Fluorescence behaviour of an anthracene–BODIPY system affected by spin states of a dioxolene–cobalt centre
作者:Koichi Katayama、Masakazu Hirotsu、Akitaka Ito、Yoshio Teki
DOI:10.1039/c6dt00864j
日期:——
Dioxolene cobaltcomplexes, [Co(L)(TPA)]PF6 (1) and [Co(L)(Me3TPA)]PF6 (2), were synthesized using a catechol with anthracene and boron-dipyrromethene (BODIPY), H2L, and tris(pyridin-2-ylmethyl)amine (TPA) or tris[(6-methylpyridin-2-yl)methyl]amine (Me3TPA) and characterised by UV-vis absorption, IR and NMR spectroscopy. Complexes 1 and 2 are a low-spincobalt(III) catecholate form and a high-spin
A functionalized verdazyl radical, 1, was synthesized, which consists of a bodipy acceptor (A), a phenyl-anthracene donor (D), and a stable verdazyl radical (R). Optical measurements, electron spin resonance (ESR), time-resolved ESR (TRESR), and laser-excitation pulsed ESR experiments were carried out. The efficient intra-molecular energy transfer (EnT) from the anthracene moiety to the bodipy functional component was observed by time-resolved fluorescence spectroscopy and TRESR measurements. A unique dynamic electron-spin polarization (DEP) was detected for the quartet photo-excited state of 1 by TRESR and pulsed ESR. Such a unique DEP was not detected for either the parent verdazyl radical2 without the bodipy acceptor or new compound 3 with an anthraquinone moiety instead of the bodipy component. The spectral simulation of the quartet spectrum of 1 revealed that the unique DEP was generated by competition between a mechanism involving the intra-molecular ion pair *AââD+âR and spinâorbit intersystem crossing. The dynamic electron-spin polarization via the ion-pair state and the mechanism were discussed based on the experimental data and theoretical calculations. The electronic structure and the spin delocalization in the photo-excited quartet state of 1 were discussed by comparison with the results of 3.
Design, synthesis, magnetic properties of a π-radical ligand with photo-excited high-spin state and its Fe(ii) complex. The first stage of a new strategy for LIESST materials
作者:Koichi Katayama、Masakazu Hirotsu、Isamu Kinoshita、Yoshio Teki
DOI:10.1039/c2dt31831h
日期:——
quartet state (S = 3/2) and its iron(II) complex [Fe(L11)H2B(Pz)2}2] (1) H2B(Pz)2− = dihydrobis(1-pyrazolyl)borate} were synthesized as a candidate for a new strategy for spin-crossovercompounds exhibiting light-induced excited spin state trapping (LIESST), which is via the photo-excited high-spin state of the π-conjugated aromatic system. Control compounds, ligand L22 and [Fe(L22)H2B(Pz)2}2] (2), in
The novel compound of the present invention has the diphenylanthracene structure at the center and a specific structure substituted with an aryl group at end portions. The organic electroluminescence device of the present invention comprises a plurality of layers of thin films of organic compounds which comprise a light emitting layer or a plurality of layers comprising a light emitting layer and are disposed between a pair of electrodes and at least one of the layers of thin films of organic compounds comprises the above novel compound. The novel compound exhibits excellent efficiency of light emission and heat resistance, has a long life and emits bluish light having excellent purity of color and the organic electroluminescence device comprises the novel compound and exhibits the same advantageous properties.