Redox active alkenyl-bridged bi- and trinuclear arene–Cr(CO)3-complexes by Horner–Emmons–Wadsworth olefinations

Alkenyl-bridged arene–Cr(CO) 3 -complexes 2 are readily synthesized in good yields by Horner–Emmons–Wadsworth (HEW) olefinations from Cr(CO) 3 -complexed benzylphosphonates 1 and organometallic aldehydes. The resulting bi- and trinuclear homo- and heterometallic complexes display a strong electronic coupling between the metal fragments as shown by a strong correlation of the CO resonances in the carbon NMR spectra and the chromiumcarbonyl metal–ligand charge transfer (MLCT) bands in the UV/vis spectra. Furthermore, the electrochemistry of the oligonuclear complexes 2 was investigated by cyclic voltammetry.