Influence of monomer deformation on the competition between two types of σ-holes in tetrel bonds

Abstract

Competition between two competing sites on a tetrel atom is explained by balance between structural deformation and σ-hole intensity.

Chalcogen bonding of two ligands to hypervalent YF4(Y = S, Se, Te, Po)

“…There is some prior confirmation of our observation here that formation of a noncovalent bond is sufficient incentive for a molecule to undergo substantial deformation so as to maximize this interaction, mainly in the context of tetrel and pnicogen bonds 107,108 and that this distortion can influence the preference of an incoming base for one σ-hole over another 109 . In the context of hypervalent molecules, ZF5, where Z represents a pnicogen atom, [110][111] takes on a trigonal bipyramid shape as a monomer, but then distorts into a square pyramid so as to accommodate an incoming nucleophile, at significant cost in terms of deformation energy.…”

Zero-, one-, two- and three-dimensional supramolecular architectures sustained by Se…O chalcogen bonding: A crystallographic survey

“…This observation is consistent with expectation in terms of the σ-hole model to explain the nature of these interactions [45] , [46] , [47] , [251] . It might be concluded that while to a first approximation, there is a general understanding of the mode of bonding leading to Se … O and related secondary bonding interactions, further investigations, such high-level crystallographic, including charge density studies and analysis [11] , [252] , [253] , along with reliable computational chemistry studies [254] , [255] , [256] are required in order to gain a more complete picture of Se … O interactions. Also of interest would be the determination, experimental and theoretical, of the energies of stabilisation provided by specific Se … O contacts.…”

Competition between Inter and Intramolecular Tetrel Bonds: Theoretical Studies Complemented by CSD Survey

“…As a second important difference, the normal tetravalency of the tetrel atom leads to a great deal of steric repulsions with any potential nucleophile. Earlier works [8f,h,22] have shown the crowded nature of the surrounding groups causes a good deal of geometric rearrangement in order to accommodate an additional ligand. Indeed, in some cases, this deformation can entirely alter the competition between different modes of bonding.…”