4612-64-0Relevant academic research and scientific papers
Unexpected coupling reaction of 9-lithiobromomethylene-9H-fluorene with 6,6-dicyclopropylfulvene
Paul, Gitendra C.,Gajewski, Joseph J.
, p. 524 - 526 (1997)
Metallation of 9-bis(bromomethylene)-9H-fluorene with one equivalent of BuLi at -78°C followed by quenching with 6,6-dicyclopropylfulvene and subsequent warming (room temperature, 18 h) gave an adduct identified as compound 5 (~ 70% yield). Under identical conditions dimethylfulvene and cyclopropylmethylfulvene failed to give a similar adduct. Simple and efficient syntheses of 9-bromomethylene- and 9-bis(bromomethylene)-9H- fluorene are also described.
A new class of singlet carbene ligands
Alcarazo, Manuel,Suarez, Rosa M.,Goddard, Richard,Fuerstner, Alois
, p. 9746 - 9749 (2010)
(Figure Presented) What are you? Deprotonation of fluorenylidene phosphonium salts generates reactive intermediates that can be described as push-pull cumulenes or singlet carbenes (see scheme). Whereas the NMR data are ambiguous, the coordination behavior shows the ready availability of a lone pair at the central C atom. The donor ability of singlet carbene ligands of this new class exceeds that of the commonly used N-heterocyclic carbenes (NHCs).
Controlling optical properties and function of BODIPY by using asymmetric substitution effects
Banuelos-Prieto, Jorge,Agarrabeitia, Antonia R.,Garcia-Moreno, Inmaculada,Lopez-Arbeloa, Inigo,Costela, Angel,Infantes, Lourdes,Perez-Ojeda, M. Eugenia,Palacios-Cuesta, Marta,Ortiz, Maria J.
, p. 14094 - 14105 (2010)
Asymmetrically substituted BODIPY analogues of the dye PM567 have been synthesised from 2-acylpyrroles and pyrroles that bear indene, fluorene or difluorene units. The type of linkage between the fluorene and the BODIPY core plays an important role in the photophysics of the BODIPY chromophore. Indeed, an aliphatic bridge gives rise to an energy-transfer process between the chromophores, whereas a vinyl spacer allows an electronic interaction between them, leading to a large red shift of the spectral bands. The laser action of the new dyes has been analysed under transversal pumping at 10 Hz repetition rate, in both liquid phase and incorporated into solid polymeric matrices. Lasing efficiencies of up to 40 % were reached with high photostabilities with the laser output remaining at the initial level after 1a- 105 pump pulses in the same position of the sample. The laser action of the new dyes outperforms the laser behaviour of commercial dyes that emit in the same spectral region. The replacement of fluorene by indene quenches the fluorescence and laser emission, but allows the development of an iron cation fluorescent sensor.
Alumina-Mediated π-Activation of Alkynes
Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
, p. 15420 - 15426 (2021/09/30)
The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.
Bromination of 1,1-diarylethylenes with bromoethane
Yu, Ze,Jiang, Jialiang,Chen, Hongtai,Tang, Xiangyang
supporting information, p. 2544 - 2552 (2021/07/06)
Aliphatic bromide was used as a halogenation reagent in the presence of DMSO, resulting in 2,2-diarylvinyl bromides from the corresponding 1,1-diarylethylenes. This protocol not only provides a convenient and straightforward strategy for the rapid construction of various 2,2-diarylvinyl bromides without bromine and extra oxidants, but also can improve the atom economy of Kornblum oxidative reaction.
