Study of the Interaction of [Ru(C5H5)Cl(dippe)] and [Ru(C5Me5)Cl(dippe)] with Dihydrogen, Dinitrogen, and Other Small Molecules. X-ray Crystal Structures of [Ru(C5Me5)H2(dippe)][BPh4], [Ru(C5H5)(CNBut)(dippe)][BPh4], and [Ru(C5H5)(è2-C2H4)(dippe)][BPh4]

Resumen

The complexes [CpRuCl(dippe)] and [Cp*RuCl(dippe)] (Cp = C5H5; Cp* = C5Me5; dippe = 1,2-bis(diisopropylphosphino)ethane) react with H2 and Na[BPh4] in EtOH or MeOH to furnish the dihydrides [CpRuH2(dippe)][BPh4] (1) and [Cp*RuH2(dippe)][BPh4] (2). These compounds are deprotonated by KOBut to yield the monohydrides [CpRuH(dippe)] (3) and [Cp*RuH(dippe)] (4), which can be protonated back by HBF4·OEt2 at low temperatures to give the dihydrogen adducts [CpRu(H2)(dippe)][BF4] (5) and [Cp*Ru(H2)(dippe)][BF4] (6). These compounds rearrange irreversibly to the dihydride form as the temperature is raised. A kinetic study of these rearrangement processes suggests that the isomerization mechanism is different in each case. The dinitrogen complex [CpRu(N2)(dippe)][BPh4] (7) and the acetone adduct [CpRu(Me2CO)(dippe)][BPh4] (8) were obtained by reaction of [CpRuCl(dippe)] with Ag+ in acetone under dinitrogen or argon, respectively, followed by NaBPh4/EtOH. Both compounds react with atmospheric oxygen yielding [CpRu(η6-C6H5BPh3)] (9) and iPr2P(O)CH2CH2P(O)iPr2. The dinitrogen adduct [Cp*Ru(N2)(dippe)][BPh4] (10) was also obtained, but it reacts irreversibly with traces of O2 to give the dioxygen complex [Cp*Ru(O2)(dippe)][BPh4], previously known. A range of neutral donors L also react with [CpRuCl(dippe)] or [Cp*RuCl(dippe)] and NaBPh4 furnishing the corresponding complexes [CpRu(L)(dippe)][BPh4] (L = CO (11), CNBut (12), C2H4 (13)), or [Cp*Ru(L)(dippe)][BPh4] (L = CO (14), CNBut (15), C2H4 (16)). The ethylene adduct 16 is only stable under an ethylene atmosphere, whereas 13 is a stable species. The X-ray crystal structures of compounds 2, 12, and 13 are also reported.