The use of two new highly sterically bulky a-diimine ligands for the stabilization of neutral, monomeric platinum(H) hydroxo complexes is described. Halide abstraction from LPtCl2 complexes of these ligands in the presence of water, followed by deprotonation of the cationic aquo complex, leads to LPt(OH)Cl and LPt(OH)(2). The latter can be reprotonated with HNTf2 to yield a highly fluxional hydroxoaquoplatinum(II) cation.