Scheiner S. Highly Selective Halide Receptors Based on Chalcogen, Pnicogen, and Tetrel Bonds.
Chemistry 2016;
22:18850-18858. [PMID:
27740702 DOI:
10.1002/chem.201603891]
[Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Indexed: 11/09/2022]
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-1 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.
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