Synthesis and characterization of xylene-based group-six metal PCP pincer complexes

In the present study, the Cr(III) complex trans-[Cr(PCPCH2-iPr)(CH3CN)(Br)2] as well as seven-coordinate cationic bromo carbonyl Mo(II) and W(II) complexes of the type [M(PCPCH2-iPr)(CO)3Br] (M=Mo, W) featuring PCP pincer ligands based on a xylene scaffold were prepared and characterized. The seven-coordinate bromo tricarbonyl complexes exhibit fluxional behavior in solution due to rapid CO ligand interconversions. The mechanism of this process was studied by means of DFT calculations. Structures of representative complexes were determined by single-crystal X-ray analyses.