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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Hydride Affinities for Main-Group Hydride Reductants: Assessment of Density Functionals and Trends in Reactivities
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Hydride Affinities for Main-Group Hydride Reductants: Assessment of Density Functionals and Trends in Reactivities

机译：主要液体氢化物还原剂的氢化物亲态：对密度函数的评估和反应性的趋势

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In the present study, we have examined hydride affinities relevant to a range of group 13 and group 14 reductants. We use the high-level W1X-G0, G4(MP2)-XK, and DSD-PBEP86 methods to obtain the RHA42 set of accurate reductant hydride affinities. Assessment of DFT methods with the RHA42 set shows that all functionals that we have examined are fairly accurate. Overall, we find ωB97X-V to be the most accurate. The MN12-SX screened-exchange functional and the nonhybrid B97-D3BJ method also perform well, and they may provide a lower-cost means for obtaining hydride affinities. The trend in the hydride affinities suggests an increased reducing power when one moves down the periodic table, e.g., with TlH_(3) being a stronger reductant than BH_(3). We also find that group 13 hydrides are stronger reductants than the group 13 analogues. In general, substitution of a hydrogen, e.g., BH_(2)~(+) → BHMe~(+), and the formation of dimer, e.g., BH_(2)~(+) → B_(2)H_(5)~(+), also lead to stronger reductants. A notable observation is the small hydride affinities for silyl cations, which are indicative of the potential of silanes as strong reducing agents. In particular, poly(methylhydrosiloxane) (PMHS) cations are associated with especially small hydride affinities owing to the presence of intramolecular oxygen atoms that can stabilize the cation center. We have further found the germanium analogues of the silanes to be more reactive, and they may further widen the scope of main-group hydride reducing agents.
机译：在本研究中，我们研究了与一系列13族和14族还原剂相关的氢化物亲和力。我们使用高水平的W1X-G0、G4（MP2）-XK和DSD-PBEP86方法来获得RHA42组精确的还原剂氢化物亲和力。使用RHA42集对DFT方法进行评估表明，我们所研究的所有泛函都相当准确。总的来说，我们发现ωB97X-V是最准确的。MN12-SX筛选交换函数法和非杂交B97-D3BJ法也表现良好，它们可能为获得氢化物亲和力提供一种成本较低的方法。氢化物亲和力的趋势表明，当元素周期表向下移动时，还原力增加，例如，TlH_3是比BH_3更强的还原剂。我们还发现，13族氢化物比13族类似物的还原剂更强。一般来说，氢的取代，例如BH_2~（+）→ BHMe~（+），以及二聚体的形成，例如BH_2~（+）→ B_2）H_5~（+），也会产生更强的还原剂。一个值得注意的观察是，硅基阳离子的氢化物亲和力很小，这表明硅烷作为强还原剂的潜力。特别是，由于分子内存在可以稳定阳离子中心的氧原子，聚（甲基氢硅氧烷）（PMHS）阳离子与特别小的氢化物亲和力有关。我们进一步发现硅烷的锗类似物更具反应性，它们可能进一步扩大主族氢化物还原剂的范围。

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