Synthesis of (Imido)vanadium(V) Alkyl and Alkylidene Complexes Containing Imidazolidin-2-iminato Ligands: Effect of Imido Ligand on ROMP and 1,2-C-H Bond Activation of Benzene
Synthesis of (Imido)vanadium(V) Alkyl and Alkylidene Complexes Containing Imidazolidin-2-iminato Ligands: Effect of Imido Ligand on ROMP and 1,2-C-H Bond Activation of Benzene
复制标题
含咪唑烷-2-亚氨基配体的(亚氨基)钒(V)烷基和亚烷基配合物的合成：亚氨基配体对ROMP和苯1,2-C-H键活化的影响
DOI：
10.1021/om500986m
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发表时间：
2014
期刊：
影响因子：
2.8
通讯作者：
and Atsushi Igarashi
中科院分区：
文献类型：
--
作者：
Kotohiro Nomura;Bijal Kottukkal Bahuleyan;Ken Tsutsumi;and Atsushi Igarashi
一系列含有 V(CHSiMe3)(NR)(X)(PMe3) 型咪唑啉-2-亚氨基配体的 (亚氨基)钒 (V) 亚烷基配合物 (R = 2,6-Me2C6H3(Ar,3a), 1-金刚烷基 (Ad,3b), C6H5(3c)；X = 1,3-Ar′2(CH2N)2CN; Ar′ = 2,6-iPr2C6H3) 在 PMe3 存在下由相应的二烷基配合物 V(NR)(CH2SiMe3)2(X) (2a–c) 制备。这些亚烷基配合物 (3a–c) 对降冰片烯的开环易位聚合 (ROMP) 具有催化活性：苯基亚氨基类似物 (3c) 在 80 °C 下表现出显着的活性（例如 TOF 值为 84800 h–1（5 分钟后 7070 次转换）），提供具有均匀分子量分布的高分子量聚合物。 (芳基亚氨基)钒(V)二烷基配合物2a与C6H6的反应通过亚烷基中间体通过1,2-C–H活化得到苯基配合物V(NAr)(CH2SiMe3)(C6H5)(X) (4a)，最终产物为二苯基配合物V(NAr)(C6H5)2(X)。 3a-c对ROMP的活性、2a-c通过α-氢消除形成这些亚烷基的反应性以及2a-c对苯的反应性很大程度上受到亚氨基配体性质的影响。
A series of (imido)vanadium(V) alkylidene complexes containing an imidazolidin-2-iminato ligand of the type V(CHSiMe3)(NR)(X)(PMe3) (R = 2,6-Me2C6H3(Ar,3a), 1-adamantyl (Ad,3b), C6H5(3c); X = 1,3-Ar′2(CH2N)2CN; Ar′ = 2,6-iPr2C6H3) have been prepared inn-hexane in the presence of PMe3from the corresponding dialkyl complexes V(NR)(CH2SiMe3)2(X) (2a–c). These alkylidene complexes (3a–c) exhibit catalytic activities for ring-opening metathesis polymerization (ROMP) of norbornene: the phenylimido analogue (3c) exhibits remarkable activity at 80 °C (e.g. a TOF value of 84800 h–1(7070 turnovers after 5 min)), affording high-molecular-weight polymers with uniform molecular weight distributions. The reaction of the (arylimido)vanadium(V) dialkyl complex2awith C6H6afforded the phenyl complex V(NAr)(CH2SiMe3)(C6H5)(X) (4a) by 1,2-C–H activation via an alkylidene intermediate and the diphenyl complex V(NAr)(C6H5)2(X) as the final product. The activity by3a–cfor ROMP, the reactivity of2a–cfor formation of these alkylidenes by α-hydrogen elimination, and the reactivity of2a–ctoward benzene were highly affected by the nature of the imido ligand.