Agostic interaction refers to the bonding between a coordinatively unsaturated metal atom and its ligand, and is characterized by the drawing of the ligand towards the metal. The most important type of agostic interaction in organometallic chemistry is the C-H⋯Metal coordination that has the capability of activating the inert C–H bond in transition metal complexes. While the existence of such CH⋯M coordination seems unambiguous and well recognized, there are a few quite different theoretical interpretations on the agostic interaction, leading its origin remaining elusive. Therefore, an improved understanding of the nature for agostic interactions is in need with improved theoretical approaches. So far, significant efforts have been made for the purpose of characterizing and elucidating the agostic interaction by means of a wide range of computational approaches, including the natural orbital bond (NBO) method, the quantum theory of atoms in molecules (QTAIM) approach, various energy decomposition analysis (EDA) schemes and the block-localized wavefunction (BLW) method. To this end, in this review, we discussed the development of the agostic interaction concept in history and outlined the computational tools for characterizing the agostic interaction. More importantly, we summarized the popular theoretical perspective on the origin of the agostic interaction in early-transition metal compounds, especially from the view of valence bond theory, and demonstrated that the nature of the agostic effect is complicated and varies in different compounds.

固相相互作用是指配位不饱和金属原子与其配体之间的键合，其特征在于配体向金属的拉伸。有机金属化学中最重要的异质相互作用类型是CH⋯金属配位，具有激活过渡金属配合物中惰性C–H键的能力。尽管这种CH⋯M配位的存在似乎是明确的和公认的，但对于这种相互影响的相互作用有一些完全不同的理论解释，导致其起源仍然难以确定。因此，需要使用改进的理论方法来更好地理解自然相互作用的本质。至今，为了通过多种计算方法来表征和阐明混乱的相互作用，已经做出了巨大的努力，包括自然轨道键（NBO）方法，分子中的原子量子论（QTAIM）方法，各种能量分解方法。分析（EDA）方案和块局部波函数（BLW）方法。为此，在这篇评论中，我们讨论了历史互动的概念的发展，并概述了表征互动的计算工具。更为重要的是，我们总结了关于早期过渡金属化合物中原子间相互作用的起源的流行理论观点，尤其是从价键理论的角度，并证明了原子间效应的性质是复杂的，并且在不同化合物中会有所不同。