85282-54-8Relevant academic research and scientific papers
Preparation, characterization, and reactivity of osmium(VI) complexes of the type trans-OsO2X2(PR3)2 (X = Cl or Br)
Armstrong, John E.,Walton, Richard A.
, p. 1545 - 1549 (2008/10/08)
At room temperature the reactions between osmium tetraoxide, concentrated hydrohalic acids (HCl or HBr), and tertiary phosphines in ethanol produce the diamagnetic, light-sensitive Os(VI) compounds OsO2X2(PR3)2 (PR3 = PPh3, PMePh2, PEtPh2, and PEt2Ph) as intermediates on the way to trans-OsX4(PR3)2 and mer-OsX3(PR3)3. The compound previously formulated as OsOBr3(PPh3)2 has been shown to be a mixture of OsO2Br2(PPh3)2 and trans-OsBr4(PPh3)2. The reactions of OsO2X2(PPh3)2 (X = Cl and Br) with HL (HL = 2-hydroxypyridine, 2-hydroxy-6-methylpyridine, and picolinic acid) in refluxing ethanol give mononuclear OsX2(L)(PPh3)2. When OsO2X2(PPh3)2 (X = Cl and Br) is reacted with a mixture of 1,3-diphenyltriazine and n-butyllithium in tetrahydrofuran, the related Os(III) species OsX2(PhN3Ph)(PPh3)2 are produced. In contrast to this, OsO2Cl2(PEt2Ph)2 reacts with 2-hydroxy-6-methylpyridine in ethanol to yield OsCl3(CO)(PEt2Ph)2. The monocarbonyl derivatives of Os(II) OsX(mhp)(CO)(PPh3)2 are prepared by reacting trans-OsX4(PPh3)2 with 2-hydroxy-6-methylpyridine (Hmhp). X-ray photoelectron spectroscopy (XPS) and ESR spectroscopy have been used to characterize many of these complexes. A comparison has been made between the redox chemistry of these Os(VI), Os(IV), and Os(III) complexes by using the cyclic voltammetry technique.
