Blackaby William J M, Sabater Sara, Poulten Rebecca C, Page Michael J, Folli Andrea, Krewald Vera, Mahon Mary F, Murphy Damien M, Richards Emma, Whittlesey Michael K
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
Dalton Trans. 2018 Jan 15;47(3):769-782. doi: 10.1039/c7dt04187j.
Bromide abstraction from the three-coordinate Ni(i) ring-expanded N-heterocyclic carbene complex [Ni(6-Mes)(PPh)Br] (1; 6-Mes = 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) with TlPF in THF yields the T-shaped cationic solvent complex, [Ni(6-Mes)(PPh)(THF)][PF] (2), whereas treatment with NaBAr in EtO affords the dimeric Ni(i) product, [{Ni(6-Mes)(PPh)}(μ-Br)][BAr] (3). Both 2 and 3 act as latent sources of the cation [Ni(6-Mes)(PPh)], which can be trapped by CO to give [Ni(6-Mes)(PPh)(CO)] (5). Addition of [(EtSi)(μ-H)][B(CF)] to 1 followed by work up in toluene results in the elimination of phosphine as well as halide to afford a co-crystallised mixture of [Ni(6-Mes)(η-CHMe)][B(CF)] (4), and [6MesHCHMe][B(CF)]. Treatment of 1 with sodium salts of more strongly coordinating anions leads to substitution products. Thus, NaBH yields the neutral, diamagnetic dimer [{Ni(6-Mes)}(BH)] (6), whereas NaBH(CN) gives the paramagnetic monomeric cyanotrihydroborate complex [Ni(6-Mes)(PPh)(NCBH)] (7). Treatment of 1 with NaOBu/NHPh affords the three-coordinate Ni(i) amido species, [Ni(6-Mes)(PPh)(NPh)] (8). The electronic structures of 2, 5, 7 and 8 have been analysed in comparison to that of previously reported 1 using a combination of EPR spectroscopy and density functional theory.
在四氢呋喃中，用六氟磷酸铊从三配位镍（Ⅰ）环扩展的N - 杂环卡宾配合物[Ni(6 - Mes)(PPh)Br]（1；6 - Mes = 1,3 - 双（2,4,6 - 三甲基苯基）- 3,4,5,6 - 四氢嘧啶 - 2 - 亚基）中提取溴化物，得到T形阳离子溶剂配合物[Ni(6 - Mes)(PPh)(THF)][PF]（2），而在乙醚中用四（3,5 - 双（三氟甲基）苯基）硼酸四丁基铵处理则得到二聚镍（Ⅰ）产物[{Ni(6 - Mes)(PPh)}(μ - Br)][BAr]（3）。2和3都作为阳离子[Ni(6 - Mes)(PPh)]的潜在来源，它可以被一氧化碳捕获生成[Ni(6 - Mes)(PPh)(CO)]（5）。向1中加入[(EtSi)(μ - H)][B(CF)]，然后在甲苯中后处理，导致膦和卤化物消除，得到[Ni(6 - Mes)(η - CHMe)][B(CF)]（4）和[6MesHCHMe][B(CF)]的共结晶混合物。用配位能力更强的阴离子的钠盐处理1会得到取代产物。因此，硼氢化钠生成中性、抗磁性的二聚体[{Ni(6 - Mes)}(BH)]（6），而硼氢化钠氰基则得到顺磁性的单体氰基三氢硼酸配合物[Ni(6 - Mes)(PPh)(NCBH)]（7）。用叔丁醇钠/氨基苯处理1得到三配位镍（Ⅰ）氨基物种[Ni(6 - Mes)(PPh)(NPh)]（8）。通过电子顺磁共振光谱和密度泛函理论相结合的方法，与先前报道的1相比，对2、5、7和8的电子结构进行了分析。
