Preparation and reactivity of p-cymene complexes of ruthenium and osmium incorporating 1,3-triazenide ligands

Ruthenium complexes with triazenide ligands bearing an N-heterocyclic moiety, and their catalytic properties in the reduction of nitroarenes

A series of ruthenium complexes of formulae [RuCl(triazenide)(p-cymene)] have been synthesized using as ligand a triazenide monofunctionalized with an N-heterocyclic moiety. Nuclear magnetic resonance, high resolution mass spectrometry and X-ray diffraction were used to characterize the triazenide ligands and their complexes. In addition, these ruthenium complexes catalyzed the reduction of nitrobenzene to aniline in the presence of sodium borohydride and ethanol as solvent at room temperature. Notably, complex 5 was especially active in the reduction of nitroarenes substituted at the aromatic ring with electron-withdrawing or electron-donating fuctional groups affording the desired arylamines in good to excellent yields (80-100%). The role of the N-heterocyclic moiety on catalysis was explored.

Synthesis of New Ruthenium Complexes and Their Exploratory Study as Polymer Hybrid Composites in Organic Electronics

Polymeric hybrid films, for their application in organic electronics, were produced from new ruthenium indanones in poly(methyl methacrylate) (PMMA) by the drop-casting procedure. Initially, the synthesis and structural characterization of the ruthenium complexes were performed, and subsequently, their properties as a potential semiconductor material were explored. Hence hybrid films in ruthenium complexes were deposited using PMMA as a polymeric matrix. The hybrid films were characterized by infrared spectrophotometry and atomic force microscopy. The obtained results confirmed that the presence of the ruthenium complexes enhanced the mechanical properties in addition to increasing the transmittance, favoring the determination of their optical parameters. Both hybrid films exhibited a maximum stress around 10.5 MPa and a Knoop hardness between 2.1 and 18.4. Regarding the optical parameters, the maximum transparency was obtained at wavelengths greater than 590 nm, the optical band gap was in the range of 1.73-2.24 eV, while the Tauc band gap was in the range of 1.68-2.17 eV, and the Urbach energy was between 0.29 and 0.50 eV. Consequently, the above comments are indicative of an adequate semiconductor behavior; hence, the target polymeric hybrid films must be welcomed as convenient candidates as active layers or transparent electrodes in organic electronics.

Arene-Osmium(II) Complexes in Homogeneous Catalysis

Although the application of arene-osmium(II) complexes in homogeneous catalysis has been much less studied than that of their ruthenium analogues, different works have shown that, in some instances, a comparable or even superior effectiveness can be achieved with this particular class of compounds. This review article focuses on the catalytic applications of arene-osmium(II) complexes. Among others, transfer hydrogenation, hydrogenation, oxidation, and nitrile hydration reactions, as well as different C-C bond forming processes, are comprehensively discussed.

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-NH[double bond, length as m-dash]C(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 RN3 yielded imine [OsCl(η6-p-cymene){κ1-NH[double bond, length as m-dash]C(H)Ar}{P(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).

Preparation and reactivity of half-sandwich dioxygen complexes of ruthenium

The preparation of dioxygen complexes [Ru(η⁵-C₅Me₅)(η²-O₂){P(OR)₃}L]BPh₄ and their intramolecular oxygen transfer reaction in the presence of acid affording bis(phosphate) derivatives are described.

Dichlorido(η(6)-p-cymene)(eth-oxy-diphenyl-phosphane)ruthenium(II)

The title compound, [RuCl₂(C₁₀H₁₄)(C₁₄H₁₅OP)], is an Ru^II complex in which an η⁶-p-cymene ligand, two chloride anions and the P atom of an ethoxydiphenylphosphane ligand form a piano-stool coordination environment about the central Ru^II atom.