Stable Boron Peroxides with a Subporphyrinato Ligand

Subporphyrin B-peroxides have been synthesized in good yields by acid-catalyzed exchange reactions of subporphyrin B-methoxide with the corresponding hydroperoxides. Thermal dimerization of the subporphyrin B-hydroperoxide provided the peroxo-bridged bis(subporphyrin) quantitatively. These subporphyrin B-peroxides are fairly stable under ambient conditions, which allowed their isolation and full characterization as the first examples of structurally authenticated boron hydroperoxides, acyclic boron organylperoxides, and neutral peroxo-bridged diboron species. The subporphyrin B-peroxides thus prepared were investigated through their crystal structures, IR spectra, and cyclic voltammograms as well as by DFT calculations. The subporphyrin B-hydroperoxide oxidizes triphenylphosphine quantitatively to triphenylphosphine oxide.