Tomut Alex-Cristian, Aghion Iulia-Andreea, Septelean Raluca, Porumb Ioan-Dan, Moraru Ionut-Tudor, Nemes Gabriela
Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University 1 M. Kogalniceanu Street RO-400084 Cluj-Napoca Romania
RSC Adv. 2024 Mar 27;14(15):10161-10171. doi: 10.1039/d4ra01515k. eCollection 2024 Mar 26.
The steric and electronic effects of specific ligands can play crucial roles in stabilizing unsaturated tetrylene species. In this work, hybrid density functional theory (DFT) methods, quantum theory of atoms in molecules (QTAIM) investigations and natural bond orbital (NBO) calculations are employed to evaluate the stabilization of low-valent E(ii) centers (E = Si, Ge, Sn, Pb) through the chelating effect generated by an electron-rich ligand containing the P[double bond, length as m-dash]C-P[double bond, length as m-dash]X moiety (X = O or S). Based on several types of analyses, such as the bond dissociation energy (BDE) or the interplay between attractive (, charge-transfer) and repulsive (, Pauli-exchange) effects, we highlight that the stabilization energy induced by chelation is up to 70 kcal mol for silylenes, yet slightly decreases within the heavier analogues. Moreover, it is emphasized that chelate-stabilized silylenes can form highly stable hybrid metal-metalloid complexes with transition metals (, gold). Due to push-pull effects occurring in the X→Si(ii)→Au fragment, the Si(ii)→Au bonding is significantly stronger than the X→Au, P(sp)→Au or π(C[double bond, length as m-dash]P)→Au donor-acceptor bonds, which are potentially formed by the electron-rich P[double bond, length as m-dash]C-P[double bond, length as m-dash]X unit with the AuCl fragment. These findings are supported by energy decomposition analysis (EDA) calculations.
特定配体的空间和电子效应在稳定不饱和四价烯物种方面可能起着关键作用。在这项工作中，采用杂化密度泛函理论（DFT）方法、分子中的原子量子理论（QTAIM）研究和自然键轨道（NBO）计算，通过含有P═C - P═X部分（X = O或S）的富电子配体产生的螯合效应来评估低价E（ii）中心（E = Si、Ge、Sn、Pb）的稳定性。基于几种类型的分析，如键解离能（BDE）或吸引（电荷转移）和排斥（泡利交换）效应之间的相互作用，我们强调螯合诱导的稳定能对于硅烯高达70 kcal/mol，但在较重的类似物中略有降低。此外，强调了螯合稳定的硅烯可以与过渡金属（如金）形成高度稳定的混合金属 - 类金属配合物。由于在X→Si（ii）→Au片段中发生的推 - 拉效应，Si（ii）→Au键明显强于X→Au、P（sp）→Au或π（C═P）→Au供体 - 受体键，这些键可能由富电子的P═C - P═X单元与AuCl片段形成。这些发现得到了能量分解分析（EDA）计算的支持。
