Cytostatic lanthanum compounds

A compound of general formula (I)

• Rni+Yin− (I),
• wherein R is a group of general formula (A):
• 14
• wherein
• R1 and R3 are independently selected from the substituted and unsubstituted group consisting of C1-C10-alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkenyl, C2-C10-alkenyl, C6-C14-aryl and a heterocycle, and hydrogen;
• R2 is selected from the substituted and unsubstituted group consisting of C1-C6-alkylene, C3-C6-cycloalkylene, C3-C6-cycloalkenylene, C2-C6-alkenylene, C6-C14-arylene and a heterocycle;
• R1 and R2 and/or R2 and R3 can form an heterocycle optionally containing further nitrogen atoms;
• Y is a physiologically compatible anion;
• i and n are independently natural numbers ≧1, and
• physiologically compatible addition salts,
• provided that R is not:
• 15
• 16
• and that if Y is NO3−R is not
• 17
• and
• that if Y is NO3−, CIO4− or CI−, R is not
• 18