Fig. 4: DFT-simulated reaction mechanisms for oxymethyl group formation.

a, b DFT-simulated reaction mechanisms for oxymethyl group formation in absence/presence of H2O are reported in (a) and (b), respectively. The charge difference density plots for their Intermediate states are show in (c, d) with isovalue of ± 0.4 eÅ−3, respectively; green and blue colours represent the charge accumulation and depletion regions respectively. Colour code: carbon (tan), oxygen (red), nitrogen (blue), hydrogen (white) and aluminium (pink). All distances indicated are in Å and the energies in kJ mol−1.