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.

Description of solvent effect on the visible absorption spectrum of fluorenone radical anion

Abstract: The solvatochromic shift of the most intensive band of fluorenone radical anion (FN*-) in the visible region has been examined in 10 polar formally aprotic media. It has been found that this shift depends on the solvent acceptor number (AN) and static dielectric constant (D) according to planar regression: It is suggested that the ground state of FN*- is relatively stabilized in a solvent with a high acceptor number and the dipole moment of the solute increases during an excitation.

Phosphorus-31 contact shifts as a measure of weak ligand affinities. interaction between alkali metal fluorenone radical anions and certain phosphorus (iii or v) ligands

Abstract: The nuclear magnetic resonance shifts, δobs, induced to 31P in Ph3P, (MeO)3P and (MeO)3PO by alkali metal fluorenone radical anions in tetrahydrofuran solutions were measured. These parameters, which depend significantly on the cation for a given ligand, and also on the ligand for a given cation, were used to extract the corresponding 31P contact shifts, δc(M). The latter parameters are proposed as a measure of the ligand affinity of a given phosphorus compound for a particular alkali metal. Trimethyl phosphate exhibits the greatest affinity for the lithium cation. The magnitudes of δc(M) imply some covalency between the cation and the radical anion and the ‘paradox’ of a heavier alkali metal such as potassium being covalently bonded to fluorenone radical anion has been explained. The transferability of the reported ligand affinities of Li+, Na+ and K+ is discussed. © John Wiley & Sons, Ltd.

Production of fluorenone and oxidation catalyst used therein

Abstract: PURPOSE:To permit the efficient production of fluorenone of high purity from fluorene with no formation of by-products using a specific amine derivative as an oxidation catalyst economically in a shortened time. CONSTITUTION:To 2.5 to 30wt.% fluorene solution, is added 35 to 50wt.% of alkali aqueous solution and a catalyst aqueous solution. Then, oxygen is introduced into the mixture in an amount of 1.0 to 1.5 mole per mole of the fluorene. As the oxidation catalyst, is used an aqueous solution of 30 to 70wt.% concentration of one or more amine derivatives of the formula I (R is H, lower alkyl; R is lower alkyl; a is 1 to 2; X is SO4 , CH3SO4 where when X is SO4 , a=2; when X is CH3SO4 , a=1), particularly N,N-dimethylaniline is preferred). The catalyst is obtained, for example, by mixing N,N-dimethylaniline with dimethyl sulfate, stirring the mixture at room temperature, admixing water thereto, dripping IN sodium hydroxide until the pH reaches 7, filtering off the precipitate and adding water to the filtrate.

Positive photoresist composition

Abstract: A chemical amplifying type positive photoresist composition, excellent in various properties, particularly in TDE resistance as well as sensitivity and resolution, and able to suppress unfavorable halation effect without deteriorating profile, which comprises (A) a resin which is converted to alkali-soluble from alkali-insoluble or only slightly alkali soluble by the action of an acid, (B) an acid generator, (C) a basic compound and (D) a fluorenone compound represented by the following formula (I): wherein R1, R2, R3, R4, R5, R6, R7 and R8 each independently represent hydrogen, alkyl having 1 to 6 carbon atoms which may be optionally substituted with halogen, halogen or nitro is provided; and a precise fine photoresist pattern can be formed in high precision using the photoresist composition.