Steric congestion in heavy pnictines alters oxidative halogenation pathways
Steric congestion in heavy pnictines alters oxidative halogenation pathways
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DOI：
10.1016/j.poly.2023.116730
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发表时间：
2023-11-15
期刊：
影响因子：
2.6
通讯作者：
Johnstone，Timothy C.
中科院分区：
文献类型：
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作者：
Wenger，John S.;Getahun，Addis;Johnstone，Timothy C.
二卤代三有机氮杂环戊烷是第15族化学中重要的合成前体，但有机取代基对这些化合物的合成和反应性的影响对于重氮族化合物仍有待研究。我们最近报道了Dipp 3Sb（Dipp = 2，6-二异丙基苯基）的分离。庞大的Dipp取代基允许单体四面体锑氧化物Dipp 3SbO的隔离，但也允许形成的三角双锥Dipp 3SbF 2。我们现在报告的空间拥挤铋，Dipp 3Bi的分离。Dipp 3Bi与XeF 2反应生成Dipp 3BiF 2，其在固态下具有扭曲的三角双锥几何构型。Dipp 3Bi与PhICl 2反应生成1-氯-2，6-二异丙基苯。Dipp 3Sb与PhICl 2反应生成Dipp 3SbCl 2，其固态结构为四方锥结构。Mes 3SbCl 2，Mes 3SbBr 2，Mes 3BiCl 2，和Mes 3BiBr 2（Mes = mesityl）的结构特征，并在固态下都表现出三角双锥几何形状。溶液相光谱测量反映了所有这些分子的fluxionality，但在气相中的理论分析表明，四方锥的Dipp 3SbCl 2的几何形状比三角双锥的几何形状，可能是由于存在分子内的二次相互作用的Dipp和Cl取代基。这些结果突出了Dipp取代基改变重磷腈的反应性途径的能力。
Dihalotriorganopnictoranes serve as important synthetic precursors in Group 15 chemistry, but the influence of the organic substituents on the synthesis and reactivity of these compounds remains underexplored for the heavy pnictogens. We recently reported the isolation of Dipp3Sb (Dipp = 2,6-diisopropylphenyl). The bulky Dipp substituents permit the isolation of monomeric tetrahedral stibine oxide Dipp3SbO, yet also allow for the formation of the trigonal bipyramidal Dipp3SbF2. We now report the isolation of a sterically crowded bismuthine, Dipp3Bi. Reaction between Dipp3Bi and XeF2afforded Dipp3BiF2, which features a distorted trigonal bipyramidal geometry in the solid state. Reaction between Dipp3Bi and PhICl2resulted in the generation of 1-chloro-2,6-diisopropylbenzene. Reaction between Dipp3Sb and PhICl2resulted in the formation of Dipp3SbCl2, which features a square pyramidal geometry in the solid state. Mes3SbCl2, Mes3SbBr2, Mes3BiCl2, and Mes3BiBr2(Mes = mesityl) were structurally characterized and all exhibit trigonal bipyramidal geometries in the solid state. Solution-phase spectroscopic measurements reflect the fluxionality of all of these molecules, but theoretical analyses in the gas phase suggest that the square pyramidal geometry of Dipp3SbCl2is more thermodynamically favorable than the trigonal bipyramidal geometry, possibly due to the presence of intramolecular secondary interactions between the Dipp and Cl substituents. These results highlight the ability of Dipp substituents to alter reactivity pathways of heavy pnictines.