On the binding of SF6 to cucurbit[6]uril host: density functional investigations.

摘要: Interactions of sulfur hexafluoride (SF6) with cucurbit[6]uril (CB[6]) have been investigated using the density functional calculations. An encapsulation guest within CB[6] cavity as well its binding to either exterior host protons or portal uredio oxygens analyzed. The present calculations predict that complexes complete inclusion SF6 are favored over those possessing lateral external interactions. interactions between fluorine and ureido carbons (F---C) contribute lowering energy complex. Normal mode analyses from calculated vibrational spectra show a red-shifted stretching (∼928 cm−1) S−F bonds perpendicular axis when is encapsulated in cavity. On other hand, parallel exhibit blue shift compared corresponding vibration isolated guest. These frequency shifts further analyzed by mapping difference electron on bon...