Chromocene, ferrocene, cobaltocene, and nickelocene derivatives with isopropyl and methyl or trimethylsilyl substituents

Bauer, Horst; Weismann, Julia; Saurenz, Dirk; Färber, Christian; Schär, Marion; Gidt, Wjatscheslaw; Schädlich, Ina; Wolmershäuser, Gotthelf; Sun, Yu; Harder, Sjoerd; Sitzmann, Helmut

doi:10.1016/j.jorganchem.2016.02.038

Cited by 13 publications

(16 citation statements)

References 59 publications

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“…e.g. 184.7 and 184.9 pm for hexa( tert ‐butyl)chromocene or 180.3 pm for hexaisopropylchromocene, and the 185.3 pm value for [Cp′′′Cr(CO) 3 CH 3 ]}…”

Section: Resultsmentioning

confidence: 99%

“…Organometallic complexes of chromium have shown intriguing metal‐metal bonding properties and are well‐known for catalytic activity in ethylene oligomerization, epoxidation, epoxide/carbon dioxide copolymerization,, alternating epoxide/phthalic anhydride ring‐opening copolymerization, dioxygen activation and other processes. Bulky alkylcyclopentadienyl ligands have been seen in a small number of chromocenes, and in one mono(cyclopentadienyl)chromium complex [Cp′′′Cr(µ‐Cl)] 2 . Chromium(II) half sandwich complexes without π acceptor ligands promise to be even more reactive than the nickel, or iron precedents studied before: The 94 pm radius of chromium(II) ions in their high spin state is surpassed among the M 2+ cations of the 3d row only by Ti 2+ and opens Cr II half sandwich complexes for chemical reactions.…”

Section: Introductionmentioning

confidence: 99%

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Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

et al. 2018

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Easily available chromium(II) acetate was used for an entry into chromium chemistry: sodium tetraisopropylcyclopentadienide (Na4Cp), sodium 1,2,4‐tri(tert‐butyl)cyclopentadienide (NaCp′′′), or lithium pentaisopropylcyclopentadienide (Li5Cp) convert the acetate to the acetate‐bridged dimers [4CpCr(µ‐OOCCH3)]2 (1a), [Cp′′′Cr(µ‐OOCCH3)]2 (1b), or [5CpCr(µ‐OOCCH3)]2 (1c) in yields well above 70 %. These acetates could be converted into the halide‐bridged dimers [4CpCr(µ‐Cl)]2 (2a), [4CpCr(µ‐Br)]2 (3a), [Cp′′′Cr(µ‐Br)]2 (3b), or [5CpCr(µ‐Br)]2 (3c), [4CpCr(µ‐I)]2 (4a), or [Cp′′′Cr(µ‐I)]2 (4b) with the corresponding trimethylsilyl halides in nearly quantitative yield. With bis(trimethylsilyl)sulfate the acetate 1a gave crude bis(tetraisopropylcyclopentadienylchromium)sulfate (5a). From the bromide 3b and sodium bis(trimethylsilyl)amide the mononuclear chromium(II) silylamide [Cp′′′CrN(SiMe3)2(THF)] (7b) was obtained as a tetrahydrofuran adduct. Upon reaction with sodium azide, the iodide 4a afforded the tetranuclear chromium(IV) nitride cubane [(4CpCr)3(µ3‐N)4CrOH] (8a) after extraction with heptane containing traces of water. The analogous chromium nitride derivative [(Cp′′′Cr)3(µ3‐N)4CrBr] (9b) was obtained from the bromide 3b and sodium azide.

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“…e.g. 184.7 and 184.9 pm for hexa( tert ‐butyl)chromocene or 180.3 pm for hexaisopropylchromocene, and the 185.3 pm value for [Cp′′′Cr(CO) 3 CH 3 ]}…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

et al. 2018

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“…All other solvents were dried over activated 4 Å mol sieves and degassed prior to use. NiBr 2 ·DME, 30 NiCl 2 ·DME, 31 DippN(H)Li, 32 and PPh 2 CH 2 Li·TMEDA 33 were synthesized according to known literature procedures. All other reagents were used as received.…”

Section: Methodsmentioning

confidence: 99%

Reversible metathesis of ammonia in an acyclic germylene–Ni⁰ complex

2021

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“…The compounds [ 5 CpFeBr(dme)] ( 3 ) and [FeBr 2 (dme)] were prepared as described in the literature.…”

Section: Methodsmentioning

confidence: 99%

Iron(II) High‐Spin and Low‐Spin Complexes from Pentaisopropylcyclopentadienyliron(II) Bis(trimethylsilyl)amide

et al. 2017

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Two new complexes, [(C5Me5)FeBr(tmeda)] (tmeda = tetramethylethylenediamine) and [{C5(CHMe2)5}FeN(SiMe3)2], have been synthesized and characterized as high‐spin iron(II) complexes with typical distances between the iron atom and the center of gravity of the C5 ring (Fe–Cpcent) exceeding 190 pm and displaying paramagnetic behavior in solution. Both are analogues of known complexes, namely, the Jonas complex [(C5Me5)FeCl(tmeda)] and the Siemeling “pogo‐stick” complex [(C5Me5)FeN(SiMe3)2]. The silylamide [{C5(CHMe2)5}FeN(SiMe3)2] was treated with water to yield the bridged hydroxo dimer [{C5(CHMe2)5}Fe(µ‐OH)]2 with high‐spin iron(II) configuration. With 2,5‐dimethylpyrrole the azaferrocene derivative [{C5(CHMe2)5}Fe(NC4H2Me2‐2,5)] was obtained, and with diphenylphosphine a few crystals of the diphosphine hydride [{C5(CHMe2)5}FeH(HPPh2)2] as well as a sample of its dehydrogenative P–P coupling product [{C5(CHMe2)5}FeH(Ph2P–PPh2)]n (n = 1 or 2) have been obtained, which are both diamagnetic 18‐valence‐electron complexes. Two‐coordinated [{C5(CHMe2)5}FeN(SiMe3)2] features sizeable negative magnetic anisotropy and slow magnetic relaxation with an effective energy barrier for spin reversal of 113 cm–1 under an applied field of 3000 Oe.

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Chromocene, ferrocene, cobaltocene, and nickelocene derivatives with isopropyl and methyl or trimethylsilyl substituents

Cited by 13 publications

References 59 publications

Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

Reversible metathesis of ammonia in an acyclic germylene–Ni⁰ complex

Iron(II) High‐Spin and Low‐Spin Complexes from Pentaisopropylcyclopentadienyliron(II) Bis(trimethylsilyl)amide

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Chromocene, ferrocene, cobaltocene, and nickelocene derivatives with isopropyl and methyl or trimethylsilyl substituents

Cited by 13 publications

References 59 publications

Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

Paramagnetic Chromium(II) Complexes and Chromium(IV) Nitrides with Bulky Alkylcyclopentadienyl Ligands

Reversible metathesis of ammonia in an acyclic germylene–Ni0 complex

Iron(II) High‐Spin and Low‐Spin Complexes from Pentaisopropylcyclopentadienyliron(II) Bis(trimethylsilyl)amide

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Reversible metathesis of ammonia in an acyclic germylene–Ni⁰ complex