Divalent tetra- and penta-phenylcyclopentadienyl europium and samarium sandwich and half-sandwich complexes: synthesis, characterization, and remarkable luminescence properties

Kelly, Rory P., Bell, Toby D.M., Cox, Rosalind P., Daniels, Daisy P., Deacon, Glen B., Jaroschik, Florian, Junk, Peter C., Le Goff, Xavier F., Lemercier, Gilles, Martinez, Agathe, Wang, Jun, and Werner, Daniel (2015) Divalent tetra- and penta-phenylcyclopentadienyl europium and samarium sandwich and half-sandwich complexes: synthesis, characterization, and remarkable luminescence properties. Organometallics, 34 (23). pp. 5624-5636.

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Abstract

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)(μ-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.

Item ID: 43086
Item Type: Article (Refereed Research - C1)
ISSN: 1520-6041
Funders: Australian Research Council (ARC), Centre National de la Recherche Scientifique (CNRS), Université de Reims, Ecole Polytechnique, PLAneT, Ministry of Higher Education and Research (MESR), European Union (EU)
Projects and Grants: ARC DP130100152, ARC DP130101861, ARC DP160101640, EU FEDER
Date Deposited: 03 Mar 2016 03:35
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030202 f-Block Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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