The condensation of platinum complex (I) with N-Boc-hexane-1,6-diamine (II) by means of 1 mole of AgNO3 in DMF gives the platinum complex (III), which is deprotected with HCl in methanol/ethanol to yield complex (IV). Finally, platinum complex (I) is condensed with two moles of complex (IV) by means of two moles of AgNO3 in DMF to afford the target trinuclear complex.