Heteroleptictris-complexes of osmium(III/IV)8-quinolinolates: synthesis, characterization and link-up of oxidation levels

✍ Scribed by Bijan K. Roy; Tapan K. Mallick; Pradyut K. Das; Barindra K. Ghosh

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 408 KB
• Volume: 18
• Category: Article
• ISSN: 0340-4285
• DOI: 10.1007/bf00136059

✦ Synopsis

A series of mixed-tris chelates of Os m and Os w of the general formula [OsDQz] ~ + [D = fl-ketoenolates (D1-D 3) or tropolonate (D4); Q = deprotonated 8-quinolinol] has been prepared and characterized by physico-chemical and spectroscopic methods. In MeCN solution the OsN20 ~ unit displays reversible OsW-Os m and Osm-Os n couples in the ca. -1.2 to + 0.3 V range versus s.c.e. An irreversible oxidative response corresponding to a higher degree of oxidation is also observed at ca. 1.6 V. The chemistry in different oxidation states is discussed in terms of the electrochemical results.

Experimental

Materials

The complex species FOsX2Q2] and [Et4N][OsX2Qz] were prepared as reported earlier ~1). All other chemicals and organic solvents used in syntheses were reagent grade commercial materials. For electrochemical work the solvent MeCN was purified and the supporting electrolyte [EtgN] [CIO4] was prepared following a reported procedural TM. The solvent was stored over molecular sieves (4 ~). The synthetic reactions were carried out in air without any particular precautions.