Considering the importance of silylene ligands in transition metal‐mediated catalytic reactions, we have scrutinized eight novel monodentate (1–4) and bidentate (1^′‐4^′) derivatives of 2,5‐diX‐cyclopentasilylene‐2,4‐dienes (X = NH₂, OH, PH₂, and SH), at M06/6‐311++G** level of theory. To probe the complexation ability of our scrutinized silylene ligands with Rh atom (1_Rh‐4_Rh and 1^′_Rh‐4^′_Rh, respectively), thermodynamic and structural parameters such as complexation energy (ΔE_Com), singlet‐triplet energy gap (ΔE_s‐t), bond length, along with NBO and atoms in molecules analyses are provided. In going from less electron donating groups (EDGs) to more EDGs (NH₂ > OH > PH₂ > SH), the σ‐donor strength and ligand flexibility increase. Structures 1 and 1^′ turn out as the most nucleophilic species for showing the highest nucleophilicity (N = 5.47 and 5.40 eV, respectively). Furthermore, they exhibit the highest proton affinity values (PA = 271.46 and 271.23 kcal/mol, respectively). The results indicate that bidentate coordination mode of silylene leads to a stronger Si‐Rh complex. The overall orders of σ‐donation ability for monodentate and bidentate silylene ligands are 1 > 2 > 3 > 4 and 1^′ > 2^′ > 3^′ > 4^′, respectively.

中文翻译：

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DFT新的单齿和双齿甲硅烷基配体

考虑亚甲硅烷配位体的过渡金属-介导的催化反应的重要性，我们已经审查8个新颖的单齿（1 - 4）和二齿（1 ^' - 4 ^'）2,5- DIX-cyclopentasilylene -2,4-二烯衍生物（ X = NH ₂，OH，PH ₂和SH），理论值为M06 / 6-311 ++ G **。探测我们与铑原子审查亚甲硅烷配体（的络合能力1_铑- 4_的Rh和1 ^'_铑- 4 ^'_的Rh，分别地），热力学和结构参数，如络合能量（ΔE _Com），单重态-三重态能隙（ΔE _s-t），键长以及分子分析中的NBO和原子。从较少的给电子基团（EDG）变为更多的EDG（NH ₂ > OH> PH ₂ > SH），σ-给体强度和配体柔性增加。结构1和1 ^'证明是亲核性最高的物种，显示出最高的亲核性（N分别为5.47和5.40 eV）。此外，它们表现出最高的质子亲和力值（分别为PA = 271.46和271.23 kcal / mol）。结果表明，甲硅烷基的双齿配位模式导致更强的Si-Rh配合物。单齿和双齿甲硅烷基配体的σ捐赠能力的总阶数分别为1 > 2 > 3 > 4和1 ^' > 2 ^' > 3 ^' > 4 ^'。