Synthetic investigations of the diisocyanide-bridged Cp-cobalt rectangles

This study explores the utilization of 1,4-diisocyanobenzene as a linear bridging ligand for the assembly of organometallic CpCo or Cp*Co complexes. Overcoming solubility challenges, the synthesis of organometallic Cp* cobalt complexes incorporating bridging 1,4-diisocyanobenzene ligands was successfully achieved, while similar CpCo complexes were not attainable. The presented approach encompasses investigations into both stepwise and self-assembly synthetic pathways, leading to the construction of a rectangular tetranuclear complex [(Cp*CoI)4(mu-1,4-CNC6H4NC)4](OTf)4 (3). Through single-crystal x-ray diffraction and spectroscopic techniques such as infrared, nuclear magnetic resonance, and electrospray ionization-mass spectrometry, the cobalt-isocyanides complexes were characterized. The presented approach encompasses the investigations into both stepwise and self-assembly synthetic pathways, leading to the construction of a rectangular tetranuclear complex [(Cp*CoI)4(mu-1,4-CNC6H4NC)4](OTf)4 containing 1,4-diisocyanobenzene as a spacer bridge ligand. image