TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises reacting (II) with a metal compound. Preferred Definitions:    M = Cr, Mo, W, Mn, Re, Ru, Os, Rh, Ir, Ni, Pd, Pt, Cu, Ag or Au;    G = carbon monoxide, alkyl cyanide, aryl cyanide, alkylisocyanide, arylisocyanide, amine, phosphine, phosphite, arsine, stibine, nitrogen containing heterocycle, carbene, hydride, D, F, Cl, Br, I, alkyl acetylene, aryl acetylene, CN, cyanate, isocyanate, thiocyanate, isothiocyanate, aliphatic or aryl alcoholate, aliphatic or aryl thioalcoholate, amide, carboxylate, aryl, ionic, nitrogen containing heterocycle, O2-, S2-, carbide, nitrene, N3-, diamine, imine, heterocycle containing two nitrogen atoms, diphosphine, 1,3-diketonate derived from 1,3-diketone, 3-ketonate derived from 3-ketoester, carboxylate derived from aminocarboxylic acid, salicyliminate derived from salicylimine, dialcoholate derived from dialcohol, dithiolate derived from dithiol, eta 5-cyclopentadienyl, eta 5-pentamethylcyclopentadienyl, eta 6-benzene or eta 7-cycloheptatrienyl; and    L = N or P.    SPECIFIC COMPOUNDS - 119 Compounds (I) are disclosed e.g. a platinum complex of formula (Ia1)-(Ia5).    EXAMPLE - Potassium-tetra-chloroplatinate (3.2 g) was dissolved in water (120 ml) and transferred under stirring with 57 wt.% of aqueous hydrogen iodide solution (6.9 g). After 2 hours of stirring, methanol (120 ml) and a solution of potassium hydroxide pellets (950 mg) in water (30 ml) were added and stirred for 5 minutes. After 30 minutes, a solution of N,N-dimethyl-N,N'-bis-naphthylen-1-ylmethyl-propan-1,3-diamine (3 g) in methanol (100 ml) was added, heated for 4 hours under reflux and cooled. The solid material was washed thrice with a mixture of methanol and water (100 ml) and dried in vacuum to obtain N,N'-dimethyl-N,N'-bis-naphthylen-1-ylmethyl-propan-1,3-diamino-bis-iodo-platinum(II) (5.6 g). A suspension of N,N-dimethyl-N,N'-bis-naphthylen-1-ylmethyl-propan-1,3-diamino-bis-iodo-platinum (II) (1.67 g) and silver(I)fluoride (254 mg) in sulfolane (10 ml) was stirred for 24 hours at 50 degrees C. Subsequently the solid materials were sublimated in vacuum at 330 degrees C and 10-5 mbar to obtain platinum complex of formula (Im) (208 mg).