Synthesis and structural characterization of unsymmetrical osmocenes containing the pentamethylcyclopentadienyl ligand

Arachchige, Shamindri M.; Heeg, Mary Jane; Winter, Charles H.

doi:10.1016/j.jorganchem.2005.07.039

Cited by 13 publications

(6 citation statements)

References 70 publications

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“…Selected bond lengths and angles are listed in Table . The solid-state structure of compound 4 is, in essence, similar to that of a typical metallocene and resembles that previously reported for Cp*(Flu)Ru. 13a, The two Cp-type ligands exhibit η 5 -coordination to the Ru center with a staggered conformation and are essentially parallel to each other, with a dihedral angle of 3.0° between the mean planes of the five-membered rings and a centroid−Ru−centroid angle of 179.2(7)°. However, the molecular structure reveals a Flu* ligand that is significantly distorted from planarity due to steric repulsions between methyl groups, which results in a twist of the fluorene core.…”

Section: Resultssupporting

confidence: 76%

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

2006

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Two highly methylated fluorene derivatives have been synthesized and used for the preparation of mixed-ligand fluorenyl ruthenocenes. Specifically, reaction of 2,2‘,3,3‘,4,4‘,5,5‘-octamethylbiphenyl with paraformaldehyde in the presence of CF3CO2H provided 1,2,3,4,5,6,7,8-octamethylfluorene (C13Me8H2), which was subsequently methylated by reaction with n-BuLi followed by addition of MeI to yield 1,2,3,4,5,6,7,8,9-nonamethylfluorene (C13Me9H). Reaction of the lithium fluorenyl derivatives with [Cp*RuCl]4 generated the mixed-ligand ruthenocenes Cp*(C13Me8H)Ru and Cp*(C13Me9)Ru. Electrochemical measurements indicate that these ruthenocene derivatives undergo quasi-reversible oxidations at low potentials consistent with strongly donating character for the highly methylated fluorenyl ligands. X-ray diffraction studies on C13Me8H2, C13Me9H, and Cp*(C13Me9)Ru revealed a twisted fluorene core in all cases.

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Section: Resultssupporting

confidence: 76%

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

2006

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“…It should be noted that η 5 ‐pz‐Nd binding has been observed in [Nd 3 (pz) 9 (pzH) 2 ] as part of a unique μ 3 ‐η 5 :η 1 :η 1 binding mode,5e and there is η 5 ‐binding of pyrazole ligand (pzH) in [Eu(pz) 2 (pzH) 2 ] ∞ 5e,6c. The mixed sandwich compounds [Ru(C 5 Me 5 )(η 5 ‐Me 2 pz)]12 and [Os(C 5 Me 5 )(η 5 ‐ t Bu 2 pz)]13 remain special examples of standalone η 5 ‐pyrazolate binding.…”

Section: Introductionmentioning

confidence: 99%

The Synthesis, Structures and Polymorphism of the Dimeric Trivalent Rare‐Earth 3,5‐Dimethylpyrazolate Complexes [Ln(Me₂pz)₃(thf)]₂

et al. 2014

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A variety of rare-earth 3,5-dimethylpyrazolate (Me 2 pz) complexes have been synthesised by (i) the direct reaction of Hgactivated metal with Me 2 pzH as a pro-ligand at elevated temperatures, (ii) by redox transmetalation/protolysis with the lanthanoid element, Hg(C 6 F 5 ) 2 , and Me 2 pzH, and (iii) by protolysis of tris[bis(trimethylsilyl)amido]cerium(III) with Me 2 pzH. Each product, upon crystallisation from tetrahydrofuran (thf), formed a dimeric complex, [Ln(Me 2 pz) 3 -(thf)] 2 (Ln = La, Ce, Pr, Nd, Ho, Yb, or Lu). Despite the common formulation, two completely different structures were observed in two distinct crystallographic "domains of existence", together presumptively spanning the gamut of Ln and Y. For the larger rare-earth ions (La-Pr), there are two [a]

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“…Well-examined unsymmetrical metallocenes relate to the metals Fe, Ru, and Os, for example, FluFeCp or FluRuCp*, where haptotropic rearrangements of the fluorenyl ligands are known. 16,28,46 The ligand rearrangement processes involving the pyrazolato ligand have been elucidated in more detail, as not only the halfsandwich complex 3 Pz (vide supra) could be isolated (Scheme 4). Additionally, the sandwich complex Flu 2 Ce(Me 2 Pz)(THF) (4 Pz ) could be obtained in 37% yield upon warming to ambient temperature.…”

Section: ■ Introductionmentioning

confidence: 99%

Cerium Fluorenyl Complexes Including CC Coupling Reactions

et al. 2022

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The first structurally characterized fluorenyl (Flu) complexes of cerium are reported, bearing one, two, and three fluorenyl ligands. The reaction of CeX 3 (THF) x (X = Cl and I) with KFlu led to the half-sandwich complexes FluCeX 2 (THF) 3 . The chloride derivative was utilized in salt metathesis reactions, affording complexes FluCeR 2 (THF) x with R = OtBu, OSiMe 3 , OC 6 H 3 iPr 2 -2,6, Me 2 Pz, and Cp (x = 1 or 2; Me 2 Pz = 3,5dimethylpyrazolato, Cp = C 5 H 5 ). The mono(fluorenyl) complexes FluCeR 2 (THF) x are prone to ligand redistribution at ambient temperature, leading to the respective sandwich complexes Flu 2 CeR(THF). Utilization of K(2,10-tBu 2 Flu) (KFlu tBu ) afforded tris(fluorenyl) complex Flu tBu 3 Ce(THF) instead, showcasing two η 5 -and one η 1 -bound fluorenyl ligands. Treatment of FluCeCl 2 (THF) 3 with halogenating oxidants such as C 2 Cl 6 , I 2 , or TeBr 4 did not afford stable cerium(IV) species but mixtures of 9halogenidofluorene and 1,1′-bifluorene. Selective fluorenyl coupling reactions could be achieved for C 2 Cl 6 . Respective investigations with lanthanum and neodymium complexes support σ-bond metathesis as the main reaction path for C−C-bond formation.

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Synthesis and structural characterization of unsymmetrical osmocenes containing the pentamethylcyclopentadienyl ligand

Cited by 13 publications

References 70 publications

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

The Synthesis, Structures and Polymorphism of the Dimeric Trivalent Rare‐Earth 3,5‐Dimethylpyrazolate Complexes [Ln(Me₂pz)₃(thf)]₂

Cerium Fluorenyl Complexes Including CC Coupling Reactions

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Synthesis and structural characterization of unsymmetrical osmocenes containing the pentamethylcyclopentadienyl ligand

Cited by 13 publications

References 70 publications

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

Octa- and Nonamethylfluorene and an Electron-Rich Permethylfluorenyl Ruthenocene Derivative

The Synthesis, Structures and Polymorphism of the Dimeric Trivalent Rare‐Earth 3,5‐Dimethylpyrazolate Complexes [Ln(Me2pz)3(thf)]2

Cerium Fluorenyl Complexes Including CC Coupling Reactions

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The Synthesis, Structures and Polymorphism of the Dimeric Trivalent Rare‐Earth 3,5‐Dimethylpyrazolate Complexes [Ln(Me₂pz)₃(thf)]₂