Carbatriphyrin(3.1.1)-A Distinct Coordination Approach of B^III to Generate Organoborane and Weak C-H⋅⋅⋅B Interactions

Carbatriphyrin(3.1.1) is the structural isomer of biphenylcorrole and achieved by switching the bonding mode of biphenyl unit from 3,3' to 2,3' which turns the corrole into a triphyrin analogue. The presence of a m-arene unit in the framework restricts the overall conjugation and thus leads to a nonaromatic macrocycle. The protonation experiments afford a trifluoroacetate ion complex. The coordination chemistry reveals that the bottom approach of boron(III) ion forms weak C-H⋅⋅⋅B interactions, however a top approach stabilizes the organoborane complex and the product distribution relies on the basicity of the proton scavengers. These results are unambiguously confirmed by single-crystal X-ray analyses.