LAUSR

The multiple electronic state mechanisms of the reaction of carboryne with benzene were investigated by M11 calculations. Mechanisms leading to [4 + 2] cycloaddition product P4 + 2, [2 + 2] cycloaddition product P2 + 2, CC insert product PC-Cins and CH insert product PC-Hins were considered. The barrier/stability to structural characteristics correlations revealed that, 1) [2 + 2] addition is a two-step mechanism which exhibits three electronic state reactivity, and both the addition steps are controlled by the barriers on open-shell singlet (OSS) potential energy surface (PES); 2) [4 + 2] product P4 + 2 is a kinetic product on the experimental condition, and other products should be obtained under more harsher condition. The theoretical results well explain the experimental facts.