Elusive Scorpionates: C3-Symmetric, Formally Dianionic, Facially Tridentate Ligands.

The reaction of AlCl3 with [(2-HO-3,5-tBu2C6H2)3P] (H3[O3P]) results in AlCl[O3PH] ([O3PH]2- = [(2-O-3,5-tBu2C6H2)3PH]2-), which is a zwitterionic molecule containing an unprecedented C3-symmetric but formally dianionic chelate. Derivatization of [O3PH]2- gives [O3PR]2- (R = hydrocarbon), demonstrating the development of a novel class of long elusive scorpionates.