Monomeric Au(II) complex with hematoporphyrin IX

A stable monomeric Au(II) complex has been synthesized in the course of the Au(III)–hematoporphyrin IX (Hp, I) interaction in aqueous alkaline solution. Distorted octahedral structure with (dxy)1 ground state and general formula Au(II)Hp-2H·2H2O are suggested for the complex. Gold is located in the hole of the porphyrin macrocycle and the water molecules are in axial position. The +2 oxidation state of gold was proven by the corresponding EPR signal and the μeff value of 2.20 BM obtained. The α2 value of 0.56 indicated a high degree of covalency of the gold–nitrogen bonds.