The role of solvent in the stepwise electrochemical oxidation of nickelocene to the nickelocenium dication

Ferrocenyl‐Pyrenes, Ferrocenyl‐9,10‐Phenanthrenediones, and Ferrocenyl‐9,10‐Dimethoxyphenanthrenes: Charge‐Transfer Studies and SWCNT Functionalization

“…The redox properties of compounds 3 , 5 a , b , 7 a , b , 10 , and 12 were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and spectroelectrochemistry (in situ UV/Vis/NIR). As supporting electrolyte, an anhydrous dichloromethane solution containing 0.1 mol L −1 of [N n Bu 4 ][B(C 6 F 5 ) 4 ] was used . Contrary to smaller counter ions such as [PF 6 ] − or [Cl] − , [B(C 6 F 5 ) 4 ] − stabilizes highly charged species in solution and minimizes ion pairing effects .…”

Anodic oxidation of organometallic sandwich complexes using [Al(OC(CF3)3)4]− or [AsF6]− as the supporting electrolyte anion

“…Oxidation of nickelocene to the dication (E pa ca. 0.6 V), however, gave every indication of severe adsorption of [NiCp 2 ][AsF 6 ] 2 onto the electrode, accompanied by a cathodic stripping wave at about À0.35 V. These scans are highly reminiscent of those seen for [PF6 ] À -based electrolytes in this solvent[24].…”

“…3). This kind of behavior has been shown to be indicative of voltammetric complications in the NiCp 2 +/2+ process [24]. In the present case, in which the chemical reversibility argues against a fast follow-up reaction between NiCp 2 2+ and [Al(OC(CF 3 ) 3 ) 4 ] À , it is likely that the nickelocene dication is strongly adsorbed on the electrode, an explanation supported by the fact that the working electrode had to be re-polished in between scans to avoid electrode ''history'' effects.…”

“…Another metallocene anodic process which is quite mediumdependent is the second oxidation of nickelocene [24]. The neutral complex undergoes two successive one-electron oxidations (Eq.…”

“…Interest in this anion derives in part from the report that the anodic oxidation of C 60 is chemically reversible in CH 2 Cl 2 /[NBu 4 ][AsF 6 ], with even the trication [C 60 ] 3+ being detected by low-temperature cyclic voltammetry (CV) [15,16]. Owing to the fact that the oxidation of [AsF 6 ] À is very difficult, its anodic ''window'' is extended to more positive values than those of TFAB or BArF 24 , and, as it turns out [Al(OC(CF 3 ) 3 ) 4 ] À . This property could be of value in probing more difficult to oxidize organometallic systems.…”