An Integrated View of Nitrogen Oxyanion Deoxygenation in Solution Chemistry and Electrospray Ion Production
An Integrated View of Nitrogen Oxyanion Deoxygenation in Solution Chemistry and Electrospray Ion Production
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DOI：
10.1021/acs.inorgchem.1c02591
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发表时间：
2021-10-27
影响因子：
4.6
通讯作者：
Caulton, Kenneth G.
中科院分区：
文献类型：
--
作者：
Beagan, Daniel M.;Cabelof, Alyssa C.;Caulton, Kenneth G.
人们对涉及氮氧阴离子的化学越来越感兴趣，这主要是由于这些阴离子浓度增加导致富营养化和水生“死亡区”所带来的环境危害。在此，我们报告了一套 MNOx 配合物 (M = Co, Zn: x = 2, 3) 的合成和表征。双(亚硝酸)钴与双(硼基)吡嗪络合物的还原脱氧对于钴来说比之前报道的镍更快，并且侧挂的O-结合亚硝基配体仍然很容易脱氧，尽管可能存在异亚硝基初级产物。尽管锌不能稳定亚硝酰基配体，但锌氧阴离子络合物的脱氧也很容易，并释放一氧化氮和一氧化二氮，表明形成了 N-N 键。 X 射线光电子能谱可有效区分这些分子中氮的类型。一组 M(NOx)(y)（x = 2, 3 和 y = 1, 2）的 ESI 质谱表明，电离的主要形式是氧阴离子配体的损失，可以通过添加四丁基铵 (TBA) 作为中性氧阴离子配合物的非直观阳离子对来减轻这种损失。我们已经证明这些复合物会发生脱氧作用，并且有证据表明在 ESI 羽流中的几种情况下氮氧阴离子会减少。通过实验和计算探索了阳离子和中性之间的吸引力，并将其归因于氮氧阴离子配体与铵α-CH2质子的氢键合。 ESI 诱导的还原二聚化的一个例子是通过本体溶液合成来模拟的，并且该产物通过 X 射线衍射表征为包含两个由高度共轭二氮杂多烯连接的 Co(NO)(2)(+) 基团。
There has been an increasing interest in chemistry involving nitrogen oxyanions, largely due to the environmental hazards associated with increased concentrations of these anions leading to eutrophication and aquatic "dead zones". Herein, we report the synthesis and characterization of a suite of MNOx complexes (M = Co, Zn: x = 2, 3). Reductive deoxygenation of cobalt bis(nitrite) complexes with bis(boryl)pyrazine is faster for cobalt than previously reported nickel, and pendant O-bound nitrito ligand is still readily deoxygenated, despite potential implication of an isonitrosyl primary product. Deoxygenation of zinc oxyanion complexes is also facile, despite zinc being unable to stabilize a nitrosyl ligand, with liberation of nitric oxide and nitrous oxide, indicating N-N bond formation. X-ray photoelectron spectroscopy is effective for discriminating the types of nitrogen in these molecules. ESI mass spectrometry of a suite of M(NOx)(y) (x = 2, 3 and y = 1, 2) shows that the primary form of ionization is loss of an oxyanion ligand, which can be alleviated via the addition of tetrabutylammonium (TBA) as a nonintuitive cation pair for the neutral oxyanion complexes. We have shown these complexes to be subject to deoxygenation, and there is evidence for nitrogen oxyanion reduction in several cases in the ESI plume. The attractive force between cation and neutral is explored experimentally and computationally and attributed to hydrogen bonding of the nitrogen oxyanion ligands with ammonium alpha-CH2 protons. One example of ESI-induced reductive dimerization is mimicked by bulk solution synthesis, and that product is characterized by X-ray diffraction to contain two Co(NO)(2)(+) groups linked by a highly conjugated diazapolyene.