Rhenium complexes cyclic voltammetry

Keywords CO reduction, cyclic voltammetry, polymetalhc complexes, rhenium polypyridyl, spectroelectrochemical analysis... 

The lability of the N2 ligand towards alkyl and aryl isocyanides has been demonstrated by equation (2) which occurs readily with both alkyl and aryl isocyanides.40 The resulting complexes are electron rich , the alkyl isocyanide derivatives ReCl(CNR)(dppe) (R = Me or Bul) undergoing electrophilic attack upon treatment with HBF4 to form the carbyne complexes trcms-[ReCl(CNHR)(dppe)2]BF4.41 Other noteworthy features of the series of complexes ReCl(CNR)(dppe)2 and ReCl(CNAr)(dppe)2, are the low value of v(CN), the presence of a bent M—CNR coordination mode, and their ease of oxidation (as measured by cyclic voltammetry) to the corresponding rhenium(II) monocations.40... 

When the reactions between various aryl isocyanides ArNC and (Bu4N)2Re2Cl8 are carrried out in methanol at room temperature, then rhenium(III)-containing complexes of the types [Re(C-NAr)6]+[ReCl4(CNAr)2] and ReCl3(CNAr)3 can be isolated.21 These compounds display well-defined electrochemistry (cyclic voltammetry) in 0.2 M (Bu4 N)PF6-CH2Cl2, the mononuclear Re111... 

SECM feedback measurements have been applied, together with cyclic voltammetry and controlled potential electrolysis (30), to the reduction of the rhenium aryldiazenido complex [Cp Re(CO)2(/7-N2CsH4OMe)] [BF4] (III(BF4) Cp = T -C5Me5). A one-electron reduction results in the 19-elec-tron complex, IV [Eq. (40)], which then decomposes to give products [Eq. (41)]. 

Within the course of our studies on the activation (towards protonation) of small unsaturated species by electron-rich metal sites [7], we have observed that the complexes cis-[ReCl(NCR)(dppe)7] are susceptible to proton attack at either the nitrile ligand or the rhenium atom (eq. 1) to give the methyleneamido [8] or the hydrido [9] complexes [ReCl(NCHR) (dppe)2] or [ReClH(NCR) (dppe) 2] (J ) j respectively, and now we report the preliminary investigation of the electrochemical behaviour of the latter compounds, undertaken by controlled potential electrolysis and cyclic voltammetry. 

SECM feedback measurements have been applied, together with cyclic voltammetry and controlled potential electrolysis, to the reduction of the rhenium aryldiazenido complex... 

---