First transition metal complex of 1,8-bis(dimethylamino)naphthalene (proton sponge)

First transition metal complexes of 1,8-bis(dimethyl-amino)naphthalene (proton sponge), N,N'-chelated Pd(II) complexes, were prepared and the strong coordination ability of the proton sponge was demonstrated. The high transition energy for the coordination could be lowered by the existence of the intermediate charge-transfer complex which was isolated.