PURPOSE: To obtain a new compound capable of selectively reacting with noble metal ion to form a complex and useful for the recovery of noble metals.

CONSTITUTION: The compound of formula I ((n) is 0 or 1), e.g. 6,6-dimethyl-5,7- dioxo-1,11-dithia-4,8-diazacyclotetradecane. The compound of formula I can be produced by reacting 1,9-diamino-3,7-dithianonane (n=0) or 1,13-diamino-4,7,10- trithiadodecane (n=1) of formula II with dimethylmalonyl dichloride of formula III in the presence of cesium carbonate in a solvent such as chloroform. The compound of formula I is made to react with noble metal ion such as platinum ion and palladium ion to recover the noble metal in the form of a complex of the compound of formula I and the noble metal ion. It is especially useful for the recovery of platinum in cisplatin.