| abstract |
The invention concerns the use of stannylenes and germylenes of general formula (1) wherein: M represents a tin or germanium atom; L1 and L2 independently represent 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; 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 variable groups as polymerisation catalysts of heterocycles. |