Tetranuclear Ru μ-nitrido complexes have been synthesized by reactions of Ru­(II) cyclopentadienyl and pentamethylcyclopentadienyl complexes with Ru­(VI) terminal nitrides. Treatment of [RuCp2] (Cp = η5-C5H5) with [LOEtRuVI(N)­Cl2] (LOEt – = [CpCo­{P­(O)­(OEt)2}3]−) (1) afforded a tetranuclear RuIV 2-RuIII 2 μ-nitrido complex, [CpRu­{(μ-N)­RuCl2LOEt}­{(μ-Cl)­RuClLOEt}­{(μ-NC5H4NH)­RuCl2LOEt}] (2), that contains a bridging monodeprotonated cyclopent-4-ene-1,3-diimine ligand. The formation of 2 possibly involves the migratory insertion of the Ru nitride with a Ru-η1-C5H5 intermediate derived from the η5–η1 ring slippage of [RuCp2] and subsequent C–H activation of the cyclopentadienylimido ligand by another molecule of 1. Treatment of [Cp*Ru­(MeCN)3]­(PF6) (Cp* = η5-C5Me5) with [LOEtM­(N)­Cl2] afforded [{Cp*Ru­(μ-N)­M­(LOEt)}2(μ-Cl)4]­(PF6)2 (M = Ru (3), Os (4)). Treatment of [Cp*Ru­(MeCN)3]­(PF6) with mer-[Ru­(N)­Cl3(AsPh3)2] yielded [{Cp*Ru­(μ-N)­RuCl­(AsPh3)}2(μ-Cl)4(μ-O2PF2)]­(PF6) (5), which contains a bridging difluorophosphate ligand. The crystal structures of 2, 3, and 5 have been determined. The short Cp*Ru–N distances in 3 (1.777(7) Å) and 5 (1.772(7) and 1.775(7) Å) are indicative of the RuIVNRuIV bonding description.

The treatment of [M(LOEt)(N)Cl2] (LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) with the Pt(II) bis(cyclometalated) complex [Pt(C N CBu)(DMSO)] (H2C N CBu=2,6‐di(4‐tert‐butylphenyl)pyridine; DMSO=dimethylsulfoxide) afforded the heterotrinuclear nitrido complexes [LOEtCl2M(μ‐N)Pt(C N CBu)] (M=Ru (1‐Ru), Os (1‐Os)). The Pt−N(nitrido) (1.821(5) Å) and Ru−N (1.673(5) Å) distances in 1‐Ru are consistent with the Ru=N=Pt bonding description. The Pt−N(nitrido) distance in 1‐Os (1.859(7) Å) is longer than that in 1‐Ru, suggesting the π interaction between Pt(II) and Os≡N is weaker than that for the Ru counterpart. Oxidation of 1‐Ru with PhICl2 afforded the Pt(IV) dichloride complex [LOEtCl2Ru(μ‐N)Pt(C N CBu)Cl2] (2) that has a longer Pt−N distance (1.893(3) Å) than that in 1‐Ru, indicating the weakening of the Pt−N(Ru) π bonding upon oxidation of Pt(II) to Pt(IV). Treatment of [Pt(C N CBu)(DMSO)] with [nBu4N][Ru(N)Cl4] in tetrahydrofuran (THF) afforded [nBu4N][(THF)Cl4Ru(μ‐N)Pt(C N CBu)] (3), which reacted with K[N(Ph2PS)2] and K[N(iPr2PO)2] to yield [Cl{N(Ph2PS)2}2Ru(μ‐N)Pt(C N CBu)] (4) and [nBu4N][Cl3{N(iPr2PO)2}Ru(μ‐N)Pt(C N CBu)] (5), respectively. The short Pt−N(nitrido) distances in 3 (1.816(5) Å) and 4 (1.809(2) Å) are indicative of Pt=N double bond character.

Heterometallic μ‐nitrido complexes have been synthesized from organometallic complexes containing O/S‐donor ligands and a ruthenium(VI) nitride. The treatment of [Ir(tpip)(L)2] (tpip−=[N(Ph2PO)2]−; L=cyclooctene (coe) or 2,6‐dimethylphenylisocyanide (xylNC)) and [Ir{N(iPr2PS)2}(coe)] with [Ru(LOEt)(N)Cl2] (LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) (1) afforded [(L)(tpip)Ir(μ‐N)Ru(LOEt)Cl2] (L=coe (2) or xylNC (3)) and [(coe){N(iPr2PS)2}Ir(μ‐N)Ru(LOEt)Cl2] (4), respectively, in which the Ir−N(nitride) bonds show double bond character. The bonding in 2–4 can be described by two resonance forms: Ir(I)−N≡Ru(VI) and Ir(III)=N=Ru(IV). The treatment of [Ph4P][Ir(CO)2Cl2] with 1 afforded (PPh4)[(CO)Cl2Ir(μ‐N)Ru(LOEt)Cl2] (5) that reacted with [Tl(SR)] to give (PPh4)[(CO)(RS)2Ir(μ‐N)Ru(LOEt)Cl2] (R=xyl (6), C6F4H (7)). The reaction of [M(acac)(CO)2)] or [Ru(acac)2(coe)2] (acac−=acetylacetonate) with 1 gave [(CO)(acac)M(μ‐N)Ru(LOEt)Cl2] [M=Ir (8), Rh (9)] or [(H2O)(acac)2Ru(μ‐N)Ru(LOEt)Cl2] (10), whereas the treatment of [Ru(acac)2(MeCN)2] with 1‐azidoadamantane (AdN3) yielded a Ru(II) tetrazene complex, [Ru(acac)2(N4Ad2)] (11).