s‐Block Metal Complexes with Bis‐ and Tris(pyrazolyl)methane and ‐methanide Ligands

Krieck, Sven; Koch, Alexander W.; Hinze, Kay; Müller, Christoph; Länge, J.D.; Görls, Helmar; Westerhausen, Matthias

doi:10.1002/ejic.201501263

Cited by 28 publications

(25 citation statements)

References 132 publications

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“…Furthermore, the carbon at the 5-position of the pyrazole ring at 132.30 ppm exhibits a short-distance interaction with the hydrogen at 7.57-7.59 ppm. [29,30] Other chemical shifts for L1-L5 are in agreement with the values reported for similar pyrazolylphosphine ligands described in the literature.…”

Section: Synthesis and Characterization Of The Ligandssupporting

confidence: 89%

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Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

Junges

Dresch

Costa

et al. 2019

Applied Organom Chemis

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A series of new nickel (II) complexes of general formula [NiBr 2 (N,O) 2 ] (Ni1-Ni5) based on bidentate pyrazolyl-phosphinoyl ligands were prepared and characterized by IR spectroscopy, elemental analysis, high-resolution mass spectrometry (HRMS), and X-ray crystallography for Ni1. X-ray crystallographic analyses of Ni1 revealed a six-coordinate species, in which Ni (II) lies in an octaedral environment. The nickel center is chelated by two pyrazolyl-phosphinoyl ligands with the two bromide ligands occupying mutually trans positions. Upon activation with methylaluminoxane (MAO), all nickel complexes were able to oligomerize ethylene with turnover frequencies (TOFs) varying from 5.0 to 16.6 × 10 3 (mol ethylene) (mol Ni) −1 h −1 producing selectively 1-butene (91.0-95.5 wt%). The substitution on the pyrazolyl group and the length of the backbone chain play a significant role in the catalytic activity. The use of MAO/TMA (1:1) or MAO/TiBA (1:1) instead of MAO drastically reduced the activities. The TMA content has no significant influence on the selectivity. However, the use of TiBA leads to a reduction of 1-butene (from 94.9 to 71.0 wt%) and an improvement in the hexene production (from 1.5 to 23.3 wt%). Under optimized reaction conditions (10°C, 20 min, 20 bar ethylene, [Al/Ni] = 600), Ni1/MAO catalytic system yielded TOF = 24.7 × 10 3 (mol ethylene) (mol Ni) −1 h −1 with good selectivities for α-C4 (94.9 wt%).

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Section: Synthesis and Characterization Of The Ligandssupporting

confidence: 89%

“…The X-ray diffraction results corroborate with the proposed structure, and the P=O bond distance 1.4904(8) Å founding in L1 is similar to that founding in other organic compounds containing phosphinoyl groups. [29,30]…”

Section: Synthesis and Characterization Of The Ligandsmentioning

confidence: 99%

Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

Junges

Dresch

Costa

et al. 2019

Applied Organom Chemis

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“…Since the first report of the tris(pyrazolyl)hydroborate( Tp R ) ligand in 1967 by Trofimenko, [1] fac-coordinating N-donorl igands of this type [2][3][4] have been studied in detail, predominantly in the contexto fc oordination, bioinorganic and organometallic chemistry.T he furtherd evelopment of Tp ligand scaffolds, and the synthesis and reactionso ft heir complexes, have been summarisedi nmany reviews. [5] Many Tp derivatives have been synthesised ever since, primarily focussing on the introductiono ff unctionalg roups on the pyrazolyl moieties.…”

Section: Introductionmentioning

confidence: 99%

“…Herein, we report on the so-far unprecedented boron-fluorinated F Tp* ligand ([FB(3,5-Me 2 pz) 3 ] À with pz = pyrazolyl) and its mono-a nd dinuclearc opper complexes [Cu 2 ( F Tp*) 2 ]( 3)a nd [Cu( F Tp*) 2 ]( 4). Although boron-chlorination has been observed withinp oly(pyrazolyl)borate chemistry,t oo ur knowledge,complexes 3 and 4 are the first examples of cleanly isolated and fully characterised tris(pyrazolyl)borate complexes with BÀF bonds.…”

Section: Introductionmentioning

confidence: 99%

A Boron‐Fluorinated Tris(pyrazolyl)borate Ligand (^FTp) and Its Mono‐ and Dinuclear Copper Complexes [Cu(^FTp)₂] and [Cu₂(^FTp*)₂]: Synthesis, Structures, and DFT Calculations

