Capture of CO2 by novel diiodo‐N,N‐imidazoliumvinylidene: A theoretical quest

Capture of CO2 by diiodo‐N,N‐imidazoliumvinylidene, with singlet and triplet minima (1s and 1t, respectively), is probed at M06‐2X/6‐311++G** level of theory. Ground state appears to be triplet 1t, which exhibits a rather large singlet–triplet energy gap (ΔEs–t = +10.30 kcal mol−1). Adsorption of CO2 over 1t releases −3.70 kcal mol−1 energy and gives the initial CO2 adduct, with no transition state (TS). Sequentially, the latter goes through a reactant‐like TS, which leads to an internal exothermic attack of the carbene carbon to the adsorbed CO2 and forms 3t with conversion energy (Econ) of −6.77 kcal mol−1. Additional calculations involve endothermic capture of CO2 by the rather unstable 1s. The immense potential of the natural bond orbital (NBO) and atom in molecule (AIM) data in elucidating a reaction mechanism is unveiled by employing the electron‐pushing technique. Results appear consistent with the proposed mechanism. Exothermic capture of CO2 by the ground state triplet diiodo‐N,N‐imidazoliumvinylidene (1t) gives two products (2t and 3t) at DFT levels: initial spontaneous adsorption of CO2 adduct (2t) and internal exothermic attack of the carbene carbon of 2t to its adsorbed CO2 that forms 3t.