Scheiner Steve
Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322-0300, USA.
Chemistry. 2016 Dec 23;22(52):18850-18858. doi: 10.1002/chem.201603891. Epub 2016 Nov 23.
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.
通过量子化学方法研究了卤化物与多种双足受体的相互作用。这些受体基于二噻吩并噻吩骨架，其中两个硫原子可与卤化物形成一对硫属元素键。将这两个硫原子分别替换为磷和砷原子，以比较硫属元素键与氮族元素键，还将硫原子替换为与受体形成碳族元素键的锗原子。在不直接参与与卤化物相互作用的噻吩硫原子上添加零个、一个和两个氧原子。氟化物结合得最强，其次是氯、溴和碘。用磷的氮族元素键取代硫增强了结合，在元素周期表第三行中向下至砷时也是如此。向锗的碳族元素键转变会带来进一步的大幅增加。尽管噻吩硫原子远离结合位点，但添加到其上的每个额外氧原子都会提高结合能，这可能相当大，对于锗···氟相互作用高达63千卡/摩尔。这些受体对氟相对于其他卤化物具有明显的选择性，高达二十七个数量级。数据表明，引入碳族原子可能会产生新的、更强大的卤化物受体。
