Synthesis and Characterization of Iron(II) and Ruthenium(II) Hydrido Hydrazine Complexes

Field, Leslie D.; Li, Hsiu L.; Dalgarno, Scott J.; Jensen, Paul R.; McIntosh, Ruaraidh D.

doi:10.1021/ic102519f

Cited by 33 publications

(22 citation statements)

References 71 publications

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“…For example, the Ru-C bond distances in molecule A (shown in 5 The average N-N bond distance of 1.451(4)Å in A and 1.461(4)Å in B fall within the range found in a related structure. 5 The Ru1-N5 bond lengths of 2.248(3)Å in A and Ru2-N11 of 2.280(3)Å in B are slightly greater than the sum of the covalent radii of the ruthenium and nitrogen atoms (2.17 Å), 6 but are considerably less than the van der Waals radii of the two atoms (3.55 Å), 7 indicating a significant Ru-N interaction. The Ru1-H1 distance, 1.53(3)Å, in molecule A and the Ru2-H2 distance, 1.54(4) in molecule B, are slightly shorter than the reported values for ruthenium-hydride complexes.…”

mentioning

confidence: 51%

Crystal Structure of (Cycloocta-1,5-diene)tris(hydrazine)hydrido-ruthenium(II) tetraphenylborate

Owalude¹,

Eke²,

Odebunmi³

et al. 2012

X-ray Structure Analysis Online

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Our interest in the ruthenium(II) complexes with chelating phosphine ligands stem from their demonstrated utility in the asymmetric hydrogenation of a wide range of substrates. 1 The title complex is therefore synthesized by modifying a literature procedure, 2 as a precursor to preparing a series of catalytically active phosphine and diphosphine ruthenium(II) compounds. The product was recrystallized from N2H4·H2O and ethanol as colourless needles.The structure of the related dimethylhydrazine complex was reported by Singleton et al. 3 In that report, the presence of a hydride ligand in the dimethylhydrazine derivative was only inferred from the observed peak of 0.65 eÅ -3 , since it could not be located from the final difference-Fourier map during analysis. However, in the present molecule, the hydrogen atoms of the Ru-H as well as those of the NH2 and NH2NH2 moieties were located from a difference Fourier map and refined isotropically. The remaining hydrogen atoms in both molecules were placed at idealized positions, and were refined using a riding model. The largest residual electron density for structure (2.881 e/Å 3 ) was located close to (less than 1.0 Å from) the ruthenium atom, and was most likely due to imperfect absorption corrections frequently X-ray Structure Analysis Online

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confidence: 51%

Crystal Structure of (Cycloocta-1,5-diene)tris(hydrazine)hydrido-ruthenium(II) tetraphenylborate

Owalude¹,

Eke²,

Odebunmi³

et al. 2012

X-ray Structure Analysis Online

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“…Gas chromatography‐flame ionization detection (GC‐FID) analysis was performed using a YL instrument 6500GC system equipped with an HP–PONA (50 m × 0.200 mm × 0.50 μm) column. CrCl 3 (THF) 3 and [H(OEt 2 ) 2 ] + [B(C 6 F 5 ) 4 ] − were prepared via previously reported methods …”

Section: Methodsmentioning

confidence: 99%

MAO‐free and extremely active catalytic system for ethylene tetramerization

Kim

Lee

Park

et al. 2019

Applied Organom Chemis

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The original Sasol catalytic system for ethylene tetramerization is composed of a Cr source, a PNP ligand, and MAO (methylaluminoxane). The use of expensive MAO in excess has been a critical concern in commercial operation. Many efforts have been made to replace MAO with non‐coordinating anions (e.g., [B(C6F5)4]−); however, most of such attempts were unsuccessful. Herein, an extremely active catalytic system that avoids the use of MAO is presented. The successive addition of two equivalent [H(OEt2)2]+[B(C6F5)4]− and one equivalent CrCl3(THF)3 to (acac)AlEt2 and subsequent treatment with a PNP ligand [CH3(CH2)16]2C(H)N(PPh2)2 (1) yielded a complex presumably formulated as [1‐CrAl (acac)Cl3(THF)]2+[B(C6F5)4]−2, which exhibited high activity when combined with iBu3Al (1120 kg/g‐Cr/h; ~4 times that of the original Sasol system composed of Cr (acac)3, iPrN(PPh2)2, and MAO). Via the introduction of bulky trialkylsilyl substituents such as –SiMe3, –Si(nBu)3, or –SiMe2(CH2)7CH3 at the para‐position of phenyl groups in 1 (i.e., by using [CH3(CH2)16]2C(H)N[P(C6H4‐p‐SiR3)2]2 instead of 1), the activities were dramatically improved, i.e., tripled (2960–3340 kg/g‐Cr/h; more than 10 times that of the original Sasol system). The generation of significantly less PE (<0.2 wt%) even at a high temperature is another advantage achieved by the introduction of bulky trialkylsilyl substituents. NMR studies and DFT calculations suggest that increase of the steric bulkiness on the alkyl‐N and P‐aryl moieties restrict the free rotation around (alkyl)N–P (aryl) bonds, which may cause the generation of more robust active species in higher proportion, leading to extremely high activity along with the generation of a smaller amount of PE.

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“…108 The six coordinate complexes have been This journal is © The Royal Society of Chemistry 2012 (dmpe = 1,2-bis(dimethylphosphino)ethane). 116 This type of complex represents a potential reaction intermediate in an iron-mediated nitrogen reduction scheme. Once more, the hydrazine complex exhibited decomposition in solution and was only found to be stable in the presence of excess N 2 H 4 .…”

Section: Iron Dinitrogen Complexesmentioning

confidence: 99%