Toward reversible dihydrogen activation by borole compounds

Efficient catalytic dihydrogen (H) activation is crucial in many fundamental chemical transformations. Detailed B97D/TZVP computational study shows that the H molecule can be cooperatively activated over polar B-C bonds of various borole compounds through a concerted four-center transition structure of partial zwitterionic nature. The remarkable H activation reactivity of borole compounds is attributed to the enhanced Lewis acidity at boron and Lewis basicity at α-carbons within the antiaromatic borole ring, and such theoretical insights are important for the design of new metal-free H activation catalysts. For the first time, new borole compounds are designed as promising catalysts for direct H delivery and even reversible H activation by fusing the central borole ring into extended aromatic rings. © 2013 American Chemical Society.