Five shades of green: substituent influence on the (spectro-) electrochemical properties of diferrocenyl(phenyl)methylium dyes?

Dalton Transactions Pub Date: 2021-10-06 DOI: 10.1039/D1DT03009D

Abstract

Five new, intensely green diferrocenylphenylmethylium complexes 1+–5+ with electron donating (EDG: 4-MeO, 4-Me, 4-Br) or withdrawing (EWG: 3,5-CF3, 4-nC6F13) substituents were synthesized and fully characterized. The substituent influence on their electrochemical and spectroscopic properties was investigated by cyclic voltammetry, UV/Vis/NIR and T-dependent EPR spectroscopy of the cationic as well as the oxidized (12+–52+) and reduced (1˙–5˙) species. The reduced forms equilibrate with their corresponding dimers (65–83%) with a clear substituent influence as expressed by their Hammett parameters in an ordering 4+ > 5+ > 3+ > 2+ > 1+. The structures of all five precursor carbinols 1-OH–5-OH and those of three of the diferrocenylphenylmethylium cations (1+, 4+–5+) were established by X-ray crystallography.

Graphical abstract: Five shades of green: substituent influence on the (spectro-) electrochemical properties of diferrocenyl(phenyl)methylium dyes
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