Divalent Tetra- and Penta-phenylcyclopentadienyl Europium and Samarium Sandwich and Half-Sandwich Complexes: Synthesis, Characterization, and Remarkable Luminescence Properties
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- 作者：Rory P. Kelly ; Toby D. M. Bell ; Rosalind P. Cox ; Daisy P. Daniels ; Glen B. Deacon ; Florian Jaroschik ; Peter C. Junk ; Xavier F. Le Goff ; Gilles Lemercier ; Agathe Martinez ; Jun Wang ; Daniel Werner
- 刊名：Organometallics
- 出版年：2015
- 出版时间：December 14, 2015
- 年：2015
- 卷：34
- 期：23
- 页码：5624-5636
- 全文大小：667K
- ISSN：1520-6041
文摘
The synthesis of the bulky divalent (polyphenylcyclopentadienyl)lanthanoid sandwich complexes [Ln(C5Ph5)2] (Ln = Sm, Eu) and [Ln(C5Ph4H)2(solv)] (Ln = Sm, solv = thf; Ln = Eu, solv = dme)], from redox-transmetalation/protolysis (RTP) reactions, has been achieved. An analogous reaction with Yb afforded the solvent-separated ion pair [Yb(dme)4][C5Ph4H]2. In addition, rare divalent samarium halide complexes [Sm(C5Ph5)(渭-Br)(thf)2]2 and [Sm(C5Ph4H)I(thf)3], were also prepared, either by RTP or ligand rearrangement. X-ray studies showed that the [Ln(C5Ph5)2] complexes adopt highly symmetrical sandwich structures, whereas the [Ln(C5Ph4H)2(solv)] complexes have open sandwich structures. The unexpected, but limited, solubility of the [Ln(C5Ph5)2] complexes allowed for variable-temperature NMR spectra of [Sm(C5Ph5)2] to be obtained. Detailed 1D and 2D NMR studies were conducted on [Sm(C5Ph4H)2(thf)] to ascertain its structure in donor and nondonor solvents. During the course of these studies, the mixed tetraarylcyclopentadienyl sandwich complex [Sm{C5(2,5-Ph)2(3,4-p-tol2)H}2(thf)] was also prepared in order to fully assign the spectrum of [Sm(C5Ph4H)2(thf)]. The europium sandwich complexes [Eu(C5Ph5)2] and [Eu(C5Ph4H)2(dme)] exhibit remarkable luminescence properties with high quantum yields (45% and 41%, respectively) coupled with long emission lifetimes (approximately 800 and 1300 ns, respectively) in toluene.