Komplexkatalyse

Taube, Rudolf; Gehrke, Jörg‐Peter; Böhme, Peter; Scherzer, K.

doi:10.1016/0022-328x(91)83013-t

Cited by 36 publications

(13 citation statements)

References 12 publications

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“…They have also been applied as unique initiators for the polymerization of olefins and cyclic esters 8a. 12a,b, 13 Moreover, the transfer of an allyl group (catalyzed and noncatalyzed) is of tremendous importance in organic synthesis, for example, in chemo‐ and regioselective reactions,14 in diastereo‐ and enantioselective reactions,15 including umpolung of the allyl ligand,15g, 16 in (de)protection of diverse functional groups17 as well as in tandem,18 cascade,19 and multicomponent reactions 20…”

Section: Introductionmentioning

confidence: 99%

Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity

Lichtenberg

Okuda

2013

Angew Chem Int Ed

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Organometallic allyl compounds are important as allylation reagents in organic synthesis, as polymerization catalysts, and as volatile metal precursors in material science. Whereas the allyl chemistry of synthetically relevant transition metals such as palladium and of the lanthanoids is well-established, that of main group metals has been lagging behind. Recent progress on allyl complexes of Groups 1, 2, and 12-16 now provides a more complete picture. This is based on a fundamental understanding of metal-allyl bonding interactions in solution and in the solid state. Furthermore, reactivity trends have been rationalized and new types of allyl-specific reactivity patterns have been uncovered. Key features include 1) the exploitation of the different types of metal-allyl bonding (highly ionic to predominantly covalent), 2) the use of synergistic effects in heterobimetallic compounds, and 3) the adjustment of Lewis acidity by variation of the charge of allyl compounds.

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Section: Introductionmentioning

confidence: 99%

Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity

Lichtenberg

Okuda

2013

Angew Chem Int Ed

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“…The most active well‐defined Ni(II) initiator, a so‐called “ligand‐free” system, [Ni(C 12 H 19 )][PF 6 ], was described by Taube [see Scheme (C)]. This catalyst is reported to achieve turnover frequencies up to 12,000/h for BD polymerization at room temperature and yields 93% cis ‐1,4‐PBD 36, 37…”

Section: Introductionmentioning

confidence: 99%

Polymerization of 1,3‐dienes and styrene catalyzed by cationic allyl Ni(II) complexes

O’Connor

Brookhart

2010

J. Polym. Sci. A Polym. Chem.

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Polymerizations of 1,3-dienes using in situ generated catalyst [(2-methallyl)Ni][B(Ar F ) 4 ], 6, (Ar F ¼ 3,5-bis(trifluoromethyl)phenyl) as well as [(2-methallyl)Ni(mes)][B(Ar F ) 4 ], 14, (mes ¼ mesitylene) are reported. Highly sensitive complex 6 polymerizes butadiene (BD) at -30 C to yield polybutadiene with a M n of ca. 10 K and 94% cis-1,4-enchainment while less reactive isoprene (IP) was polymerized at 23 C to yield polyisoprene with M n ca. 7 K. Complex 6 was also shown to polymerize a functionalized diene, 2,3-bis(4-trifluoroethoxy-4oxobutyl)-1,3-BD, to polymer with M n ¼ 113 K. The stable and readily isolated arene complex 14 initiates BD and IP polymerizations at somewhat higher temperatures relative to 6 and delivers polymers with higher molecular weights. Complex [(allyl)Ni(mes)][B(Ar F ) 4 ], 13, catalyzes polymerization of styrene to yield polystyrene with high conversion, M n 's ¼ ca. 6 K and MWD ¼ 2. The p-benzyl complex [(g 3 -1-methylbenzyl)Ni(mes)] [B(Ar F ) 4 ], 19, was detected as an intermediate following chain transfer by in situ NMR studies.

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“…Although not as popular as the corresponding phosphine derivatives, neutral and cationic η 3 ‐allyl nickel(II) complexes containing arsine or stibine donor ligands have also been prepared, showing very high catalytic activity in the polymerization of butadiene,[11a] oligomerization of ethylene[4b] and oligo‐/polymerization of styrenes . On the other hand, cyclopentadienyl nickel(II) complexes bearing arsine or stibine donor ligands, with general formulas [Ni(η 5 ‐Cp)(EPh 3 )X] and [Ni(η 5 ‐Cp)(EPh 3 ) 2 ] + (E = As, Sb; X = halides), have been known for several years .…”

Section: Introductionmentioning

confidence: 99%

Cationic R‐Substituted‐Indenyl Nickel(II) Complexes of Arsine and Stibine Ligands: Synthesis, Characterization, and Catalytic Behavior in the Oligomerization of Styrene

et al. 2018

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A series of new cationic Rn‐substituted‐indenyl nickel(II) complexes containing arsine or stibine ligands were synthesized in moderate to very high yields by the protonation of the corresponding bis(indenyl) nickel derivatives [Ni(η‐Rn‐Ind)2] with HBF4, in the presence of 2 equiv. of AsPh3 or SbPh3 donor ligands. These complexes, with the general formula [Ni(η‐Rn‐Ind)(EPh3)2]BF4 (E = As, Sb), were structurally characterized by NMR spectroscopy and X‐ray diffraction, and subsequently tested as single‐component catalysts for the oligomerization of styrene, leading to the formation of very low molecular weight head‐to‐tail oligomers (typically consisting of dimers, trimers and tetramers). The new 1‐ or 2‐monosubstituted‐indenyl NiII catalyst precursors exhibit extremely high catalytic activities, considerably higher than those observed for the symmetrical unsubstituted‐ and the 1,3‐disubstituted‐indenyl nickel analogues (i.e. monosubstituted >> non‐substituted > 1,3‐disubstituted), their reactivity pattern showing similarities with that of the corresponding allyl derivatives. A simpler and more straightforward experimental procedure for the high yield preparation of [NiBr2(DME)], an important nickel starting material, which was used in the preparation of the bis(indenyl) nickel precursors of this work, is also described.

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Komplexkatalyse

Cited by 36 publications

References 12 publications

Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity

Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity

Polymerization of 1,3‐dienes and styrene catalyzed by cationic allyl Ni(II) complexes

Cationic R‐Substituted‐Indenyl Nickel(II) Complexes of Arsine and Stibine Ligands: Synthesis, Characterization, and Catalytic Behavior in the Oligomerization of Styrene

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