Upconversion Photoluminescence and Energy Transfer Mechanism of a Novel Terbium-mercury Compound

摘要

A novel terbium-mercury complex [Tb(IA)3(H3O)2]2n(2nHgCl4)(nHg2Cl5)·nH3O·3nH2O (1,HIA =isonicotinic acid) has been synthesized through hydrothermal reactions and characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in the C2/c space group of monoclinic system with a =24.2347(5),b =20.8342(6),c =15.3206(3) (A),β =128.257(2)°,V =6074.3(2) (A)3,C36H41Cl13Hg4N6O20Tb2,Mr =2458.80,Z =4,Dc =2.689 g/cm3,μ(MoKa) =13.014 mm-1 and F(000) =4520.The crystal structure of 1 is characterized by a one-dimensional (1-D)chain-like structure.Solid-state UWVis diffuse reflectance spectrum reveals the existence of a wide optical band gap of 3.36 eV.Solid-state photoluminescence experiment uncovers that it shows reddish brown upconversion emission.The emission bands are originated from the characteristic emission of the 4felectrons intrasheli transition of the 5D4 → 7FJ (J =6,5,4) of the Tb3+ ions.Energy transfer mechanism is explained by the energy level diagram of the Tb3+ ion and the isonicotinic acid ligand.It shows a remarkable CIE chromaticity coordinates (0.4158,0.4005).