Formation of [Ru(III)(edta)(SNO)](2-) in Ru(III)(edta)-Mediated S-Nitrosylation of Bisulfide Ion.

The reaction of hydrogen sulfide (H2S) and nitric oxide (NO) is of great physiological significance in human organisms. Our present studies show that Ru(III)(edta) (edta(4-) = ethylenediaminetetraacetate) mediates the S-nitrosylation of bisulfide ion (HS(-)) using NO to form [Ru(III)(edta)(SNO)](2-), the first-ever example of a ruthenium complex containing thionitrite (SNO(-)) in aqueous solution. The reaction product [Ru(III)(edta)(SNO)](2-) was characterized by IR, electron paramagnetic resonance, and electrospray ionization mass spectroscopy. Our studies further show that formation of the putative thionitrous acid coordinated to Ru(III)(edta) does not occur via the reaction of [Ru(III)(edta)NO](-) with HS(-).