Electron Transfer Activity of Nickelacyclic Complex Analogues of Nickelocene:  Synthesis of (η⁵-R-cyclopentadienyl){η⁴-[1-(η⁵-R-cyclopentadienyl)]-2,3,4,5-tetraphenyl-1-nickela-2-cyclopentenyl}nickel Complexes (R = H, CH₃) and Crystal Structures of the Redox Couples [(η⁵- Methylcyclopentadienyl){η⁴-[1-(η⁵-methylcyclopentadienyl)]-2,3,4,5-tetraphenyl-1-nickela-2-cyclopentenyl}nickel]^(0/+) and [(η⁵-Methylcyclop

Abstract

Following previous reports on the synthesis and structure of different nickelacyclic complexes analogues of nickelocene, we now deal with the new metallacyclic compounds (eta5-R-cyclopentadienyl){eta4-[1-(eta5-R-cyclopentadienyl)]-2,3,4,5-tetraphenyl-1-nickela-2-cyclopentenyl}nickel (R = H, CH3). The redox ability of the whole series of nickelacyclic derivatives has been also investigated by electrochemical and spectroelectrochemical techniques, and the nature of the frontier orbitals responsible for the rich electron transfer activity of this class of compounds has been supported by theoretical considerations. On the basis of the redox properties of a few neutral members of the series, their chemical oxidation afforded the corresponding monocations and the crystal structures of the pertinent redox couples were determined by X-ray single-crystal analysis.

Synthesis and structures of the novel triple-decker complexes with 9-nickelafluorenyl ring

“…This value corresponds to nearly undistorted g 5 -coordination of the 9-nickelafluorenyl ring to the Ni2 atom. The Ni1-Ni2 bond length (2.389(2) Å) is similar to nickel-nickel distances in other complexes which possess nickelafluorenyl ring [9,20].…”

“…This value corresponds to nearly undistorted g 5 -coordination of the 9-nickelafluorenyl ring to the Ni2 atom. The Ni1-Ni2 bond length (2.389(2) Å) is similar to nickel-nickel distances in other complexes which possess nickelafluorenyl ring [9,20].The possible course of the formation of the triple-decker compounds 2 and 2a most probably contains two steps. The first one should be the decomposition of complexes 1 and 1a in acetone and formation of the unstable neutral species {Cp x Ni}.…”

“…We have recently started studying the redox properties of different compounds possessing the nickelacyclic rings [9]. After dissolving compound 1 in acetone, we have observed that the color of the solution changed.…”

“…Another type of tripledeckers are the complexes in which the heterocyclic ring possesses the transition metal. So far such compounds were reported only for ruthenium [8].In this paper we want to report the synthesis and structure of the first triple-decker compounds which possess the nickelacyclic ring.We have recently started studying the redox properties of different compounds possessing the nickelacyclic rings [9]. After dissolving compound 1 in acetone, we have observed that the color of the solution changed.…”

Novel, axially chiral analogues of nickelocene with nickeladibenzofluorenyl ligand

“…Metallametallocenes are the compounds in which one or two cyclopentadienyl groups of metallocene is replaced by a metallacyclopentadienyl ring [2]. In previous papers we described the synthesis of new nickelametallocenes [3] which possessed one nickelaindenyl or nickelafluorenyl ring [4]. More recently we have employed 9-nickelafluorenyllithium [1], in the synthesis of the first analogues of nickelocene and cobaltocene with two nickelafluorenyl rings [5].…”