High-efficiency photoreductive vapor generation of osmium

Abstract

Photochemical vapor generation of Os. OsO4 oxidative product from photolysis of 5% HNO3 medium; reductive product from 1% acetic acid/50 mg L−1 Fe3/2+ an uncharacterized organometallic Os compound [Osw(CO)x(CH3)yHz] detected by ICP-MS.

GC-MS exploration of photochemically generated species of Os, W and Ru from reductive and oxidative media

“…28) and W(CO) 6 (ref. 26) from a formic acid medium, OsO 4 (and RuO 4 ) from dilute nitric acid, 6,27 and a carbonylated compound of Os in a reductive solution of acetic acid. 27…”

“…Both laboratories used the same photochemical reactor, a low pressure 19 W flow-through Hg discharge lamp (Beijing Titan Instrument Co. Ltd., Beijing, China) fitted with an internal channel of synthetic quartz (0.72 mL internal irradiated volume) through which the sample was continuously pumped to expose the analyte solution to (primarily) 185 and 254 nm radiation. 26–28 The irradiated sample was conducted to gas–liquid phase separators (GLS system) fed with a flow of Ar purge gas which served to strip volatile species from the liquid phase and permitted convenient manual syringe sampling of 100–500 μL effluent volumes of gas for analyte characterization by GC-MS.…”

“…PVG was undertaken in accordance with the optimized procedures, apparatus and reagents recently reported for W, 26 Os 27 and Ru. 28 Several minor deviations from the published protocols included use of a lower (100 mL min −1 ) flow rate of Ar transfer gas through the GLS unit(s) to decrease dilution of the analyte in the sampled gas phase and, for studies of W, two gas–liquid phase separators (GLS, 15 mL volume) used in series in an effort to ensure elimination/minimization of water droplet carryover to the syringe sampler.…”

“…Samples were continuously photolysed at a solution flow rate of 2 mL min −1 to provide for a steady-state supply of analyte species from elevated concentrations of W( vi ), Os( iv ) and Ru( iii ), in the 5–40 mg L −1 range in appropriate media, 26–28 to enhance their detection using GC-MS.…”

“…Herein, we provide GC-MS evidence identifying W(CO) 6 as the stable product of PVG of W( vi ) generated from a reductive solution of formic acid in the presence of 500 mg L −1 Cd( ii ) sensitizer, 26 as well as OsO 4 arising from the oxidative PVG of a solution of Os( iv ) in dilute nitric acid. 5,6,27 Analytical products of reductive PVG of Ru( iii ) 28 from formic acid in the presence of 10 mg L −1 Co( ii ) and 25 mg L −1 Cd( ii ) sensitizers, as well as Os( iv ) 27 from acetic acid containing 50 mg L −1 Co( ii ), remain unidentified.…”