1689-64-1Relevant articles and documents
Visual sensing of Ca2+ ion via photoreaction of fluorenyl ester-armed cyclen
Player, Tomoko N.,Shinoda, Satoshi,Tsukube, Hiroshi
, p. 1615 - 1616 (2005)
Fluorenyl ester-armed cyclen gave fluorenone and related decomposition compounds upon photoirradiation. The reaction was effectively suppressed by the formation of an octacoordinated Ca2+ complex while Na+ and other alkali/alkaline earth metal cations had little influence. Since the production efficiency of fluorescent fluorenone related well to the concentration of the Ca2+ ion, the photoreaction of this armed cyclen offered the naked-eye detection of Ca2+ ion in aqueous samples. The Royal Society of Chemistry 2005.
Non-heme iron(III) complex with tridentate ligand: Synthesis, structures and catalytic oxidations of alkanes
Tyagi, Nidhi,Singh, Ovender,Ghosh, Kaushik
, p. 83 - 87 (2017)
We report synthesis and characterization of a mononuclear iron(III) complex [Fe(LH2)Cl2]+, 1 having tridentate ligand LH2 and their application in oxidation of alkanes. Complex, 1 was characterized by various analytical, spectroscopic, electrochemical, crystallographic and theoretical studies. The molecular structure determination showed the presence of distorted square pyramidal FeN3Cl2 coordination sphere. Selective oxidation of benzyl alcohol, fluorene, adamantane, 1-phenyl ethanol and n-octane in presence of catalytic amount [FeIII(LH2)Cl2]+ with H2O2 under mild conditions give products in good to excellent yields through FeIV[dbnd]O intermediate. Several studies were done to support the reactive intermediate. Generation of FeIV[dbnd]O intermediate was also supported by UV–visible titration of [FeIII(LH2)Cl2]+ and H2O2 at low temperature and their visual colour change from red (500 nm, ? = 1050 M? 1 cm? 1) to green (770 nm, ? = 153 M? 1 cm? 1).
REACTIONS OF METHYLYTTERBIUM IODIDE WITH ACTIVE HYDROGEN COMPOUNDS
Yokoo, Kazuhiri,Kijima, Yasushi,Fujiwara, Yuzo,Taniguchi, Hiroshi
, p. 1321 - 1322 (1984)
Methylytterbium iodide (CH3YbI) has been found to react with active hydrogen compounds such as phenylacetylene and fluorene to give phenylpropynoic acid and fluorenol in modest yields.The reactivity of CH3YbI to these active hydrogen compounds is far higher than of CH3MgI.
One-pot diastereoselective synthesis of new racemic and achiral spirohydantoins
Mahmoodi, Nosrat O.,Khodaee, Ziba
, p. 304 - 306 (2004)
An efficient and versatile method was used for the diastereoselective synthesis of achiral and racemic spirohydantoins based on ketones 4, 5, 7 and 10.
Structural basis for the properties of two single-site proline mutants of CYP102A1 (P450BM3)
Whitehouse, Christopher J. C.,Yang, Wen,Yorke, Jake A.,Rowlatt, Benjamin C.,Strong, Anthony J. F.,Blanford, Christopher F.,Bell, Stephen G.,Bartlam, Mark,Wong, Luet-Lok,Rao, Zihe
, p. 2549 - 2556 (2010)
The crystal structures of the haem domains of Ala330Pro and Ile401Pro, two single-site proline variants of CYP102A1 (P450BM3) from Bacillus megaterium, have been solved. In the A330P structure, the active site is constricted by the relocation of the Pro329 side chain into the substrate access channel, providing a basis for the distinctive C-H bond oxidation profiles given by the variant and the enhanced activity with small molecules. I401P, which is exceptionally active towards non-natural substrates, displays a number of structural similarities to substrate-bound forms of the wild-type enzyme, notably an off-axial water ligand, a drop in the proximal loop, and the positioning of two I-helix residues, Gly265 and His266, the reorientation of which prevents the formation of several intrahelical hydrogen bonds. Second-generation I401P variants gave high in vitro oxidation rates with non-natural substrates as varied as fluorene and propane, towards which the wild-type enzyme is essentially inactive. The substrate-free I401P haem domain had a reduction potential slightly more oxidising than the palmitate-bound wild-type haem domain, and a first electron transfer rate that was about 10 % faster. The electronic properties of A330P were, by contrast, similar to those of the substrate-free wild-type enzyme. Protein evolution with proline: The crystal structures of two contrasting single-site proline mutants of CYP102A1 (P450BM3) have been solved. The two mutations combine to give a variant that shows substantially enhanced catalytic activity with small non-natural substrates (see graph).
