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.

Electronic structure calculations for large planar molecules by SCF‐scattered wave method

Abstract: Electronic structure calculations using the SCF‐scattered wave program of Johnson and Smith for the molecules carbazole, fluorenone, dinitrofluorenone, and trinitrofluorenone are reported. A qualitative description of the lowest excited states of these molecules is presented and a brief review of the theory underlying the calculations is given. Our calculations predict that the lowest excitation in carbazole should be polarized along the short molecular axis and in fluorenone along the long molecular axis. Polarized light absorption experiments should then provide an excellent check on the validity of these calculations. It is also shown that the lowest excitation in carbazole, fluorenone, and dinitrofluorenone should be a π→π* transition whereas in trinitrofluorenone it is suspected to be an n →π* transition. Comparison with minimal basis LCAO Hartree‐Fock calculations and experiments is made where possible.

Conjugated fluorenes prepared from azomethines connections--II: The effect of alternating fluorenones and fluorenes on the spectroscopic and electrochemical properties.

Abstract: The photophysics and electrochemistry of fluorene and fluorenone azomethine derivatives were examined in order to understand the deactivation pathways responsible for the quenched fluorescence of these compounds, which should otherwise be fluorescent. Steady-state fluorescence showed that the fluorene singlet excited state is quenched both by fluorenone (1) and a model aliphatic azomethine compound (14) with kq ≈ 1010 M−1 s−1. The quencher concentration required to deactivate 95% of the excited singlets formed was 8.4 mM for fluorenone and 34 mM for 14. Intramolecular photoinduced electron transfer (PET) from fluorene to both 1 and 14 was found as the principle deactivation mode of the fluorene’s excited state. The high degree of conjugation of the azomethines promotes intersystem crossing to the triplet manifold by narrowing the singlet−triplet energy gap, which is also in part responsible for the reduced fluorescence observed for the fluorenone azomethine derivatives 5−11. Fluorescence quenching by PET ...

Synthesis and Characterization of Dibenzoheterocycle‐Bridged Dinuclear Ruthenium Alkynyl and Vinyl Complexes

Abstract: A series of dinuclear ruthenium alkynyl and vinyl complexes bridged by carbazole, dibenzofuran, dibenzothiophene, and fluorenone have been prepared, and some representative molecular structures have been determined. The electrochemical and spectroscopic properties of the compounds were explored by cyclic voltammetry (CV), square-wave voltammetry (SWV), and in situ infrared and UV/Vis/near-IR spectroelectrochemical methods. The electrochemical results indicate that the greater the electron density on the ligand, the more stable the bridge-based oxidation product and the larger the electrochemical splitting. The UV/Vis/near-IR spectroelectrochemical studies revealed that the bridged ligands strongly contribute to or even dominate the oxidation processes. In addition, IR spectroelectrochemistry strengthens the theory of redox noninnocence in the bridging ligands, which was further confirmed by DFT calculations.

Spectroscopic Studies of Fluorenone Derivatives

Abstract: The absorption and steady-state fluorescence spectra of fluorenone, 1-hydroxyfluorenone, and 3-dimethylaminofluorenone have been obtained for various concentrations in a series of non-polar and polar solvents. The substituents (-OH and -N(CH3)2) as the electron-donating functional groups cause a large shift of the longwave absorption band and Stokes' shift of the monomer- and excimer-fluorescence bands in comparison with fluorenone. The total emission spectrum of 3-dimethylaminoflourenone in polar aprotic solvents exhibits a new band at λ ≃ 500 nm originating form the emission of the twisted intramolecular charge transfer (TICT) isomer. The excited state dipole moments of the emiting species of the molecule studied are determined using the solvatation shift method and calculated values of the ground state dipole moments.