NMR spectroscopic identification of Ni(ii) species formed upon activation of (α-diimine)NiBr2 polymerization catalysts with MAO and MMAO†,Dalton Transactions

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NMR spectroscopic identification of Ni(ii) species formed upon activation of (α-diimine)NiBr2 polymerization catalysts with MAO and MMAO†
Dalton Transactions ( IF 3.5 ) Pub Date : 2018-03-07 00:00:00 , DOI: 10.1039/c8dt00483h
Igor E. Soshnikov _{1,

2,

3,

4,

5} , Nina V. Semikolenova _{1,

2,

3,

4} , Konstantin P. Bryliakov _{1,

2,

3,

4,

5} , Artem A. Antonov _{1,

2,

3,

4,

5} , Vladimir A. Zakharov _{1,

2,

3,

4,

5} , Evgenii P. Talsi _{1,

2,

3,

4,

5}

Affiliation

The nature of Ni(II) species formed upon the activation of the Brookhart's α-diimine polymerization pre-catalyst LNiBr₂ with MAO and MMAO (L = 1,4-bis-2,4,6-dimethylphenyl-2,3-dimethyl-1,4-diazabuta-1,3-diene) has been established using ¹H and ¹³C NMR spectroscopy. The heterobinuclear ion pair [LNi^II(μ-Me)₂AlMe₂]⁺[MeMAO]⁻ is observed at the initial stage of the reaction of LNiBr₂ with MAO at −40 °C, whereas the ion pair [LNi^II–^tBu]⁺[MeMMAO]⁻ predominates at the initial stage of the reaction of LNiBr₂ with MMAO under the same conditions. At higher temperatures, both ion pairs transform into a Ni(I) species displaying an axially anisotropic EPR spectrum (g_‖ = 2.21, g_⊥ = 2.06, A_⊥ = 1.06 mT).

中文翻译：

核磁共振光谱鉴定的Ni（II）时的（α-二亚胺）NIBR活化形成物种_2个与MAO和MMAO聚合催化剂†

Ni（II）物种的性质是通过用MAO和MMAO（L = 1,4-bis-2,4,6-二甲基苯基-2,3-二甲基）活化Brookhart'sα-二亚胺聚合预催化剂LNiBr ₂形成的使用¹ H和¹³ C NMR光谱确定了-1,4-二氮杂丁烯1,3-二烯）。在−40°C下，LNiBr ₂与MAO反应的初始阶段观察到异核双离子对[LNi ^II（μ-Me）₂ AlMe ₂ ] ⁺ [MeMAO] ^-，而离子对[LNi ^II - ^t Bu] ⁺ [MeMMAO] ^-在相同条件下，LNiBr ₂与MMAO反应的初始阶段占主导地位。在较高温度下，这两种离子对变换为镍（我）物种显示轴向各向异性EPR谱（克_‖ = 2.21，克_⊥ = 2.06，甲_⊥ = 1.06 MT）。

更新日期：2018-03-07

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