Pd-Catalyzed Assembly of Fluoren-9-ones by Merging of C-H Activation and Difluorocarbene Transfer
Liu, Xiaobing,Sheng, Heyun,Zhou, Yao,Song, Qiuling
, p. 2543 - 2547 (2021)
We disclose a novel Pd-catalyzed assembly of fluoren-9-ones by merging of C-H activation and difluorocarbene transfer. ClCF2COONa served as a difluorocarbene precursor to be harnessed as a carbonyl source in this transformation. The current protocol enables us to afford fluoren-9-ones in high yields with excellent functional group compatibility, which also represents the first example of using difluorocarbene as a coupling partner in transition-metal-catalyzed C-H activation.
Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion
Knorr, Rudolf,Schmidt, Barbara
, p. 3018 - 3024 (2018)
Sterically well-shielded against unsolicited Michael addition and polymerization reactions, α-metalated α-(1,1,3,3-tetramethyl-indan-2-ylidene)acetonitriles added reversibly to three small aldehydes and two bulky ketones at room temperature. Experimental conditions were determined for transfer of the nucleofugal title carbanion unit between different carbonyl compounds. These readily occurring retro-additions via C-C(O) bond fission may also be used to generate different metal derivatives of the nucleofugal anions as equilibrium components. Fluoride-catalyzed, metal-free desilylation admitted carbonyl addition but blocked the retro-addition.
ENHANCEMENT OF Si-H BOND REACTIVITY IN PENTACOORDINATED STRUCTURES
Boyer, J.,Breliere, C.,Corriu, R. J. P.,Kpoton, A.,Poirier, M.,Royo, G.
, p. C39 - C43 (1986)
The reactions of pentacoordinated silicon dihydrides with alcohols, carboxylic acids and carbonyl compounds have been studied.The dihydrides are markedly more reactive than the corresponding tetracoordinated species.
Isolation, structure and iridium-mediated decarbonylation of a sodium fluorenone dianion complex
Hou, Zhaomin,Fujita, Akira,Yamazaki, Hiroshi,Wakatsuki, Yasuo
, p. 669 - 670 (1998)
Reaction of fluorenone with 2 equiv. of Na in THF at room temp, gave the polymeric Na-fluorenone dianion complex 1 in 79% isolated yield, which upon reaction with 0.5 equiv. of [(C5Me5)IrCl(μ-Cl)]2 afforded the decarbonylation product 2; both 1 and 2 have been structurally characterized.
Selective aerobic benzylic C-H oxidation co-catalyzed by N-hydroxyphthalimide and Keplerate {Mo72V30} nanocluster
Rezaeifard, Abdolreza,Khoshyan, Ashkan,Jafarpour, Maasoumeh,Pourtahmasb, Mehrdad
, p. 15754 - 15761 (2017)
The catalytic efficiency of a Keplerate {Mo72V30} nanocapsule in the aerobic benzylic C-H oxidation of alcohols and hydrocarbons was exploited. The aerobic reactions were conducted using catalytic amounts of {Mo72V30} and under the co-catalytic effects of NHPI (N-hydroxyphthalimide) to furnish desired aldehydes and ketones in high yields and excellent selectivity. Different benzylic alcohols and hydrocarbons were shown to be amenable to oxidation under standard conditions presented here. Spectral data and leaching experiments revealed that the cluster had a long-term stability and could be used repeatedly in consecutive runs.
