Near IR luminescent rare earth 3,4,5,6-tetrafluoro-2-nitrophenoxide complexes: Synthesis, X-ray crystallography and spectroscopy

摘要

3,4,5,6-Tetrafluoro-2-nitrophenoxide (L-) forms complexes with rare earth M3+ ions. X-ray crystal structures of substances with the stoichiometry Cs2ML5 - mEt(2)O (M = Er, m = 0; M = Er, m = 1; M = Y, m = 1.5; M = Yb, m = 1) have been determined. Each M3+ ion is coordinated to two bidentate and three monodentate L- ions; Et2O does not coordinate to M3+. The complexes absorb both visible and ultraviolet light. The solid Er3+ and Yb3+ complexes have unusually long lifetimes (tau = 20.2 mu s and 142 mu s, respectively) for the decay of their luminescence in the near-infrared region following photoexcitation; this is attributed to the lack of C-H bonds and other high frequency oscillators that could cause vibrational quenching. (C) 2008 Elsevier Ltd. All rights reserved.