Combined experimental and theoretical study of the novel ferrocene derivatives and examining the effect of E-Z stereoisomerism on their optical properties

Herein, we present the primary results on two valuable E-Z stereoisomers containing ferrocene scaffold [(E)-5,5-dimethyl-3-oxo-2-(2-phenyl-2-ferrocenyl-vinyl)cyclohex-1-en-1-yl acetate (E-FerCycAc) and its Z-stereoisomer (Z-FerCycAc)]. These compounds were both prepared from 1-phenylvinyl-ferrocene and 5,5-dimethyl-1,3-cyclohexanedione under catalysis of manganese(III) acetate according to the radical addition mechanism. The prominent spectroscopic data of the target stereoisomers were provided by FT-IR, LC-MS, ¹H NMR, ¹³C NMR techniques, and their stereochemical identification was made primarily by NOESY analysis. The corresponding data (absorbance, transmittance and optical and transport energy gap) were collected from UV–vis studies. The optical properties of the glass slides coated with E-FerCycAc and Z-FerCycAc films were examined and consequently, the optical and transport energy band gap values of the E-FerCycAc were found significantly lower than Z-FerCycAc. The physicochemical and spectroscopic findings (HOMO-LUMO energies, bandgap values, UV–vis, FT-IR, ¹H, and ¹³C NMR spectra) were also compared and supported with the acquired DFT calculations.