Augenstein

Dorner

Reiter

et al. 2016

Chemistry A European J

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Reaction of [Si(3,5-Me2 pz)4 ] (1) with [Cu(MeCN)4 ][BF4 ] (2) gave the mono- and dinuclear copper complexes [Cu2 ((F) Tp*)2 ] (3) and [Cu((F) Tp*)2 ] (4). Both complexes contain the so-far unprecedented boron-fluorinated (F) Tp* ligand ([FB(3,5-Me2 pz)3 ](-) with pz=pyrazolyl) originating from 1, acting as a pyrazolyl transfer reagent, and the [BF4 ](-) counter anion of 2, serving as the source of the {BF} entity. The solid-state structures as well as the NMR and EPR spectroscopic characteristics of the complexes were elaborated. Pulsed gradient spin echo (PGSE) experiments revealed that 3 retains (almost entirely) its dimeric structure in benzene, whereas dimer cleavage and formation of acetonitrile adducts, presumably [Cu((F) Tp*)(MeCN)], is observed in acetonitrile. The short Cu⋅⋅⋅Cu distance of 269.16 pm in the solid-state is predicted by DFT calculations to be dictated by dispersion interactions between all atoms in the complex (the Cu-Cu dispersion contribution itself is only very small). As revealed by cyclic voltammetry studies, 3 shows an irreversible (almost quasi-reversible at higher scan rates) oxidation process centred at E(pa) =-0.23 V (E(0) 1/2 =-0.27 V) (vs. Fc/Fc(+) ). Oxidation reactions on a preparative scale with one equivalent of the ferrocenium salt [Fc][BF4 ] (very slow reaction) or air (fast reaction) furnished blue crystals of the mononuclear copper(II) complex [Cu((F) Tp*)2 ] (4). As expected for a Jahn-Teller-active system, the coordination sphere around copper(II) is strongly distorted towards a stretched octahedron, in accordance with EPR spectroscopic findings.

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“…This overview would not be complete without the mention of two other types of heteroscorpionate ligands that have yielded alkylmagnesium compounds. The tertiary hydrogen of tris(pyrazolyl)methanes (HTpm) is acidic, and deprotonation can lead to anionic tris(pyrazolyl)methanides (Tpm) . Accordingly HTpm Me2 reacts with Mg( n Bu) 2 to yield the zwitterionic complex [(κ 3 ‐Tpm Me2 ) 2 Mg], which has no Mg–C bond .…”

Section: Introductionmentioning

confidence: 99%

Cyclopropylmagnesium Scorpionates: A Missing Member of the Series with Both Staggered and Eclipsed Rotamers in the Crystal

et al. 2018

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The reaction of the hydrotris(3,5-dimethylpyrazolyl)borate potassium salt KTp Me2 with [Mg(c-C 3 H 5 ) 2 (dioxane) x ] gives [Tp Me2 Mg(c-C 3 H 5 )] (1) in 70 % yield. Full characterization includes an X-ray diffraction study, which reveals the presence of both staggered and eclipsed rotamers around the Mg-C bond of 1 in the unit cell. There is no evidence for any agostic interaction. Complex 1 does not undergo the Schlenk equilibrium. The complex [(F 12 -Tp 4Bo,3Ph )Mg(c-C 3 H 5 )] (2) containing a [a]

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s‐Block Metal Complexes with Bis‐ and Tris(pyrazolyl)methane and ‐methanide Ligands

Cited by 28 publications

References 132 publications

Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

A Boron‐Fluorinated Tris(pyrazolyl)borate Ligand (^FTp) and Its Mono‐ and Dinuclear Copper Complexes [Cu(^FTp)₂] and [Cu₂(^FTp*)₂]: Synthesis, Structures, and DFT Calculations

Cyclopropylmagnesium Scorpionates: A Missing Member of the Series with Both Staggered and Eclipsed Rotamers in the Crystal

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s‐Block Metal Complexes with Bis‐ and Tris(pyrazolyl)methane and ‐methanide Ligands

Cited by 28 publications

References 132 publications

Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

Pyrazolyl‐phosphinoyl nickel (II) complexes: synthesis, characterization and ethylene dimerization studies

A Boron‐Fluorinated Tris(pyrazolyl)borate Ligand (FTp*) and Its Mono‐ and Dinuclear Copper Complexes [Cu(FTp*)2] and [Cu2(FTp*)2]: Synthesis, Structures, and DFT Calculations

Cyclopropylmagnesium Scorpionates: A Missing Member of the Series with Both Staggered and Eclipsed Rotamers in the Crystal

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A Boron‐Fluorinated Tris(pyrazolyl)borate Ligand (^FTp) and Its Mono‐ and Dinuclear Copper Complexes [Cu(^FTp)₂] and [Cu₂(^FTp*)₂]: Synthesis, Structures, and DFT Calculations