| Abstract
| - Oxidative electrochemical properties in dichloromethane have beenexamined for compounds of the types cis- ortrans-[Re(CO)2(P−P)2]+and trans-Re(CO)(P−P)2X (P−P=diphosphine ligand, X = Cl, Br) which exhibit a range of charge andligand types. In allcases 17e Re(II) species are formed, although the oxidationpotentials vary over a reasonablywide range. The Re(II) compounds have been characterized byspectroelectrochemical (IR)and electrospray mass spectrometry (ESMS) studies. The stabilitiesof the Re(II) speciesare dependent upon charge and ligand types. The transconfiguration is strongly preferredin the Re(II) state, so when the starting material is cis, thereis rapid isomerization followingelectron transfer. The major form of reactivity detected is facilereduction of the trans-[Re(CO)2(P−P)2]2+ species.The particularly high stability oftrans-[Re(CO)(dpe)2X]+(dpe =Ph2P(CH2)2PPh2)allows solid-state studies to be undertaken for thetrans-[Re(CO)(dpe)2X]+/0couple when the compounds are mechanically attached to a graphiteelectrode immersed inwater (electrolyte).
- Electrochemical, spectroelectrochemical and chemicaloxidation of 18e Re(I) carbonyl compounds of the types cis- ortrans-[Re(CO)2(P−P)2]+,and trans-[Re(CO)(P−P)2X] (P−P= diphosphine; X = Cl or Br) produce the analogous trans 17eRe(II) species. Their stabilities have been studied as afunction of the charge, nature of the ligands, and the reversiblepotential of the 17e/18e redoxcouple.
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