Synthesis, structural and spectroscopic characterization of four [(η⁶-PAH)Cr(CO)₃] complexes (PAH = pyrene, perylene, chrysene, 1,2-benzanthracene)

The thermal reaction of hexacarbonylchromium with the polycyclic aromatic hydrocarbons (PAHs) pyrene, perylene, chrysene and 1,2-benzanthracene has afforded four organometallic complexes of the type [(η⁶-PAH) Cr(CO)₃], whose unprecedented structures were obtained by single-crystal X-ray analysis. The topology of the coordination of the Cr(CO)₃ fragment and its asymmetry with respect to the coordinating ring may depend on the opportunity to maintain the maximum aromaticity of the complexed ligand. DFT calculations, ¹H NMR, FT-IR and Raman spectroscopy have been used to elucidate the type of interaction between the PAH ligand and the carbonylmetal moiety, giving insight into the ligand-to-metal donor capacity and the intra- and intermolecular interactions.