title: Organogels of 8-quinolinol/metal(II)-chelate derivatives that show electron- and light-emitting properties.
abstract: 8-quinolinol/copper(II)-, palladium(II)-, and platinum(II)-chelate-based organogelators (1 M) and their nongelling reference compounds (2 M) were synthesized. Complexes 1 M could gelate various organic solvents at very low concentrations. Electron microscope measurements gave visual images of well-developed fibrous structures characteristic of low-molecular-weight organogels. UV/Vis and FTIR spectroscopy revealed that the good gelation ability of 1 M arises from the pi-pi interactions of the chelate moieties and the hydrogen-bond interactions among the amide groups. Very interestingly, field emission performances of the nanofibers prepared from the 1 M gels are evidently different depending on the electronic states of the three kinds of central metals. In addition, the 1 Pt gel shows unique thermo- and solvatochromism of visible and phosphorescent color in response to a sol-gel phase transition. Furthermore, the 1 Pt gel possesses an attractive ability to inhibit dioxygen quenching of excited triplet states, which increases the phosphorescence quantum yield of this gel. This effect is attributed to the isolation effect of the phosphorescent chelate moiety from the dioxygen-containing solution phase.
authors.affiliation: Department of Chemistry & Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Norifumi
authors.initials: N
authors.lastname: Fujita
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tani
authors.forename: Kenji
authors.initials: K
authors.lastname: Kaneko
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Ojima
authors.forename: Akihiko
authors.initials: A
authors.lastname: Fujii
authors.forename: Masanori
authors.initials: M
authors.lastname: Ozaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Shinkai