The DFT/B3LYP method is used to study geometric and electronic structures of ions formed in the mass spectrum upon electron ionization of molecular forms in the vapor of aluminum tris-dipivaloylmethanate (Al(C11H19O2)3, Al(dpm)3). It is shown that the most energetically favorable processes upon dissociative ionization of molecular form AlL3 (L = dpm) are related to the detachment of radicals CH3•, t-Bu• and the anionic form of the ligand dpm–. It is established that one chelate ring is broken upon the formation of ions [AlL3–t-Bu]+, [AlL3–2t-Bu]+, [AlL3–6t-Bu]+ and the structure of the latter contains one monodentate ligand and two bidentate ligands. In the ions with compositions [AlL2]+, [AlL2–CH3]+, [AlL2–2CH3]+, [AlL2–4CH3]+, and [AlL2–2t-Bu–CH3]+, the cores of two bidentate ligands are located in mutually perpendicular planes. The energies of reactions leading to the formation of the above ions are calculated. The energies of frontier orbitals of these ions are considered; the reasons of high-intensity [AlL2]+ current are revealed. Detailed examination of ions in the mass spectrum of aluminum tris-dipivaloylmethanate (a typical representative of tris-β-diketonate complexes) reveals a number of structural features that can be used to predict the structure of such ions in the mass spectra of numerous similar complexes belonging to the ML3 type.

中文翻译：

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电子电离时饱和三-二异丙基甲酸铝蒸气中的离子结构及其形成能量

DFT / B3LYP 方法用于研究在三-二新戊酰甲烷酸铝 (Al (C11H19O2) 3, Al (dpm) 3) 蒸气中分子形式的电子电离后质谱中形成的离子的几何和电子结构。结果表明，分子形式 AlL3 (L = dpm) 的解离电离过程中最有利的过程与自由基 CH3 •、t-Bu • 和配体 dpm– 的阴离子形式的分离有关。确定在形成离子[AlL3-t-Bu] +, [AlL3-2t-Bu] +, [AlL3-6t-Bu] + 时，一个螯合环被破坏，后者的结构包含一个单齿配体和两个双齿配体。在组成为[AlL2] +、[AlL2-CH3] +、[AlL2-2CH3] +、[AlL2-4CH3] + 和[AlL2-2t-Bu-CH3] + 的离子中，两个双齿配体的核心是位于相互垂直的平面内。计算导致上述离子形成的反应能量。考虑了这些离子的前沿轨道能量；揭示了高强度[AlL2] + 电流的原因。对三-二新戊酰甲烷酸铝（三-β-二酮酸配合物的典型代表）质谱中离子的详细检查揭示了许多结构特征，可用于预测许多类似配合物质谱中此类离子的结构属于ML3型。