Preparation and reactivity of half-sandwich organic azide complexes of osmium

Organic azide complexes [Os(η5-C5H5)(κ1-N3R)(PPh3)P(OR1)3]BPh4(1, 2) [R = CH2C6H5(a), CH2C6H4-4-CH3(b), CH(CH3)C6H5(c), C6H5(d); R1 = Me (1), Et (2)] were prepared by allowing bromo-compounds [OsBr(η5-C5H5)(PPh3)P(OR1)3] to react first with AgOTf and then with an excess of azide in toluene. Benzylazide complexes reacted in solution leading to imine derivatives [Os(η5-C5H5)κ1-NHC(R2)Ar(PPh3)P(OR1)3]BPh4(3, 4) [R2 = H (a, b), CH3(c); Ar = C6H5, C6H4-4-CH3; R1 = Me (3), Et (4)]. Phenylazide, on the other hand, reacted in solution affording the dinuclear dinitrogen complex [Os(η5-C5H5)(PPh3)[P(OMe)3]2(μ-N2)](BPh4)2(5). Depending on the nature of the R substituent, the reaction of the p-cymene complex [OsCl2(η6-p-cymene)(PPh3)P(OEt)3] with RN3yielded imine [OsCl(η6-p-cymene)κ1-NHC(H)ArP(OEt)3]BPh4(6) (Ar = C6H4-4-CH3) and amine derivatives [OsCl(η6-p-cymene)(κ1-NH2C6H5)P(OEt)3]BPh4(7). The complexes were characterised spectroscopically (IR,1H,31P,15N NMR) and by the X-ray crystal structure determination of [Os(η5-C5H5)(PPh3)[P(OMe)3]2(μ-N2)](BPh4)2(5).