Highly Selective Halide Receptors Based on Chalcogen, Pnicogen, and Tetrel Bonds

Abstract

The interactions of halides with a number of bipodal receptors were examined by quantum chemical methods. The receptors were based on a dithieno thiophene framework in which two S atoms can engage in a pair of chalcogen bonds with a halide. These two S atoms were replaced by P and As atoms to compare chalcogen with pnicogen bonding, and by Ge which engages in tetrel bonds with the receptor. Zero, one, and two O atoms were added to the thiophene S atom which is not directly involved in the interaction with the halides. Fluoride bound the most strongly, followed by Cl , Br , and I , respectively. Replacing S by the pnicogen bonds of P strengthened the binding, as did moving down to As in the third row of the periodic table. A further large increment is associated with the switch to the tetrel bonds of Ge. Even though the thiophene S atom is remote from the binding site, each additional O atom added to it raises the binding energy, which can be quite large, as much as 63 kcal mol for the Ge⋅⋅⋅F interaction. The receptors have a pronounced selectivity for F over the other halides, as high as 27 orders of magnitude. The data suggest that incorporation of tetrel atoms may lead to new and more powerful halide receptors.

Close contacts involving germanium and tin in crystal structures: experimental evidence of tetrel bonds

“…This is consistent with theoretical calculations which show that the region of most positive electrostatic potential opposite to a covalent bond deviates from the extension of the bond to the greatest extent in pnictogen derivatives and to the least extent in tetrel derivatives [134,135]. The greater linearity of TBs may be related to the fact that the electronic asymmetry generated around germanium and tin atoms by the four residues bonded to them is usually smaller than the electronic asymmetry generated around pnictogen and chalcogen atoms by the residues bonded to them and their lone pair(s) [136].…”

Hexacoordinated Tetrel‐Bonded Complexes between TF4 (T=Si, Ge, Sn, Pb) and NCH: Competition between σ‐ and π‐Holes

“…But the question arises as to whether a tetrel atom, within a tetravalent covalent bonding situation, is limited to only a single such bond. [25,[55][56][57][58][59][60] There has been a certain amount of consideration of the general topic of hypervalent pnicogen, halogen, and even aerogen atoms [9,[61][62][63][64][65][66][67][68][69][70][71][72][73][74] but not in the context of tetrel atoms, which have their own unique electronic and spatial issues. The theoretical literature to date has little to say on this issue.…”

Chalcogen‐Bonding Catalysis: From Neutral to Cationic Benzodiselenazole Scaffolds

“…They have been studied extensively in crystal engineering and for intramolecular conformational control in solution, including prominent use in medicinal chemistry and pioneering applications in covalent catalysis . The use of intermolecular chalcogen bonds in functional systems in solution is rare and recent, non‐covalent chalcogen‐bonding catalysis has been introduced only last year. [ ][ ][ ] The key to success was the idea that the somewhat awkwardly ‘hidden’ position of the σ holes on the side of chalcogen‐bond donors turns into an advantage as soon as transition‐state recognition in the focal point of two adjacent donors is considered .…”