Depending on the H+ concentration and solvent, reaction of [RuCl3(NO)(PPh3)2] with 'S2N2H2′2-- alternatively yields either [Ru(NO)PPh3(′S2N2H2′)]Cl 1 or [Ru(NO)(′S2N2H′)]2 2. 1 gives 2 upon treatment with base, 2 yields 1 when reacted with HC1 and PPh3 in THF. In MeOH, 2 is completely insoluble, but reacts with HC1 to give [Ru(NO)(′S2N2H2′)]2Cl2, 4a, which is converted into [RuCl(NO)(′S2N2H2′)] 3 when dissolved in THF. Reactions of 2 with phosphines such as PMe3, PPr3 or PBu3 in THF yield the

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... rresponding [Ru(NO)PR3(′S2N2H′)] complexes, which is proof that not a protonation of the amido donor in 2, but sufficient solubility of 2 in the respective solvent and a subsequent dissociation into mononuclear complex fragments are decisive for cleavage of 2. Protonation or deprotonation of the N donors are more likely to influence the fine-tuning of the Ru center in [Ru(NO)(′S2N2H2′)] fragments with respect to coordination of hard or soft co-ligands.