Perturbation theory and "quasi-lone pairs" in main group angular and trigonal pyramidal compounds
Perturbation theory and "quasi-lone pairs" in main group angular and trigonal pyramidal compounds
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主族角锥体和三角锥体化合物中的微扰理论和“拟孤对”
DOI：
10.1021/ja00509a014
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发表时间：
1979
影响因子：
15
通讯作者：
P. Dobosh
中科院分区：
文献类型：
--
作者：
E. Shustorovich;P. Dobosh
本文发展了一种分析LCAO MO微扰方法，用于处理主族原子A不具有最高氧化态A（NHOS），而具有准孤对电子（QLP）的八重角AL_2和三角锥AL_2化合物的电子结构和某些性质。QLP的形成被认为是所讨论的Aln化合物的A1不可约表示内的三轨道四电子（30 - 4 e）价相互作用的正交化问题。一个QLP的标准，如本地化，SP1？杂化和成键特性。结果表明，化学和空间活性QLP总是对应于具有节状结构的2ai MO，导致S反键和P键对AL键强度的贡献。由于这个原因，QLP可以是成键的、非键的或反键的，这取决于相反的s和p贡献的相对值，使得在配位LmA-> X下的初始Aln、分子性质的变化可以根据A、L和性质本身而不同。它已被证明，通过适当的sp正交化所提到的A（NHOS）分子的电子结构可以减少到4 o-4 e键，这是典型的线性AL 2和三角平面AL 3分子，其中A是最高的氧化态，A（HOS），这已经被认为是较早。的能量顺序，组成，和节点结构的LCAO MO以及L '的替代L的AL键强度（长度）的影响已经提出了明确的形式，并同意与已知的实验和计算数据。该模型可以解释和预测八隅体AL 2和AL 2分子的电子结构和性质的基本规律。
An analytical LCAO MO perturbation approach has been developed for treating the electronic structure and some properties of octet angular AL2 and trigonal pyramidal AL2 compounds where the main group atom A is not of highest oxidation state, A (NHOS), and has a “quasi-lone pair”,(QLP). The formation of a QLP has been considered as an orthogonalization problem for the three-orbital four-electron (3o-4e) valence interactions within the A] irreducible representation of the AL „, compounds in question. The criteria of a QLP such as localization, sp1? hybridization, and bondingcharacter havebeen discussed. It has been shown that the chemically and sterically active QLPs always correspond to the 2ai MOs with the nodal structure resulting in s antibonding and p bonding contributions to the AL bond strengths. For this reason the QLPs may be bonding, nonbonding, or antibonding depending on the relative values of the opposing s and p contributions so that changes of the initial AL „, molecularproperties under coordination LmA-» X may be different depending on A, L, and the properties themselves. It has been shown that by the proper sp orthogonalization the electronic structure of the mentioned A (NHOS) molecules can be reduced to the 4o-4e bonding which is typical for linear AL2 and trigonal planar AL3 molecules where A is of the highest oxidation state, A (HOS), and which has been considered earlier. The energy orders, composition, and nodal structures of the LCAO MOs as well as the effects of substitution of L by L'on the AL bond strengths (lengths) have been presented in explicit form and agree with the known experimental and computational data. Thedeveloped model permits the fundamental regularities of the electronic structures andproperties of the octet AL2 and AL2 molecules to be explained and predicted.