Understanding the geometry and [3+2] cycloadditions of nitrile imine in terms of molecular electron density theory.

Nitrile imine has been classified as carbenoid type three atom component (TAC) by coupled cluster single doubles plus perturbative triples (CCSD(T)) calculations. [3+2] cycloaddition (32CA) reactions of nitrile imine with a set of olefins has been studied in this report in terms of Global electron density transfer (GEDT), Bonding evolution theory (BET) and Quantum theory of atoms in molecules (QTAIM) analyses at B3LYP and MPW1K levels. The reactions have been nonpolar showing non-covalent interactions and hence GEDT doesn't make the reaction feasible by inducing significant electrophilic-nucleophilic interaction between reactants as occurs in case of polar processes. Mutual penetration of forming bonds to the Van-der Waals' surface has been reproduced in asymmetry indices at the transition states. BET and QTAIM study confirmed initial rupture of olefinic bond, followed by the formation of pseudoradical centres and subsequently the bond-formation processes. [ABSTRACT FROM AUTHOR]