New method for the synthesis of trans-hydroxotetraamminenitrosoruthenium(II) dichloride and its characterization

A procedure for the synthesis of mpa h c-[Ru(NO)(NH3)4(OH)]Cl2 in a nearly quantitative yield (∼95%) comprising treatment of a solution of (NH4)2[Ru(NO)Cl5] with ammonium carbonate at t ∼80°C was developed. It was found that [Ru(NO)(NH3)4(H2O)]Cl3·H2O and trans-[Ru(NO)(NH3)4Cl]Cl2 formed in the reaction of [Ru(NO)(NH3)4(OH)]Cl2 with hydrochloric acid at various temperatures most often contain some initial hydroxy complex. The former compound is unstable, even at room temperature, it slowly eliminates water and HCl. A procedure for preparing the latter compound in a pure state in 85–90% yield was proposed. The acidity constant of the complex trans-[Ru(NO)(NH3)4(H2O)]3+ at room temperature (K a = (4 ± 1) × 10−2) was estimated by 14N NMR spectroscopy.