Stability and Solution Behavior of [(dpp-Bian)Ln] and [(dpp-Bian)LnX] (Ln = Yb, Tm, or Dy; X = I, F, or N₃)

Abstract

Treatment of an excess of ytterbium metal with dpp-Bian {dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene} in the presence of 0.5 equiv of iodine resulted in a mixture of [(dpp-Bian)2–Yb2+(DME)2] (1) along with [YbI2(DME)2]2 and an over-reduced byproduct [(dpp-Bian)3–Yb2+I(DME)Yb2+(DME)2] (2). Oxidation of 1 with iodine is accompanied by electron transfer from the ligand to the metal atom to give [(dpp-Bian)−Yb2+I(THF)2]2 (3). Azide complexes [(dpp-Bian)2–Yb3+N3(DME)]6 (4) and [(dpp-Bian)2–Yb3+N3(THF)2]2 (5) were obtained by either oxidation of 1 with TMSN3 or salt metathesis reaction of 3 with NaN3. Fluorine complexes [(dpp-Bian)2–Yb3+F(DME)]2 (7) and [(dpp-Bian)2–Yb3+F(THF)1.5]2 (8) were obtained by oxidation of 1 with F2CCF2. Complex 3 in solution revealed reversible thermally induced intramolecular electron transfer {[(dpp-Bian)−Yb2–] ⇄ [(dpp-Bian)2–Yb3+]}. Unstable solutions of [(dpp-Bian)Dy(DME)2] (11) and [(dpp-Bian)Tm(DME)2] (12) were obtained by salt metathesis reaction of [(dpp-Bian)K2] with DyI2 or TmI2. These solutions treated with TMSN3 result in [(dpp-Bian)Dy(N)3(DME)]6 (13) and [(dpp-Bian)Tm(N)3(DME)]6 (14). The crystalline structure of azide and fluorine compounds depended on the crystallization solvent. New compounds are characterized by nuclear magnetic resonance, infrared spectroscopy, magnetic moment and differential scanning calorimetry measurements, and elemental and X-ray diffraction analysis. Solution transitions were probed by absorption spectroscopy.

Ligand-Induced Intramolecular Redox Diversity in Titanium Complexes with Acenaphthene-1,2-diimine

“…The simultaneous presence of a metal ion, which is able to exist in various oxidation states, and a redox-active ligand in a complex generally allows for a range of possible transformations through intra- or intermolecular routes. A striking example of intramolecular reactivity of such complex systems is the reversible electron transfer from metal to ligand, as reported for the ytterbium complexes [(dpp-Bian)­Yb II (dme)­Br] 2 , [(dpp-Bian)­Yb III (dme)­Cl]­[(dpp-Bian)­Yb II (dme)­Cl], and [(dpp-Bian)­Yb II I­(THF) 2 ] 2 …”

Multi‐electron Oxidation of Ce(III) Complexes Facilitated by Redox‐Active Ligands

“…[8] In the lanthanide row, Fedushkin and coworkers have presented extensive work on redox-active ligands supporting lanthanides, [9][10][11][12] such as the recent case of rare earth-dpp-Bian compounds (RE=Yb, Tm, or Dy) (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)-imino]acenaphthene). [13] Mazzanti and co-workers have recently reported an exciting example where a cerium derivative supported by the LO 3 ligand framework (LO 3 = 1,3,5-(2-OSi(OtBu) 2 C 6 H 4 ) 3 C 6 H 3 ) has been isolated and characterized in four different redox states. [14] In this example, the central arene is redox active, storing electrons in delta bonds and facilitating this rich redox chemistry.…”

“…For example, J. Arnold has demonstrated that storing two electrons in a bipyridine ligand facilitates reductive elimination at a thorium(IV) centre [8] . In the lanthanide row, Fedushkin and co‐workers have presented extensive work on redox‐active ligands supporting lanthanides, [9–12] such as the recent case of rare earth‐dpp‐Bian compounds (RE=Yb, Tm, or Dy) (dpp‐Bian=1,2‐bis[(2,6‐diisopropylphenyl)‐imino]acenaphthene) [13] . Mazzanti and co‐workers have recently reported an exciting example where a cerium derivative supported by the LO 3 ligand framework (LO 3 =1,3,5‐(2‐OSi(OtBu) 2 C 6 H 4 ) 3 C 6 H 3 ) has been isolated and characterized in four different redox states [14] .…”

Bromobenzene Transforms Lanthanoid Pseudo‐Grignard Chemistry

“…If the definition of lanthanoid pseudo‐Grignard compounds is extended to Ln II L(X) where L=N or O donor, then more known complexes fall into this category. For example, pseudo‐Grignard complexes, [Sm(dpp‐Bian)(dme)Br] 2 {dpp‐Bian=1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene}, [13] [Eu(dpp‐Bian)(dme)(μ‐X)] 2 (X=Cl, Br), [14] [Yb(dpp‐Bian)(dme)(μ‐Br)] 2 , [15a] [Yb(dpp‐Bian)I(thf) 2 ] 2 , [15b] [Sm(ArO)(μ‐I)(thf) 3 ] 2 , [16] (Ar=C 6 H 2 Bu t 2 ‐2,6‐Me‐4), [Sm(Ap)I(thf) 2 ] 2 , [17] {ApH=(2,6‐diisopropylphenyl)‐[6‐(2,4,6‐triisopropylphenyl)pyridine‐2‐yl]amine}, [Yb(Ap)I(thf) 2 ] 2 , [17] [YbDmp(Tph)N 3 Cl(thf)] 2 , {Dmp=2,6‐Mes 2 C 6 H 3 , Tph=2′,4′,6′‐triisopropylbiphenyl‐2‐yl}, [18] have been were synthesized previously by a variety of routes.…”