Department of Chemistry & Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
Inorg Chem. 2010 Feb 1;49(3):1071-81. doi: 10.1021/ic901981y.
A mononuclear Ni(II) complex having an acireductone type ligand, and supported by the bnpapa (N,N-bis((6-neopentylamino-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine) ligand, [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)]ClO(4) (14), has been prepared and characterized by elemental analysis, (1)H NMR, FTIR, and UV-vis. To gain insight into the (1)H NMR features of 14, the air stable analogue complexes [(bnpapa)Ni(CH(3)C(O)CHC(O)CH(3))]ClO(4) (16) and [(bnpapa)Ni(ONHC(O)CH(3))]ClO(4) (17) were prepared and characterized by X-ray crystallography, (1)H NMR, FTIR, UV-vis, mass spectrometry, and solution conductivity measurements. Compounds 16 and 17 are 1:1 electrolyte species in CH(3)CN. (1)H and (2)H NMR studies of 14, 16, and 17 and deuterated analogues revealed that the complexes having six-membered chelate rings for the exogenous ligand (14 and 16) do not have a plane of symmetry within the solvated cation and thus exhibit more complicated (1)H NMR spectra. Compound 17, as well as other simple Ni(II) complexes of the bnpapa ligand (e.g., [(bnpapa)Ni(ClO(4))(CH(3)CN)]ClO(4) (18) and (bnpapaNi)(2)(mu-Cl)(2)(2) (19)), exhibit (1)H NMR spectra consistent with the presence of a plane of symmetry within the cation. Treatment of [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)]ClO(4) (14) with O(2) results in aliphatic carbon-carbon bond cleavage within the acireductone-type ligand and the formation of [(bnpapa)Ni(O(2)CPh)]ClO(4) (9), benzoic acid, benzil, and CO. Use of (18)O(2) in the reaction gives high levels of incorporation (>80%) of one labeled oxygen atom into 9 and benzoic acid. The product mixture and level of (18)O incorporation in this reaction is different than that exhibited by the analogue supported the hydrophobic 6-Ph(2)TPA ligand, [(6-Ph(2)TPA)Ni(PhC(O)C(OH)C(O)Ph)]ClO(4) (2). We propose that this difference is due to variations in the reactivity of bnpapa- and 6-Ph(2)TPA-ligated Ni(II) complexes with triketone and/or peroxide species produced in the reaction pathway.
一种单核镍（II）配合物，具有一个烯醇酮型配体，并由 bnpapa（N，N-双（（6-新戊基氨基-2-吡啶基）甲基）-N-（（2-吡啶基）甲基）胺）配体支持，[（bnpapa）Ni（PhC（O）C（OH）C（O）Ph）]ClO 4（14），已被制备和通过元素分析，（1）H NMR，FTIR 和 UV-vis 进行了表征。为了深入了解 14 的（1）H NMR 特征，制备并通过 X 射线晶体学，（1）H NMR，FTIR，UV-vis，质谱和溶液电导率测量对空气稳定的类似物配合物[（bnpapa）Ni（CH 3 C（O）CHC（O）CH 3）]ClO 4（16）和[（bnpapa）Ni（ONHC（O）CH 3）]ClO 4（17）进行了表征。化合物 16 和 17 在 CH 3 CN 中是 1:1 电解质物种。对 14、16 和 17 及其氘代类似物的（1）H 和（2）H NMR 研究表明，具有外源配体六元螯合环的配合物（14 和 16）在溶剂化阳离子内没有对称面，因此表现出更复杂的（1）H NMR 谱。化合物 17 以及 bnpapa 配体的其他简单 Ni（II）配合物（例如[（bnpapa）Ni（ClO 4）（CH 3 CN）]ClO 4（18）和[（bnpapaNi）（2）（μ-Cl）（2）]（ClO 4）（2）（19）），表现出与阳离子内存在对称面一致的（1）H NMR 谱。用 O 2 处理[（bnpapa）Ni（PhC（O）C（OH）C（O）Ph）]ClO 4（14）会导致烯醇酮型配体中的脂肪族碳-碳键断裂，并形成[（bnpapa）Ni（O 2 CPh）]ClO 4（9）、苯甲酸、苯偶酰和 CO。在反应中使用 18O 2 会导致 9 和苯甲酸中一个标记氧原子的高掺入水平（>80％）。该反应的产物混合物和 18O 掺入水平与类似物支持疏水性 6-Ph 2 TPA 配体[（6-Ph 2 TPA）Ni（PhC（O）C（OH）C（O）Ph）]ClO 4（2）不同。我们提出，这种差异是由于 bnpapa 和 6-Ph 2 TPA 配体的 Ni（II）配合物与在反应途径中产生的三酮和/或过氧化物的反应性变化所致。
