperature via CIDEP spectroscopy.The observed absorptive polarization is in agreement with direct observations of the spin polarization of diphenylmethylene at low temperature.

Generation and reactivity toward oxygen of carbon-centered radicals containing indane, indene, and fluorenyl moieties

Resonance-stabilized radicals containing indane, indene, and fluorenyl moieties exhibit attenuated reactivity toward oxygen. Rate constants of ～105 M-1 s-1 were observed for the most stabilized radicals. The dependence of kox (rate constant for radical trapping by oxygen) on the corresponding bond dissociation energies revealed that stereoelectronic effects are more important than steric effects in determining the low radical reactivity with oxygen. Scavenging by the nitroxide TEMPO was also examined, and revealed that in this case steric effects are more important than in the case of oxygen. The rate constants for the hydrogen abstraction by cumyloxyl and tert-butoxyl radicals generated thermally and photochemically have been determined in benzene, and were in the range of ca. (1-13) × 106 M-1 s-1, showing that benzylic stabilization has a modest effect on substrate reactivity as a hydrogen donor toward alkoxyl radicals.

Direct Comparison of the reactivity of model complexes for compounds 0, I, and II in oxygenation, hydrogen-abstraction, and hydride-transfer processes

The iron(III) meso-tetramesitylporphyrin complex is a good biomimetic to study the catalytic reactions of cytochrome P450. All of the three most discussed reactive intermediates concerning P450 catalysis (namely, Cpd 0, Cpd I, and Cpd II) can be selective

C-H activation by a mononuclear manganese(III) hydroxide complex: Synthesis and characterization of a manganese-lipoxygenase mimic?

Lipoxygenases are mononuclear non-heme metalloenzymes that regio- and stereospecifically convert 1,4-pentadiene subunit-containing fatty acids into alkyl peroxides. The rate-determining step is generally accepted to be hydrogen atom abstraction from the p

Kinetic study of the hydrogen abstraction reaction of the benzotriazole-N-oxyl radical (BTNO) with H-donor substrates

The aminoxyl radical (>N-O.) BTNO (benzotriazole-N-oxyl) has been generated by the oxidation of 1-hydroxybenzotriazole (HBT; >N-OH) with a CeIV salt in MeCN. BTNO presents a broad absorption band with λmax 474 nm and e 184

Kinetics of the reaction of the TEMPO radical with alkylarenes

The kinetics of the reaction of the stable radical 2,2,6,6- tetramethylpiperidine-N-oxyl (TEMPO) with a series of alkylarenes containing primary and secondary benzyl C-H bonds was studied by ESR, and the reaction rate constants were determined. The scheme

Hydrocarbon oxidation by bis-μ-oxo manganese dimers: Electron transfer, hydride transfer, and hydrogen atom transfer mechanisms

