Reactions of complexes of ruthenium and osmium halides with ammonia, amines, and hydrazine

Abstract

Ammonia and primary amines (am) react with [MX3(PR3)3](M = Ru or Os, X = Cl or Br, and PR3= tertiary phosphine) in ethanol at 20° to form M(II) complexes, mer-[MX2am(PR3)3], and acetaldehyde. Secondary and tertiary amines with [MX3(PMe2Ph)3] also cause reduction, but the product is an alcohol complex [MX2(C2H5OH)(PMe2Ph)3]. The reduction may occur through a hydride complex intermediate because some hydrogen is produced in all the above reactions. The alcohol complexes are probably formed for steric reasons because the least sterically hindered secondary amine, piperidine, forms a piperidine complex.When the alcohol contains a small amount of water di-n-alkylamines (CnH2n+ 1)2NH are dealkylated to form the corresponding primary amine complexes [MX2 am (PR3)3](cf. similar decarbonylation of alcohol and aldehydes). The cleaved alkyl group generally appears as Cn–1H2n and all the lower n-alkanes down to methane, but from dimethylamine higher hydrocarbons are obtained and from diethylamine a little propane.Hydrazine in limited amounts forms mononuclear complexes [MCl2(N2H4)(PMe2Ph)3] or more commonly hydrazine-bridged complexes [M2X4(N2H4)2(PR3)4]. Nitrogen, hydrogen, and hydrazine hydrochloride are also produced. Under more vigorous reaction conditions [Ru(NH3)5N2]2+ is formed.