Dataset Information

Polysubstituted ferrocenes as tunable redox mediators.

ABSTRACT: A series of four ferrocenyl ester compounds, 1-methoxycarbonyl- (1), 1,1'-bis(methoxycarbonyl)- (2), 1,1',3-tris(methoxycarbonyl)- (3) and 1,1',3,3'-tetrakis(methoxycarbonyl)ferrocene (4), has been studied with respect to their potential use as redox mediators. The impact of the number and position of ester groups present in 1-4 on the electrochemical potential E_1/2 is correlated with the sum of Hammett constants. The 1/1⁺ -4/4⁺ redox couples are chemically stable under the conditions of electrolysis as demonstrated by IR and UV-vis spectroelectrochemical methods. The energies of the C=O stretching vibrations of the ester moieties and the energies of the UV-vis absorptions of 1-4 and 1⁺ -4⁺ correlate with the number of ester groups. Paramagnetic ¹H NMR redox titration experiments give access to the chemical shifts of 1⁺ -4⁺ and underline the fast electron self-exchange of the ferrocene/ferrocenium redox couples, required for rapid redox mediation in organic electrosynthesis.

SUBMITTER: Waniek SD

PROVIDER: S-EPMC6009500 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Polysubstituted ferrocenes as tunable redox mediators.

Waniek Sven D SD Klett Jan J Förster Christoph C Heinze Katja K

Beilstein journal of organic chemistry 20180507

A series of four ferrocenyl ester compounds, 1-methoxycarbonyl- (1), 1,1'-bis(methoxycarbonyl)- (2), 1,1',3-tris(methoxycarbonyl)- (3) and 1,1',3,3'-tetrakis(methoxycarbonyl)ferrocene (4), has been studied with respect to their potential use as redox mediators. The impact of the number and position of ester groups present in 1-4 on the electrochemical potential E1/2 is correlated with the sum of Hammett constants. The 1/1< ...[more]

PMID: 29977372

Similar Datasets

Project description:Different synthetic methods have been developed to prepare eight new redox-active pincer-type ligands, H(X,Y), that have pyrazol-1-yl flanking donors attached to an ortho-position of each ring of a diarylamine anchor and that have different groups, X and Y, at the para-aryl positions. Together with four previously known H(X,Y) ligands, a series of 12 Ni(X,Y)2 complexes were prepared in high yields by a simple one-pot reaction. Six of the 12 derivatives were characterized by single-crystal X-ray diffraction, which showed tetragonally distorted hexacoordinate nickel(II) centers. The nickel(II) complexes exhibit two quasi-reversible one-electron oxidation waves in their cyclic voltammograms, with half-wave potentials that varied over a remarkable 700 mV range with the average of the Hammett ?(p) parameters of the para-aryl X, Y groups. The one- and two-electron oxidized derivatives [Ni(Me,Me)2](BF4)n (n = 1, 2) were prepared synthetically, were characterized by X-band EPR, electronic spectroscopy, and single-crystal X-ray diffraction (for n = 2), and were studied computationally by DFT methods. The dioxidized complex, [Ni(Me,Me)2](BF4)2, is an S = 2 species, with nickel(II) bound to two ligand radicals. The mono-oxidized complex [Ni(Me,Me)2](BF4), prepared by comproportionation, is best described as nickel(II) with one ligand centered radical. Neither the mono- nor the dioxidized derivative shows any substantial electronic coupling between the metal and their bound ligand radicals because of the orthogonal nature of their magnetic orbitals. On the other hand, weak electronic communication occurs between ligands in the mono-oxidized complex as evident from the intervalence charge transfer (IVCT) transition found in the near-IR absorption spectrum. Band shape analysis of the IVCT transition allowed comparisons of the strength of the electronic interaction with that in the related, previously known, Robin-Day class II mixed valence complex, [Ga(Me,Me)2](2+).

Dataset Information

Polysubstituted ferrocenes as tunable redox mediators.

Publications

Polysubstituted ferrocenes as tunable redox mediators.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets