Use of stannylenes and germylenes as polymerisation catalysts for heterocycles

Use of stannylenes and germylenes of general formula 1

• 5
• in which
• M represents a tin or germanium atom;
• L1 and L2 represent, independently, a group of formula —E14(R14)(R′14)(R″14), —E15(R15)(R′15) or —E16(R16), or together form a chain of formula —L′1—A—L′2—;
• A represents a saturated or unsaturated chain comprising one, two or three elements of group 14, each being optionally and independently substituted by one of the following substituted or non-substituted radicals:
• alkyl, cycloalkyl, aryl, in which said substituent is a halogen atom, the alkyl, aryl, nitro or cyano radical;
• L′1 and L′2 represent, independently, a group of formula —E14(R14)(R′14)—,
• —E15(R15)—or — E16—,
• E14 is an element of group 14;
• E15 is an element of group 15;
• E16 is an element of group 16;
• R14, R′14, R″14, R15, R′15 and R16 represent, independently, the hydrogen atom;
• one of the following substituted or non-substituted radicals:
• alkyl, cycloalkyl or aryl, in which said substituent is a halogen atom, the alkyl, cycloalkyl, aryl,
• nitro or cyano radical;
• a radical of formula —E′14RR′R″;
• E′14 is an element of group 14;
• R, R′ and R″ represent, independently, the hydrogen atom or one of the following substituted (by one or more identical or different substituents) or non-substituted radicals:
• alkyl, cycloalkyl, aryl, in which said substituent is a halogen atom, the alkyl, aryl, nitro or cyano radical
• as polymerization catalysts of heterocycles.