Role of encapsulation of Na⁺ and F^-ions on the diels–alder reactivity of C₃₂

Abstract

The density functional theory (DFT)-based Becke’s three parameter hybrid exchange functional and Lee–Yang–Parr correlation functional (B3LYP) calculations have been performed to understand the role of encapsulation of Na⁺ and F^-ions on the Diels–Alder reactivity of C₃₂. In this context, C₃₂ has been taken as the dienophile and cis-1,3-butadiene has been considered as diene. Results obtained from the calculations on the Na⁺@C₃₂ and F^- have also been compared with that of C₃₂. It is found from the results that encapsulated Na⁺ ion acts as a catalyst, whereas the encapsulated F^- does not accelerate the reaction between C₃₂ and cis-1,3-butadiene. Thus, the reactivity of F^-@C₃₂ is less than that of free C₃₂ and Na⁺@C₃₂. Formation of adduct involving [5,5]-B bond is preferred over other bonds. The energy decomposition analysis has been applied to understand the role of confinement on an encaged ion. The part played by the charge transfer interaction is evident from the NBO analysis. The frontier orbital analysis points out that the reaction is driven by the normal electron demand.