Fluorenone

About: Fluorenone is a research topic. Over the lifetime, 1067 publications have been published within this topic receiving 17162 citations. The topic is also known as: Diphenylene ketone & 9-Oxofluorene.

Formation of 9,9′:9′,9″-Terfluorenyl Isomers Using Metalated Fluorenes as Synthetic Intermediates

Abstract: Rotational isomers of 9,9′: 9′,9″-terfluorenyl were obtained by the addition of 9-lithiofluorene to 9,9′-bifluorenylidene (III). 2,7-Dibromo- (VI) and 2,7,2″,7″-tetrabromo-9′,9″-terfluorenyl (VIII) resulted from similar reactions of the corresponding bromo-derivatives. 9-Lithio-9,9′-bifluorenyl was treated with 9-bromo-9,9′-bifluorenyl to give 9,9′-bis(9,9′-bifluorenyl) (X), 9,9′: 9′,9″-terfluorenyl isomers (mp 293 °C (dec) (I) and mp 257 °C (dec) (II)), 9,9′-bifluorenyl (IX), III, and fluorenone. The isomerization of I by metallic potassium gave the other rotamer II, which decomposed into its components, IX, III, and fluorene (IV).

Intramolecular deactivation of photoexcited anthracenes by aromatic ketones

Abstract: The excited state properties of anthracenes non-conjugatively linked to various types of aromatic ketone were investigated in non-polar solution by determination of the quantum yields of fluorescence and intersystem crossing. In a series of substituted bichromophoric ω-(9-anthryl)propiophenones, the degree of intramolecular fluorescence quenching by the ketone was found to be associated with an increase in the quantum yield of anthracene triplet state formation. Excitation of 4′-piperazinoacetophenone tethered to anthracene resulted in deactivation within the acetophenone chromophore, rather than singlet energy transfer to anthracene. For photoexcited anthracene linked to 2-amido-substituted fluorenone, intramolecular exothermic transfer of the singlet excitation energy to the fluorenone chromophore was found to proceed with high efficiency.

Base-catalyzed Autoxidation of Fluorene in the Presence of Phase Transfer Catalysts

Abstract: Base-catalyzed autoxidation of fluorene to fluorenone has been carried out in an aqueous potassium hydroxide–benzene two-phase system in the presence of 18-crown-6 as a phase transfer catalyst. The initial rate of oxidation is proportional to the amount of fluorene. The addition of 18-crown-6 leads to the increased concentration of potassium hydroxide and water in the benzene phase, which is responsible for the increased rate of oxidation. Increasing the concentration of potassium hydroxide in the aqueous phase increases the concentration of 18-crown-6 and potassium hydroxide in benzene, resulting in a large increase in the rate of oxidation. The ease of oxidation with respect to the base is KOH>NaOH>LiOH>Ba(OH)2. Less polar solvents such as cyclohexane used as an organic phase decrease the oxidation rate.