Interactions of (MY)6 (M = Zn, Cd; Y = O, S, Se) quantum dots with N-bases

Abstract

Se, form double-layer drum-like structures containing MY covalent bonds. The positive regions near the M atoms attract the N atom of both NH 3 and NMe 3 so as to form a noncovalent M•••N bond. This bond is quite strong, with interaction energies exceeding 35 kcal/mol. The bond strength diminishes with reduced electronegativity of the Y atom (O > S > Se) and is stronger for M = Zn than for Cd. Trimethylation of the base enhances the bond strength. The interaction is dominated by the electrostatic component which accounts for some 60-70% of the total attractive force. The interaction increases the highest occupied molecular orbital-lowest unoccupied molecular orbital gap by between 0.1 and 0.2 eV.

Types of noncovalent bonds within complexes of thiazole with CF4 and SiF4

“…The four electron-withdrawing F substituents of CF 4 provide the C atom with four s-holes, each of which have the capability to engage in a tetrel bond (TB) with a nucleophile, as has been demonstrated in the literature. 42,59,60 With its higher electropositivity and polarizability, the Si atom of the analogous SiF 4 ought to have deeper s-holes on the central atom, and serve as a stronger partner in any such TB. Added to these options, each of the CH groups of thiazole can engage in a H-bond with any of the F atoms of the CF 4 or SiF 4 .…”

Tuneable tetrel bonds between tin and heavy pnictogens

“…13 Extensive computational work with a focus on nitrogen-based electron donors has established the strength of such interactions in vacuo, as well as the role of steric crowding and structural deformations. [14][15][16][17] The strength and utility of tetrel bonds involving a heavier pnictogen as the electron donor is an open question. In the case of halogen bonds, the use of heavier pnictogens such as P, As, and Sb as electron donors remains uncommon and has only recently been explored in a deliberate manner.…”