Substantial Intensification of the Quantum Yield of Samarium(III) Complexes by Mixing Ligands: Microwave-Assisted Synthesis and Luminescence Properties

Abstract

A luminescence quantum yield of 7.8% was obtained for a quaternary mixed-ligand samarium complex; this value is higher than those previously reported in the literature for such complexes in solution. The complex was prepared by microwave-assisted synthesis in 15 min with a yield of 69%; that is, ∼400 times faster than the usual synthesis that required 4 days and led to a yield of only 30%. Therefore, we propose microwave-assisted synthesis as the method of choice for preparing mixed-ligand lanthanoid complexes.

Visible, Near-Infrared, and Dual-Range Luminescence Spanning the 4f Series Sensitized by a Gallium(III)/Lanthanide(III) Metallacrown Structure

“…105 This effect is the most sizable for Sm-1 and Yb-1, the τobs and of which increase by 8-12 times reaching values of 721 µs/83% and 196 µs/8.4%, respectively (Table 1). These values are exceptional for Sm 3+ coordination compounds 59,[106][107][108] and are among the highest reported today for Yb 3+ complexes formed with non-deuterated and nonhalogenated ligands. 51,69,[109][110][111] To quantify the parameters that impact the total quantum yield ( ) and to get a potential explanation for the photophysical properties of the studied series of Ln 3+ /Ga 3+ MCs, the values of τrad were determined for Eu-1 (Table 2) and Yb-1 (Table 3) using Eqs.…”

“…This effect is the most sizable for Sm-1 and Yb-1 , the τ obs and Q Ln L of which increase by 8–12 times reaching values of 721 μs/83% and 196 μs/8.4%, respectively (Table ). These values are exceptional for Sm 3+ coordination compounds ,− and are among the highest reported today for Yb 3+ complexes formed with nondeuterated and nonhalogenated ligands. ,,− …”

“…5 Moreover, in the case of Eu-1, Tb-1, Dy-1 or visible ( 4 G5/2→ 3 HJ) transitions of Sm-1 the values of are, respectively, 3.7-, 1.4-, 5.5times higher or the same in CH3OH solution than in the solid state. It should be noted that Sm of Sm-1 in CH3OH solution (~10 %) is exceptionally high since this value usually does not exceed 2% for Sm 3+ complexes in protic solvents, 106 while b of Yb-1 is 3-times larger in respect to the value recorded for [YbGa4(shi)4(benzoate)4] 5 (Table 3). In deuterated CD3OD solutions of Ln-1, the values of τobs and are enhanced compared to those obtained in CH3OH being in line with lower contribution of O-D vibrations to the non-radiative deactivation of Ln 3+ .…”

Synthesis of Samarium-Based Metal Organic Compound Nanoparticles with Polychromatic-Photoluminescence for Bio-Tissue Fluorescence Imaging

“…Samarium-based compounds are interesting lanthanide emitters. They typically show orange/red fluorescence [6,7,8,9,10,11,12,13,14,15,16], which is just at the edge of the visible light and the beginning of the NIR light. Reports of Sm–based compounds showing luminescence other than orange/red are fairly rare in the literature [17,18,19].…”

“…The spectroscopic chemistry behind the luminescence of the compounds may be related to ligand-to-metal charge transfer [6,7,8,9,10,11,12,13,14,15,16,17,18,19]. In order to tailor the luminescence of the Sm compound, a special design can be made in the ligands, where the electron can transfer between Sm atoms and the ligands.…”