Controlled Formation of Thiol-Thiolate Hydrogen versus Disulfide Bonds between Two Iridium(III) Centers.

Here, we report an iridium(III) coordination system with 2-aminoethanethiolate (aet), which shows the formation of S-H⋅⋅⋅S hydrogen and S-S disulfide bonds in a controlled manner. Treatment of fac-[Ir(aet) ] with aqueous HBF under aerobic conditions gave dinuclear [Ir (aet) (cysta)] ([1] ; cysta=cystamine) with a single S-S disulfide bond, while dimeric [Ir (aet) (Haet) ](BF ) ([2](BF ) ) with a triple S-H⋅⋅⋅S hydrogen bond was formed by similar treatment under anaerobic conditions. Upon exposure to air, [2] was converted to dinuclear [Ir (aet) (Haet) (cysta)] ([3] ), in which two Ir centers are spanned by a double S-H⋅⋅⋅S hydrogen bond and a single S-S disulfide bond. Complex [3] was interconvertible with [1] via the removal/addition of protons on S donors, accompanied by the intermolecular exchange of the fac-[Ir(aet) ] units. Complexes [1] , [2] , and [3] , isolated as BF salts, were fully characterized by single-crystal X-ray crystallography.