Strength of Si–H ⋯ B charge-inverted hydrogen bonds in 1-silacyclopent-2-enes and 1-silacyclohex-2-enes

Abstract

It is shown that the H· · · B contacts in 1-silacyclohex-2-enes are clearly stabilizing and strong, whereas those in 1-silacyclopent-2-enes are much weaker. This result is supported by analysis of QTAIM-based parameters and appropriate structural changes taking place upon the open form → closed form transformation and is in full agreement with previous NMR spectroscopic data [Wrackmeyer et al. (2006) Appl Organometal Chem 20:99-105]. Also, the influence of electronic and steric effects originating from the presence of specific substituents on the strength of the H· · · B contacts is discussed in detail. Some problems and ideas associated with the use of the so-called open-closed method utilized in assessing values of interaction energies are discussed in detail. Particular attention is paid to the correct choice of reference open systems. It is shown that their partial geometry optimization leads to reliable values of interaction energies.

Hydride‐Triel Bonds

“…Importantly, this also shows that hydride‐triel bond may have significant role in molecular binding and in determining molecular structure. For example, most recently we have shown that the SiH⋯B contacts in some 1‐silacyclohex‐2‐enes are clearly stabilizing and strong with interaction energies of the order of 4–5 kcal/mol—the result in a full agreement with earlier studies by Wrackmeyer et al based on NMR spectroscopic data. Moreover, these energies can even be enhanced to 13–14 kcal/mol if 9‐borabicyclo[3.3.1]nonane group is substituted by the BH 2 one (see Fig.…”

“…As a consequence, the main purpose of this article is to see how the strength of the H⋯Y hydride‐triel bond in systems investigated here can be influenced by substituents attached to X and Y, that is R X and R Y , respectively. Moreover, this is also to show that hydride‐triel bonds can be strong enough to considerably determine structure and properties of molecular systems …”

Triel–hydride triel bond between ZX3 (Z = B and Al; X = H and Me) and THMe3 (T = Si, Ge and Sn)

“…Unfortunately, they formed a new product with the triel donor molecule. It was also demonstrated that a weakly polarized Si–H bond can bind with a strong hydrogen‐bond donor in solution . Therefore, the Si–H bond in SiHMe 3 is introduced to the triel donor atom in ZX 3 (Z = B and Al; X = H and Me).…”

“…Triel bonding exhibits some surprising cooperativity with other types of interactions including hydrogen, halogen, pnicogen and tetrel bonds since the binding distance in the strong triel bond undergoes a prominent contraction. Numerous studies have demonstrated that the intramolecular Si–H···B bridge can maintain the conformation of compounds simultaneously containing silicon and boron atoms …”

“…Numerous studies have demonstrated that the intramolecular Si-H···B bridge can maintain the conformation of compounds simultaneously containing silicon and boron atoms. [37][38][39][40][41][42] In the present paper, we study the triel bond between ZX 3 (Z = B and Al; X = H and Me) and THMe 3 (T = Si, Ge and Sn). The T-H bond in THMe 3 acts as the Lewis base in the triel bond; thus this interaction is named triel-hydride triel bond, coining the name of halogenhydride halogen bond, [43] chalcogen-hydride chalcogen bond, [44] pnicogen-hydride pnicogen bond, [45] tetrelhydride tetrel bond [46] and lithium-hydride lithium bond.…”