Highly luminescent lanthanide complexes based on dendrimeric phosphinoxides
摘要:
Novel ligands incorporating diphenylphosphinoxide groups form very stable and extremely luminescent complexes with Eu(III) and Tb(III) ions, when excited with UV radiation. Their luminescence is very stable in water media, indicating that water has no influence on vibronic OH quenching of the luminescence. Ligand 1, based on cyclotriphosphazene, contains six Ph2PO groups, whereas the ionisable compound 2 contains a bidentate model ligand (N-diphenylphosphinoxidep-toluenesulphonamide). Both ligands form lanthanide complexes very poorly soluble in water. The complex luminescence characteristics were investigated in aqueous media, but due to their incomplete solubilisation only qualitative data were obtained. (C) 2002 Elsevier Science B.V. All rights reserved.
New class of P-stereogenic chiral Brønsted acid catalysts derived from chiral phosphinamides
作者:Zhengxu S. Han、Hao Wu、Bo Qu、Yuwen Wang、Ling Wu、Li Zhang、Yibo Xu、Linglin Wu、Yongda Zhang、Heewon Lee、Frank Roschangar、Jeff J. Song、Chris H. Senanayake
DOI:10.1016/j.tetlet.2019.06.013
日期:2019.7
A new class of NH Brønsted acid organocatalysts that feature P-stereogenic chirality was developed. These catalysts were prepared from P-stereogenic chiral phosphinamides and show similar reactivity to BINOL derived phosphoric acid toward the reduction of quinolines via transfer hydrogenation. It shows that stereoselectivity is induced by the P-chiral environment that is created by the substituents