The basicity of [tris-(trimethylphosphine)(cyclooctadiene)iridium(I)]

[Tris-(trimethylphosphine)(cyclooctadiene)iridium(I)]chloride, [Ir(COD)(PMe3)3]Cl, is very electron rich. In this report, that electron rich character is probed by examining the protonation of the complex at the metal center to form the dicationic [tris-(trimethylphosphine)(cyclooctadiene)(hydrido)iridium(III)], [HIr(COD)(PMe3)3]+2. The exact formulation of the species formed depends on the nature of the Bronsted acidʹs counterion. Protonation with hydrogen chloride, fluoroboric acid, and triflic acid are all described and the structure of the dication and some products from further reaction of the dication are elucidated. Simple aqueous acid/base titration of [Ir(COD)(PMe3)3]Cl is described yielding a pKa for [HIr(COD)(PMe3)3]+2 of 4.2.