Se···N Chalcogen Bond and Se···X
Halogen Bond Involving F<sub>2</sub>CSe: Influence of Hybridization,
Substitution, and Cooperativity
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Abstract
Quantum-chemical
calculations have been performed for the chalcogen-
and halogen-bonded complexes of F<sub>2</sub>CSe with a series of
nitrogen bases (N<sub>2</sub>, NCH, NH<sub>3</sub>, NHCH<sub>2</sub>, NCLi, and NMe<sub>3</sub>) and dihalogen molecules (BrCl, ClF,
and BrF), respectively. Both types of interactions are mainly driven
by the electrostatic and orbital interactions. The chalcogen bond
becomes stronger in the order of NCH (sp) < NH<sub>3</sub> (sp<sup>3</sup>) < NHCH<sub>2</sub> (sp<sup>2</sup>), showing some inconsistence
with the electronegativity of the hybridized N atom. The Li and methyl
groups have an enhancing effect on the strength of chalcogen bond;
however, the former is jointly achieved through the electrostatic
and orbital interactions, whereas the orbital interaction has dominant
contribution to the latter enhancement. The halogen bond with F<sub>2</sub>CX (X = O, S, Se) as the electron donor is stronger for the
heavier chalcogen atom, exhibiting a reverse dependence on the chalcogen
atom with that in hydrogen bonds. The halogen bond is further strengthened
by the presence of chalcogen bond in the ternary complexes. In addition,
CSD research confirms the abundance of Se···N interaction
in crystal materials