Electrochemistry of coordination compounds: II. Electrochemical reduction of di-(1,2-bisdiphenylphos-phinoethane)M(I) chloride: A new route to hydrido di-(1,2-bisdiphenylphosphinoethane)M(I) (M=Rh, Ir)
✍ Scribed by Giuseppe Pilloni; Enrico Vecchi; Mario Martelli
- Publisher
- Elsevier Science
- Year
- 1973
- Weight
- 357 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0022-0728
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✦ Synopsis
One objective of our current investigations 1'2 in the field of d s platinum group metal compounds is to examine the factors which are important in determining the reduction and/or oxidation mechanism of the electrode processes and the relative stabilities of the products obtained.
Recently 1 we discussed the electrochemical reduction of non-ionic rhodium complexes witha set ofmonodentate ligands, i.e. RhCI(CO)(PPh3)2 andRhCl(PPh3)3, in the presence of added phosphine. We found that the reduction products, d 1° rhodium anions, were very reactive with electrophilic reagents. Such reactivity, on the analogy of that of neutral d x° compounds, could be attributed to the great tendency of these systems to yield reactive coordinatively unsaturated species 3. In order to avoid or reduce this tendency we have used complexes with the bidentate ligand Ph2P~H2-CH2-PPh2(DPE ) which is able to form stable five membered ring complexes 4. In the present study, carried out as an extension of the previous one, we report on the electrochemical behaviour of [M(DPE)2]CI (M=Rh, Ir) and on the effect of a chelate group on the reactivities of the reduced species.
EXPERIMENTAL
Chemicals and reagents
The rhodium and iridium complexes, [M(DPE)2]C1, were synthesized and purified according to standard procedures available in the literature 5'6. Their identity was checked by i.r. spectra and purity by elemental analysis.
Tetrabutylammonium perchlorate (TBAP) was made from tetrabutylammonium hydroxide and perchloric acid. The salt was crystallized twice from ethanol and dried in a vacuum oven at 50°C.
Purification of acetonitrile has been described previously 1.