Described here are oxidations of alkylaromatic compounds by dimanganese μ-xo and μ-hydroxo dimers [(phen)2MnIV (μ-O)2MnIV(phen)2]4+ ([Mn2(O)2]4+), [(phen)2MnIV (μ-O)2MnIII(phen)2]3+ ([Mn2(O)2]3+), and [(phen)2MnIII (μ-O)(μ-OH)MnIII(phen)2]3+ ([Mn2(O)(OH)]3+). Dihydroanthracene, xanthene, and fluorene are oxidized by [Mn2(O)2]3+ to give anthracene, bixanthenyl, and bifluorenyl, respectively. The manganese product is the bis(hydroxide) dimer, [(phen)2MnIII (μ-OH)2Mn(phen)2]3+ ([Mn2(OH)2]3+). Global analysis of the UV/vis spectral kinetic data shows a consecutive reaction with buildup and decay of [Mn2(O)(OH)]3+ as an intermediate. The kinetics and products indicate a mechanism of hydrogen atom transfers from the substrates to oxo groups of [Mn2(O)2]3+ and [Mn2(O)(OH)]3+. [Mn2(O)2]4+ is a much stronger oxidant, converting toluene to tolyl-phenylmethanes and naphthalene to binaphthyl. Kinetic and mechanistic data indicate a mechanism of initial preequilibrium electron transfer for p-methoxytoluene and naphthalenes because, for instance, the reactions are inhibited by addition of [Mn2(O)2]3+. The oxidation of toluene by [Mn2(O)2]4+, however, is not inhibited by [Mn2(O)2]3+. Oxidation of a mixture of C6H5CH3 and C6H5CD3 shows a kinetic isotope effect of 4.3 ± 0.8, consistent with C-H bond cleavage in the rate-determining step. The data indicate a mechanism of initial hydride transfer from toluene to [Mn2(O)2]4+. Thus, oxidations by manganese oxo dimers occur by three different mechanisms: hydrogen atom transfer, electron transfer, and hydride transfer. The thermodynamics of e-, H?, and H- transfers have been determined from redox potential and pKa measurements. For a particular oxidant and a particular substrate, the choice of mechanism is influenced both by the thermochemistry and by the intrinsic barriers. Rate constants for hydrogen atom abstraction by [Mn2(O)2]3+ and [Mn2(O)(OH)]3+ are consistent with their 79 and 75 kcal mol-1 affinities for H?. In the oxidation of p-methoxytoluene by [Mn2(O)2]4+, hydride transfer is thermochemically 24 kcal mol-1 more facile than electron transfer; yet the latter mechanism is preferred. Thus, electron transfer has a substantially smaller intrinsic barrier than does hydride transfer in this system.

The reaction of cyclopentadienylidine, fluorenylidene and tetrachlorocyclopentadienylidene with alcohols. A laser flash photolysis study

Rate constants of reaction of cyclopentadienylidene, fluorenylidene and tetrachlorocyclopentadienylidene with alcohols and other quenchers were determined by laser flash photolysis methods. The rate constants of reaction of cyclopentadienylidene and fluorenylidene with various alcohols were determined and found to increase with increasing alcohol acidity. Alcohols as a group reacted faster with cyclopentadienylidene and fluorenylidene than likely ylide formers such as pyridine, ethyl acetate and tetrahydrofuran. Bronsted plots of the reaction of cyclopentadienylidene and fluorenylidene with alcohols are linear with slopes of 0·061 and 0·082, respectively. In the case of tetrachlorocyclopentadienylidene, an ylide type of reaction mechanism with alcohols is indicated. Tetrachlorocyclopentadienylidene reacts most rapidly with the least acidic alcohol studied and this carbene reacts more rapidly with tetramethylurea, pyridine and tetrahydrofuran than with methanol.

Rate Constants for Termination and TEMPO Trapping of Some Resonance Stabilized Hydroaromatic Radicals in the Liquid Phase

The rate constants for the termination reaction (2k1) of some resonance stabilized carbon centered radicals (SR.) derived from hydroaromatics (Sr. + SR. -> P) have been determined at 294 +/- 2 K by laser flash photolysis with UV-vis detection.The radicals were generated by hydrogen atom abstraction by t-BuO-radicals from the corresponding hydrocarbon (SRH + t-BuO. -> SR. + t-BuOH. k4).The extinction coefficients (e) of the SR., essential to calculate 2k1, were obtained using a relative kinetic technique.The change in 2k1 for the radicals derived from 1,4-cyclohexadiene, fluorine, 9,10-dihydroanthracene, diphenylmethane, tetralin, indan, indene, and phenol appeared to be modest; a range of 2k1 = 2-10 x 1E9 M-1 s-1 in mixtures of benzene and di-tert-butyl peroxide was observed.Most of the rate constants are near the diffusion controlled limit.In contrast, quenching the radicals with a persistent radical, 2,2,5,5-tetramethylpiperidin-1-oxyl (TEMPO), resulted in a larger variation of -1 s-1.The strength of the N-O bond formed in the latter process may have an important contribution to the observed rate constant.