“…Compounds 2-4 are unique and the structural motif {MOOB} (M = metal) involving trivalent boron is without precedent in main group or transition metal coordination chemistry, although 1,3,4-trioxadiborolanes and alkylperoxyboron entities have been described. [11,19] Note that , but it is not clear whether the Lewis acid is bound to the oxo or to the peroxo ligand. [20] Moreover, only a limited number of transition metal derivatives of boric acid, boronic acid or borinic acid is known.…”