23648-06-8Relevant articles and documents
Instability of the oxidation catalysts [OsIII(tpy)(bpy)(py)] 3+ and [OsIII(bpy)3]3+ in alkaline solution
Lebeau, Estelle L.
, p. 83 - 89 (2008/10/09)
The Os(III) complexes [OsIII(tpy)(bpy)(py)]3+ and [OsIII(bpy)3]3+ (bpy: 2,2′-bipyridine, py: pyridine, tpy: 2,2′,2″-terpyridine) are unstable toward self-reduction in alkaline solution. Product analysis performed by using UV-Vis spectroscopy, cyclic voltammetry, HPLC and GC show that ca. 90% of the reduced product that appears is the unmodified polypyridyl complex of Os(II), [Os II(tpy)(bpy)(py)]2+ or [OsII(bpy) 3]2+. The remaining 10% of the products are accounted for by other Os(II) complexes, including several which appear to have undergone varying degrees of ligand oxidation or substitution. Another product of the reduction of [OsIII(tpy)(bpy)(py)]3+ in basic solution has been identified as [OsII(tpy)(bpy)(OH2)]2+ which results from metal reduction and concomitant pyridine ligand loss. No O2 was detected as a product of the base-catalyzed self-reduction reaction. The Os(III) complexes are stable towards self-reduction and ligand loss in the dark in acetonitrile or aqueous solutions buffered below pH = 6. The rates observed for the self-reduction processes are sufficiently rapid at pH values above 7 that useful catalytic rate data cannot be obtained in basic solution unless the substrate of interest is sufficiently reactive and is present in large excess. Triple mixing, pH jump techniques have successfully been employed to observe reaction rates under strongly alkaline conditions.
Ruthenate(VI)-catalysed dehydrogenation of primary amines to nitriles, and crystal structures of cis-2*0.5MeOH and cis-2*CH2Cl2
Griffith, William P.,Reddy, Bharti,Shoair, Abdel G. F.,Suriaatmaja, Maria,White, Andrew J. P.,Williams, David J.
, p. 2819 - 2826 (2007/10/03)
Catalytic dehydrogenation of benzylic and other primary amines RCH2NH2 to the corresponding nitriles RCN by the system trans-2-/S2O82- has been investigated.The complex cis-2+ and the new cis-2+ (R = o-, m- or p-ClC6H4, o-MeC6H4, o- or p-MeOC6H4); cis-2+ (R = Ph or p-MeOC6H4) and cis-2+ have been made, and dehydrogenation of the co-ordinated amine in the ruthenium complexes to the corresponding nitriles in cis-2+ (L-L = bipy or phen) by peroxodisulfate demonstrated.The crystal structures of cis-*0.5MeOH and cis-2*CH2Cl2, the latter a product of co-ordinated amine dehydrogenation by peroxodisulfate to give cis-2+, were determined.Raman, infrared and 1H NMR data for the complexes have been measured; the latter suggest that the cis configurations of the amine complexes are retained in solution.
Outer-sphere oxidation. 2. 1 Pulse-radiolysis study of the rates of reaction of the I2-. and (SCN)2-. Radical anions with the tris(2,2′-bipyridyl)2 complexes of Os(II) and Os(III)
Nord, Gwyneth,Pedersen, Britta,Floryan-L?vborg, Eva,Pagsberg, Palle
, p. 2327 - 2330 (2008/10/08)
The rate constants at 22°C and an ionic strength of 0.1 M for the following reactions are (Chemical Equation Presented) No adduct intermediates were detected. Formal reduction potentials for the following couples under the above conditions are as follows: Os(bpy)33+-Os(bpy)32+, 0.857 ± 0.004 V; I2-·-I-, 1.063 ± 0.011 V; I2-·I2,0.172 ± 0.011 V; (SCN)2-·-SCN-, 1.331 ± 0.008 V.
