A theoretical thermodynamic investigation of cascade reactions in dinuclear octa-azacryptates involving carbon dioxide

This paper investigates the thermodynamics of gas-phase CO2 cascade uptake-reactions in the form of carbonate or methoxycarbonate anions in the host cavity of various dinuclear octa-azacryptates of m-CH2C6H4CH2 and 2,5-furano-spaced hosts, L1 and L2 cryptands, using density functional theory (DFT). The cascade process involves two stages, namely the formation of dinuclear cryptate complexes and the subsequent formation of either μ-carbonato cryptate complexes or μ-monomethylcarbonato cryptates. The geometric and electronic structures are also investigated to determine the parameters which affect the stability of the complexes. Natural bond orbital (NBO) analysis has been used to investigate the interactions between the trapped anion and its host. The ion selectivity has been studied in terms of the formation of dinuclear crypate complexes, while the basicity and nucleophilicity of cryptands towards Lewis acids have also been studied, and good agreement was found vis-à-vis available experimental data.Science Foundation IrelandOther funderIrish Centre for High End Computing12 months embargo until March 2012 - AV 15/03/201