Hydropentalenyl ligand (${\mathrm{C}}_8{\mathrm{H}}_7^{-}$)

The monoanionic ${\mathrm{C}}_8{\mathrm{H}}_7^{-}$ coordination ligand obtained by removing one proton from dihydropentalene. An aromatic five-membered portion can bind a metal in an eta-five mode while the fused ring retains an uncoordinated alkene.