38100-19-5Relevant academic research and scientific papers
Facile rearrangement and electron transfer of 19-electron radicals from the reduction of the bischelated manganese carbonyl cation Mn(CO)2[PPh2(CH2)2PPh 2]2+
Kuchynka,Kochi
, p. 2574 - 2581 (2008/10/08)
The cathodic reduction of the bischelated manganese carbonyl cation trans-Mn(CO)2(η2-DPPE)2+ (I+, where DPPE = PPh2-(CH2)2PPh2) produces the metastable anion Mn(CO)2(η2-DPPE)(η1-DPPE)- (II-) via an overall 2e process at a Pt electrode in either tetrahydrofuran or acetonitrile solution. The unusual observation of a cathodic curve crossing and two isopotential points in the cyclic voltammogram of I+ can be traced to an electron transfer with II- to afford a pair of neutral radicals, i.e., the 19e I? and the 17e II?. The former (which is also generated during the initial step in the reduction of I+) is a metastable species and spontaneously extrudes an end of one DPPE ligand to afford the second radical II? with the rate constant kr ≈ 4 × 106 s-1. The structures of the anionic and radical intermediates II-, II?, and I? are discussed in the context of their transient electrochemical behavior as well as their 31P NMR and ESR spectra. The rather slow rate of electron transfer between I+ and II- is ascribed to steric effects in carbonylmanganese ions encumbered with a pair of DPPE ligands.
