| abstract |
The invention relates to alkylidine N-heterocyclic carbene complexes of general formulas (I) to (VI), wherein A 1 represents NR 2 or PR 2 , A 2 represents CR 2 R 2 ', NR 2 , PR 2 , O or S, A 3 represents N or P, and C represents a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R 2 and R 2' represent, inter alia, a linear or branched C 1 -C 18 -alkyl group and, if A 1 and A 2 each represent NR 2 or PR 2 , are the same or different, M in formulas (I) to (VI) represents Mo or W, X 1 or X 2 in formulas (I) to (VI) are the same or different and represent, inter alia, C 1 -C 18 carboxylates and C 1 -C 18 , Z 1 and Z 2 represent, inter alia, a linear or branched C 1 -C 18 -alkylenoxy group, and R 1 in formulas (I) to (VI) are, inter alia, an aliphatic or aromatic group. Said compounds are particularly suitable as a catalyst for alkyne metathesis reactions and have, compared to known alkyne metathesis catalysts, the advantage of having a significantly improved activity and stability. |