Synthesis, spectroscopic characterization, and molecular structure of triphenyl butene derivatives containing a cyclopentadienyl iron unit

Three hydroxyl substituted triphenyl butene compounds (PHB) and their derivatives containing a cyclopentadienyl iron (PHB-Fc) unit were efficiently synthesized. The synthesis involved the McMurry cross-coupling reaction of appropriate ketones and the nucleophilic aromatic substitution (SNAr) reaction of (η6-chlorobenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (Fc-Cl). The target compounds were characterized by IR, 1H NMR, 13C NMR, and MS. Their photophysical processes were investigated by UV–Vis absorption and fluorescence emission spectra in acetonitrile. The geometric structure was optimized based on the density functional theory at the B3LYP level. Theoretical results reveal that electron transfer occurred from the HOMO to the LUMO in PHB-Fc. The change in electron distribution subsequently led to the improved second-order optical susceptibility of PHB-Fc.