Following our quest for new divalents, we report the synthesis of P-heterocyclic silylenes (PHSis) by adding from one to four phosphorous atoms to saturated cyclopentasilylene (1) and unsaturated cyclopentasilylene-3-ene (1′) resulting in respective PHSis (2-10 and 2′-10′, respectively) and their study at the B3LYP/6-311++G** level of theory. Stabilities of 1-10 and 1′-10′ assumed as the energy gaps between the singlet (s) and triplet (t) states (ΔEs-t) are compared and contrasted. With increasing number of phosphorous atoms, singlet-triplet energy gap (ΔEs-t), nucleophilicity (N), electrophilicity (ω), chemical potential (μ), band gap (ΔEH-L), positive natural bond orbital (NBO) charge on the Si atom, and reactivity decrease. Changes in the hydrogenation enthalpy (ΔHHyd) of 1-10 and 1′-10′ show negative values indicating that the formation of hydrogenated divalent silylenes is exothermic (1H-10H and 1H′-10H′, respectively). The positive overall change in the Gibbs free energy of reaction (ΔGover for the conversion of 1′-10′ to 1-10, respectively) confirms that every 1′-10′ is more stable than its corresponding 1-10.

中文翻译：

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NEWP-杂环甲硅烷的DFT研究

在我们对新二价化合物的探索之后，我们报告了通过将 1 到 4 个磷原子添加到饱和环戊亚硅基 (1) 和不饱和环戊亚硅基-3-烯 (1') 中产生各自的 PHSis (2) 来合成 P-杂环亚甲硅烷 (PHSis) -10 和 2'-10'）以及他们在 B3LYP/6-311++G** 理论水平的研究。1-10 和 1'-10' 的稳定性被假定为单线态 (s) 和三线态 (t) 之间的能隙 (ΔEs-t) 进行比较和对比。随着磷原子数量的增加，单线态-三线态能隙（ΔEs-t）、亲核性（N）、亲电性（ω）、化学势（μ）、带隙（ΔEH-L）、正自然键轨道（NBO）电荷在 Si 原子上，反应性降低。1-10 和 1'-10' 的氢化焓 (ΔHHyd) 的变化显示负值，表明氢化二价亚甲硅烷的形成是放热的（分别为 1H-10H 和 1H'-10H'）。Gibbs 反应自由能的总体正向变化（分别用于将 1'-10' 转化为 1-10 的 ΔGover）证实，每个 1'-10' 比其相应的 1-10 更稳定。