Global reaction route mapping on potential energy surfaces of formaldehyde, formic acid, and their metal-substituted analogues.

Global reaction route mapping of equilibrium structures, transition structures, and their connections on potential energy surface (PES) has been done for MCHO (M = H, Li, Na, Al, Cu) and HCO2M (M = H, Li). A one-after-another technique based on the scaled hypersphere search method has been successfully applied to exploring unknown chemical structures, transition structures, and reaction pathways for organometallic systems. Upon metal substitution, considerable changes of stable structures, reaction pathways, and relative heights of transition structures have been discovered, though some features are similar among the analogues. Al and Cu atoms were found to behave as very strong scissors to cut the CO double bond in MCHO. Energy profiles of the CO insertion into Li-H and Li-CH3 bonds were found to be very similar, especially around the structures where the Li atom is not directly connected with the methyl group, which indicates little effects of alkyl substitution on the reaction route topology.