NEW MATERIAL:The compound of formula I [R1 and R2 are NO3, MOOC (CH OH)2COO- (M is alkali metal), group of formula II, formula III, etc. or together form group of formula IV, formula V, etc., provided that R1 and R2 are not NO3 at the same time; the steric configuration of 1,2-diaminocyclohexane is cis, trans-d or trans-l].

EXAMPLE: Mucato(trans-l-1,2-diaminocyclohexane) platinum (II).

USE: Antitumor agent.

PREPARATION: The objective compound can be produced by reacting Pt(II) (NO3)2(cis-1,2-diaminocyclohexane), etc. with mucic acid, malic acid or glutaric acid, etc. in an aqueous medium, if necessary, under heating.