Chemistry Department, M.V. Lomonosov Moscow State University, Leninskye Gory 1, 3, 119991 Moscow, Russia.
Faculty of Chemistry, National Research Tomsk State University, Lenin Av., 36, 634050 Tomsk, Russia.
Int J Mol Sci. 2023 Jun 16;24(12):10218. doi: 10.3390/ijms241210218.
Polydentate ligands are used for thermodynamic stabilization of tetrylenes-low-valent derivatives of Group 14 elements (E = Si, Ge, Sn, Pb). This work shows by DFT calculations how the structure (the presence or absence of substituents) and type (alcoholic, Alk, or phenolic, Ar) of tridentate ligands 2,6-pyridinobis(1,2-ethanols) []H and 2,6-pyridinobis(1,2-phenols) []H (R = H, Me) may affect the reactivity or stabilization of tetrylene, indicating the unprecedented behavior of Main Group elements. This enables the unique control of the type of the occurring reaction. We found that unhindered []H ligands predominantly led to hypercoordinated -liganded {[]}Ge complexes, where an E(+2) intermediate was inserted into the ArO-H bond with subsequent H evolution. In contrast, substituted []H ligands gave []Ge: germylenes, which may be regarded as kinetic stabilized products; their transformation into E(+4) species is also thermodynamically favorable. The latter reaction is more probable for phenolic []H ligands than for alcoholic []H. The thermodynamics and possible intermediates of the reactions were also investigated.
多齿配体用于热力学稳定 14 族元素（E = Si、Ge、Sn、Pb）的低价四聚体衍生物。这项工作通过 DFT 计算表明三齿配体 2,6-吡啶双（1,2-乙醇）[]H 和 2,6-吡啶双（1,2-苯酚）[]H（R = H，Me）的结构（有无取代基）和类型（醇，Alk，或酚，Ar）如何影响四聚体的反应性或稳定性，这表明了主族元素前所未有的行为。这使得可以控制发生反应的类型。我们发现，无阻碍的[]H 配体主要导致超配位的 -配体{[]}Ge 配合物，其中 E(+2)中间体插入 ArO-H 键中，随后发生 H 消除。相比之下，取代的[]H 配体给出[]Ge：锗烯，它们可以被视为动力学稳定的产物；它们转化为 E(+4)物种也是热力学有利的。对于酚式[]H 配体而言，这种反应比醇式[]H 更有可能发生。还研究了反应的热力学和可能的中间体。
