Abstract: Theoretical calculations at MP2/6-311+G* level were employed to investigate various reaction mechanisms between singlet dichloromethylene germylene and methanethial. Calculation results indicate that the dominant reaction pathway for this reaction consists of three steps. The two reactants initially forman intermediate INT through a barrier-free exothermic reaction of 103.4 kJ·mol-1. This intermediate then isomerizes to P31 via a transition state TS3 with an energy barrier of 0.7 kJ·mol-1. P31 finally reacts with methanethial to form the germanic heteropolycyclic product P33 with an energy barrier of 32.3 kJ·mol-1. This cycloaddition reaction thus has excellent selectivity.

Key words: Dichloromethylene germylene, Methanethial, Reaction mechanism, Selectivity